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  • Selective Reduction of NO3--N from Wastewater to N2 by Zn/Ag Bimetallic Particles Combined with Wet Ammonia Oxidation Process
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2018-01-17
    Lu Fan, Shixiang Wang, Yanlan Liu, Wenjing Yang, Xianyu Hou, Ying Su, Yi Zhao, Xuan Zhou, Qian Chen, Yong Liu
    更新日期:2018-01-17
  • Efficiency evaluation of arsenic(III) adsorption of novel graphene oxide@iron-aluminium oxide composite for the contaminated water purification
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2018-01-16
    Sweta Maji, Ayan Ghosh, Kaushik Gupta, Abir Ghosh, Uttam Ghorai, Angshuman Santra, Palani Sasikumar, Uday Chand Ghosh

    Prolong consumption of arsenic-rich drinking water causes serious health problem. Aiming to minimize the problem, it is attempted to develop cheap and advanced materials for arsenic extraction from the contaminated water. Thus, multifunctional graphene oxide (GO)-incorporated iron-aluminium mixed oxide (GIAMO) composite has been prepared with five different GO content, and evaluated by batch method for the arsenic(III) removal efficiency. Among the as-prepared GIAMO samples, three samples consisting 1.0, 2.0 and 3.0 g of GO show equally good (92 – 95%) arsenic(III) removal efficiency, which is 30-35% higher than pristine iron-aluminium oxide (IAMO) from an aqueous solution (5.0 mg AsIII.L-1) at pH 7.0 (± 0.2) and 303 K. Thus, 1.0 g GO-inserted GIAMO (GIAMO-1) sample was characterized as microcrystalline (10-15 nm) with BET surface area about 1.45 times higher than IAMO and investigated for the arsenic(III) adsorption. Optimized pH for arsenic(III) adsorption is 6.0-8.0. The kinetic data agree more closely with pseudo-first order equation (R2 = 0.98-0.99) than pseudo-second order equation (R2 = 0.92-0.93). The equilibrium data describe the Langmuir isotherm (R2 = 0.97-0.98) better than the Freundlich isotherm (R2 = 0.91-0.92), showing the Langmuir monolayer capacity 42.2836 mg. g-1 at 293 K which drops to 24.9170 mg. g-1 at 313K. High negative enthalpy change (ΔH° ∼ -224 kJ. mol-1) is responsible for the spontaneous reaction (ΔG0 = negative) despite unfavorable entropy change (ΔS° = -0.71 kJ. mol-1). The order of competitive effect of PO43-, SO42- and HCO3- on arsenic(III) removal efficiency is PO43->SO42->HCO3-. However, the high HCO3- (> 200 mg. L-1) enhances the arsenic(III) removal efficiency of this material. 2.0M NaOH can regenerate arsenic adsorbed GIAMO-1 only up to 50-60%. 0.65 g. of composite per L of high arsenic (Astotal: 0.115 mg L-1) groundwater can upgrade to potable standard, encouraging possible safe use for high arsenic water treatment. Highly negative enthalpy change, poor regeneration, FTIR, XRD and CV analyses of arsenic-rich solid suggested that arsenic(III) is stabilized over the solid surface without oxidation by surface complex formation.

    更新日期:2018-01-17
  • Effect of spacer configuration on hydraulic conditions using PIV
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2018-01-11
    A.H. Haidari, S.G.J. Heijman, W.G.J. van der Meer

    Making improvements to feed spacers of spiral-wound membrane (SWM) modules of reverse osmosis (RO) is a necessary step towards a wider application of these modules. This study sets out to evaluate the performance of six commercial feed spacers by comparing their actual velocity profiles and their pressure drop. Velocity profiles are obtained from Particle Image Velocimetry (PIV). Comparing images from PIV with corresponding friction losses revealed that the transition from steady to unsteady flow occurs at the moment when the incline of the friction factor changes from steep to slight. From the two types of spacers used, zigzag spacers showed a better distribution of flow than the cavity spacers did, but at the cost of higher pressure drop. The flow was in a straight line from inlet to outlet with zigzag spacers only at low Reynolds numbers and with cavity spacers for the entire studied range of Reynolds numbers. Additionally, results showed that hydraulic conditions in channels with cavity spacers are mainly affected by geometric characteristics of transverse filaments. The results from this study can be used to understand the effects of spacer geometry on the hydraulic conditions inside the feed channel and as a validation tool for computational modeling.

    更新日期:2018-01-12
  • 更新日期:2018-01-12
  • Recovery of Levulinic acid by Reactive Extraction using Tri-n-octylamine in Methyl isobutyl ketone: Equilibrium and Thermodynamic Studies and Optimization using Taguchi Multivariate approach
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2018-01-11
    Sumalatha Eda, Anoosha Borra, Rajarathinam Parthasarathy, Satyavathi Bankupalli, Suresh Bhargava, Prathap Kumar Thella
    更新日期:2018-01-12
  • Experimental benchmark data of CH4, CO2 and N2 binary and ternary mixtures adsorption on MOF-5
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2018-01-09
    F.A Kloutse, A. Hourri, S. Natarajan, P. Benard, R. Chahine

    We present benchmark adsorption data of CH4, CO2 and N2 binary and ternary mixtures on MOF-5 at 297 K and pressures up to 1500 kPa obtained via the isotope exchange technique (IET) and a predictive volumetric method. The ternary mixtures data are organized in two different domains: constant composition and constant pressure planes. The constant composition data show quasi-constant selectivity in the entire pressure range. The constant pressure data showed the existence of azeotrope-like crossover for CH4 along the N2 and CO2 paths. However, these crossovers do not correspond to a reversal in the adsorbent’s affinity for CH4. The obtained experimental data is in accord with ideal adsorption solution theory (IAST).

