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  • Removal of anionic and cationic dyes from wastewater by adsorption using Multiwall Carbon Nanotubes
    Arab. J. Chem. (IF 3.298) Pub Date : 2020-01-20
    Ola A.Shabaan; Hossam S.Jahin; Gehad G.Mohamed

    This paper evaluated the efficiency and reusability of multiwall carbon nanotubes (MWNTs) on removal of cationic and anionic dyes under effect of pH, dose of MWNTs and concentration of dyes. The characterization of MWNTs is characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), Raman spectra and BET (Brunauer, Emmett and Teller) surface area. SEM and TEM analyses showed that MWNTs had size within nano scale range of 10-50 nm. The experimental results indicated that the efficiency of removal of MWNTs increase under condition of normal pH, at contact time 60 min with agitation speed 240 rpm and initial concentration of dyes 10 mg/l. Under these optimal conditions, the removal reached 98.7% and 97.2% for anionic dyes and cationic dyes, respectively. For economic use, MWNTs can be used more than one time where the same experiments with the already used MWNTs was repeated and it was found that the percent removal is almost the same.

  • A systematic strategy for rapid identification of chlorogenic acids derivatives in Duhaldea nervosa using UHPLC-Q-Exactive Orbitrap mass spectrometry
    Arab. J. Chem. (IF 3.298) Pub Date : 2020-01-16
    Wei Cai; Kai-lin Li; Pei Xiong; Kai-yan Gong; Lian Zhu; Jian-bo Yang; Wei-hua Wu

    Duhaldea nervosa (Wallich ex Candolle) A. Anderberg was widely used for food spice and folk medicine. However, it is still insufficient in the constituent’s characterization of D. nervosa. In this study, a systematic strategy for rapid detection and identification of constituents was proposed based on UHPLC-Q-Exactive Orbitrap mass spectrometry in parallel reaction monitoring mode combining anion exchange resin separation, expected compounds predicted and diagnosis fragmentation ions techniques. Finally, 149 chlorogenic acids derivatives were unanimously and tentatively characterized from D. nervosa, 102 of them were report for the first time. This results widely extended the chemical constituents of D. nervosa, which will facilitate understanding the effective substance and quality control. Meantime, it is possible for this strategy to exhibit a wide application for chemical’s characterization in different sample.

  • Green synthesis, characterization and photocatalytic application of silver nanoparticles synthesized by various plant extracts
    Arab. J. Chem. (IF 3.298) Pub Date : 2020-01-16
    Kishore Chand; Dianxue Cao; Diaa Eldin Fouad; Ahmer Hussain Shah; Abdul Qadeer Dayo; Kai Zhu; Muhammad Nazim Lakhan; Ghazanfar Mehdi; Shu Dong

    Recently, the discharge of effluent containing dyes and other chemicals into river, lakes, and land has become a serious problem which increases the pollution level drastically. The dyes in the effluent are very difficult to be removed by conventional water treatment methods. Thus, there is a great need for more advanced methods that are cost-effective and more efficient. In this study, silver nano particles (AgNps) were synthesized by green method using extracts of onion (O), tomato (T), acacia catechu (C)alone, and mixed COT extracts. The reduction and formation of AgNps and its ions have been characterized by using several techniques, Ultra visible spectroscopy (UV-vis), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM)-energy dispersive X-ray spectrometer (EDX), Fourier transmission infrared spectroscopy (FTIR), and dynamic light scattering (DLS). These techniques revealed that the particle sizes of synthesized AgNps in all the extracts were ranged in between 5 – 100 nm with a crystalline nature. The synthesized AgNps were used as catalysts for the degradation of three different types of dyes, methyl orange (MO), methyl red (MR), and congo red (CR) in the liquid state. The excellent catalytic application of all the synthesized AgNps on the degradation of the studied dyes was confirmed via UV-visible results by studying the reduction in the absorbance maxima value within a very short interval of time. COT synthesized products were found to achieve the best performance for all dyes degradation among all products.

  • Preparation, characterization of some transition metal complexes of hydrazone derivatives and their antibacterial and antioxidant activities
    Arab. J. Chem. (IF 3.298) Pub Date : 2020-01-14
    S.A. Aly; S.K. Fathalla

    A new series of metal complexes of Pd(II), Cd(II) and Cu(II, I)of polydentate Schiff base ligand (H2L) , namely ((Z)-2-(phenylamino)-N'-(thiophen-2-ylmethylene) acetohydrazide) have been prepared. The ligand and its metal complexes have been characterized based on various physicochemical studies as elemental analyses, molar conductance, spectral (UV-Vis, MS, IR,1H NMR, 13C NMR and XRD), magnetic moment measurements and thermal studies (TG, DTG). In the view of previous studies, the ligand (H2L) acts as polydentate one and coordinates with metal ions to form all metal complexes. The kinetic and thermodynamic parameters of decomposition process (ΔG, ΔH, ΔS) were calculated. The possible structures of the metal complexes have been computed using the molecular mechanic calculations using the hyper chem. 8.03 molecular modeling program. The calculations are performed to obtain the optimized molecular geometry. The antibacterial study of the selected compounds was assayed against two pathogenic bacteria. Moreover, the complexes (Cu II, I), Cd(II), Pd(II)) and the ligand revealed excellent antioxidant properties and could be useful in fighting the free radicals which occur in close connection with cancerous cells. It was remarkable that the two complexes (Cu II, I) demonstrated stronger antioxidant effects than their parent compounds. It is clear that the new complexes are good active compounds for use in a variety of applications.

  • Enhancement of bioavailability and hepatoprotection by Silibinin through conversion to nanoparticles prepared by liquid antisolvent method
    Arab. J. Chem. (IF 3.298) Pub Date : 2020-01-13
    Muhammad Umar Khayam Sahibzada; Abdul Sadiq; Muhammad Zahoor; Sumera Naz; Muhammad Shahid; Najam Afaq Qureshi

    The current research was intended to establish the impact of Silibinin nanoparticles (SB-APSP) produced by the antisolvent precipitation with a syringe pump (APSP). The in-vivo bioavailability and hepatoprotective activity of SB-APSP were evaluated in experimental animals. To determine the pharmacokinetic parameters, silibinin and its nanoparticles were given orally to rabbits at a dose of 50 mg/Kg body weight. Blood samples were drawn at different time intervals and were analyzed using HPLC. The bioavailability of un processed silibinin was lower as compared to silibinin nanoparticles (3.45 ± 0.07 and 23.76 ± 0.07 µg/mL respectively). The AUC and Cmax of SB-APSP were found to be 15.56 and 6.88 folds greater for nanoparticles when compared to silibinin. Hepatoprotective study in Male Sprague Dawley rats revealed that SB-APSP provide better recovery of the damaged liver cell induced by CCl4. Histopathology of the liver revealed that SB-APSP provide better protection to the liver cells from the damage induced by CCl4 and maintained the hepatic lobule histopathology more efficiently. It was concluded that the SB-APSP can more effectively protect the liver in experimental animals in a far better way compared to the un-processed Silibinin and could be used as an efficient hepatoprotective agent.

  • Preparation of the Mn-Fe-Ce/γ-Al2O3 ternary catalyst and its catalytic performance in ozone treatment of dairy farming wastewater
    Arab. J. Chem. (IF 3.298) Pub Date : 2020-01-13
    Jiayao Li; Weifeng Song; Zefeng Yu; Qiuhua Li

    The quality of dairy farming wastewater in different regions is particular and different. In Southern China, the Chemical Oxygen Demand (CODCr) and colourity of effluent from conventional dairy farming wastewater treatment processes are similar. Catalytic ozonation is a very promising technical method. In this paper, the Mn-Fe-Ce/γ-Al2O3 catalyst was prepared via the optimized preparation method of impregnation roasting using γ-Al2O3 as the carrier, and this catalyst was used in the ozonation of actual dairy farming wastewater from treatment facilities. The performance of the Mn-Fe-Ce/γ-Al2O3 catalyst on dairy farming wastewater was investigated using a simulated dynamic test. The effects of the reaction time, pH and catalyst dosage on CODCr and the colourity removal ratio were investigated. The results show that the optimum treatment conditions were a reaction time of 20 min, pH 9, and catalyst dosage of 15 g/L. The CODCr removal ratio reached 48.9% and the colourity was 95% under the optimum conditions. BOD5/CODCr increased from 0.21 to 0.54 after catalytic ozonation, indicating that the biodegradability of wastewater was significantly improved. This research provides a new method and theoretical guidance for dairy farming wastewater treatment.

