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  • Preparation of some compounds and study their thermal stability for use in dye sensitized solar cells
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-12
    Abdulraheem S.A. Almalki, A. Alhadhrami, Rami J. Obaid, Meshari A. Alsharif, Abdel Majid A. Adam, Ivo Grabchev, Moamen S. Refat

    The present work aimed to prepare some compounds for use in pigmented solar cells based on charge transfer (CT) complexation. For this purpose, first, several derivatives of 1,8–naphthalimide and benzanthrone fluorescent dyes were synthesized. Secondly, the synthesized fluorescent dyes were complexed with picric acid (PA) acceptor via CT interaction in methanol solvent at room temperature. Then, the synthesized CT complexes were stoichiometrically, spectroscopically and thermally characterized. The results obtained from CHN elemental analyses and spectrophotometric titrations indicated the formation of CT complexes with a molar ratio of 1:1 between the PA and each dye. The spectroscopic and physical parameters (KCT, εmax, ECT, f, μ, RN, IP, and ΔG°), the band gap energy (Eg), and the kinetic–thermodynamic parameters (E⁎, A, ΔS⁎, ΔH⁎ and ΔG⁎) were calculated for each CT product in methanol solvent at room temperature. IR results indicated that the complexation between each dye and PA acceptor occurs through π → π* and proton transfer interactions.

    更新日期:2018-04-17
  • Evaluation of the emulsion liquid membrane performance on the removal of gadolinium from acidic solutions
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-12
    Payman Davoodi-Nasab, Ahmad Rahbar-Kelishami, Jaber Safdari, Hossein Abolghasemi

    This work evaluates the performance of emulsion liquid membrane (ELM) for the extraction of gadolinium(III) from acidic solution. The ELM was made up of di-(2-ethylhexyl) phosphoric acid (D2EHPA) as carrier, Span 80 (sorbitol monooleate) as emulsifying agent, commercial kerosene as organic diluent and Nitric acid as stripping phase. Important physical and chemical variables affecting the ELM performance for the extraction of gadolinium(III) such as carrier concentration, mixing time, surfactant concentration, agitation speed, initial pH of the feed phase, internal phase concentration, treatment ratio, and feed phase concentration were systematically investigated. Results indicated that the highest gadolinium(III) extraction can be attained after 10 min of mixing by using 0.05 M D2EHPA, 1.5% (v/v) Span 80, 1.0 M nitric acid as stripping phase at feed phase pH of 2, agitation speed of 180 rpm, and treatment ratio of 1:10. At the optimum condition, simultaneous quantitative extraction (>99%) and stripping (>79%) of gadolinium were achieved. Furthermore, the overall mass transfer coefficient was calculated and the results revealed that the extraction was interfacially controlled.

    更新日期:2018-04-17
  • Molecular dynamics simulations on homogeneous condensation of R600a refrigerant
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-11
    Md. Sarwar Alam, Ji Hwan Jeong

    Molecular Dynamics (MD) simulations have been employed to study the homogeneous condensation phenomenon of R600a (isobutane) refrigerant in the vapor compression refrigeration system. The molecular system consists of superheated vapor isobutane in a cuboid simulation cell with periodic boundary conditions in all directions. A more physically reliable thermostat and a barostat are applied to control the temperature and pressure of the cell containing the molecules. Based on AHRI standard 460 rating conditions, the simulations started from the initial configuration of vapor phase isobutane system, and once the equilibration is established at 361 K with 1 atm, the system is suddenly cooled to the ambient temperature of 308 K and is set under the condensing pressure of 7.1658 bar corresponding to the saturation temperature at 325 K of the compound at supersaturation ratio 1.548. The density, internal potential energy, and volume changing with time of superheated vapor molecules in the homogeneous condensation process of the system are investigated. The results show that vapor molecules have underwent a rapid phase transition to the subcooled liquid at a certain critical time period. Subcritical clusters of isobutane molecules are formed in the preliminary part of the simulations, which then aggregate to generate the critical condensate nucleus over time. An examination of the radial distribution functions (RDFs) shows that the bonding and non-bonding interactions are formed in the vapor and liquid phases of isobutane. It is truly consistent with the internal potential energy and phase change properties. The computed densities of both phases agree well with the NIST standard reference thermodynamic and transport property data of the compound. A comparative study is executed through several simulations for various values of supersaturation and undersaturation ratios with different numbers of molecules to investigate the critical time of phase transition in the homogeneous condensation process.

    更新日期:2018-04-12
  • A viscosity model for ionic liquids based on the Eyring's theory and a cubic EoS
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-11
    Ricardo Macías-Salinas

    A thermodynamic model based on the combined use of the Eyring's activated state theory and a cubic equation of state was developed here to accurately represent the dynamic viscosity of pure ionic liquids (ILs). Within the Eyring's theory, the net viscous flow of a pure IL is assumed to be governed by four main variables: (1) the energy necessary for a molecule to jump from an initial equilibrium position to a new one, (2) the energy necessary to break the molecular bonds to create a hole (vacant sites) of molecular size in the liquid, (3) the availability of the vacant sites, and (4) the frequency or the mean residence time of the jumping molecules. The various activation-state variables were then related to well-known thermodynamic potentials that in turn were estimated from two simple cubic equations of state of the van der Waals type (Soave or Peng-Robinson). The resulting model was successfully validated during the representation of experimental dynamic viscosities of three families of imidazolium-based ILs ([CXmim][BF4], [CXmim][PF6] and [CXmim][Tf2N]), four pyridinium-based ILs ([bmpy][BF4], [empy][EtSO4], [Et2Nic][EtSO4] and [hemmpy][Tf2N]) and two ammonium-based ILs ([cpmam][MeSO4] and [4bam][doc]) within a temperature range varying from 0 to 80 °C and at pressures from 1 up to 3000 bar thus covering a wide viscosity range of 10–19,610 mPa-s.

    更新日期:2018-04-11
  • Multiple dissociation constants of the intepirdine hydrochloride using regression of multiwavelength spectrophotometric pH-titration data
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-11
    Milan Meloun, Lucie Pilařová, Filip Bureš, Tomáš Pekárek

    Spectrophotometric and potentiometric pH-titrations of the Neurotransmitter Intepirdine hydrochloride INN·HCl for three dissociation constants determination were compared. A nonlinear regression of the pH-spectra (REACTLAB, SQUAD84) and of the pH-titration curve (ESAB) determined three multiple dissociation constants. A sparingly soluble neutral molecule LH of INN·HCl was capable of protonation to form the still soluble three cations LH2+, LH32+ and LH43+ in pure water. Although the change of pH somewhat less affected changes in the chromophore, three consecutive thermodynamic dissociation constants were estimated pKTa1 = 5.64, pKTa2 = 7.31, pKTa3 = 8.85 at 25 °C and pKTa1 = 5.51, pKTa2 = 7.15, pKTa3 = 8.77 at 37 °C. The graph of molar absorption coefficients of variously protonated species according to wavelength shows that the spectrum of species LH2+ and LH vary in colour, while protonation of chromophore LH2+ to LH32+ and LH43+ has less influence on chromophores in Intepirdine hydrochloride molecule. As the spectral response on the chromophore in the INN·HCl molecule is not large, it was necessary to test a reliability whether it is possible to estimate the dissociation constants even from such small spectrum changes. Three multiple thermodynamic dissociation constants of 3 × 10−4 M INN·HCl were determined by the regression analysis of potentiometric titration curves pKTa1 = 5.14, pKTa2 = 8.38, pKTa3 = 9.33 at 25 °C and pKTa1 = 5.17, pKTa2 = 8.31, pKTa3 = 9.07 at 37 °C. The macro-dissociation constants of INN·HCl were estimated according to the chemical structure analyzed by two pKa predictors, the MARVIN and ACD/Percepta programs. The resulting protonation scheme of INN·HCl was suggested.

    更新日期:2018-04-11
  • A comparison of protic and aprotic ionic liquids as effective activating agents of kraft lignin. Developing functional MnO2/lignin hybrid materials
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-11
    Tadeusz J. Szalaty, Łukasz Klapiszewski, Beata Kurc, Andrzej Skrzypczak, Teofil Jesionowski

    Protic and aprotic ionic liquids (1-butylimidazolium hydrogen sulfate(VI) and 1-butyl-3-methylimidazolium methyl sulfate(VI)) were investigated for the first time as potential activators of lignin. The activation process was expected to increase the content of carbonyl groups, which have the capacity to transport protons and electrons in electrochemical applications. Fourier transform infrared (FTIR) spectra showed that activation with the protic ionic liquid (PIL) leads to a more intense and better isolated carbonyl group band than in the case of the aprotic ionic liquid (AIL). Use of the PIL also led to better results for porous structure parameters and microstructural and morphological properties. The most significant positive effect of the PIL, however, was the increased electrokinetic stability of the activated biopolymer. The highly satisfactory results obtained at this stage suggested the use of the activated lignins to produce functional, electrochemically active hybrid systems. This was done by combining them with hydrothermally synthesized manganese oxide. The electrochemical properties of the resulting systems were determined by means of impedance spectroscopy, galvanostatic charging/discharging and cyclic voltammetry. The results confirmed that the electrode material based on lignin activated in the PIL had significantly better electrochemical properties. In cyclic charging/discharging tests a capacity of approximately 600 mAh/g was obtained, and the reversibility of the cell was 98%. The stable operation of the electrode demonstrates that the newly obtained electrode material may be successfully used in lithium-ion cells.