    更新日期:2018-01-10
  • Solvent extraction of zinc from synthetic Zn-Cd-Mn chloride solution using D2EHPA: Optimization and thermodynamic studies
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2018-01-09
    Hossein Jafari, Hadi Abdollahi, Mahdi Gharabaghi, Ali Asghar Balesini
    更新日期:2018-01-10
  • Bio-regeneration of Activated Carbon: A Comprehensive Review
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2018-01-09
    Maisa El Gamal, Hussein A. Mousa, Muftah H. El-Naas, Renju Zacharia, Simon Judd

    The use of microorganisms to regenerate activated carbon (AC), bio-generation, can avert costly and logistically challenging ex-situ steam regeneration of carbon normally required to recover its adsorptive capacity. Bio-regeneration employs microbial metabolism in which the microbes use the available organic substrates (contaminants) to generate energy. During this process, they generate equivalent protons and electrons, which are transferred to the substrates to finally break them down to simpler molecules or ions, such as CO2, methane and Cl-. The optimal microbial conditions depend on the temperature, available nitrogen and phosphorus levels, dissolved oxygen levels, and microbe/substrate stoichiometric ratios and the residence time of the AC particles within the reactor. In this review, the authors highlight the most recent development in bio-regeneration including the regeneration mechanism, the relationship between the reversibility of adsorption and the efficiency of bio-regeneration, the general aspects affecting bio-regeneration, the principle and target compounds for bio-regeneration, different established methods for quantifying the bio-regeneration and the efficiency of bio-regeneration. Few case studies of bio-regeneration of activated carbon loaded with different contaminants are presented. Research on microbiology regeneration has gained considerable attention in recent years, but it still needs more contribution from other disciplines including process engineering, biochemistry and material sciences for optimizing the process performance

    更新日期:2018-01-09
  • Evaluation of titanium tetrachloride and polytitanium tetrachloride to remove phosphorus from wastewater
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2018-01-08
    Kyeong-Jun Jeon, Johng-Hwa Ahn

    Coagulation of titanium tetrachloride (TiCl4) and polytitanium tetrachloride (PTC) was studied at various conditions in treating wastewater that contained phosphorus (P). Jar-test experiments were performed at various chemical doses (0.02–0.49 mM), alkalinities (50 ≤ AT ≤ 150 mg CaCO3/L of NaHCO3), pH levels (3.0–8.5), and OH/Ti ratio (0.3 ≤ B ≤ 3.0) to determine the conditions at which P (2 mg/L) removal was most efficient. The TiCl4 concentration ([TiCl4]) required to achieve 98–99% P removal was 0.25 mM at 50 mg CaCO3/L, 0.31 mM at 100 mg CaCO3/L, and 0.49 mM at 150 mg CaCO3/L. Response surface analysis predicted that P removal would reach 100% at controlled pH = 3.5 with minimum [TiCl4] = 0.21 mM. PTC removed P most effectively at B = 0.3, and the optimal dose at B = 0.3 was 0.27 mM. Laboratory results and a pilot experiment will help to optimize use of Ti-based coagulants to remediate wastewater that contains P.

    更新日期:2018-01-09
  • Synchronously Degradation Benzotriazole and Elimination Bromate by Perovskite Oxides Catalytic Ozonation: Performance and Reaction Mechanism
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2018-01-08
    Yuting Zhang, Yijing Xia, Qingwei Li, Fei Qi, Bingbing Xu, Zhonglin Chen
    更新日期:2018-01-09
  • A facile strategy to prepare superhydrophilic polyvinylidene fluoride (PVDF) based membranes and the thermodynamic mechanisms underlying the improved performance
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2018-01-08
    Renjie Li, Xuena Wang, Xiang Cai, Hongjun Lin, Liguo Shen, Jianrong Chen, Huachang Hong, Bao-Qiang Liao
    更新日期:2018-01-09
  • Ultrasound assisted fabrication of AgBr/TiO2 nano-tube arrays photoelectrode and its enhanced visible photocatalytic performance and mechanism for detoxification of 4-chlorphenol
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2018-01-08
    Yuqi Cui, Zixuan Zhang, Bo Li, Ruonan Guo, Xinyi Zhang, Xiuwen Cheng, Mingzheng Xie, Qingfeng Cheng
    更新日期:2018-01-08
  • 更新日期:2018-01-06
  • Photocatalytic degradation of thiobencarb by a visible light-driven MoS2 photocatalyst
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2018-01-04
    Shiyun Huang, Chiingchang Chen, Hweiyan Tsai, Janah Shaya, Chungshin Lu
    更新日期:2018-01-05
  • Advanced treatment of bio-treated coal chemical wastewater by a novel combination of microbubble catalytic ozonation and biological process
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2018-01-04
    Chun Liu, Xiao-Xuan Chen, Jing Zhang, Hong-Zheng Zhou, Lei Zhang, Yan-Kai Guo
    更新日期:2018-01-05
  • Chemisorption of Microcystins to a Thiol and Amine Functionalized Organosilica
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2018-01-04
    Paul L. Edmiston, Kimberly A. Carter, Amy L. Graham, Emily J. Gleason

    Microcystins are cyclic heptapeptide toxins produced by cyanobacteria that are frequently detected in surface waters during seasonal blooms. Chemisorption of microcystin through covalent bond formation to the acryloyl group common to all congeners was hypothesized to be a high affinity adsorption mechanism. Sol-gel derived organosilica materials were synthesized as sorbents that could potentially facilitate a Michael addition reaction between an immobilized thiol group on the adsorbent and the acryloyl group of microcystin. Amine groups were also added to the organosilica to catalyze the thiol addition reaction at neutral pH. Adsorption isotherms of microcystin-LR, -LA, and –RR were measured for sol-gel derived sorbents and compared to adsorption by wood-based powdered activated carbon, which has been demonstrated to be an effective adsorbent for microcystin. The amine/thiol containing organosilica demonstrated a broad specificity to remove all three congeners from water. Adsorption capacities for MC-LR from natural water were reduced compared to deionized water, especially for the thiol-amine organosilica media. Adsorption of Cu(II) ions by the amine/thiol organosilica was measured which indicated metal ions were bound, however, the degree of metal ion binding was insufficient to significantly decrease adsorption microcystin. Overall, the reaction of microcystin with a surface thiol appeared to be promoted by an initial physical adsorption event and thiol deprotonation by the amines to create a better nucleophile for the Michael addition reaction.