  • Improved simultaneous adsorption of Cu(II) and Cr(VI) of organic modified metakaolin-based geopolymer
    Arab. J. Chem. (IF 3.298) Pub Date : 2020-01-13
    Zefeng Yu; Weifeng Song; Jiayao Li; Qiuhua Li

    In this paper, a metakaolin-based mesoporous geopolymer (GP-CTAB) was used as adsorbent for Cu(II) and Cr(VI) through a novel and simple synthetic route using cetyltrimethylammonium bromide (CTAB) as an organic modifier. The application of GP-CTAB for the simultaneous removal of metal anions and cations in aqueous solution was studied for the first time. The results of X-ray diffraction (XRD) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Brunauer, Emmett and Teller (BET), and Barrett, Joyner, and Halenda (BJH) methods indicate that GP-CTAB is still geopolymer even in the presence of quaternary ammonium salt cations. The material was tested to simultaneously adsorb Cu(II) and Cr(VI) from an aqueous solution. The results show that GP-CTAB can adsorb anions simultaneously without sacrificing the adsorption properties of heavy metal cations, which is superior to conventional geopolymers. The maximum theoretical adsorption capacity of GP-CTAB for Cu(II) and Cr(VI) was 108.2 mg/g and 95.3 mg/g in the binary system, respectively. It was also found that the presence of Cu(II) in the solution promoted the adsorption of Cr(VI). Given this characteristic of GP-CTAB, it has shown great application prospects in the prevention and control of heavy metal pollution. ___________________________

  • Observation of Unusual Griffith’s Phase behavior in Quadruple perovskite oxide CaCu3Mn4O12 (CCMO) Synthesized through Chemical Route
    Arab. J. Chem. (IF 3.298) Pub Date : 2020-01-13
    Vinod Kumar; Atendra Kumar; Manish Kumar Verma; Shruti Singh; Santosh Pandey; Laxman Singh; N.B. Singh; K.D. Mandal

    The CaCu3Mn4O12 (CCMO) ceramic was successfully synthesized through the chemical route. The phase formation was confirmed by the X-ray diffraction pattern. Thermogravimetric (TGA), FT-IR, SEM, TEM, EDX, and XPS analysis were performed for investigation of the thermal behavior, phase identification, microstructural analysis, elemental analysis and oxidation state of the CCMO ceramic respectively. FT-IR spectra confirmed the existence of MnO6 octahedral in body-centered cubic (BCC) complex perovskite oxide that resembles the CaCu3Ti4O12 structure. The average particle size was observed by TEM in the range between 100 to 200 nm. AFM shows the average roughness of the surface was found to be in the range of 30 ±5 nm. XPS and EDX studies confirmed the purity and oxidation state of the CCMO ceramic. The synthesized material shows very interesting unique Griffith’s phase(TG) results that arise disorder in magnetic susceptibility in which ferromagnetic transition was to be observed in the paramagnetic region.

  • Aryl-oxadiazole Schiff bases: Synthesis, α-glucosidase in vitro inhibitory activity and their in silico studies
    Arab. J. Chem. (IF 3.298) Pub Date : 2020-01-13
    Hayat Ullah; Fazal Rahim; Muhammad Taha; Raffaqat Hussain; Nida Tabassum; Abdul Wadood; Mohsan Nawaz; Ashik Mosaddik; Syahrul Imran; Zainul Wahab; Ghulam Abbas Miana; Kanwal; Khalid Mohammed Khan

    α-Glucosidase enzyme is a therapeutic target for diabetes mellitus and its inhibitors play a vital role in the treatment of this disease. A new series of aryl-oxadiazole Schiff bases (1-18) were synthesized and evaluated for α-glucosidase inhibitory potential. Fifteen compounds 1-8, 11-13, and 15-18 showed excellent inhibition with IC50 values ranging from 0.30 ± 0.2 to 35.1 ± 0.80 µM as compared to the standard inhibitor acarbose (IC50 = 38.45 ± 0.80 µM), nonetheless, the remaining compounds were found to have moderate activity. Among the series, compounds 7 (IC50 = 0.30 ± 0.2 μM) with hydroxy groups at phenyl rings on either side of the oxadiazole ring was identified as the most potent inhibitor of α-glucosidase. The molecular docking studies were conducted to understand the binding mode of active inhibitors with the active site of enzyme and results supported the experimental data.

  • Nanostructured pyramidal black silicon with ultra-low reflectance and high passivation
    Arab. J. Chem. (IF 3.298) Pub Date : 2020-01-13
    Chia-Hsun Hsu; Shih-Mao Liu; Wan-Yu Wu; Yun-Shao Cho; Pao-Hsun Huang; Chien-Jung Huang; Shui-Yang Lien; Wen-Zhang Zhu

    In this study, nanostructured pyramidal black silicon is prepared by metal assisted chemical etching method, in which the silver nitrate (AgNO3) is used as the metal catalyst. Effects of the concentration of AgNO3 on passivation and optical properties of the black silicon are investigated. The experimental results show that at the AgNO3 concentration of 0.03 M, the nanostructure length is about 300 nm, and the reflectance of the black silicon with a stack of silicon nitride (SiNx) and aluminum oxide (Al2O3) is 0.8%, which is comparable to that of the conventional black silicon with micrometer-long nanowires. In addition, an acceptably low surface recombination rate of 42 cm/s can be obtained. Plasma chemical vapor deposited SiNx is deposited well on the top of nanostructures of black silicon, but shows poor coverage at the bottom region. Spatial atomic layer deposited Al2O3 can conformally cover the nanostructures with high passivation quality. Simulation result indicates an improvement of 5.5% of conversion efficiency for the nanostructured pyramidal black silicon solar cell compared to industrial silicon solar cell. The short nanostructured pyramidal surface with low reflectance and high passivation is expected to be helpful for black silicon technology applied to photovoltaic applications.

  • In silico, In vitro antioxidant and Density Functional Theory based Structure Activity Relationship Studies of Plant Polyphenolics as Prominent Natural Antioxidants
    Arab. J. Chem. (IF 3.298) Pub Date : 2020-01-08
    Aluru Rammohan; Baki Vijaya Bhaskar; Alexandre Camilo; Duvvuru Gunasekar; Wei Gu; Grigory V. Zyryanov
  • Nucleophilicity and solvent effects on the kinetics of 4-(pyren-1-yl)thiazol-2-amine interaction with 4,6-dinitrobenzofuroxan
    Arab. J. Chem. (IF 3.298) Pub Date : 2020-01-08
    Nizar El Guesmi; Essam M. Hussein; Saleh A. Ahmed; Basim H. Asghar; Hatem M. Altass; Ismail I. Althagafi; Ziad Moussa; Rami J. Obaid; Ahmed Alharbi; Rabab S. Jassas

    A multistep synthesis of novel pyrene-based thiazole moiety been has been realized following some synthetic challenges and complications. The chemical structure of the synthesized compound has been established on the basis of both spectroscopic and analytical tools. Its nucleophilic reactivity with 4,6-dinitrobenzofuroxan (DNBF) has been successfully studied in solution. A kinetic study of the covalent electrophile/nucleophile combination of dinitrobenzofuroxan (DNBF, electrophile) and 4-(pyren-1-yl)thiazol-2-amine (nucleophile) resulting in the formation of the corresponding σ-adduct in solution is reported. The rate constant (k1) of the second-order relating to the C–C bond forming step of this complexation process has been found to fit into the linear correlation log k = sN (N+ E), thereby permitting the evaluation of the nucleophilicity parameter (N) of the 4-(pyren-1-yl)thiazol-2-amine. 4-(Pyren-1-yl)thiazol-2-amine has been subsequently ranked according to its reactivity profile on the general nucleophilicity scale developed recently by Mayr et al., leading to an interesting and direct comparison over a large domain of π-, σ-, and n-nucleophiles.