    更新日期:2018-04-11
  • Theoretical investigations on the excited state hydrogen bonding dynamics and proton transfer behavior for novel DHDA-23-00 system
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-11
    Dapeng Yang, Jinfeng Zhao, Junsheng Chen, Min Jia, Xiaoyan Song

    In this work, using density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods, we theoretically explore the excited state dynamical process about a novel DHDA-23-00 system [Phys. Chem. Chem. Phys. 19 (2017) 28641-28646]. Combining electrostatic potential surface (EPS) and the reduced density gradient (RDG) methods, we can affirm the two intramolecular hydrogen bonds (O1-H2⋯O3 and O4-H5⋯O6) should be formed in the S0 state for DHDA-23-00. Exploring primary chemical structural changes (bond lengths and bond angles involved in hydrogen bonds) upon the photo-excitation, we verify these two hydrogen bonds are strengthening in the S1 state. In view of the infrared (IR) vibrational spectra, the phenomenon of strengthening O1-H2⋯O3 and O4-H5⋯O6 can be confirmed once again. Analyses about frontier molecular orbitals (MOs) in the excitation process, it can be found charge redistribution around hydroxide radical moiety could play important roles in enhancing intramolecular hydrogen bonds O1-H2⋯O3 and O4-H5⋯O6. Given this kind of charge transfer may facilitate excited state proton transfer (ESPT) process, we construct the potential energy surfaces (PESs) along with two hydrogen bonds to provide the excited state dynamical overall perspective. For DHDA-23-00, even though the charge transfer supports the ESPT process in acetonitrile solvent, excited state potential energy barriers confirm ESPT reaction does not occur for DHDA-23-00 system that is consistent with experimental phenomenon.

    更新日期:2018-04-11
  • Glycolipid biosurfactant as an eco-friendly microbial inhibitor for the corrosion of carbon steel in vulnerable corrosive bacterial strains
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-11
    Punniyakotti Parthipan, Devaraj Sabarinathan, Subramania Angaiah, Aruliah Rajasekar

    In the present studies, glycolipid type of biosurfactant was used as a microbial inhibitor for corrosive bacterial strains (Bacillus subtilis A1, Streptomyces parvus B7, Pseudomonas stutzeri NA3 and Acinetobacter baumannii MN3). Biosurfactant was produced by using the bacterial strain, Pseudomonas mosselii F01 and characterized by using Fourier transform infrared spectroscopy and thin layer chromatography. Weight loss experiment and electrochemical analysis (Tafel polarization and AC-impedance) were used to confirm the corrosion reaction. X-ray diffractometer analysis was carried out to confirm the nature of the corrosion product formed during the corrosion reactions. Microdilution methods confirm that biosurfactant has higher antibacterial activity in the range of 1280–2560 μg/ml in presence of those corrosive bacterial strains. Further, lower corrosion rate of carbon steel (0.0215 mm/y) was recorded in presence of the mixed consortia included with biosurfactant as inhibitor/biocide compared to the mixed bacterial system (0.1653 mm/y). The inhibition efficiency was found about 87% for mixed consortia included with biosurfactant system. The decreased level of corrosion current and potential was also recorded in the biosurfactant added system, similarly higher resistant capacity was found in the mixed consortia included with biosurfactant system. The XRD analysis supports other analysis that biosurfactant play a key role in the corrosion inhibition process in presence of the indigenous corrosive bacterial consortia. Anti-biofilm properties of the biosurfactant over the wide range of the bacterial strains make them as an efficient microbial corrosion inhibitor for the diverse environment.

    更新日期:2018-04-11
  • Molecular dynamics study of melting proprieties of gold nanorods
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-11
    R. Essajai, N. Hassanain

    The melting properties of gold nanorods (AuNRs) are investigated by means of molecular dynamics simulations based on the Embedded-Atom-Method (EAM) potential. The diameters and lengths of the AuNRs are varied from 2.03 nm to 9.44 nm and from 19.43 nm to 93.04 nm, respectively. The premelting of AuNRs is characterized by studying the variation of the Lindemann index with temperature. The simulation results revealed that the melting of AuNR surface is an inhomogeneous, gradually occurring process. This behavior is discussed in the context of the surface atoms of AuNRs requiring different energy values to lose the solid ordering resulting from the fact that they are in contact with irregular number of nearest-neighbors. Furthermore, the ratio between the premelting temperature (Tsm) and melting temperature (Tpm) of the AuNR (also called premelting ratio (Tsm/Tpm)) is calculated for all sizes to provide a new insight into the size dependence of the premelting phenomenon. It is found that the AuNR premelting ratio increases as NP size decreases, thus suggesting that the premelting phenomenon is less pronounced in the smallest NPs.

    更新日期:2018-04-11
  • Possible use of synthesized nano silica functionalized by Prussian blue as sorbent for removal of certain radionuclides from liquid radioactive waste
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-11
    M.F. Attallah, A.I. Abd-Elhamid, I.M. Ahmed, H.F. Aly

    The Prussian blue functionalized SiO2 (nano-material of SiO2-Fe-CN) was successfully prepared using a novel and simple preparation route. The SiO2 nanoparticles were functionalized by amino group by refluxing with (3-Aminopropyl) trimethoxysilane, iron (III) immobilized the modified nanoparticles through interaction with the amino group, finally, SiO2-Fe-CN nanomaterial produced as a result of potassium ferrocyanide addition. SEM, FTIR and XRD techniques were used for detecting the morphology, particle size, different functional groups and the crystal structure of the prepared nano-materials. The sorption potential of nano-material of SiO2-Fe-CN towards cationic and anionic radioisotopes from aqueous and HNO3 solutions were tested using carrier free method. The experimental results showed that nano-material of SiO2-Fe-CN have high effective retention and recovery for 134Cs, 60Co and 99Mo from nuclear liquid waste. Moreover, sorption of 90Sr/90Y is insignificant using SiO2-Fe-CN nano adsorbent material. It is a promising and efficient nano adsorbent that could be used for upscaling design and application on liquid radioactive waste treatment facility.

    更新日期:2018-04-11
  • Green synthesis of the Fe3O4@polythiophen-Ag magnetic nanocatalyst using grapefruit peel extract: Application of the catalyst for reduction of organic dyes in water
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-11
    Mohammad Saleh Najafinejad, Pourya Mohammadi, M. Mehdi Afsahi, Hassan Sheibani

    In this research Fe3O4@polythiophen-Ag magnetic nanocatalyst was synthesized. First Fe3O4 nanoparticles were prepared in the solution and the branched polythiophene was coated on the magnetic particles. This polymer provides enough surface for precipitation of the silver nanocatalyst produced by grapefruit peel extract reduction of AgNO3. The synthesized catalyst was characterized by XRD, FTIR, SEM, FESEM, EDX, TEM, TGA and VSM. Finally, it was used to degrade azo dyes (methyl orange (MO) and methylene blue (MB)) in order to evaluate its catalytic performance. Ratio of the rate constants of the catalytic and non-catalytic reactions was in order of 105 and 104 for reduction reaction of MB and MO respectively. Reaction rate in the presence of catalyst was very high and just 1 min was enough to degrade the MB and MO colorant reagents. The prepared catalyst is able to take part many times in the reaction. It was recovered by a magnet after each experiment and reused 8 times without considerable loss of the activity.

    更新日期:2018-04-11
  • Removal of diethyl phthalate via adsorption on mineral rich waste coal modified with chitosan
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-11
    Mohd. Azfar Shaida, R.K. Dutta, A.K. Sen
    更新日期:2018-04-11
  • Surfactants and fatty alcohol based novel nanovesicles for resveratrol: Process optimization, characterization and evaluation of functional properties in RAW 264.7 macrophage cells
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-11
    Jaya Sravani Vankayala, Surendra Nath Battula, Ruckmani Kandasamy, Gover Antoniraj Mariya, Magdaline Eljeeva Emerald Franklin, Heartwin Amaladhas Pushpadass, Laxmana Naik Naik

    Resveratrol, a natural polyphenol widely applauded for its cardio-protective and anti-cancer activity, has limited application due to its poor solubility and low bioavailability. Hence, an attempt was made to optimize the preparation of biocompatible resveratrol loaded niosomes (R-niosomes) using non-ionic surfactants and fatty alcohol as stabilizer employing the novel and green method of sonication. R-niosomes exhibited mean particle size of 108 nm with narrow size distribution (PDI = 0.24) and high zeta potential (−56.8 mV). The niosomes had >80% of resveratrol encapsulated into the vesicles and exhibited controlled release under simulated gastro-intestinal conditions. FTIR, XRD and DSC analyses confirmed successful encapsulation of resveratrol into the vesicles. Assays in macrophage RAW264.7 cell lines showed that R-niosomes had lower cytotoxicity and higher intracellular ROS scavenging activity when compared to resveratrol in its free form. This study demonstrated that nanoencapsulation of resveratrol through niosomes using non-ionic surfactant and fatty alcohol has dramatically improved its solubility and functionality.