    更新日期:2018-01-05
  • Microwave enhanced advanced oxidation treatment of sewage sludge from the membrane-enhanced biological phosphorus removal process
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2018-01-04
    Kwang Victor Lo, Indre Tunile, Hanji Tan, Tim Burton, Tiffany Kang, Asha Srinivasan, Ping Huang Liao

    This study investigated the effectiveness of bench and pilot-scale microwave enhanced advanced oxidation process (MW-AOP) for treatment of sewage sludge in neutral, acidic (pH 4) and alkaline (pH 9) conditions. The MW-AOP treatments were very effective: total suspended solids reduction and chemical oxygen demand solubilization were better in the sets at pH 9 than at pH 4. Alkaline conditions would be more favorable for the subsequent anaerobic digestion for biogas production. Release of orthophosphate, particle size distribution, dewatering properties and settling of the sets at pH 4 were better than at pH 9. The supernatants obtained from the sets at pH 4 had a high orthophosphate concentration and a low total suspended solids content, which were more suitable for struvite (a fertilizer) recovery process. Energy consumption was lower for the pH adjusted treatment sets compared to those of MW only and MW-AOP at neutral conditions; energy for the pH adjusted sets varied between 0.32 and 0.41 kWh/L of sludge treated. The results indicated that the MW-AOP could reduce the volume of sludge for disposal, and produce a high quality treated effluent suitable for further resource and energy recovery. Depending on the needs of each wastewater treatment plant’s treatment priority, the experimental conditions applied in the process can be adjusted accordingly.

    更新日期:2018-01-05
  • 更新日期:2018-01-04
  • Self-assembled synthesis of PbS quantum dots supported on polydopamine encapsulated BiVO4 for enhanced visible-light-driven photocatalysis
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2018-01-04
    Yan-Ran Lv, Rui Huo, Si-Yuan Yang, You-Qin Liu, Xin-Jun Li, Yue-Hua Xu

    A simple self-assembled method for the deposition of PbS quantum dots (PbS QDs) on the surface of polydopamine (PDA)-encapsulated BiVO4 nanoparticles is proposed to synthesize PbS@PDA/BiVO4 nanocomposite photocatalysts with the assistance of ultrasonication. In the PbS@PDA/BiVO4 nanocomposites that was designed to improve the charge separation efficiency, PDA served as a natural adhesive and a stabilizer that can help to prevent PbS quantum dots from agglomeration, and PbS quantum dots served as the multiple exciton donor. The photocatalytic degradation of glyphosate experiments indicated that PbS@PDA/BiVO4 exhibited the enhanced photocatalytic activity under visible light irradiation. As compared with that of BiVO4, PbS@BiVO4 and PDA/BiVO4, the photocatalytic activity of PbS@PDA/BiVO4 was improved by 3.03, 1.48 and 1.58 times, respectively. The enhanced activity of PbS@PDA/BiVO4 can be attributed to the rapid transport of a mass of photoelectrons generated by multiexciton generation from PbS quantum dots to the surface of BiVO4 and the enhanced charge separation efficiency of photogenerated charge carrier.

    更新日期:2018-01-04
  • Surface modification of phosphoric acid activated carbon by using non-thermal plasma for enhancement of Cu(II) adsorption from aqueous solutions
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2018-01-04
    Long Wu, Wenjie Wan, Zhongsheng Shang, Xinyuan Gao, Noriyuki Kobayashi, Guangqian Luo, Zhanyong Li
    更新日期:2018-01-04
  • Downstream processing of an oxidized industrial kraft liquor by membrane fractionation for vanillin and syringaldehyde recovery
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2018-01-03
    Inês Ferreira Mota, Paula Rodrigues Pinto, Ana Mafalda Ribeiro, José Miguel Loureiro, Alírio Egídio Rodrigues
    更新日期:2018-01-04
  • Photo-crosslinked PVA/PEI electrospun nanofiber membranes: Preparation and preliminary evaluation in virus clearance tests
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2018-01-03
    Bihter Zeytuncu, Melike Ürper, İsmail Koyuncu, Volodymyr V. Tarabara

    We report on the preparation of electropositive nanofiber membranes by electrospinning with in situ photo-crosslinking and their preliminary evaluation in virus adsorption and removal tests. Poly(vinyl alcohol) (PVA) and polyethyleneimine (PEI) were modified with glycidyl methacrylate, to form an acrylated crosslinked polymer (a-PVA/a-PEI) upon UV exposure during the electrospinning process. The a-PVA/a-PEI nanofibers were electrospun on a non-woven polyester support to form an electropositive (ζ = 7 mV at pH 7.4) and hydrophilic (θw≅ θ w ≅ 53°) membrane with the mean pore size of 0.48 µm. The microfilter had the specific permeate flux of ∼ 6.9⋅104 L/(m2⋅h⋅bar), comparable with that of commercially available membranes of similar nominal pore sizes. Adsorption of the negatively charged and hydrophilic bacteriophage MS2 (d≅ d ≅ 27 nm) onto the membrane followed Freundlich isotherm and could be classified as favorable with the average adsorption intensity n-1≅ n - 1 ≅ 0.91. The 99% retention of MS2 in flow-through virus clearance tests was attributed to adsorption and was likely controlled by the limited detention time within the membrane.