  • Simultaneous determination of hg(ii) and cu(ii) in water samples using fluorescence quenching sensor of n-doped and n,k co-doped graphene quantum dots
    Arab. J. Chem. (IF 3.298) Pub Date : 2020-01-08
    Chayanee Kaewprom; Yonarpach Areerob; Won-Chun Oh; Keshav Lalit Ameta; Saksit Chanthai

    The present study explored the use of N doped graphene quantum dots (N-GQDs) and N,K co-doped graphene quantum dots (N,K-GQDs) as a fluorescence quenching sensor to determine both mercury and copper in water sample, simultaneously using simple fluorescence protocol. Each of N-GQDs or N,K-GQDs was optimized separately with 1-5% (w/v) HNO3 or KNO3, respectively, and their quantum yields were determined and compared. It was found that N-GQDs, obtained from 3% (w/v) HNO3 doped resulted higher fluorescence intensity at the maximum excitation and emission wavelengths of 370 and 460 nm, respectively, with higher quantum yield (QY = 83.42%) compared with that of undoped GQDs (QY = 16.35%). While N,K-GQDs obtained from 5%(w/v) KNO3 gave somewhat different fluorescence spectrum, but still had the same maximum excitation and emission wavelengths with rather highest QY (94.07%). However, it is interesting that detection sensitivity expressed as slope of their calibration curve (y = 5.43x – 19.48; r2 = 0.9971) of the N-GQDs is rather higher than that (y = 1.29x + 17.66; r2 = 0.9977) of the N,K-GQDs for Hg2+ fluorescence quenching sensor, and the fluorescence intensity of N-GQDs had better selectively quenching effect only by both Hg2+ and Cu2+. Thus, their quenching effects were selected to develop the fluorescence turn-off sensor for trace level of both metal ions in real water samples. For method validation, the N-GQDs exhibited high sensitivity to detect both Hg2+ and Cu2+ with wide linear ranges of 20-100 μM and 100-500 μM, respectively. Limit of detection (LOD) and limit of quantitation (LOQ) were 0.42 μM & 1.41 μM for Hg2+ and 13.19 μM & 43.97 μM for Cu2+, respectively, with their precision expressed as an intra-day and an inter-day analysis of 6.98% & 11.35 % for Hg2+ and 11.78% & 9.43 % for Cu2+, respectively. Also the study of matrix analysis of the water samples (drinking water and tap water), was carried out and conformed that their good percentage recoveries using N-GQDs were found than the N,K-GQDs.

  • Preparation of Nano-Co3O4-coated Albizia procera-derived Carbon by Direct Thermal Decomposition Method for Electrochemical Water Oxidation
    Arab. J. Chem. (IF 3.298) Pub Date : 2020-01-07
    Ismail A. Buliyaminu; Md. Abdul Aziz; Syed Shaheen Shah; A.K. Mohamedkhair; Zain H. Yamani

    It is obtained that nano-Co3O4-coated carbon prepared by thermal decomposition of Co(NO3)2.6H2O at 300 oC on home-made Albizia procera (Roxb.) leaves derived carbon is an efficient electrocatalyst for electrochemical water oxidation in 0.1 M NaOH (aq.) solution. The loading of nano-Co3O4 on the carbon was changed by varying the amount of precursor of cobalt (100-1000 mg) and using a constant amount of the carbon (200 mg) during thermal decomposition. The prepared samples were characterized by physical techniques, including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), thermo-gravimetric analysis (TGA), fourier transform infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HRTEM), diffuse reflectance spectroscopy (DRS), Brunauer-Emmett-Teller (BET) and X-ray photoelectron spectroscopy (XPS). XRD, TEM, FESEM, and EDS confirmed the formation of uniformly distributed nanoparticles of single-phase Co3O4 on the surface of carbon. The XRD data reveals formation of nano-Co3O4 with average particle sizes in the range of 9 - 17 nm. The FESEM micrographs demonstrate that Co3O4 nanoparticles, having irregular morphology, are uniformly and densely covered on the surface of supporting carbon.. The prepared samples were immobilized on the filter paper derived carbon electrode (FPCE) to study their electrocatalytic properties toward water oxidation. The cyclic voltammetric studies showed that the nano-Co3O4-C prepared using 400 mg of Co(NO3)2.6H2O (nano-Co3O4-C-400), which possesses meso- and macropores with BET surface area of 192.4 m2/g, reaches a current density of 28 mAcm−2 at 1.5 V and electrochemical water oxidation starting potential of 0.7 V. In this work, it is also shown that the current densities, at 1.5 V, increase by increasing the amount of cobalt oxide in the prepared samples though. The nano-Co3O4-C-400 catalyst shows optimum performance for electrochemical water oxidation in terms of starting water oxidation potential, reasonable amount of Co3O4 and moderate level of current density at 1.5 V.

  • A comprehensive study on the impact of RGO/MWCNT hybrid filler reinforced Polychloroprene rubber multifunctional nanocomposites
    Arab. J. Chem. (IF 3.298) Pub Date : 2020-01-03
    M.G. Maya; Jiji Abraham; P. Mohammed Arif; Grace Moni; Jinu Jacob George; Soney C. George; Sabu Thomas
  • Recent Progress in TiO2-based Photocatalysts for Hydrogen Evolution Reaction: A Review
    Arab. J. Chem. (IF 3.298) Pub Date : 2020-01-02
    Ha Huu Do; Dang Le Tri Nguyen; Xuan Cuong Nguyen; Thu-Ha Le; Thang Phan Nguyen; Quang Thang Trinh; Sang Hyun Ahn; Dai-Viet N. Vo; Soo Young Kim; Quyet Van Le
  • Synthesis, characterization and batch assessment of groundwater fluoride removal capacity of trimetal Mg/Ce/Mn oxide-modified diatomaceous earth
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-01-17
    Wilson M. Gitari; Anthony A. Izuagie; Jabulani R. Gumbo

    In this study, trimetal Mg/Ce/Mn oxide-modified diatomaceous earth (DE) was synthesized at optimal conditions. Comparison of the SEM images and the results of EDX analyses of the raw and the modified DE confirmed the surface modification of the raw DE with the trimetal oxide. Groundwater fluoride removal capacity of the sorbent was evaluated by batch method at various defluoridation conditions. At a sorbent dosage of 0.6 g/100 mL (contact time: 60 min, mixing speed of 200 rpm and temperature: 297 K), the fluoride removal was >93% for solutions containing initial fluoride concentration of 10–60 mg/L. Sorbent’s optimum fluoride uptake capacity was 12.63 mg/g at the initial fluoride concentration of 100 mg/L. Fluoride removal was >91% for solutions with initial pH range of ∼4–11 (initial fluoride concentration: 9 mg/L, sorbent dosage: 0.6 g/100 mL). Appraisal of the effect of co-existing anions on fluoride removal showed that CO32− would reduce the amount of fluoride removed from solution, while other anions such as PO43−, NO3− and SO42− had no observable effect. K2SO4 solution was found to be most suitable for regeneration of spent Mg/Ce/Mn oxide-modified DE compared to Na2CO3 and NaOH. The mechanism of fluoride removal at pH > 5.45 (pHpzc = 5.45) occurred by exchange of hydroxyl groups on surface of sorbent with fluoride ions from solution. Sorption data fitted better to Langmuir isotherm and pseudo-second-order model. External diffusion was observed to be the sorption rate limiting factor.

  • In silico and in vitro antioxidant and cytotoxicity evaluation of oxygenated xanthone derivatives
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-01-25
    Honorina Cidade; Verónica Rocha; Andreia Palmeira; Cláudia Marques; Maria Elizabeth Tiritan; Helena Ferreira; José Sousa Lobo; Isabel Filipa Almeida; Maria Emília Sousa; Madalena Pinto

    Many natural products play important roles as antioxidants and represent useful scaffolds for the development of new agents. Particularly, polyphenols in which oxygenated xanthones can be included have proven their efficacy as antioxidants for several applications. To better understand the antioxidant potential of oxygenated xanthones, a library of twenty mono and di-oxygenated xanthones was investigated. The antioxidant properties were evaluated by their 2,2-diphenyl-1-picrylhydrazyl (DPPH) and peroxyl radical scavenging effect as well as their inhibitory effect on the prooxidant enzyme myeloperoxidase (MPO). A quantitative structure-activity relationship (QSAR) model predicted the maximal atomic partial charge (Qmax) as the descriptor being implied in the antioxidant activity of the referred xanthones. From the antioxidant screening, emerged the hit compound, 1,2-dihydroxyxanthone (10), that was further characterized for its chelating properties and its effect on a human keratinocyte cell line. Taken together, the results suggest the possible effectiveness of xanthone derivatives as antioxidants with potential for topical administration.

  • Synthesis of PAMAM dendrimers with porphyrin core and functionalized periphery as templates of metal composite materials and their toxicity evaluation
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-02-02
    Raquel E. Hernández Ramírez; Irina V. Lijanova; Natalya V. Likhanova; Octavio Olivares Xometl; Alfredo Hernández Herrera; J. Federico Chávez Alcalá; Octavio Trejo Chavero

    Experiments were performed for the synthesis of meso-substituted tetraphenyl porphyrins in order to obtain growth active points for PAMAM branches and a functionalized periphery with thiazole groups for increasing the metal complexation activity. Characterization by 1H and 13C NMR, mass spectrometry and infrared spectrometry confirmed the produced dendrimeric nanostructures; the chemical reduction of metallic Ag and Cu inside the dendrimer was proved by XPS. Finally, the toxicity of the metal-dendrimer complex was analyzed by means of the bacterial respiration test.