    更新日期:2018-04-11
  • Immobilization of nanoscale zero-valent iron particles (nZVI) with synthesized activated carbon for the adsorption and degradation of Chloramphenicol (CAP)
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-11
    Yuwei Wu, Qinyan Yue, Zhongfei Ren, Baoyu Gao

    Nanoscale zero-valent iron particles (nZVI) immobilized by Enteromorpha prolifera based-activated carbons were applied for Chloramphenicol (CAP) treatment. The porous structure, morphology and chemical composition of as-synthesized adsorbents were detected by scanning electron microscope (SEM), transmission electron microscope (TEM), N2 adsorption–desorption isotherms, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The kinetics models (pseudo-first-order and pseudo-second-order model) and isotherms models (Langmuir, Freundlich and Temkin model) were introduced to investigate the CAP removal mechanisms, and the degradation products were analyzed using 3D-EEM fluorescence, Ultraviolet-visible spectroscopy (UV–VIS) and mass spectrograph. The modified nZVI exhibited excellent removal capacity for CAP (545.25 mg/g) because of the cooperative effects of adsorption and degradation of nZVI/AC system. Thermodynamic parameters revealed an endothermic, spontaneous and feasible process for nZVI/AC with a tendency of out-of-order. Besides, 3D-EEM fluorescence and UV–VIS analysis implied that could be thoroughly decomposed by nZVI/AC but decomposition of CAP was less efficient by the nZVI. According to the degradation products of CAP analyzed utilizing mass spectrometry, dechlorination by radicals was inferred to be the potential degradation routine of CAP by nZVI/AC.

    更新日期:2018-04-11
  • Unsteady flow and heat transfer past a permeable stretching/shrinking sheet in a nanofluid: A revised model with stability and regression analyses
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-10
    Shah Jahan, Hamzah Sakidin, Roslinda Nazar, Ioan Pop

    This article investigates the unsteady flow and heat transfer in a nanofluid over a stretching/shrinking sheet with injection/suction effects to overcome the deficiency found in the previous model that was to control the nanoparticles fraction actively. Besides, this study controls the nanoparticles volume fraction on the boundary passively rather than actively in order to make the model physically more realistic with zero flux at the surface. This approach makes the Buongiorno's nanofluid model more effective for the plate problems in reality. The governing partial differential equations are transformed into ordinary differential equations via the similarity transformation and are then solved numerically using the bvp4c function. Effects of different flow parameters on the velocity profile, the temperature distribution, the skin friction coefficient and the local Nusselt number are deliberated in detail. Dual solutions are observed for the stretching/shrinking sheet and suction/injection parameter in some certain range. Stability analysis is conceived to check the reliability and stability of the solutions. The local Nusselt number is estimated through multiple linear and quadratic regressions. A comparison is made to validate the obtained results. Results indicate that the first solution is stable and physically realizable as compared to the second solution either fluid flow is under suction or injection effect. The Brownian motion parameter is not significant, and the local Nusselt number is almost independent of the Brownian motion parameter, but it depicts decreasing behavior for the Schmidt number and the thermophoresis parameter for suction and opposite behavior for the injection case. The rise in the suction parameter causes the streamlines to get closer to each other while for the impermeable case, the oncoming flow is the same as for the stagnation point flow.

    更新日期:2018-04-11
  • A heating-assisted liquid-liquid microextraction approach using menthol: Separation of benzoic acid in juice samples followed by HPLC-UV determination
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-10
    Irina Timofeeva, Daria Kanashina, Dmitry Kirsanov, Andrey Bulatov

    A heating-assisted liquid-liquid microextraction (HA-LLME) procedure was developed as a new approach for pretreatment of complex sample matrix. The procedure was applied for HPLC-UV determination of preservative (benzoic acid) in juices. Menthol was investigated as an extractant for the HA-LLME. The procedure consists in heating of an aqueous sample in a polymeric vial with solid-phase menthol located at the bottom of extraction vial. The heating promotes the melting of menthol and its dispersion in a sample phase. The extractant drops are moving from the bottom to the surface of the sample, forming a liquid organic phase containing target analyte. Thus separation is taken place without centrifugation. It was found that menthol provides for microextraction of benzoic acid from fruit and berry juice samples with recovery from 93 to 117%. The conditions of the HA-LLME were optimized using factorial experimental designs. Under optimal experimental conditions the linear detection range was found to be 0.5–50 mg L−1 with LOD at 0.15 mg L−1. The HA-LLME with menthol allowed for significant improvement of the selectivity of benzoic acid determination. The advantages of the HA-LLME are the simplicity, low cost, and using of environmentally friendly extractant.

    更新日期:2018-04-11
  • The structure and diffusion behaviour of the 1:1 copper(II) complex of ethambutol in aqueous solution
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-10
    L.M.P. Verissimo, M.L. Ramos, L.L.G. Justino, H.D. Burrows, P.F. Cruz, A.M.T.D.P.V. Cabral, F.J.B. Veiga, M.A. Esteso, A.C.F. Ribeiro

    Ethambutol (as its dihydrochloride) is a bacteriostatic drug, which is widely used as part of the Tuberculosis treatment protocol. It can also act as a ligand for various metal ions, such as copper(II), leading to complexes with potentially interesting applications in medicinal and analytical chemistry. The structure of such complexes is relevant to the question of the coordination geometry of the copper(II) ion in aqueous solution. We report a structural study of the 1:1 complex formed between ethambutol (Emb) and copper(II), using visible absorption, multinuclear NMR (1H and 13C), and EPR spectroscopies, and density functional theory (DFT) calculations. These all support a pentacoordinate structure with a distorted square pyramidal geometry involving a central Cu(II) ion coordinated by a tetradentate Emb ligand and one water molecule. The diffusion behaviour of this complex has been studied, and is compared with that of the free ligand by measuring limiting mutual diffusion coefficients for aqueous systems at 25 °C using the Taylor dispersion method. From these results, we have estimated the tracer diffusion coefficient of ethambutol in supporting solutions of copper nitrate and the limiting diffusion coefficients of the 1:1 complex formed between ethambutol and copper ion. By using the Stokes-Einstein equation, the limiting hydrodynamic radii of this complex, Rh, have also been estimated and are compared with the free Emb.

    更新日期:2018-04-11
  • Prediction of Henry's law constant of CO2 in ionic liquids based on SEP and Sσ-profile molecular descriptors
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-10
    Xuejing Kang, Chunjiang Liu, Shaojuan Zeng, Zhijun Zhao, Jianguo Qian, Yongsheng Zhao

    Nowadays, greenhouse gas CO2 emissions have caused serious global warming problems. Unique properties of ionic liquids (ILs), such as negligible vapor pressure, good thermal and chemical stability, high gas dissolution capacity, etc., have made them highly promising in capturing CO2. Although researchers have done a lot of experimental work using ILs to capture CO2, time-consuming and high experimental economic costs have led to a strong interest in establishing predictive models. In this work, 297 experimental data points including 16 cations and 9 anions for 34 ILs are collected and the structures of cations and anions are optimized by quantum chemistry. Then the electrostatic potential surface area (SEP) and charge distribution area (Sσ-profile) descriptors are calculated and used to predict the Henry's law constant (HLC) of CO2 in ILs. Three new models, namely, the multiple linear regression (MLR), support vector machine (SVM), and extreme learning machine (ELM) are finally developed based on the above-calculated descriptors. Results show that the ELM model with AARD = 3.22% for the entire data set is the most valid and powerful one to predict the HLC of CO2.

    更新日期:2018-04-11
  • Effect of ZrO2 nanoparticles on thermophysical and rheological properties of three synthetic oils
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-10
    María J.G. Guimarey, Miguel R. Salgado, María J.P. Comuñas, Enriqueta R. López, Alfredo Amigo, David Cabaleiro, Luis Lugo, Josefa Fernández

    This article presents an experimental study on some thermophysical properties (density, viscosity and adiabatic bulk modulus) of six synthetic oils-based ZrO2 nanolubricants. Two-step method with ultrasonic disruptor was used to prepare the nanodispersions. The morphology, crystalline degree and elemental composition of nanoparticles were analyzed by electron microscopy. Visual observation, temporal variation of refractive index and dynamic light scattering were used to analyze the stability of the nanolubricants and the average size of the aggregates. The presence of new interactions between nanoparticles and base oils was studied through Fourier transform infrared spectrometer. Vibrating tube densimeters, rotational viscometer and rheometer equipped with cone-plate geometry were used within the temperature range from 278.15 to 373.15 K. The ability of some theoretical simple models to predict densities and viscosities of these nanolubricants as a function of temperature and nanoparticle concentration was also checked.