    更新日期:2018-01-04
  • Rejection of Trace Organic Water Contaminants by an Aquaporin-Based Biomimetic Hollow Fiber Membrane
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2018-01-02
    Sebastian Engelhardt, Anwar Sadek, Stephen Duirk

    Forward osmosis (FO) is a promising key strategy for energy efficient water purification. Different draw solutions, that create an osmotic gradient, and water selective FO membranes exist that allow for a significant concentration of waste streams while water is being filtered and absorbed into the draw solution. Such technologies are often limited by the solute rejection and water flux characteristics of the membrane used. A new approach is the utilization of aquaporin-based membranes (ABMs). These biomimetic membranes make use of the high water permeability and selectivity of aquaporin proteins, which are embedded into the active layer of the membrane. In this study, a 0.6 m2 hollow fiber ABM module was tested for its rejection of three different trace organic contaminants: the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), the plastic component bisphenol A (BPA) and the preservative methyl paraben. Over 95% of methyl paraben was rejected by the membrane while for 2,4-D and BPA rejection rates of over 99% were attained. However, it could also be observed that BPA and methyl paraben adsorbed on the aquaporin membrane and were flushed out again during subsequent experiments. This phenomenon may have to be addressed in future studies by developing specific cleaning protocols for ABMs.

    更新日期:2018-01-03
  • Pure silica CHA-type zeolite membranes for dry and humidified CO2/CH4 mixtures separation
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2018-01-02
    Koji Kida, Yasushi Maeta, Katsunori Yogo

    Dense and thin pure silica CHA-type zeolite (Si-CHA) membranes have been synthesized on porous α-alumina supports and investigated for CO2 permeation and CO2/CH4 separation performance under dry and humidified conditions. Si-CHA membranes with ultra-high permeance were greatly affected by performance suppression due to concentration polarization under high pressure and low feed-rate conditions. Under high feed-rate conditions at 298 K and a feed pressure of 0.1 MPaG, the CO2/CH4 selectivity was 130 with a CO2 permeance of 4.0×10–6 mol/(m2sPa) for an equimolar CO2/CH4 dry gas mixture. The presence of water vapor significantly reduced CO2 permeance, but the performance improved as feed pressure increased. The CO2/CH4 selectivities at high pressure with and without water vapor were essentially the same.

    更新日期:2018-01-02
  • Kinetic study on enhanced reactive extraction separation of terbutaline enantiomers by hydrophobic phase transfer
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-30
    Weifeng Xu, Qing Cheng, Panliang Zhang, Lelin Zeng, Kewen Tang

    This paper reports a complex kinetic study on enhanced reactive extraction separation of terbutaline (TBTL) enantiomers by hydrophobic phase transfer. The hydroxypropyl-β-cyclodextrin (HP-β-CD) was selected as hydrophilic chiral selector to preferentially combine the S-TBTL enantiomer in the aqueous phase and the sodium tetraphenylborate (NaTPB) was used as hydrophobic phase transfer reagent to transfer more R-TBTL enantiomer into the organic phase. A specific kinetic model was derived and established for describing the complex chiral extraction process. In the model, the inclusion reaction of TBTL enantiomers with HP-β-CD in the aqueous phase was assumed in equilibrium, and the phase transfer reaction of TBTL enantiomers with NaTPB in the phase interface was controlled by kinetic factors. The different conditions such as agitation speed, interfacial area, and concentration of TBTL, HP-β-CD, and NaTPB were investigated, separately. The forward and backward rate constant of the extraction reaction was 1.49×10-6 m4/(mol⋅s) and 2.33×10-9 m4/(mol⋅s), respectively. The experimental data were in good agreement with the model predicted results, which confirmed the model assumptions that the phase transfer reaction has not chiral recognition functions but improved the distribution of TBTL in the organic phase, and the inclusion reaction provided the enantioseparation ability.

    更新日期:2017-12-31
  • 更新日期:2017-12-31
  • Electrocoagulation Process for the Removal of Co-Existent Fluoride, Arsenic and Iron from Contaminated Drinking Water
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-29
    João F.A. Silva, Nuno S. Graça, Ana M. Ribeiro, Alírio E. Rodrigues

    The study of the EC process on the removal of iron, fluoride and arsenic from drinking water is an important step on the development of effective water treatment technologies for some world regions where the presence of those contaminants is a major health concern. Experimental results show that arsenic can be easily removed even in the presence of the other contaminants. Despite the slight reduction on the arsenic removal rate in the presence fluoride, the total removal can be achieved in less than 30 minutes of EC operation. On the other hand, the presence of iron presents a positive effect on the arsenic removal rate. Both fluoride and iron removal seem to benefit from each other presence in the EC operation. Moreover, the removal of both components is not significantly affected by the presence of arsenic. The simultaneous removal of the three pollutants can be achieved in less than 1h of operation.

    更新日期:2017-12-31
  • Optimal Design Of Industrial Scale Continuous Process For Fractionation By Membrane Technologies Of Protein Hydrolysate Derived From Fish Wastes
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-29
    R. Abejón, M.P. Belleville, J. Sanchez-Marcano, A. Garea, A. Irabien

    The fractionation in an industrial-scale continuous process of a protein hydrolysate obtained from tuna wastes has been proposed. A model based on membrane transport equations, mass balances and economic equations to calculate the main costs of the process was developed. This model was applied to the evaluation of the main technical, environmental and economic aspects of the process and their optimization. The basic cascade configuration resulted better than alternative options like the linear or dual cascades. The freshwater consumption was minimized to improve the environmental and economic performance of the process. Indeed, the implementation of a water recovery and reuse system was the most effective solution. This system was based on the installation of an additional tight nanofiltration stage that reduced the environmental impact of the process (avoiding the need of auxiliary freshwater streams) and increased its economic competitiveness.