  • Porous polyurethane-polystyrene composites produced in a co-expansion process
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-02-06
    Elżbieta Malewska; Aleksnader Prociak

    Porous polyurethane (PUR) and polystyrene (PS) composites can be obtained by co-expansion process. This method involves simultaneous foaming of PUR and expanding PS beads (PSB), what is possible by utilizing exothermic heat of PUR formation. In this study, PUR-PS porous composites were obtained by using different types of commercial PS beads having various initial sizes. Co-expansion processes were characterized using Foamat device. The following parameters of co-expanded materials were measured: the rise profile, the reaction temperature, the rise pressure and the dielectric polarization. The results analyzes allowed to divide the co-expansion process into 3 stages: PUR foaming below the PS softening temperature, expansion of PUR and PS in the same time, PS expansion after PUR gelling. The addition of PS filler causes: a reduction of the core temperature, increasing the pressure, slowing the PUR reaction formation and the slowdown in the rise velocity of reaction mixture. It also causes the elongation of start, gelling, rise and curing times.

  • Fatty acid patterns of the kelps Saccharina latissima, Saccorhiza polyschides and Laminaria ochroleuca: Influence of changing environmental conditions
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-02-04
    Mariana Barbosa; Fátima Fernandes; David M. Pereira; Isabel C. Azevedo; Isabel Sousa-Pinto; Paula B. Andrade; Patrícia Valentão

    Kelps play a key role in coastal ecosystems and exhibit great potential as feedstock of valuable compounds with potential biotechnological applications. This study established the fatty acid patterns of Saccharina latissima (Linnaeus) C.E. Lane, C. Mayes, Druehl & G.W. Saunders, Saccorhiza polyschides (Lightfoot) Batters, and Laminaria ochroleuca Bachelot de la Pylaie, subjected to seasonal variations, from different sources (wild and aquaculture), and cultivated at different depths at sea. Stipes, blades and whole specimens were studied. S. latissima and S. polyschides specimens exhibited a higher total fatty acid content during the colder winter months and a general tendency of decreasing unsaturation towards the warmer ones. An inverse trend was found for L. ochroleuca samples. Total fatty acid content of S. latissima stipes and blades increased by over 21.5% and 31.4% with increasing depth, respectively. There were also distinct within-thallus variations, S. latissima blades exhibiting generally higher total fatty acid amounts and slightly more n-3 polyunsaturated fatty acids (PUFA) than stipes. The whole specimens of S. polyschides and L. ochroleuca grown in an integrated multi-trophic aquaculture (IMTA) system revealed no significant differences of fatty acid content compared to the ones collected at sea. Conversely, in S. latissima from IMTA the content of fatty acids per dry weight was nearly 60% higher than in the ones from natural wild stocks, registering a large increase in the amount of the most appreciated health beneficial PUFA, cis-5,8,11,14,17-eicosapentaenoic acid (C20:5n-3c), and a significant decline in the n-6/n-3 ratio, making these edible algal specimens potentially adequate for nutritional purposes. Altogether, our results reinforce the major contribution of surrounding environmental conditions, as well as of species-specific factors, in the chemical composition of algal material. Furthermore, it encourages the optimization of culture conditions and the careful selection of algal thallus sections to improve the recovery of natural valuable compounds.

  • Amides as a model system of low molar mass algal organic matter. Influence on the adsorption of p-nitrophenol on activated carbon
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-02-06
    Branislav Jović; Branko Kordić; Vukoslava Miškov; Jelena Tričković; Marina Kovačević; Slobodan Petrović

    In this study, the adsorption equilibrium and diffusivity parameters of p-nitrophenol were estimated for water containing different concentrations of secondary amides. Commercial powdered activated carbon was used as an adsorbent. The external mass transfer coefficient (kf), the surface diffusion coefficient (Ds) and the standard free Gibbs energy were calculated for p-nitrophenol in the presence of different secondary amide concentrations. The analysis established that there are correlations between structural parameters of amides, on the one hand, and diffusion and thermodynamic parameters for p-nitrophenol adsorption process, on the other. It was noticed that voluminous hydrophobic amides decreased the adsorption capacity of p-nitrophenol on activated carbon. On the basis of the results obtained for external mass transfer coefficients, it is assumed that amides cause the reduction of adsorption capacity of p-nitrophenol onto activated carbon by concentrating at the solid/liquid interface.

  • Chemical composition, antibacterial and antioxidant activities of essential oils from leaves of three Melaleuca species of Pakistani flora
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-02-08
    Saima Siddique; Zahida Parveen; Firdaus-e-Bareen; Sania Mazhar

    This study presents essential oil composition of three Melaleuca species namely, Melaleuca bracteata F. Muell, Melaleuca fulgens R. Br. subsp. steedmanii and Melaleuca leucadendron (L.) L. collected from different regions of Pakistan. The chemical composition of essential oils was analyzed by GC-FID and GC–MS. Eugenol methyl ether was identified as a principal component in M. bracteata (82.3%), M. fulgens (87.8%) and M. leucadendron (95.4%) oils. In vitro antibacterial studies were done by agar well diffusion and microdilution method and the tested essential oils exhibited bacteriostatic and bactericidal effects against the tested foodborne pathogens at 4–8 µg/ml. Time kill assay showed significant bactericidal effect of oils for four weeks. The antioxidant potential was assessed by free radical scavenging activity and reducing power assay. The oils showed strong antioxidant activity with approximately 89.0–89.5% inhibition of 2,2-diphenyl-1-picrylhydrazyl radical and ferric reducing power in the range of 1.94 ± 0.007–2.04 ± 0.04% at 100 µg/ml.

  • Size and stability modulation of ionic liquid functionalized gold nanoparticles synthesized using Elaeis guineensis (oil palm) kernel extract
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-02-10
    Muhammad Irfan; Tausif Ahmad; Muhammad Moniruzzaman; Sekhar Bhattacharjee; Bawadi Abdullah

    Bio-synthesis approach for gold nanoparticles (AuNPs) has received tremendous attention as an efficient and eco-friendly process. However, kinetic growth and colloidal stability of AuNPs synthesized by this process remained challenging. In this study, Elaeis guineensis (oil palm) kernel (OPK) extract prepared in an ionic liquid (IL)[EMIM][OAc] (1-ethyl-3-methylimidazolium acetate) was employed to control and tune the size and morphology of AuNPs. Synthesized AuNPs were characterized using UV-vis spectrophotometer, dynamic light scattering (DLS) and transmission electron microscopy (TEM) to observe any changes in absorbance, surface charge and particle size, respectively. IL mediated AuNPs were examined for 120 days and found well dispersed and stable at room temperature. UV-vis analysis demonstrated that volume of extract played an important role to control the stability of AuNPs. After 120 days, only 8.86% reduction from maximum absorbance was observed using 2 mL of volume of extract, which was elevated to 47.64% in case of 0.3 mL. TEM analysis was performed periodically after day 1, day 30, day 60, day 90 and day 120 and minor increase in the size was observed. Insignificant change in zeta potential value after 120 days supported enhanced stability of IL mediated AuNPs. Crystalline nature of AuNPs was confirmed by X-ray diffraction (XRD) pattern. The particles size and zeta potential of AuNPs was measured as 8.72 nm and −18.7 mV, respectively. However, the absence of [EMIM][OAc] from OPK extract resulted into larger particles size (9.64 nm), low zeta potential value (−13.9 mV) and enhanced aggregation of particles. Finally, experimental data were used to predict the theoretical and the experimental settling time for AuNPs to evaluate colloidal stability.