    更新日期:2018-04-11
  • Impacts of ammonium based ionic liquids alkyl chain on thermodynamic hydrate inhibition for carbon dioxide rich binary gas
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-10
    Muhammad Saad Khan, Cornelius B. Bavoh, Behzad Partoon, Omar Nashed, Bhajan Lal, Nurhayati Bt Mellon

    In this work, the thermodynamic inhibition impact of four ammonium-based ionic liquids (AILs) on CO2 rich mixed gas hydrate system (70–30 mol% CO2 + CH4) is experimentally studied, and the observed behaviour is modelled. The studied AILs are; tetramethylammonium hydroxide (TMAOH), tetraethylammonium hydroxide (TEAOH), tetrapropylammonium hydroxide (TPrAOH) and tetrabutylammonium hydroxide (TBAOH). Initially, the impact of 10 wt% AILs in an aqueous solution on the CO2 enriched binary gas phase boundary is evaluated by measuring the dissociation temperature in the pressure range of 1.90–5.10 MPa. The thermodynamic inhibition influence of AILs is quantitatively analyzed by calculating the hydrate suppression temperatures for all studied systems. Further, the Clausius–Clapeyron equation is used to determine the molar hydrate enthalpy of dissociation (∆Hdiss) for the studied systems. The results revealed that the inhibition influence of AILs is observed to be decreasing with the increasing alkyl chain length of AILs. Excluding TBAOH, all the other studied AILs act as thermodynamic inhibitors due to the relatively shorter alkyl chain. The ∆Hdiss results of the binary mixed gas system in the presence and absence of AILs revealed that the presence of TMAOH, TEAOH and TPrAOH has negligible effect in hydrate cages formation. However, TBAOH exhibited a significant change in ∆Hdiss which indicates the semi-clathratic nature of it. Among the considered AILs, TMAOH shown better thermodynamic impact attributed to its shortest alkyl chain length. Therefore it is further investigated for various concentrations (1, 5 and10 wt%). Moreover, the measured, mixed gas hydrate phase boundaries of various aqueous AILs solutions are also predicted via electrolyte model proposed by Dickens and Quinby-Hunt and are found to be in good agreement with the experimental data apart from TBAOH. Therefore, this study is relevant for the understanding of structural variations (alkyl chain elongation) of AILs on the hydrate phase stability of the high CO2 content mixed gas system.

    更新日期:2018-04-11
  • A comprehensive study on the enhanced photocatalytic activity of CuO-NiO nanoparticles: Designing the experiments
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-10
    Samaneh Senobari, Alireza Nezamzadeh-Ejhieh

    Effects of coupling, calcination temperature and mole ratio were studied on the photocatalytic activity of CuO and NiO nanoparticles. Both semiconductors' nanoparticles were synthesized by sol-gel method. The coupled CuO-NiO system showed better photocatalytic activity than the mono-component NiO and CuO semiconductors. Hence, the coupled system with the best activity was characterized by the field emission scanning electron microscope (FESEM), EDX, X-ray Mapping, XRD, DRS, FT-IR and electrochemical impedance spectroscopy (EIS) techniques. The higher photocatalytic activity of the coupled system relates to its higher charge transfer ability that prevents from the electron/hole recombination. The NiO-CuO catalyst with mole ratio of 1:1 that calcined at 800 °C for 4 h, showed the best photocatalytic activity. The degradation of methylene blue (MB) was followed by UV–vis spectroscopy and the degradation extent was confirmed by chemical oxygen demand (COD) method. To investigate the interaction effects of the experimental variables on the photocatalytic activity of the coupled system, experimental design was applied based on the response surface methodology (RSM) approach. Among the interaction terms, effect of pH- time had the most importance (40%) on the created response. The best MB photodegradation result was obtained in a run included pH 3.5, catalyst dosage of 0.9 g L−1, 3.2 mg L−1 of MB during 26 min.

    更新日期:2018-04-10
  • 更新日期:2018-04-10
  • Optimization of simultaneous removal of binary mixture of indigo carmine and methyl orange dyes by cobalt hydroxide nano-particles through Taguchi method
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-10
    Javad Zolgharnein, Mahdiye Rastgordani

    The simultaneous removal of Indigo Carmine(IC) and Methyl Orange(MO) in binary mixtures by cobalt hydroxide nanoparticles in batch system is investigated. Taguchi optimization approach (an L16 orthogonal array design) was employed for estimating the important and interactive impressions of some considered variables (such as, initial concentrations of Indigo Carmine and Methyl Orange, amount of sorbent, initial pH value, and contact time) on the adsorption process. Under the optimized conditions, the maximum removal percent (%R) was equal with 75% and 87% and also the uptake capacity was obtained to be 62.5 and 81.3 mg/g for Indigo Carmine and Methyl Orange dyes, respectively. Isotherm modeling and kinetic studies indicated that modified Langmuir and pseudo-second-order are good models for illustrating the adsorption equilibrium and kinetic behavior of process. Thermodynamic parameters proved that the adsorption process was endothermic (∆H° > 0) for MO while it was exothermic (∆H° < 0) for IC. Finally, the morphology and structure of the nanosorbent was characterized by using XRD, EDX, SEM, FTIR and TEM techniques.

    更新日期:2018-04-10
  • Anti-corrosion performance of eco-friendly inhibitor (2-aminobenzyl) triphenylphosphonium bromide ionic liquid on mild steel in 0.5 M sulfuric acid
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-10
    Madhusudan Goyal, Hemlata Vashisht, Sudershan Kumar, Indra Bahadur

    The inhibition efficiency (IEinh %) of the (2-aminobenzyl)triphenylphosphonium bromide (ABTPPB) environmental friendly inhibitor on mild steel (MS) corrosion in 0.5 M H2SO4 solution at concentrations (10−5 to 10−2 M) and temperatures (298 to 328 K) have been achieved using potentiostatic polarization (PP), galvanostatic polarization (GP), electrochemical impedance spectroscopy (EIS), and surface characterized via the scanning electron microscopy (SEM) with energy dispersive x-ray (EDX) spectroscopy, and atomic force microscopy (AFM). The results confirmed that ABTPPB was a potent inhibitor for MS in corrosive medium with the IEinh (%) adequate to 99% in 10−2 M. EIS outcomes revealed the enlarged capacitive loop in the attendance of mitigator in comparison to that of the merely acid specifies a high degree of mitigation efficiency. The definite correlation between the experimental results and isotherm utility was achieved using Langmuir Adsorption (LA) isotherm, and the inhibitor is being chemisorbed predominantly on the MS surface. Both SEM-EDX and AFM analyses sustained the formation of protective layers of the ABTPPB molecules on the sample surface. Quantum chemical (QC) calculations were employed for computational calculations, and the acquired results were instigated to be reliable with the experimental findings.

    更新日期:2018-04-10
  • Mechanochemically synthesized Ag (I) coordination polymer as a new adsorbent and its application to ultrasound assisted wastewater treatment via the central composite design: Isotherm and kinetic studies
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-10
    H.R. Normohamadi, M.R. Fat'hi, M. Ghaedi, S. Azizzadeh, V. Nobakht

    In this investigation, the capability of mechanochemically synthesized silver (I) coordination polymer [Ag(I)-CP] for simultaneous removal of Congo red (CR) and Indigo carmine (IC) from aqueous solutions was described. The structure of the Ag(I)-CP adsorbent was characterized by FT-IR and PXRD instrumental techniques. The significant and interaction of parameters (pH, adsorbent mass, ultrasound time and CR and IC initial concentration) on their removal efficiency were studied by central composite design (CCD) associated with response surface methodology (RSM). The maximum adsorption was obtained at variables set at pH = 6, 15 mg Ag(I)-CP, 4 min sonication time and 12 mg L−1 of both dyes at room temperature. Under the optimized parameters, an adsorption efficiency of 99.5%, with relative standard deviation of 1.7%, was obtained via five replicated measurements at center. The results indicate that the R2 values were >0.995, while the adjusted R2 (0.9969 and 0.9971 for CR and IC respectively) values are in close conformity with R2. The equilibrium data fitted better to Langmuir model than Freundlich one with minimum error, while Langmuir adsorption capacity assign to monolayer were 60.240 and 52.360 mg g−1 for CR and IC, respectively. The kinetic studies demonstrated that the adsorption process followed pseudo-second-order kinetics.