    更新日期:2017-12-31
  • Air filtration performance of symmetric polypropylene hollow-fibre membranes for nanoparticle removal
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-29
    Pavel Bulejko, Mirko Dohnal, Jiří Pospíšil, Tomáš Svěrák
    更新日期:2017-12-31
  • 更新日期:2017-12-31
  • An overview on membrane strategies for rare earths extraction and separation
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-28
    Li Chen, Yilin Wu, Hongjun Dong, Minjia Meng, Chunxiang Li, Yongsheng Yan, Ji Chen

    Emission pollutants in rare earths hydrometallurgy industry have been the main constraint restricting its development. Membrane technology, as a sustainable green strategy with easy operation, is receiving great attentions in metal separation and wastewater treatment. Numerous membrane strategies for rare earths separation have been designed but few reviews could be found. The present article makes a state-of-the-art summary on current membrane techniques in rare earths separation including both liquid and non-liquid membranes. Further understandings of the crucial scientific and technical issues, such as REEs transport features, extraction performances, separation efficiency, transport models and mechanisms, membrane stability, operation modes and transport apparatus were discussed in details. Evaluations of each strategy and critical perspectives for future researches were suggested. Novel developments in non-liquid membrane techniques, such as polymer inclusion membranes, imprinted membranes, nanocomposite membranes and metal-organic framework membranes, were recommended and highlighted as potential strategies for rare earths separation in the near future. We hope that this overview would be a stimulator providing more opportunities for reference in membrane techniques for rare earths separation.

    更新日期:2017-12-31
  • 更新日期:2017-12-27
  • Exploring electrode capture potential in different Cr-contaminated soils with enhanced electrolytes based on chemical fractionation
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-27
    Junnian Wu, Chaozheng Xiao, Honglin Wu

    This paper investigated the electrode capture potential (ECP) of Cr in artificially and real contaminated soils during the electrokinetic remediation (EKR) with different electrolytes from a view of chemical fractionation to better understand the migration and transformation of Cr for a more efficient and environmentally friendly remediation process. The results indicated that the ECP includes the transformation potential (TP) among Cr fractions, the exchange potential (EP) and the migration potential (MP) of Cr. The ECP during Exp. 1, Exp. 2, Exp. 3 and Exp. 4 are 386.2, 0, 1412.76 and 347.73 g•m v-1, respectively. The ECP for the real contaminated soil is limited by the transformation process among Cr fractions in the solid phase. For the artificially contaminated soil, the ECP mainly depended on the migration process of exchangeable Cr in the liquid phase. The MP of Cr in the liquid phase in real contaminated soil is higher than that in artificially contaminated soil. Citric acid as an electrolyte was a better choice for the real contaminated soil compared with KCl due to the higher TP of residual Cr and the low ecotoxicity risk. The ecotoxicity risk index (ERI) shown that the ecotoxicity risks of Cr in soils after experiments followed the sequence Exp. 4 > Exp. 2 > Exp. 1 > Exp. 3. The ecotoxicity risk of remaining Cr in Exp. 1, Exp. 3 and Exp. 4 after the EKR reduced, while that in Exp. 2 increased due to the high TP to the bound to Fe–Mn oxides (FM) and bound to organic matter (OC) fractions and the very low ECP. High ECP may potentially increase the ecotoxicity risk unless the MP is greater than the TP.

    更新日期:2017-12-27
  • NOVEL METAL MODIFIED DIATOMITE, ZEOLITE AND CARBON XEROGEL CATALYSTS FOR MILD CONDITIONS WET AIR OXIDATION OF PHENOL: CHARACTERIZATION, EFFICIENCY AND REACTION PATHWAY
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-27
    Raluca Pleşa Chicinaş, Emese Gál, Horea Bedelean, Mircea Darabantu, Andrada Măicăneanu

    Metal (Co, Ce, Ni, Fe, Zn, Mn and Cu) containing Diatomite (D), Zeolite (Z) and Carbon Xerogel (CX) catalysts were prepared, characterized (SEM-EDX, TEM, FTIR and XRD) and tested as new catalysts in Catalytic Wet Air Oxidation (CWAO) of phenol in aqueous solution. Maximum values of Chemical Oxygen Demand (COD) or Total Organic Carbon (TOC) efficiencies were obtained in the case of Fe-D, Cu-Z, and Co-CX catalysts. Reaction pathway and kinetics for CWAO of phenol revealed a pseudo first-order catalytic process and a kcat between 0.0473×10-3 and 1.4183×10-3 L/min⋅g. (Di)carboxylic acids, acetic and oxalic were identified as oxidation organic products.

    更新日期:2017-12-27
  • Stripping of acetone from water in a microchannel device
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-27
    Chafika Adiche

    A liquid – vapor / gas separation microchannel device (channel length: 282.5 mm, channel width: 1 mm, gas channel depth: 1mm, liquid channel depth: 100 / 300 μm) was developed and used as microstripper to remove acetone from water using dry nitrogen as carrier gas. The interface between the liquid and vapor / gas phases was stabilized by means of a flat sheet microporous hydrophobic / oleophobic acrylcopolymer membrane on polyester support. The separation efficiency of the microstripper was investigated with respect to two liquid channel depths (100 and 300 μm) for countercurrent flow arrangement by varying alternatively the liquid flow rate and the carrier gas flow rate. All experiments were carried out at room temperature (23 ° C) and at atmospheric pressure. For all investigated process parameters in this work, fully developed laminar flow has been established in both fluid channels. Almost 100% acetone removal from the feed aqueous solution could be achieved in the microstripper with the liquid channel depth of 100 μm for a liquid flow rate of 0.025 ml /min (liquid residence time: 68 s) and for a carrier gas flow rate of 163 ml / min (gas residence time: 0.1 s). Furthermore, it was found that the overall volumetric mass transfer capacity coefficient KLa of the microstripper was strongly dependent on the liquid channel depth, while hardly affected by the liquid and carrier gas flow rates. The average value of KLa for a liquid channel depth of 100 μm was found about 0.091 s-1. It is approximately five times greater than that for a liquid channel depth of 300 μm. This results indicates clearly the potential of device miniaturization to enhancing the separation efficiency of the microstripper.