  • Photocatalytic activity of nitrogen and copper doped TiO2 nanoparticles prepared by microwave-assisted sol-gel process
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-02-14
    S.M. Reda; M. Khairy; M.A. Mousa

    Cu and N-doped TiO2 photocatalysts were synthesized from titanium (IV) isopropoxide via a microwave-assisted sol-gel method. The synthesized materials were characterized by X-ray diffraction, UV-vis diffuse reflectance, photoluminescence (PL) spectroscopy, SEM, TEM, FT-IR, Raman spectroscopy, photocurrent measurement technique, and nitrogen adsorption–desorption isotherms. Raman spectra and XRD showed an anatase phase structure. The SEM and TEM images revealed the formation of an almost spheroid mono disperse TiO2 with particle sizes in the range of 9-17 nm. Analysis of N2 isotherm measurements showed that all investigated TiO2 samples have mesoporous structures with high surface areas. The optical absorption edge for the doped TiO2 was significantly shifted to the visible light region. The photocurrent and photocatalytic activity of pure and doped TiO2 were evaluated with the degradation of methyl orange (MO) and methylene blue (MB) solution under both UV and visible light illumination. The doped TiO2 nanoparticles exhibit higher catalytic activity under each of visible light and UV irradiation in contrast to pure TiO2. The photocatalytic activity and photocurrent ability of TiO2 have been enhanced by doping of the titania in the following order: (Cu, N) - codoped TiO2 > N-doped TiO2 > Cu-doped TiO2 > TiO2. COD result for (Cu, N)-codoped TiO2 reveals ∼92% mineralization of the MO dye on six h of visible light irradiation.

  • Surfactant assisted hydrothermal synthesis of SnO nanoparticles with enhanced photocatalytic activity
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-02-28
    Bircan Haspulat; Muhammet Sarıbel; Handan Kamış

    SnO nanoparticles have been successfully synthesized in the presence of Triton-X 100 (TX-100) surfactant via hydrothermal method for the first time, and the photocatalytic activity under UV and visible light irradiation for the degradation of Methylene Blue (MB) and Rhodamine B (RdB) organic textile dyes was investigated. The structural, morphological and chemical characterizations were investigated by using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), selected area electron diffraction (SAED), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR), UV–vis. diffuse reflectance spectroscopy (UV–vis DRS) and photoluminescence (PL) analysis. The results reveal that the addition of surfactant, TX-100, in the precursor solutions leads to reduction in crystallite size with significant changes in morphological structure of SnO nanoparticles. The synthesized SnO nanoparticles show excellent photocatalytic activity under UV or visible light irradiation. MB and RdB dyes degraded completely under UV irradiation after 90 and 150 min, respectively. Also, MB and RdB dyes degraded only 150 min later under visible light illumination with a little amount of photocatalyst (0.8 g/L). Hence, this work explores the facile route to synthesizing efficient SnO nanoparticles for degrading organic compound under both UV and visible light irradiations.

  • Carbon nanotubes modified with 5,7-dinitro-8-quinolinol as potentially applicable tool for efficient removal of industrial wastewater pollutants
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-02-28
    E.T. Abdel Salam; K.M. Abou El-Nour; A.A. Awad; A.S. Orabi

    The environmental pollution due to the industrial wastewater of four different areas in the Gulf of Suez, Red Sea, Egypt, was studied. Adsorption capacities toward the concerned heavy metal ions Cu(II), Zn(II), Fe(II), and Pb(II) by multiwalled carbon nanotubes (MWCNTs) and modified-MWCNTs with 5,7-dinitro-8-quinolinol were investigated. MWCNTs as well as the modified-MWCNTs were characterized using Fourier transform infrared (FTIR), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). Adsorption of the studied divalent metal ions was measured by atomic absorption spectrometry (AAS). The effects of solution conditions such as pH, shaking time, metal ion concentration, ionic strength and adsorbent dosage on the adsorption process were also examined. The obtained results showed that removals of the heavy metal ions under consideration by MWCNTs are obviously dependent on the experimental conditions. The maximum adsorption capacities as calculated applying Langmuir equation to single ion adsorption isotherms were found to be 142.8 mg/g for Cu(II), 250 mg/g for Zn(II), 111.1 mg/g for Fe(II), and 200 mg/g for Pb(II) using MWCNTs; meanwhile, the modified-MWCNTs exhibited higher values of the respective maximum adsorption capacities as 333.3 mg/g for Cu(II), 500 mg/g for Zn(II), 200 mg/g for Fe(II), and 333.3 mg/g for Pb(II). Kinetic studies were also performed and the experimental data followed a pseudo-second order model of the adsorption process. The obtained results suggest that the tested adsorption systems of MWCNTs and modified-MWCNTs have suitable affinity toward the metal ion under consideration. Both systems could act as potentially applicable tool in environmental protection.

  • Hypervalent iodine(III) catalyzed rapid and efficient access to benzimidazoles, benzothiazoles and quinoxalines: Biological evaluation of some new benzimidazole-imidazo[1,2-a]pyridine conjugates
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-03-08
    P.V. Sri Ramya; Srinivas Angapelly; Routhu Sunitha Rani; Chander Singh Digwal; C. Ganesh Kumar; Bathini Nagendra Babu; Lalita Guntuku; Ahmed Kamal
  • Effective scrap iron particles (SIP) pre-treatment for complete mineralization of benzidine based azo dye effluent
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-03-14
    Raja Kumar; Alok Sinha; Gautam C. Mondal; Reginald E. Masto

    This study proposed that hybrid scrap cast iron particles (SIP)-aerobic biodegradation technology could enhance the biodegradability of toxic wastewater. SIP cleaved the azo linkages of Direct Green1 dye to form benzidine, 4-aminophenol, aniline and 1,2,7-triamino-8-hydroxynapthalene-3,6-disulfonic acid. SIP-mediated dye reduction was effective at wide pH range; however, kinetic analysis revealed fastest pseudo-first order dye reduction rate at acidic pH 3 (kd = 0.549 min−1) followed by pH 9 (kd = 0.383 min−1) and pH 7 (kd = 0.318 min−1). The daughter aromatic amines produced were partially adsorbed onto the SIP surface and maximally at neutral pH. The adsorption process followed pseudo-second order adsorption kinetics and Langmuir isotherm. Benzidine was adsorbed more than 4-aminophenol and aniline. BOD5 of the SIP-treated effluent increased from 0.93 to 12 mg/L showing improved biodegradability. The daughter amines were rapidly mineralized in the aerobic bioreactor within 6 h. Cost-effective SIP pre-treatment could accelerate mineralization and detoxification of recalcitrant wastewater.

  • Optical, piezoelectric and mechanical properties of xylenol orange doped ADP single crystals for NLO applications
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-03-18
    Sahil Goel; Nidhi Sinha; Harsh Yadav; Abhilash J. Joseph; Abid Hussain; Binay Kumar

    Single crystals of pure and xylenol orange (XO; C31H32N2O13S) dye doped (0.01, 0.05 and 0.1 mol%) ammonium dihydrogen phosphate (ADP; NH4H2PO4) were grown by slow evaporation method with the vision to improve the properties of pure ammonium dihydrogen phosphate crystal. The theoretical morphology of the grown crystals was drawn using Bravais–Friedel–Donnay–Harker (BFDH) law. The selective nature of xylenol orange dye to selectively stain the particular growth sectors of ADP crystal was studied. The structural analysis of as grown crystals was carried out using powder XRD study. The identification of the functional groups present in the ADP material was done using Fourier transform infrared (FTIR) spectroscopy. The linear optical study on pure and dye doped crystals was carried out using UV–vis–NIR spectroscopy. The optical band gap, extinction coefficient, refractive index and optical conductivity were calculated using the transmittance spectra for all the samples. In photoluminescence studies, the blue emission intensity got quenched and an orange emission at 597 nm was seen as a result of XO doping. The thermal stability and decomposition temperature of ADP crystal were found to decrease as an effect of dye doping. The piezoelectric charge coefficient, SHG conversion efficiency, mechanical strength and wettability were also enhanced as a result of XO dye doping.