    更新日期:2018-04-10
  • 更新日期:2018-04-10
  • Effects of different surfactants and physical properties on the coalescence of dimethyl disulfide drops with mother phase at the interface of sodium hydroxide aqueous solutions
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-08
    M. Kasmaee, F. Varaminian, P. Khadiv-Parsi, J. Saien

    This study is concerned on the coalescence behavior of dimethyl disulfide drops and its mother-phase at the planar interface of sodium hydroxide aqueous solutions. This phenomenon is an essential part of the well-known Merox process. Three surfactant types of non-ionic Tween 20, anionic sodium dodecyl sulfate (SDS) and cationic cetyl trimethyl ammonium bromide (CTAB) were used to examine the effect of surfactants on the coalescence process. Critical micelle concentrations (CMC) of the surfactants in caustic solutions were obtained by the interfacial tension measurement. The drop coalescence times were measured using a high-speed digital camera. It was found that Tween 20 was the most effective surfactant in the reduction of interfacial tension for which the coalescence time was reduced by 85.2% under its CMC of 75.4 mg/L. The results also revealed that increase in the concentration of surfactants promoted the interface deformation. Furthermore, the effects of physical properties of the phases on the coalescence time were studied. Accordingly, a correlation was proposed based on the obtained data in which effective parameters and physical properties were involved with a maximum deviation of 15.1% and an average deviation of 7.8%. The results were compared with the so far reported correlations for coalescence times.

    更新日期:2018-04-08
  • Optimization of entropy generation and dissipative nonlinear radiative Von Karman’s swirling flow with Soret and Dufour effects
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-08
    Sumaira Qayyum, T. Hayat, Muhammad Ijaz Khan, Muhammad Imran Khan, A. Alsaedi

    A computational investigation has been accomplished on nonlinear radiative flow between two impermeable stretchable rotating disks. thermo-diffusion and diffusion-thermo effects are also implemented. Furthermore nonlinear radiative heat flux, heat source/sink, dissipation and chemical reaction are considered. Thermodynamics second law is used for the investigation of entropy generation and Bejan number. Total entropy generation is inspected for various flow variables. Von Karman similarity transformations are utilized to develop coupled nonlinear ordinary differential systems and then tackled by semi computational/analytical technique namely homotopy technique. Particular consideration is given to the convergence procedure. The impacts of different flow variables like magnetic interaction, porosity, thermal diffusion, Prandtl number, diffusion thermo, radiative flux, heat source/sink, Schmidt number and chemical reaction variables on fluid velocity, concentration, temperature, volumetric entropy generation rate and Bejan number are discussed and analyzed. Velocity, temperature and concentration gradients at the disk surface are calculated numerically and discussed through Tables. Velocity reduces for both Hartman number and porosity parameter. Hartman number and radiation parameter enhances the entropy generation and Bejan number. Final conclusions of present flow analysis have been presented through concluding remarks.

    更新日期:2018-04-08
  • Aggregation induced emission of 9-Anthraldehyde microstructures and its selective sensing behavior towards picric acid
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-07
    Debasish Das, Ashim Maity, Milan Shyamal, Samir Maity, Naren Mudi, Ajay Misra

    A novel material showing aggregation induced emission (AIE) is developed by reprecipitation method using 9‑Anthraldehyde (9-AC), where Sodium dodecyl sulfate (SDS) was used as morphology directing agent. 1-dimension rod and 2-dimension elongated hexagon shaped morphology of 9-AC aggregates have been synthesized. Morphology of the materials was characterized using optical microscopy. Photophysical properties of the hydrosol were studied using UV–Vis, steady state and time resolved fluorescence emission techniques. Computation of second order Fukui parameter as local reactivity descriptor on each atomic center of the titled compound also substantiate that the neighboring 9-AC molecules are arranged in trans conformation in its aggregated structures and this is in conformity with the crystal structure of 9-AC. The ‘turn off’ fluorescence property of aggregated 9-AC has been utilized for selective detection of picric acid and the fluorescence quenching has been explained due to ground state complexation between 9-AC and picric acid. The observed detection limit of picric acid was found as low as 8.07 μM.

    更新日期:2018-04-08
  • Isobaric heat capacity and density of ethylene glycol based nanofluids containing various nitride nanoparticle types: an experimental study
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-07
    Gaweł Żyła, Javier P. Vallejo, Luis Lugo

    This work presents experimental results on the isobaric heat capacity of ethylene glycol (EG) based nanofluids containing three types of nitride nanoparticles: aluminum nitride (AlN), silicon nitride (Si3N4) and titanium nitride (TiN). The densities of the nanofluids were also investigated in this study. Each type of material was used in two different sizes of nanoparticles and with various values of specific surface area. Temperature-modulated differential scanning calorimetry and vibrating tube techniques were used, and measurements were performed at three different temperatures: 288.15~K, 298.15 K and 308.15~K. The obtained experimental results were compared with the predictions of theoretical models, and absolute average deviations were calculated. It was demonstrated that the fraction of nanoparticles strongly affects isobaric heat capacity and density, whilst the size of the particles does not significantly impact these properties.

    更新日期:2018-04-08
  • Heat transfer enhancement using Al2O3-EG/W(60/40 vol%) in multiple-pipe heat exchanger
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-07
    Alireza Rahimi, Ali Amiri, Abbas Kasaeipoor, Emad Hasani Malekshah

    The heat transfer enhancement in a D-shaped heat exchanger using nanofluid is analyzed using a modern numerical method. The double-MRT lattice Boltzmann method is utilized to simulate the fluid flow and heat transfer. On the experimental phase, the thermal conductivity and viscosity of Al2O3-EG/W(60/40 vol%) are measured using experiments with modern devices. Some correlations based on experimental data are developed as a function of temperature for different nanoparticle concentrations. These temperature/nanoparticle concentration-based correlations are used in the numerical simulations to enhance the accuracy of results. In the present investigation, the impacts of Rayleigh number (103 < Ra < 106), nanoparticle concentration (0, 0.2, 0.4, 0.6, 0.8 and 1 vol%) and different arrangements of internal pipes on the streamlines, isotherm patterns, local/average heat transfer rate, local/average entropy generation and heatlines are studied comprehensively.

    更新日期:2018-04-08
  • New generation nano-adsorbents for the removal of emerging contaminants in water
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-07
    Al Arsh Basheer

    Nowadays, water contamination due to the drugs and pharmaceuticals residues is increasing and alarming. These contaminants are called as new emerging pollutants. The contamination due to the new emerging contaminants is of great concern due to their endocrine, hormonal and genetic disturbance nature. Also, some drugs and pharmaceuticals residues are converted into chiral metabolites, which are receptor specific and have serious side effects. Water pollution by new emerging pollutants is becoming a subject of global anxiety, with hazardous environmental consequences. Many water resources have been found to have new emerging pollutants. Nano particles are used to remove these pollutants and these are called as new generation nano-adsorbents. These new generation nano-adsorbents are capable to remove new emerging pollutants even at low concentration i.e. μg/L under varied conditions of pH and temperature. The present article describes state-of-the-art of the removal of new emerging pollutants using new generation nano-adsorbents by adsorption technology. The efforts are made to discuss the sources contamination and toxicities of new emergent pollutants, preparation, characterization and separation of new generation nano-adsorbents. Besides, the attempts have also been made to discuss the future perspectives of the new emergent pollutants and new generation adsorbents.

    更新日期:2018-04-08
  • On the calculation of the surface entropy in computer simulation
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-06
    Marcello Sega, George Horvai, Pál Jedlovszky

    The surface excess of the entropy at the liquid-vapour interface of argon and water are calculated in a broad temperature range in three different ways involving the computer simulation determination of the surface tension. The three methods include (i) the calculation of the analytical derivative of a suitably chosen function fitted to the surface tension vs. temperature data, (ii) calculation of the numerical derivative of these data, and (iii) direct determination of the surface entropy through the surface excess of the energy. Our results show that this latter method provides inaccurate results with large error bars, and the calculation of the surface entropy this way with reasonable accuracy would require unfeasibly long simulations. On the other hand, the use of the numerical and the analytical derivatives leads to compatible results that can be obtained in a computationally feasible way in both cases. Thus, the present results suggest that the surface entropy, determined as the derivative of the surface tension vs. temperature data, can be used to calculate the surface excess of the energy in a computationally efficient way.

    更新日期:2018-04-07
  • Molecular dynamics simulations of freezing-point depression of TIP4P/2005 water in solution with NaCl
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-06
    M.M. Conde, M. Rovere, P. Gallo

    Molecular dynamics simulations have been performed on an aqueous solution of TIP4P/2005 water and NaCl using the direct coexistence technique to determine the equilibrium line ice/NaCl solution and the freezing point depression of water in presence of NaCl at different salt concentrations below the eutectic point. We used large samples in order to avoid finite size effects and to minimize the error on the determination of the freezing temperature. Our results are in excellent agreement with the experimental freezing point depression showing that the set of parameters used in this work for the water and NaCl is a very good choice to reproduce the thermodynamic properties of the water/NaCl system with molecular dynamics simulations.