    更新日期:2017-12-27
  • Gamma radiation mediated Green Technology for Pd Nanoparticles Recovery from Wastewater
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-27
    Sung-Min Kang, Cheol Hwan Kwak, Muruganantham Rethinasabapathy, Sung-Chan Jang, Sang-Rak Choe, Changhyun Roh, Young-Kyu Han, Yun Suk Huh

    We describe a facile, economic, and environment friendly green method for simultaneous detection of palladium ions (Pd2+) and recovery Pd nanoparticles (Pd NPs) from wastewater through a non-toxic gamma-irradiation based reduction reaction. Basic orange 2 (BO), an azo dye, is used as a sensing probe in Pd2+ detection and acts as a stabilizing agent in the recovery of monodispersed small Pd NPs. The presence of Pd2+ in waste water was easily observed by naked eye through the color change from yellow to red upon adding the Basic orange 2. More importantly, Pd forms a square-planar structured complex with Pd2+ which aids the development of smaller and monodispersed Pd NPs during radiolytic reduction. The size control mechanism during the recovery of Pd NPs was ascertained by varying the intensity of gamma-ray (from 10 to 50 kGy) and initial concentrations of Pd2+ (from 20 to 100 ppm). We are able to control the size of Pd NPs from 5 to 400 nm by irradiating gamma-ray doses from 1 and 50 kGy, as evident from UV-vis absorption spectra (UV-vis) and transmission electron microscopy (TEM) images. About 15 nm colloidal Pd NPs were formed at 10 kGy gamma-irradiation, and various sizes of aggregates, which may be attributed to Ostwald ripening crystal growth, were observed in the irradiation condition of 20 kGy to 50 kGy. Further, the size of the recovered Pd NPs increases as the Pd2+ concentration increased, due to the increase in the ion association rate. Our proposed green method is a promising strategy that can easily detect Pd2+ from waste water and recover Pd NPs in desired size and morphology.

    更新日期:2017-12-27
  • Advanced desalination of dye/NaCl mixures by a loose nanofiltration membrane for digital ink-jet printing
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-27
    Wenyuan Ye, Jiuyang Lin, Ricard Borrego, Dong Chen, Arcadio Sotto, Patricia Luis, Minghua Liu, Shuaifei Zhao, Chuyang Y. Tang, Bart Van der Bruggen
    更新日期:2017-12-27
  • Magnetic Pr6O11/SiO2@Fe3O4 nanoparticles as the heterogeneous catalyst for the catalytic ozonation of acetochlor: performance and aquatic toxicity
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-27
    Junliang Wang, Yuanyang Lou, Xiaowei Zhuang, Shuang Song, Weiping Liu, Chao Xu

    A magnetic core–shell Pr6O11/SiO2@Fe3O4 catalyst using chemical precipitation was prepared. Its structure was confirmed by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and the energy-dispersive X-ray spectrum. The catalytic activity was evaluated by the catalytic ozonation of acetochlor. The results showed that the catalyst could effectively improve the acetochlor removal and mineralization. The total organic carbon removal reached 37.3% with the catalyst at 120 min, whereas the removal was 14.1% with ozonation alone. The catalyst was proved to be stable and recyclable by determining the concentration of the leaching praseodymium ions and the catalyst’s activity after repeated use. The effect of the radical scavengers indicated that the catalytic ozonation process followed an •OH reaction mechanism. In addition, we employed Chlorella and zebrafish as model organisms to investigate the aquatic toxicity of the treated solution and the dissolved praseodymium ions. We found that the aquatic toxicity of the reaction solution decreased with an increase in the degradation time, and no obvious toxicity was found for the dissolved praseodymium ions.

    更新日期:2017-12-27
  • 更新日期:2017-12-27
  • Quantification of particulate matter attached to the bulk-biofilm interface and its influence on local mass transfer
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-26
    Chunyan Li, Fabian Brunner, Michael Wagner, Susanne Lackner, Harald Horn

    A large fraction of the chemical oxygen demand (COD) in municipal wastewater is associated with the particulate matter. The presence of these particles might impose a negative impact on the mass transfer in biofilm systems when they attach to the bulk-biofilm interface. We thus investigated the impact of real wastewater particles by combining optical coherence tomography (OCT) and oxygen microsensor measurements. The deposition of wastewater particles of different size classes onto the biofilm surface was captured in 3D by means of OCT in a lab-scale flume. The thickness of the particle layer was calculated from OCT images. The influence of the particle deposition with respect to oxygen mass transfer into the biofilm was monitored by measuring oxygen profiles before and after particle deposition. By employing OCT, the formation of the particle layer on the biofilm surface was monitored in situ and non-invasively over time. Results from oxygen microsensor measurements concluded 20% - 70% reduction of the dissolved oxygen flux from the biofilm surface into biofilm matrix. This decrease in oxygen availability lowered substrate conversion in biofilms exposed to high loadings of organic wastewater particles.

    更新日期:2017-12-27
  • Fluid structures used for wastewaters treatment with complex load
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-22
    Daniela Cadar, Nicoleta Liliana Olteanu, Elena Adina Andrei, Aurelia Meghea, Adina Roxana Petcu, Maria Mihaly

    The treatment of wastewaters with complex load including dyes and heavy metals is a subject of paramount importance since trace amounts of these compounds lead to an enormous pollution problem. The present research proposes an innovative, fast and efficient microemulsion system for simultaneous extraction of a mixture of dyes (Crystal violet and Rhodamine B) and heavy metals (cobalt(II) and copper(II) ions) from such wastewaters. The used microemulsion is an environmental friendly system containing Brij 30 as nonionic surfactant and butyl acetate as organic phase. The effect of various parameters with significant influence on the dye and metals extraction efficiencies has been investigated in order to find out the optimal compositions for an efficient extraction of dyes – heavy metals mixture from aqueous media. The results show that the optimum extraction conditions for this system corresponds to pH = 5, a water to oil volumetric ratio equal to 9 and a concentration of the complexing agent equal to 2 mol/L.