  • Biosynthesized CuO nano-platelets: Physical properties & enhanced thermal conductivity nanofluidics
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-03-22
    B.T. Sone; A. Diallo; X.G. Fuku; A. Gurib-Fakim; M. Maaza
  • New CaO-based adsorbents prepared by solution combustion and high-energy ball-milling processes for CO2 adsorption: Textural and structural influences
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-03-21
    Abel Granados-Pichardo; Francisco Granados-Correa; Víctor Sánchez-Mendieta; Héctor Hernández-Mendoza
  • Effect and mechanism of wedelolactone as antioxidant-coumestan on OH-treated mesenchymal stem cells
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-03-27
    Xican Li; Tingting Wang; Jingjing Liu; Yulong Liu; Jun Zhang; Jian Lin; Zhongxiang Zhao; Dongfeng Chen
  • Mussel-mimicking sulfobetaine-based copolymer with metal tunable gelation, self-healing and antibacterial capability
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-03-24
    Miroslav Mrlík; Mário Špírek; Jassim Al-Khori; Ali Abdulrahman Ahmad; Jaroslav Mosnaček; Mariam AlAli AlMaadeed; Peter Kasák
  • Physicochemical properties, antioxidant action and practical application in fresh cheese of the solid inclusion compound γ-cyclodextrin·quercetin, in comparison with β-cyclodextrin·quercetin
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-04-09
    Ana Bárbara Pereira; Aida Moreira da Silva; Maria João Barroca; Maria Paula M. Marques; Susana Santos Braga

    Quercetin is an antioxidant flavonol very sensible to light and oxidants that can benefit from stabilisation by encapsulation into cyclodextrins. In this work we study the solid inclusion compounds of quercetin with β- and γ-cyclodextrins (β-CD and γ-CD) obtained by freeze-drying. Combined results from microanalysis, FT-IR, powder X-ray diffraction, 13C{1H} CP/MAS NMR spectroscopy and thermogravimetry demonstrating that γ-CD, having a larger cavity, is the most adequate host to form a stable inclusion complex with quercetin. The anti-peroxidation capacity of the compounds was determined and followed the order β-CD·quercetin ≫ quercetin > γ-CD·quercetin. Both γ-CD·quercetin and β-CD·quercetin are able to inhibit DPPH radicals at a rate three times faster than pure quercetin, but their EC50 is higher (50 μM vs 17 μM for quercetin). The practical applicability of the two CD·quercetin adducts as nutraceutical additives in fresh cheese was established. Fortified fresh cheese had a firmer texture and yellowish colour, but no significant changes in the overall sensorial qualities were found by a panel of non-trained tasters when compared with the control (non-treated fresh cheese).

  • A helpful method for controlled synthesis of monodisperse gold nanoparticles through response surface modeling
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-04-27
    Jairo P. Oliveira; Adilson R. Prado; Wanderson Juvêncio Keijok; Moisés R.N. Ribeiro; Maria J. Pontes; Breno V. Nogueira; Marco C.C. Guimarães
  • Core-shell zirconia-coated magnetic nanoparticles offering a strong option to prepare a novel and magnetized heteropolyacid based heterogeneous nanocatalyst for three- and four-component reactions
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-04-10
    Somayeh Zolfagharinia; Eskandar Kolvari; Nadiya Koukabi; Maliheh M. Hosseini

    A new type of magnetically-separable nanocatalyst was prepared through the immobilization of phosphomolybdic acid (H3PMo12O40) in 10–30 wt.% on the surface of core-shell zirconia-coated magnetite nanoparticle (nano-Fe3O4@ZrO2). The developed heterogeneous nano-sized acid catalyst named nano-Fe3O4@ZrO2 supported PMA (or n-Fe3O4@ZrO2/PMA) was characterized using several techniques such as FT-IR, XRD, FE-SEM, VSM, EDX, TEM and TGA. The characterization data derived from FT-IR spectroscopy exhibited that H3PMo12O40 species on the support retained their Keggin structures. Additionally, the potentiometric titration with n-butylamine was employed to measure the acidity content of the as-obtained catalyst. Surprisingly, this novel active solid acid catalyst displayed to have a higher number of surface active sites compared to its homogeneous analogues. Besides, the catalytic activity of the catalyst was evaluated in multicomponent reactions (MRCs) for the rapid and efficient one-pot synthesis of 2, 4, 5-trisubstituted and 1, 2, 4, 5-tetrasubstituted imidazoles in high yields and selectivity. The sample of 20 wt.% displayed higher acidity content which led to its enhanced activity in the catalytic transformation. Moreover, the catalyst could be easily reused without deactivation after five runs, which made it a promising catalyst for practical and large-scale applications. This outstanding reusability was ascribed to the strong attachment of PMA molecules on the n-Fe3O4@ZrO2 support material.

  • Assembly of succinic acid and isoxazolidine motifs in a single entity to mitigate CO2 corrosion of mild steel in saline media
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-04-10
    Shaikh A. Ali; Mohammad A.J. Mazumder; Mazen K. Nazal; Hasan A. Al-Muallem
  • Removal of ionic liquids and ibuprofen by adsorption on a microporous activated carbon: Kinetics, isotherms, and pore sites
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-04-09
    Hanen Guedidi; Imadeddine Lakehal; Laurence Reinert; Jean-Marc Lévêque; Nizar Bellakhal; Laurent Duclaux

    Ionic liquids (ILs) are considered as emergent pollutants as their synthesis and further use at a large scale might generate environmental problems. The adsorption on activated carbons represents one of the most effective methods to remove ionic liquids and other micropollutants from wastewater. In this work, the adsorption properties on an activated carbon cloth of two pyridinium ionic liquids (4-tert-butyl-1-propylpyridinium bromide (IL1) and 4-tert-butyl-1-(2-carboxyethyl)pyridinium bromide (IL2)) newly synthesized, were compared with the ones of ibuprofen. The adsorption kinetics and isotherms were studied at pH 3 and 7.5. The adsorption thermodynamic parameters calculated from the isotherms indicate an exothermic process, typical of physisorption. The adsorption kinetics of a mixture of the molecules show a competition between ibuprofen and IL2. The location of each adsorbed ionic liquid and ibuprofen into the porosity of the activated carbon cloth was determined from N2 (at 77 K) and CO2 adsorption isotherms (at 273 K). The purification process of an effluent containing the ionic liquids and the ibuprofen in mixture or in single solute could be workable by adsorption on an activated cloth.

  • Preparation of mesoporous alumina electro-generated by electrocoagulation in NaCl electrolyte and application in fluoride removal with consistent regenerations
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-05-05
    A. Oulebsir; T. Chaabane; S. Zaidi; K. Omine; V. Alonzo; A. Darchen; T.A.M. Msagati; V. Sivasankar
  • Magnetically recoverable γ-Fe2O3 nanoparticles as a highly active catalyst for Friedel–Crafts benzoylation reaction under ultrasound irradiation
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-04-13
    Phuong Hoang Tran; Thuy-Duy Thi Nguyen; Tram-Anh Thi Tu; Thach Ngoc Le

    A simple, facile and efficient method has been developed for the Friedel–Crafts benzoylation of arenes using magnetic γ-Fe2O3 nanoparticles under solvent-free sonication. The γ-Fe2O3 nanoparticles were used as an efficient and magnetically recoverable catalyst for the synthesis of aromatic ketones in good to excellent yields at room temperature under solvent-free. The reaction occurred with high regioselectivity under mild condition. The magnetic γ-Fe2O3 nanoparticles are economically synthesized in large-scale, easily separated from the reaction mixture by an external magnet and able to be reused several times without significant loss of the catalytic performance, which make them easy application to industrial processes.

  • Evaluation of synthesized green carbon catalyst from waste date pits for tertiary butylation of phenol
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-04-18
    Farrukh Jamil; Ala'a H. Al-Muhtaseb; Mu Naushad; Mahad Baawain; Abdullah Al-Mamun; Sandeep K. Saxena; N. Viswanadham

    The present study is intended to adopt a facile method for preparing a sulphonated green carbon catalyst from date pits biomass. Catalyst synthesis involves in situ carbonization and sulphonation and it has been characterized by following techniques such as XRD, SEM, EDX, TEM, FTIR, TGA, and BET. Surface and internal morphology results exhibited that the synthesized sulphonated carbon material possesses a mesoporous structure, while activated carbon possesses a microporous structure. Furthermore, the Fourier transform infrared (FTIR) spectra confirmed the presence of acidic groups (OH, COOH, and SO3H) in synthesized sulphonated carbon material. Sulphonated carbon material exhibited high acidity (4.7 mmol/g) and good thermal stability. The application of this catalyst for the tertiary butylation of phenol without using any solvent has been investigated. The phenol alkylation reaction showed maximum conversion at reaction condition: temperature (140 °C) with 2 bar (nitrogen gas) pressure with maximum phenol conversion 79.27 wt%, with 68.01% selectivity towards 4TBP+2,4TBP, which is used as an intermediate in antioxidants. The catalyst exhibits comparable catalytic performance up to five reaction cycles. Thus it can be concluded that waste date pits can be successfully employed for green catalyst synthesis and used for reactions involving large molecules.