    更新日期:2018-04-07
  • Structures of Binary Mixtures of Ionic Liquid 1-Butyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)imide with Primary Alcohols: The Role of Hydrogen-Bonding
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-06
    Sraddha Agrawal, Hemant K. Kashyap

    The structure of ionic liquids (ILs) with shorter alkyl tail(s) of the constituent ions is predominantly governed by strong electrostatic interactions which are, in most cases, accompanied by specific interactions such as hydrogen bonding. Neat 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide View the MathML source Im 1 , 4 + / NTf 2 − IL possesses both of these interactions. However, in many conventional solvents such as short tail length primary alcohols, the structure is primarily determined by hydrogen bonding interactions. In this study, we aim to understand how the structure of View the MathML source Im 1 , 4 + / NTf 2 − changes with the addition of different amount of alcohol by employing atomistic molecular dynamics simulations. Specifically, we have chosen View the MathML source Im 1 , 4 + / NTf 2 − + 1-propanol and View the MathML source Im 1 , 4 + / NTf 2 − + 1-butanol mixtures as the pure components of both the mixtures possess complex interactions, including hydrogen bonding. The mixtures’ composition-dependent structures were examined through simulated X-ray scattering structure functions (S(q)s), their partial components along with radial and spatial distribution functions. It is observed that there is significant hydrogen bonding between the anion and alcohols along with strong electrostatic interactions between the cation head and anion. For the entire composition of the mixtures studied, while alcohol’s hydroxyl group is found near the cation head and the anion’s oxygen atoms, the nonpolar tail of alcohol molecules tend to align with the tails of either the cation or other alcohol molecules. It is interesting to note that on adding even small amount of the IL (10%) to alcohol, low q peak observed for the neat alcohols disappears. The X-ray scattering S(q)s reveal that the long-range charge ordering structure of the View the MathML source Im 1 , 4 + / NTf 2 − IL begin to build up at xIL = 0.3 but at larger length scales. The transitional structural changes in the both the mixtures take place for 0.3 ≤ xIL ≤ 0.8. The neat IL structure is virtually regained at and above xIL = 0.8.

    更新日期:2018-04-07
  • Interaction of anionic dyes with polyaniline implanted cellulose: Organic π-conjugated macromolecules in environmental applications
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-06
    K.L. Bhowmik, K. Deb, A. Bera, A. Debnath, B. Saha

    The selective response of most of the adsorbents towards a particular dye creates problem in launching them as adsorbent in real field applications. Owing to that we have synthesized organic macromolecule of polyaniline implanted cellulose through vapor phase polymerization method. Polyaniline implanted cellulose was found as a cationic charge transport medium and thus enthusiastically chosen to observe its interaction with anionic dyes as adsorbent media. The prepared material was found crystalline in X-ray diffraction (XRD) measurement. Scanning electron microscopy (SEM), Raman spectroscopy, optical absorbance, and electrical current-voltage measurements were carried out to explore its physical properties. The polyaniline implanted cellulose substrate has shown excellent adsorptive response with anionic dyes of methyl orange (MO) and eosin yellow (EY). More than 97% removal efficiency was observed at optimum experimental conditions for both the dyes and the MO dye adsorption process followed Langmuir isotherm strictly. However, Freundlich isotherm model has shown better fit for equilibrium adsorption data of EY dye onto polyaniline implanted paper. Kinetic analysis indicated the applicability of second order kinetic model with involvement of intra-particle diffusion. The polaron and bipolaron charged defect states in the polyaniline chain played the key role in adsorption of anionic dyes through chemical interaction. Thus it appeared as an efficient adsorbent for anionic dyes with wide range of selectivity.

    更新日期:2018-04-07
  • Supramolecular assemblies involving calix[4]resorcinol and surfactant with pH-induced morphology transition for drug encapsulation
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-06
    Ruslan R. Kashapov, Sergey V. Kharlamov, Yuliya S. Razuvayeva, Albina Yu. Ziganshina, Irek R. Nizameev, Marsil K. Kadirov, Shamil K. Latypov, Lucia Ya. Zakharova

    The present investigations concern the mixed aggregation of anionic surfactant sodium dodecyl sulfate (SDS) and aminomethylated calix[4]resorcinol (ACR) with ethylsulfonate groups on the lower rim. The interaction between these compounds was investigated by DOSY NMR, tensiometry, conductometry, dynamic and electrophoretic light scattering, atomic force microscopy and drug solubilization. The mixed supramolecular systems based on ACR and SDS can be derived due to pH-switchable properties. Supramolecular assembly took place in acidic medium which caused protonation of the amine groups of ACR and thereby the interaction of charged species in solution. Remarkably, the globular SDS micelles were observed to transform into rod-like micelles in the presence of ACR at lower pH, which can be used to encapsulate the hydrophobic guest molecules.

    更新日期:2018-04-06
  • Yuriy Reznikov: Memories of Liquid Crystal Society Commonwealth & MRSU group R&D in area of Yuriy Reznikov’s activity
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-06
    V.V. Belyaev, S.I. Torgova, N.N. Barabanova, A.K. Dadivanyan

    One chapter of the paper is devoted to memories of two members of Board of LC Society Commonwealth on Yuriy Reznikov. Another chapter is a brief description of theoretical models developed in the MRSU group under leadership of Professor Artem Dadivanyan (†2017) in area of the LC orientation and photo-induced effects are presented. Many of these R&D were initiated by Yuriy Reznikov with his colleagues from many countries.

    更新日期:2018-04-06
  • Investigation on the decomposition process of sodium aluminate solution by spectroscopic and theoretical calculation
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-05
    Wei Liu, Ya-ling Huang, Zhou-lan Yin, Zhi-ying Ding

    This study focused on the determination of intermediate (6AlO-OH) structure and its elementary reaction path design during the decomposition process of sodium aluminate solution by combining experimental and theoretical approach. The molecular structure, Raman spectra, UV–Vis spectra, frontier molecular orbitals and molecular electrostatic potential of Al(OH)4−,[(HO)2 − Al − O2 − Al − (OH)2]2−, [(HO)2 − Al − O2 − Al − (HO)2 − Al − O2 − Al − OH)2]2−, 6AlO − OH were characterized by density functional theory calculation. The calculated Raman and UV–Vis spectra of 6AlO-OH agreed with experiments results, which showed that the supposed structure of 6AlO − OH was reasonable. Combined with the theoretical calculation results, a possible elementary reaction path of intermediate (6AlO-OH) formation was designed to propose the generation mechanism of intermediate.

    更新日期:2018-04-06
  • Separation of azeotrope (ethanol and ethyl methyl carbonate) by different imidazolium-based ionic liquids: Ionic liquids interaction analysis and phase equilibrium measurements
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-05
    Ping Wang, Dongmei Xu, Peisong Yan, Jun Gao, Lianzheng Zhang, Yinglong Wang

    To separate the azeotrope of ethanol and ethyl methyl carbonate (EMC) using ionic liquids (ILs), the σ-profiles of imidazolium-based ILs with different anions [BF4]−, [HSO4]−, [PF6]− and [ClO4]− were calculated by the COSMO-SAC model. Based on the analysis results, 1-ethyl-3-methylimidazolium hydrosulfate ([Emim][HSO4]), 1-propyl-3-methylimidazolium hydrosulfate ([Prmim][HSO4]), 1-butyl-3-methyl-imidazolium hydrosulfate ([Bmim][HSO4]) were selected as extractants to separate ethanol and EMC. The liquid-liquid tie-line data for the ternary systems ethanol + EMC + ILs were measured at 298.15 K under 101.3 kPa, and the influence of ILs with the different alkyl chain length of the cations on the phase behavior was explored. The distribution coefficient and selectivity were calculated to evaluate the extraction capacity of the studied ILs. Meanwhile, the NRTL model was adopted to correlate the experimental results, and the interaction parameters of the NRTL model were also optimized.

    更新日期:2018-04-06
  • Novel aqueous biphasic system based on ethyl lactate for sustainable separations: Phase splitting mechanism
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-05
    Ishara Kamalanathan, Zeljko Petrovski, Luis C. Branco, Vesna Najdanovic-Visak

    Ethyl lactate is a hydrophilic green solvent which is bio-renewable and biodegradable with low toxicity towards humans and animals. For the first time, we report that aqueous solutions of ethyl lactate separate into two aqueous phases upon addition of salts. The performance of trisodium citrate, disodium tartrate and disodium succinate as salting-out media for the separation of natural organic compounds, such as caffeine and catechin, from their aqueous solutions was examined. In this respect, cloud points for the ternary solutions composed of ethyl lactate, water and salt were determined at ambient pressure (0.1 MPa) at 298.2 K. Partition coefficients of caffeine and catechin between two phases were determined by chemical analysis of phases in equilibrium for different initial compositions at 298.2 K. The obtained results clearly demonstrate the ability of the ternary mixture to phase separate, providing good salting-out media for the efficient and sustainable separation from aqueous solution. 1H NMR spectroscopy was employed to elucidate the mechanisms of phase splitting in the ternary (ethyl lactate + water + salt) systems at molecular level. The discovery of aqueous biphasic system (ABS) containing ethyl lactate as hydrophilic solvent opens a new and green platform for extraction of various compounds from aqueous solutions.