    更新日期:2017-12-22
  • Understanding coupling effects in pervaporation of multi-component mixtures
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-21
    Wenqi Li, Patricia Luis

    The application of pervaporation for the separation of multicomponent mixtures may involve coupling effects among components and the membrane, which could increase or decrease the permeance of the target compound. In order to study and describe this phenomenon, mixtures of components present in two model reactions have been considered: the transesterification reaction between methyl acetate and butanol to produce methanol and butyl acetate, and the transesterification reaction between methanol and ethyl acetate to produce ethanol and methyl acetate. Both reactions are of utmost interest in the chemical industry and present high cost of separation due to the presence of azeotropic mixtures (i.e., methanol/methyl acetate; butanol/butyl acetate; ethanol/ethyl acetate). The separation performance of four commercial membranes (i.e., PERVAP 1255-30, PERVAP 4155-40, PERVAP 1255-50, PERVAP 4155-80) from Sulzer Chemtech, Switzerland, is evaluated. The effect of the feed concentration and the temperature on the separation performance was studied in terms of permeance and selectivity. Coupling effects were observed when the permeance of pure solvents was compared with that of the components in the mixture. The coupling effects were analyzed by the Hansen solubility approach and by the variation of activities within the membrane.

    更新日期:2017-12-21
  • Mathematical Modeling and Experimental Coupling of Solution Layer Crystallization on a Vertically Cold Surface
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-19
    I.S. Ioannou, S.S. Kontos, P.G. Koutsoukos, C.A. Paraskeva

    Solution static layer crystallization is an effective technique that promises to overcome the challenges for the isolation, separation and purification of phenolic compounds that remained in treated Olive Mill Wastewater, after the application of a combination of other physicochemical separation processes. Crystallization in unstirred solutions is based on supercooling gradients of the different components in a liquid mixture. Due to the large number of experimental variables involved, a theoretical model was developed for the description of the system with the least possible variables. The mathematical model was compared with laboratory-scale experiments for the separation of a common phenolic compound, ferulic acid (FA), from aqueous solutions. Τhe transient profiles of the solution temperature and solute concentration were calculated numerically, solving a system of coupled partial differential equations, taking into consideration the mass and heat transfer and the crystallization kinetics. The determination of the crystal growth parameters was done by comparison of the experimental data with the values predicted by the model, for two different operational conditions. Knowledge of the solution temperature distribution allowed the determination of the solution saturation with respect to FA, which affects the crystal growth rate, the yield and the purity of the final product. The model can be further used to assist the optimization of the process design with respect to the product recovery and the duration of the process. Furthermore, despite the fact that the proposed methodology is validated at a preliminary level, focusing on the recovery of a single component from an aqueous solution, it could be served as the first step for the development of a more realistic model to predict the behaviour of a multi-component system.

    更新日期:2017-12-19
  • Application of selectrodialysis for the removal of As from metallurgical process waters: recovery of Cu and Zn
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-19
    M. Reig, X. Vecino, C. Valderrama, O. Gibert, J.L. Cortina
    更新日期:2017-12-19
  • 更新日期:2017-12-19
  • Polymer inclusion membranes (PIMs) containing purified dinonylnaphthalene sulfonic acid (DNNS): performance and selectivity
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-18
    Mandana Ershad, M. Inês G.S. Almeida, Tony G. Spassov, Robert W. Cattrall, Spas D. Kolev

    The use of purified dinonylnaphthalene sulfonic acid (DNNS) as extractant in polymer inclusion membranes (PIMs) was investigated for the first time. DNNS is commonly supplied in 50 wt% water soluble diluent, which when applied in PIMs is expected to affect their stability. Purified and commercial DNNS were characterised by gas chromatography with flame ionization detection and thermogravimetric analysis coupled with Fourier transform infrared spectrometric detection. PIMs prepared with the purified DNNS reagent containing the same amount of membrane liquid phase as the commercial DNNS-based PIMs were able to accommodate more DNNS than the PIMs incorporating the commercial product which contained a significant percentage of diluent. This resulted in better extraction efficiency and slightly lower mass loss. The affinity of a PIM containing 35 wt% purified DNNS, 10 wt% 1-tetradecanol and 55 wt% poly(vinyl chloride) towards a range of monovalent and divalent cations in 0.001 M HCl solutions, based on the percentage extracted metal ion, was found to follow the order: Fe3+ (1:1, 93.9) > Ca2+ (2:1, 63.4) > Pb2+ (2:1, 59.7) > Zn2+ (2:1, 48.5) > Cu2+ (2:1, 45.0) > Ni2+ (2:1, 40.6) > Mg2+ (2:1, 35.0) > Na+ (1:1, 20.9) ≈ K+ (1:1, 20.1), where the numerical data in the brackets correspond to the stoichiometric ratio (DNNS: ion) and the percentage of metal ion extracted from the source solution, respectively. This order can be explained by the Hard and Soft Acids and Bases Theory and the hydration energy of the metal cations. The stoichiometric composition of the corresponding metal – DNNS adducts was determined in solvent extraction experiments.

    更新日期:2017-12-18
  • Three-Liquid-Phase Extraction in Metal Recovery from Complex Mixtures
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-18
    Bertrand Braibant, Damien Bourgeois, Daniel Meyer

    Modern metal production techniques often use solvent extraction either for separation or purification purposes. Processes were developed for specific mineral ores and deserve consequent modifications to be adapted to the recovery of metals from complex mixtures, arising eg from the hydrometallurgical processing of waste of electrical and electronic equipment (WEEE), as these mixtures contain a large panel of elements in highly fluctuating content. Three-liquid-phase (TLP) extraction systems allow the separation of metallic ions in three different phases in a single apparatus, and thus open the door to the treatment of complex mixtures with fewer operations. This paper reviews the work performed on TLP systems for metals separation, and highlights the potential advantages of such a technique in the design of new processes. Several systems enable the controlled formation of three immiscible phases, and have been successfully applied to the separation of various metals of interest. Advantages and drawbacks of each system are discussed, with a perspective for further developments, and the possibility for the rapid sorting of complex mixtures into separate groups of metals, easy to process.