  • Accumulation of selected metals in the fruits of medicinal plants grown in urban environment of Islamabad, Pakistan
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-04-18
    Riffat Parveen; Arshad M. Abbasi; Nazia Shaheen; Munir H. Shah

    The present study is based on the measurement of selected metals (Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Pb, Sr and Zn) in the fruits of eight medicinal plants (Carrisa opeca, Phyllanthus emblica, Solanum nigrum, Zizyphus nummularia, Zizyphus mauritiana, Physalis minima, Opuntia dillenii and Phoenix dactylifera) and relevant soil samples by atomic absorption spectrometry. Highest average concentrations of Cu (14.4 mg/kg), Cr (19.0 mg/kg), and Zn (125 mg/kg) were found in the fruits of P. minima, C. opeca and Z. nummularia, respectively, while O. dillenii showed the elevated mean levels of Cd (3.49 mg/kg), Sr (61.4 mg/kg), Mg (0.21%), Ca (6.62%) and Mn (44.6 mg/kg). However, highest average levels of Pb (41.7 mg/kg) and Co (38.4 mg/kg) were found in Z. mauritiana. Overall, most of the fruit samples showed higher contributions of Ca and Mg, followed by Fe, Zn, Co and Pb. In the case of soil samples, highest concentration was observed for Ca, followed by Fe, Mg, Mn and Sr, while lowest concentration was shown by Cd. Bioaccumulation factors exhibited significantly higher accumulation of Co (0.813–1.829) and Pb (0.060–2.350) from the soil to the fruits. Principal component analysis revealed significant anthropogenic contributions of Pb, Fe and Co in the fruit samples. Contamination factors and enrichment factors of Cd and Pb in the soil indicated very high contamination and extreme enrichment of these metals.

  • A facile synthesis of clay – graphene oxide nanocomposite catalysts for solvent free multicomponent Biginelli reaction
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-04-26
    Divya P. Narayanan; Anila Gopalakrishnan; Zahira Yaakob; Sankaran Sugunan; Binitha N. Narayanan
  • Flow injection analysis system with electrochemical detection for the simultaneous determination of nanomolar levels of acetaminophen and codeine
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-04-26
    Anderson Martin Santos; Tiago Almeida Silva; Fernando Campanhã Vicentini; Orlando Fatibello-Filho
  • A study on solution deposited CuSCN thin films: Structural, electrochemical, optical properties
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-04-27
    Blessing N. Ezealigo; Assumpta C. Nwanya; Aline Simo; R. Bucher; Rose U. Osuji; Malik Maaza; M.V. Reddy; Fabian I. Ezema

    A cost-effective successive ionic layer adsorption and reaction (SILAR) method was used to deposit copper (I) thiocyanate (CuSCN) thin films on glass and steel substrates for this study. The deposited thin films were characterized for their structural, morphological, optical and electrochemical properties using X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–visible spectroscopy and VersaSTAT potentiostat. A direct band gap of 3.88 eV and 3.6 eV with film thickness of 0.7 μm and 0.9 μm was obtained at 20 and 30 deposition cycles respectively. The band gap, microstrain, dislocation density and crystal size were observed to be thickness dependent. The specific capacitance of the CuSCN thin film electrode at 20 mV/s was 760 F g−1 for deposition 20 cycles and 729 F g−1 for deposition 30 cycles.

  • Electrochemical oxidation of vanillic acid by electro-Fenton process: Toward a novel route of protocatechuic acid electrosynthesis
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-05-17
    Raouia Rekik; Morched Hamza; Mohamed Jaziri; Ridha Abdelhedi

    The electrochemical oxidation of vanillic acid (VA) in acetone–water mixtures, was studied by electro-Fenton (EF) process in an undivided electro-chemical cell equipped with a carbon fiber cloth as cathode and Pt anode. The objective was the conversion of VA into protocatechuic acid (PCA) well known by its high added value. To our knowledge, the EF method was not used in organic electrosynthesis. The influence of several operating parameters, such as applied current, initial VA concentration and volumic percentage of acetone was investigated. The evolution of the concentrations of VA and its main oxidation product PCA during electrolyses was monitored by means of high performance liquid chromatography (HPLC). The experimental data indicated that the kinetics of VA disappearance follow a pseudo first and zero orders for initial VA concentrations respectively equals to 6.5 and (10, 20, 30) mmol L−1. The maximum PCA concentration increases with volumic percentage of acetone and initial VA concentration. Under optimal experimental conditions of applied current (20 mA) and volumetric percentage of acetone (20%), the increase in the initial VA concentration leads to a linear increase in the maximum of PCA concentration. The very good selectivity rate of the oxidation of VA to PCA by the EF process, was interpreted by the stabilizing effects of acetone and especially the complexation of PCA by the iron ions.

  • Optimization and modeling of synthesis parameters of neodymium(III) bromide by dry method using full factorial design analysis
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-05-18
    Yassine Bounouri; Madjid Berkani; Abdelmalek Zamouche; Leszek Rycerz

    The synthesis of neodymium(III) bromide (NdBr3) by sintering brominating of neodymium oxide (Nd2O3) with ammonium bromide (NH4Br) was investigated. The influence of various synthesis parameters (temperature, contact time and stoichiometry) on the reaction yield was studied and optimized. The main interaction effects of the synthesis parameters on the reaction yield were also determined by a full 23 factorial designs with six replicates at the center point. This study showed that the optimum conditions for the synthesis of NdBr3 are following: contact time t = 60 min, stoichiometry in moles Nd2O3:NH4Br = 1:24 and temperature T = 400 °C. The reaction yield for these parameters was equal to 97.80%. The first order model was obtained to predict the reaction yield as a function of these three parameters. It was shown that all parameters have a significant positive influence on reaction yield. In addition it was pointed out also that the interaction effects between them are significant.

  • Diazenyl schiff bases: Synthesis, spectral analysis, antimicrobial studies and cytotoxic activity on human colorectal carcinoma cell line (HCT-116)
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-05-17
    Harmeet Kaur; Siong Meng Lim; Kalavathy Ramasamy; Mani Vasudevan; Syed Adnan Ali Shah; Balasubramanian Narasimhan
  • Controlled drug release behavior of metformin hydrogen chloride from biodegradable films based on chitosan/poly(ethylene glycol) methyl ether blend
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-05-17
    M. Sohail Sarwar; Abdul Ghaffar; Atif Islam; Farhat Yasmin; Zehra Oluz; Eylül Tuncel; Hatice Duran; Asif Ali Qaiser
  • Impact of ionic liquids on silver thermoplastic polyurethane composite membranes for propane/propylene separation
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-05-17
    Yu Wang; Tee Yong Goh; Peter Goodrich; Mert Atilhan; Majeda Khraisheh; David Rooney; Jillian Thompson; Johan Jacquemin

    This work describes newly synthesized composite polymeric membranes and their utilization in propane/propylene separation in a gas mixture. The nonporous composite polymers were successfully synthesized by using thermoplastic polyurethane (TPU) and several silver salts/silver salts with ionic liquids (ILs). Our studies showed that silver bis(trifluoromethanesulfonyl)imide (Ag[Tf2N]) containing membranes outperformed other silver salt containing membranes in terms of selectivity. In addition, to this finding, ILs, as additives for the membranes, enhanced the selectivity by facilitating improved coordination of the olefin with the silver ions in the dense composite polymers.

  • HPLC-ICP-MS speciation of selenium in Se-cultivated Flammulina velutipes
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-05-22
    Mei Tie; Baorui Li; Tiebiao Sun; Wei Guan; Yanqiu Liang; Huawei Li

    Selenium is an essential micronutrient required at trace levels for human health, and dietary intake is the only source of selenium, which appears mainly in the form of selenocompounds. In this study, Flammulina velutipes was grown for 80 days in standard medium containing selenite, and the level of total selenium in the organism was then determined by inductively-coupled plasma mass spectrometry (ICP-MS). In Se-cultivated F. velutipes, selenium was mainly distributed in the water-soluble form and the content of soluble selenium-containing species in Se-cultivated F. velutipes was 47.10 mg kg−1, accounted for 72.5% of the total selenium content. The water-soluble proteins in F. velutipes were extracted and precipitated by different ammonium sulfate saturation concentrations. Size-exclusion high performance liquid chromatography (SEC-HPLC) analysis of these proteins revealed the presence of at least six selenium-containing protein species, with molecular weights ranging from 9000 to 74,000 Da, Selenium-containing proteins represented about 7.0% of the total soluble selenium. The result of this study suggested that Se-cultivated F. velutipes could potentially be considered as a selenium supplement for human.