    更新日期:2018-04-06
  • Structure of supercooled water: Polarizable BK3 model versus non-polarizable models
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-05
    Jiří Škvára, Filip Moučka, Ivo Nezbeda

    The polarizable BK3 model of water was simulated, using both Monte Carlo and molecular dynamics methods, along isobars p = 1 and 1000 bar for temperatures ranging from supercritical down to 228.15 K with the focus on details of its structure and changes with temperature. Since overwhelming majority of results for supercooled model water have been obtained for non-polarizable models, in most cases the ST2 one, we also simulated at corresponding conditions this model along with another, and qualitatively different non-polarizable model, TIP4P/Ice for comparison. In addition to commonly used various order parameters to characterize the structure, and a detailed analysis of the spatial distribution function over the first three coordination shells, we also employ a geometric construction based on the Delaunay tessellation, the method independent of any a priori defined quantity. All these analyses aim at an examination to what extent qualitative differences in the models (force fields) affect the observed structure. It is found that in most cases the polarizable BK3 model and TIP4P/Ice water yield very similar structural properties. On the contrary, ST2 water exhibits, in majority cases, even qualitatively different properties and these findings are discussed in detail. The obtained results suggest that any conclusion on the behavior of supercooled water based on the ST2 model should be taken, at least, with caution.

    更新日期:2018-04-06
  • Sequestration of HEDPA, NTA and phosphonic NTA derivatives towards Al3+ in aqueous solution
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-05
    Paola Cardiano, Concetta De Stefano, Claudia Foti, Fausta Giacobello, Ottavia Giuffrè, Silvio Sammartano

    The sequestration of Al3+ by etidronic acid (1‑Hydroxyethane‑1,1‑diyil)bis(phosphonic acid) (HEDPA), nitrilotriacetic acid and its phosphonic derivatives, namely N‑(phosphonomethyl)iminodiacetic acid (PMIDA, NTAP), N,N‑bis‑(phosphonomethyl)glycine (NTA2P) and [bis(phosphonomethyl)amino]methylphosphonic acid (NTA3P) was studied in aqueous solution at T = 298.15 K and I = 0.15 mol L−1 in NaCl. Formation constants and speciation models are discussed on the basis of potentiometric results. The speciation models found for all the systems include MLH, ML and MLOH species, in addition for Al3+-NTA system ML(OH)2 and M2L2(OH)2, for NTAP system ML2, for NTA2P and NTA3P systems MLH2 species, for HEDPA system ML2 and ML2OH species were detected as well. The formation constant values for ML species show the trend NTA < NTAP < HEDP < NTA2P < NTA3P. Investigations using 1H NMR spectroscopy were also performed for the study of Al3+-NTAP system. The 1H NMR findings are in agreement with the speciation model obtained by potentiometry, confirming the stabilities of the main species. The dependence of formation constants on ionic strength over the range I = 0.15 to 1 mol L−1 in NaCl is also reported for NTA, NTAP, NTA2P systems. Enthalpy change values obtained by titration calorimetry at T = 298.15 K and I = 0.15 mol L−1 in NaCl, for the main Al3+-NTA, -NTAP, -NTA2P and NTA3P species, are mainly endothermic, as typical for hard-hard interactions. The sequestering ability of the ligands under study towards Al3+ was also evaluated, under different pH conditions by the empirical parameter pL0.5.

    更新日期:2018-04-06
  • The system of mobile ions in lattice models: Screening effects, thermodynamic and electrophysical properties
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-05
    George Bokun, Dung di Caprio, Myroslav Holovko, Vyacheslav Vikhrenko

    The lattice fluid model of the system with short range and long range Coulomb interactions is suggested. In the framework of the collective variables method, the screening of the Coulomb interactions in the bulk is considered and it is shown that the Debye length includes additional concentration dependence inversely proportional to the square root of the mean concentration of vacant sites like that was known at the plane boundary. The Coulomb interaction contribution to the free energy of the system is calculated in the approach close to the mean spherical approximation and is given in an analytical form. The influence of the variation of the crystal field near the system boundary on the structure and characteristics of the electric double layer is investigated. As compared to the system with equal crystal potentials at the lattice sites throughout the system the pronounced difference for the electric capacitance appears at low absolute values of the surface potential and it is more pronounced for negative electric potentials. The capacitance diverges as the potential values at which the electric field tends to zero and attains negative values in regions of the surface potentials depending on their polarity and values of the surface crystal potential. Negative values of the capacitance may indicate the thermodynamic instability of the system that can result from neglecting the short range interaction contribution.

    更新日期:2018-04-06
  • Enhancing sensitivity by Triton X-100 in extractive spectrophotometric determination of chromium via transforming the formed binary complex ion associate between chromate and rhodamine 6G into an adduct
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-05
    W. Ahmad, D.A. Al-Eryani, H. Alwael, Z.M. Saigl, G.I. Mohammed, M.S. El Shahawi

    The reaction of chlorochromate anion (CrO3Cl−) with rhodamine 6G hydrochloride dye (RG+) results in the formation of complex ion associate [RG+·CrO3Cl−] in non-aqueous medium. This study aimed to use t-octylphenoxypolyethoxyethanol polymer (Triton X-100) in [RG+·CrO3Cl]org extraction system to enhance the sensitivity of Cr(VI) under the optimized conditions. The produced highly electron deficient system in the binary ion associate [RG+·CrO3Cl] of Cr(VI) transforms into an adduct [(CrO3Cl−·RG+)·TX-100·nS]org in the presence of Triton X-100 (TX-100). This transformation enhanced the analytical response of the produced adduct specie in the organic phase by over 75%. The adduct formation via ether oxygen of TX-100 and the possible existence of H-bonding between NH of RG+ and ether oxygen of TX-100 are directly related to the increase in the molar absorptivity and this phenomenon was monitored by UV–Vis spectrophotometric measurement at λmax = 534 nm. The current study discusses the role of different surfactants and its influence on the extraction of Cr(III) & Cr(VI) species. A detailed proposed mechanism, structure, stoichiometry, and extraction equilibria for the produced adduct is presented. Cr(III) species after oxidation with H2O2 in KOH media were also determined by the proposed procedure. At optimal conditions, the method exhibited a wide linear range 0.0245–1.5 μg mL−1 with detection and quantification limits of 0.0073 μg mL−1 and 0.025 μg mL−1, respectively. This enhancement principle in the extraction systems could be extended to other class of surfactants and/or nano materials.

    更新日期:2018-04-06
  • A novel optimized mold release oil-in-water emulsion for polyurethane foams production
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-05
    A. Olietti, E. Pargoletti, A. Diona, G. Cappelletti

    Release agents are compounds usually sprayed on the molds surface, forming a thin film that can act as a barrier preventing the sticking. Herein, both physical and chemical optimization of a wax-based O/W emulsion for polyurethane (PU) foams is reported. E_N1.8Cet1.2Ac2.5 sample (where N, Cet and Ac stand for the percentages of linear amine, cetyl alcohol and acetic acid), emulsified by the inversion point method, turned out to have the optimal composition, in terms of smaller oil droplets size (by Dynamic Light Scattering analysis and optical measurements), long-term stability (by Abbe refractometer and backscattering tests), good spreading (contact angle and surface tension measurements) and low corrosion phenomena (by potentiodynamic polarization tests, Scanning Electron Microscopy analysis). Principal Component Analysis helped to find the best correlations among all the investigated variables and to have some predictions on the role of the different raw materials in affecting the final stability of the emulsions.

    更新日期:2018-04-06
  • A facile route to ionic liquids-functionalized ZnO nanorods for the fluorometric sensing of thiabendazole drug
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-05
    Narinder Kaur, Pushap Raj, Amanpreet Singh, Narinder Singh, Deuk Young Kim

    In this report, we introduce a simple and cost-effective hydrothermal method for the functionalization of ZnO nanorods with three different ionic liquids (ILs (1–3)) to check their sensing response with various drugs including thiabendazole, phenylbutazone, chloramphenicol, neomycin, and theophylline through fluorescence spectroscopy. The rod like-microstructure and hexagonal wurtzite structure of synthesized ZnO nanorods were examined with SEM-EDS and XRD techniques. On the other hand, ionic liquids-functionalized ZnO nanorods (ILs (1–3)/ZnO) exhibited various self-organized (layered-sheet ~ IL1, distorted nanorods ~ IL2, peanut beaded surface ~ IL3/ZnO) structures due to the intercalation of ILs on the surface of ZnO nanorods. Compared to ZnO nanorods, ILs (1–3)/ZnO nanorods showed a blue shift in UV-absorption band which resulted to the variation in optical bandgap values. Ionic liquids-functionalized nanorods samples (ILs (1–3)/ZnO) have been selected for their recognition behaviour with available drug molecules using fluorescence spectroscopic technique. Interestingly, with the addition of thiabendazole drug molecules to two samples (ILs (1,3)/ZnO), a significant response corresponding to the peaks at ~350 nm and ~357 nm was observed, which led to the development of fluorescent sensors with a detection limit of 12 and 304 nM, respectively.

    更新日期:2018-04-06
  • Piperine derivatives as green corrosion inhibitors on iron surface; DFT, Monte Carlo dynamics study and complexation modes
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-04
    M.E. Belghiti, S. Echihi, A. Mahsoune, Y. Karzazi, A. Aboulmouhajir, A. Dafali, I. Bahadur

    In the present paper, the interaction of three Piperine derivatives namely: 5-(1,3-benzodioxol-5-yl)-1-(piperidin-1-yl) pent-2-en-1-one (S1), 5-(1,3-benzodioxol-5-yl)-1-(piperidin-1-yl) penta-2,4-dien-1-one (S2) and 5-(1,3-benzodioxol-5-yl) penta-2,4-dienoic acid (S3) with iron (Fe) have been investigated theoretically by means of DFT method at the B3LYP/LANL2DZ high basis set. The interaction with iron surface therefore all possible Fe-inhibitor interaction modes at ―O― and >N― active sites. The preferred complexes are those in which the Fe-atoms is in mono-dentate mode to the studied inhibitors. The quantum chemical properties most relevant to their potential action as corrosion inhibitors have also been calculated in both isolated and Fe-inhibitor (Si) complex form for comparison. The values of the calculated interaction energy are consistent with the experimentally observed highest corrosion inhibition efficiency trend for the three S1FeN26, S2FeN24 & S3FeO26 complexes. The chemical reactivity and site selectivity of the molecule has been determined with the help of global and local reactivity descriptors of Fe-inhibitor (Si) complexes. The calculations show that S1FeN26, S2FeN24 and S3FeO26 complexes have thermodynamically favorable binding (ΔG〈0), whereas the other inactive Fe-(Si)complexes were characterized by slightly positive binding free energy values (ΔG〉0). Furthermore, molecular dynamics simulation was applied to investigate the final and most stable configuration of the inhibitors Si over Fe (111) in aqueous solution of hydrochloric acid (1.0 M HCl).

    更新日期:2018-04-04
  • 更新日期:2018-04-04
  • pH-responsive alginate-based hydrogels for protein delivery
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-04
    Diego S. Lima, Ernandes T. Tenório-Neto, Michele K. Lima-Tenório, Marcos R. Guilherme, Débora B. Scariot, Celso V. Nakamura, Edvani C. Muniz, Adley F. Rubira
    更新日期:2018-04-04
  • A novel approach for the simultaneous extraction of dihydroquercetin and arabinogalactan from Larix gmelinii by homogenate-ultrasound-synergistic technique using the ionic liquid
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-04
    Zaizhi Liu, Huiyan Gu, Lei Yang

    An ionic liquid-based homogenate-ultrasound-synergistic technique was proposed to simultaneously extract dihydroquercetin and arabinogalactan from Larix gmelinii stumps. The appropriate extraction solvent of [C2mim]Br was screened from thirteen kinds of imidazolium-based ionic liquids. The optimal conditions for the proposed method obtained by response surface methodology were a [C2mim]Br concentration of 0.87 mol/L, IL-HUSE time of 24 min, liquid/solid ratio of 14 mL/g, and ultrasound power of 240 W. Under these conditions, the satisfied extraction yields were 53.09 ± 2.24 mg/g for dihydroquercetin and 152.48 ± 5.78 mg/g for larch arabinogalactan. Validation studies suggested that the improved method was capable of extraction of dihydroquercetin and arabinogalactan from L. gmelinii stumps. High extraction yields of dihydroquercetin and arabinogalactan obtained from the recycled [C2mim]Br indicated that the proposed method is a highly efficient technique. The present research indicates that the improved process shows promising prospects for application to the preparation of bioactive substances from plant materials.

    更新日期:2018-04-04
  • Improving the solubility of acipimox by cosolvents and the study of thermodynamic properties on solvation process
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-04
    Danfeng Shao, Zehui Yang, Guoquan Zhou, Jingjing Chen, Shiyun Zheng, Xin Lv, Rongrong Li
    更新日期:2018-04-04
  • Spectral and quantum mechanical study of some azo-derivatives
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-04
    Daniela Babusca, Ana Cezarina Morosanu, Andreea Celia Benchea, Dan Gheorghe Dimitriu, Dana Ortansa Dorohoi
    更新日期:2018-04-04
  • 更新日期:2018-04-04
  • Using of g-C3N4 nanosheets for the highly efficient scavenging of heavy metals at environmental relevant concentrations
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-03
    Qing Liao, Wang Pan, Dongsheng Zou, Runpu Shen, Guodong Sheng, Xue Li, Yuling Zhu, Lijia Dong, Abdullah M. Asiri, Khalid A. Alamry, Wensheng Linghu
    更新日期:2018-04-03
  • Solubility modelling and solvent effect for domperidone in twelve green solvents
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-03
    Min Zheng, Jiao Chen, Gaoquan Chen, Ali Farajtabar, Hongkun Zhao
    更新日期:2018-04-03
  • A rapid and efficient sonophotocatalytic process for degradation of pollutants: Statistical modeling and kinetics study
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-04-02
    Soleiman Mosleh, Mahmood Reza Rahimi, Mehrorang Ghaedi, Arash Asfaram, Ramin Jannesar, Fardin Sadeghfar
    更新日期:2018-04-03
  • Critical review of abatement of ammonia from wastewater
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-03-29
    Rama Rao Karri, Jaya Narayan Sahu, Venkateswarlu Chimmiri

    Ammonia being a most common pollutant found in water streams. As the presence of ammonia and its associated compounds in effluent wastewater discharged to water bodies pose a severe threat to aquatic life and human health by consumption of seafood, removal of pollutants from wastewater is of paramount importance. A number of conventional methods have been adopted for the removal of these pollutants with varying degree of success. This article reviews the technologies implemented for removal of ammonia and its associated compounds from wastewater based on the physicochemical methods and biochemical treatment methods like biological treatment, membrane filtration, ion exchange, chemical precipitation, adsorption and some other technologies such as photocatalytic oxidation, aeration, and air stripping. Merits and demerits of each of the techniques were discussed. This paper also reviews the impact of process parameters on the ammonia removal efficiency is thoroughly discussed.

    更新日期:2018-03-30
  • Adsorption of pollutant cations from their aqueous solutions on graphitic carbon nitride explored by density functional theory
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-03-29
    Fatemeh Safdari, Amir Nasser Shamkhali, Mohsen Tafazzoli, Gholamabbas Parsafar
    更新日期:2018-03-30
  • Effect of magnetic field treatment on interfacial tension of CTAB nano-emulsion: Developing a novel agent for enhanced oil recovery
    J. Mol. Liq. (IF 3.648) Pub Date : 2018-03-29
    Amir Hossein Saeedi Dehaghani, Mohammad Hasan Badizad

    Nanoemulsion is a novel type of emulsified solutions holding great promises for utilizing in industrial applications. Although microemulsions have been the subject of numerous researchers in past decades, however, nanoemulsions are quite virgin and merit detailed investigation to scrutinize their characteristics specific to reservoir engineering, in particular, Enhanced Oil Recovery (EOR). To this end, the present study is an attempt to evaluate the effectiveness of a specific nanoemulsion for oil displacement through porous media. In this regard, flooding experiments were designed and Hexa decyl trimethylammonium ammonium bromide (CTAB), which is a cationic surfactant, was used as the emulsifying agent. Throughout experiments, surface tension together with incremental oil recovery was measured. Besides flooding experiments, to explore the effect of magnetic field on macroscopic behavior of CTAB solution, all procedures were replicated by exposing CTAB solution into magnetic field with varying intensities. Encouraging observations demonstrated the concealed capability of CTAB nanoemulsion for improving the performance of conventional waterflooding process. Also, it was pointed out exposing CTAB solution into magnetic field slightly increased oil/nanoemulsion IFT. However, it resulted in fairly higher oil recovery than the non-treated case. Since both cases were of nearly identical IFT and wettability, so we concluded that nanoemulsion is of higher viscosity while exposing to the magnetic field, which in turn gives rise to lower mobility ratio during flooding process.

    更新日期:2018-03-30
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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