  • Interaction of cholesterol with artificial bilayer lipid membrane system and development of an electrochemical sensor
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-05-26
    M. Alagappan; A. Kandaswamy; M. Kumaravel; S. Rameshkumar

    Interaction of Cholesterol with the bilayer arrangement of phospholipid molecules was studied using electrochemical impedance spectroscopy in Sodium Chloride (NaCl) bath solutions. The membrane resistance (Rm) was decreased from 3.35 GΩ in 1.0 M NaCl bath to 0.756 GΩ in 0.01 M NaCl bath. The cholesterol molecules were found to penetrate into Bilayer Lipid Membrane (BLM) and fluidized the BLM phase. Due to fluidization, the membrane resistance was decreased. The fluidization effect of cholesterol was dependent on the concentration of bath solutions. In 1.0 M NaCl bath solution, the membrane was stable up to 200 µM concentration of cholesterol. With the addition of cholesterol in NaCl bath solutions, the membrane capacitance was increased. An impedimetric sensor was developed based on the membrane resistance in the presence of cholesterol at various concentrations. The detection limit of cholesterol by impedimetric sensor was dependent on the concentration of NaCl in the bath.

  • Effect of synthesis pH on the physicochemical properties of a synthesized Bi2WO6 and the type of substrate chosen, in assessing its photo-catalytic activities
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-05-26
    C. Jaramillo-Páez; J.A. Navío; M.C. Hidalgo

    Crystalline orthorhombic Bi2WO6 powders were synthesized by a hydrothermal method from aqueous solutions of Bi(NO3)3·5H2O and Na2WO4·2H2O over a range of three selected pH values (2.0, 5.0 and 7.0), using NaOH as precipitating agent. The as-prepared catalysts were characterized by XRD, BET, FE-SEM, TEM, XPS and UV-vis spectroscopy. The effect of pH-synthesis on crystallinity, morphologies, surface area and optical absorption properties, were investigated. Although the pH has a marked influence on morphology, the nature of the precipitating agent (NaOH or TEA) also influences the morphology and surface structure composition, as it is observed in the present work. Three different probe molecules were used to evaluate the photo-catalytic properties under two illumination conditions (UV and Visible): Methyl Orange and Rhodamine B were chosen as dye substrates and Phenol as a transparent substrate. The photo-catalytic activities are strongly dependent not only on the pH used in the synthesis but also on the nature of the chosen substrate in assessing the photo-catalytic activities. Results were compared with those obtained when using TiO2(P25, Evonik) in the same experimental conditions. The photo-catalytic activity of one of the synthesised samples has been evaluated by exposing a mixture of Rhodamine B and Phenol in water, to different illumination conditions. Our results provide new evidences about the issue of whether dyes are suitable substrates to assess the activity of a photo-catalyst.

  • Organic analytes sensitivity in meso-porous silicon electrical sensor with front side and backside contacts
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-05-26
    Farid A. Harraz; Adel A. Ismail; M. Faisal; S.A. Al-Sayari; A. Al-Hajry; M.S. Al-Assiri

    Chemical sensors fabricated from porous silicon (PSi) for liquid organic analytes (ethanol, acetonitrile, methanol and acetone) are demonstrated, with an emphasis on the impact of the Ag electrical contact placement on sensor performance. Sensors with front side contact display larger shift in capacitance response (2–3 times more sensitive) compared to the backside sensor design as the solvents immediately interact with the pore openings before infiltration. Much slower response time (7–30 min range) for front side vs. (50–200 s scale range) for backside configuration is observed. Both sensor designs exhibit excellent solvent infiltration-evaporation reversible response, indicating no chemical reaction or surface modification occurred. The response time was in the order of ethanol > acetonitrile > methanol > acetone, which correlates well with the solvent vapor pressure. The capacitance shift in both sensor devices is likely related to the interface interaction, revealing a closer correlation with the dipole moments of solvents. This is supported by the photoluminescence quenching upon exposure to organic solvents, with a relative intensity decrease tracks with the dipole moment. The sensitivity remains sufficiently high during the repeated use, with excellent storage stability for backside contact. This comparative study suggests the viability of the current sensor structure and design particularly with backside contact for sensing of various chemical analytes with notably sensitivity and extremely rapid response.

  • Alkyl-malonate-substituted thiacalix[4]arenes as ligands for bottom-up design of paramagnetic Gd(III)-containing colloids with low cytotoxicity
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-05-26
    Alexey Stepanov; Irek Nizameev; Rustem Amirov; Sofia Kleshnina; Gulshat Khakimullina; Svetlana Solovieva; Alexandra Voloshina; Anastasya Strobykina; Aidar Gubaidullin; Ramil Nugmanov; Asiya Mustafina

    The present work introduces thiacalix[4]arene adopting 1,3-alternate conformation with alkyl-malonate terminal substituents as ligands for Gd(III) ions. pH-dependent complex formation of Gd(III) ions via alkyl-malonate substituents in aqueous DMSO solutions results in a precipitation. The precipitated complexes were converted into hydrophilic colloids of “plum-pudding” morphology, where the Gd(III) complexes form hard small (1.5–4 nm) cores included into larger (about 180 nm) soft PSS shells. The precipitate-to-colloid transformation is facilitated by polystyrolsulfonate (PSS) for Gd(III) complexes with thiacalix[4]arene bearing propyl-malonate groups, while the presence of PSS triggers a dissolution of the precipitated complexes for thiacalix[4]arenes with pentyl-malonate substituents. To a lesser extent the similar tendency disturbs the formation of PSS-stabilized colloids on the basis of butyl-malonate substituted thiacalix[4]arene. The PSS-stabilized colloids exhibit high longitudinal and transverse relaxivities (r1 = 23.8 and r2 = 29.4 mM−1 s−1 at 0.47 T, respectively), while the recoating of the PSS-stabilized colloids with polyethyleneimine is accompanied by the dissolution of the hard cores. High relaxivity along with low cytotoxicity of PSS-stabilized colloids indicates their applicability as contrast agents in MRI.

  • Ditopic dithiocarbamate ligands for the production of trinuclear species
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-05-26
    Edgar Marín-Carrillo; Adrián Ruíz-Martínez; Hugo Valdés; Reyna Reyes-Martínez; Simón Hernández-Ortega; Bethsy Adriana Aguilar-Castillo; David Morales-Morales
  • Luminescence properties of yttrium gadolinium orthovanadate nanophosphors and efficient energy transfer from VO43− to Sm3+ via Gd3+ ions
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-05-26
    Vishnu V. Jaiswal; Swati Bishnoi; G. Swati; Paramjeet Singh; Naina Lohia; Sivaiah Bathula; D. Haranath

    In this paper, luminescence properties of orthovanadates, Y1−x−yGdxVO4:ySm3+ (where x = 0.05–0.50, y = 0.01–0.05), and the energy transfer mechanism from VO43− to Sm3+ via Gd3+ ions were investigated in detail. X-ray diffraction (XRD) analysis confirmed the crystalline phase for synthesized nanophosphor in a tetragonal structure with I41/amd space group. The average crystallite size estimated from XRD was ∼28 nm. Field-emission scanning electron microscopy coupled with energy dispersive X-ray analysis revealed oval shaped morphology and composition of the nanophosphor, respectively. From high-resolution transmission electron microscopy observations, the particle sizes were found to be in the range 10–80 nm. The photoluminescence studies of Y0.77Gd0.20VO4:0.03Sm3+ nanophosphor under 311 nm excitation exhibits dominant emission peak at 598 nm corresponding to 4G5/2 → 6H7/2 transition. The energy transfer occurs from VO43− to Sm3+ via Gd3+ ions was confirmed by applying Dexter and Reisfeld’s theory and Inokuti-Hirayama model. Moreover, the energy transfer efficiencies and probabilities were calculated from the decay curves. Furthermore, Commission Internationale de l’Eclairage (CIE) color coordinate (0.59, 0.37) has been observed to be in the orange-red (598 nm) region for Y0.77Gd0.20VO4:0.03Sm3+ nanophosphor. These results perfectly established the suitability of these nanophosphors in improving the efficiency of silicon solar cells, light emitting diodes, semiconductor photophysics, and nanodevices.

  • Review of corrosive environments for copper and its corrosion inhibitors
    Arab. J. Chem. (IF 3.298) Pub Date : 2017-06-08
    A. Fateh; M. Aliofkhazraei; A.R. Rezvanian

    This review paper deals with corrosion of copper and its alloys in corrosive environments and their corrosion inhibitors. The main corrosion inhibitor groups for copper are introduced and a review of adsorption models is provided. The main part of this work is to investigate different corrosive environments for copper and its alloys and their corrosion inhibitors used in such environments to protect copper. According to the literature, the corrosion inhibition behavior of organic corrosion inhibitors and their derivatives in comparison with inorganic ones are further evaluated. Knowing maximum corrosion inhibition efficiency of a specific corrosion inhibitor in a specific corrosive environment is helpful to choose the most appropriate corrosion inhibitor compound.

  • 更新日期:2019-12-31
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