    更新日期:2017-12-18
  • Studies on the purification of antibody fragments
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-18
    A. Nascimento, Inês F. Pinto, Virginia Chu, Maria Raquel Aires-Barros, João P. Conde, Ana M. Azevedo

    Antigen-binding fragments (Fabs) are becoming increasingly prevalent as an alternative to full-length monoclonal antibodies. In this work, the digestion of a mixture of different human antibodies isotypes was optimized in terms of different parameters, including the concentration of papain and cysteine, and the digestion time. The recovery of the Fab fragments was subsequently evaluated by designing four different downstream purification schemes, where the use of affinity chromatography (protein A and L) was the most efficient to isolate the Fab fragments after IgG digestion. A rapid screening of optimal conditions for the binding of pure Fab fragments to four non-affinity chromatography resins was then performed using micro-columns fabricated in a PDMS microfluidic device. The goal of these studies was to screen and evaluate the performance of two cation exchange (carboxymethyl and heparin) and two multimodal (Capto MMC and phenyl boronate) ligands for the capture of Fabs under a wide range of pH (5 – 9) and conductivity (up to 8 mS/cm) conditions. Multimodal resins showed the best results in binding Fab fragments, particularly at pH 5, well below the range of isoelectric points of the target Fab molecules. In addition, these resins demonstrated to have a salt-tolerant behaviour, meaning that the binding of Fab fragments was not significantly impacted when the conductivity of the adsorption buffer was increased to near-physiological conditions (8 mS/cm).

    更新日期:2017-12-18
  • 更新日期:2017-12-18
  • 更新日期:2017-12-18
  • Disk Supported Carbon Membrane via Spray Coating Method: Effect of Carbonization Temperature and Atmosphere
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-16
    N.H. Ismail, W.N.W. Salleh, N. Sazali, A.F. Ismail, N. Yusof, F. Aziz
    更新日期:2017-12-18
  • 更新日期:2017-12-18
  • Feasibility test of cellulose filter for collection of sulfuric acid mists
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-15
    Chih-Hsiang Chien, Chufan Zhou, Hsin-Chieh Wei, Simon Yang Sing, Alexandros Theodore, Chang-Yu Wu, Yu-Mei Hsu, Brian Birky

    Exploring affordable and reliable filters to sample sulfuric acid mists is of interest because the polytetrafluoroethylene filters recommended by NIOSH Method 7908 are relatively costly. In this study, the feasibility of hardened cellulose filters such as Whatman grade 540, 541, and 542 filters were investigated for sampling sulfuric acid mists. Thirty-minute collection efficiency tests showed low collection efficiency for Whatman grade 540 and 541 filters while Whatman grade 542 filters exhibited high collection efficiency because of its smaller pore size. Eight-hour collection efficiency tests for the concentration of ca. 5000 µg/m3 showed Whatman grade 542 filters retained 95% collection efficiency. The collection efficiency over eight hours neither increased nor decreased because the mists might have been absorbed or have formed a thin layer on the fiber and the filter structural integrity did not change. The high collection efficiency was at the expense of a high pressure drop; however, the pressure drop was still under the backpressure limit for most personal pumps. The integrity test showed that under the typical concentration in the occupational environment the hardened cellulose filters can maintain integrity for more than seven days. In summary, Whatman grade 542 filter is a suitable alternative for measuring sulfuric acid mists.

    更新日期:2017-12-16
  • Chromatographic separation of glucose, xylose and arabinose from lignocellulosic hydrolysates using cation exchange resin
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-15
    Kaifei Chen, Gang Luo, Zhongfang Lei, Zhenya Zhang, Shicheng Zhang, Jianmin Chen

    Recovery of monosaccharides from hydrolysates of biomass wastes can bring environmental and economic benefits. This study aimed to explore the feasibility to separate major monosaccharides from hydrolysates of lignocellulosic biomass, i.e. glucose, xylose and arabinose by using column chromatography process. Cation exchange resin Amberlite IR120 and Amberlite IRP69 in Na+ and Ca2+ forms were chosen as adsorbents. The adsorption behaviors were firstly inspected by adsorption equilibrium and mass transfer coefficients. Then the optimal chromatography conditions were determined by using synthetic solution. Finally, hydrothermal liquefaction hydrolysate of pine branches was separated. The results showed that cation resin Amberlite IRP69 (Ca2+) had high adsorption selectivity for arabinose which could be recovered from synthetic solution with purity of 92%. The highest purity of 88% was achieved for xylose when using this resin to separate pretreated hydrolysate. This work suggests that cation exchange resin could be further developed for effective separation of monosaccharides mixture.

    更新日期:2017-12-15
  • Influence of Processing Temperature on Flux Decline during Skim Milk Ultrafiltration
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-15
    Kenneth S.Y. Ng, Dave E. Dunstan, Gregory J.O. Martin
    更新日期:2017-12-15
  • 更新日期:2017-12-14
  • Poly(dimethylamine-co-epichlorohydrin) as an alternative to alum for the demulsification of commercial dishwasher wastewater
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-14
    Wanpeng Wu, Matthew J. Palmarin, Stephanie Young

    The aim of this research was to evaluate the viability of cationic polymers for the treatment of commercial dishwasher wastewater. Commercial dishwashers use large quantities of fresh water during regular use, and produce significant amounts of high-strength oily wastewater in the process. When treating this wastewater, the particles in the dispersed phase often require destabilization to facilitate their separation via gravity. Alum and other metallic salts are generally used for this purpose, though relatively large doses are required. Cationic polymers, which can destabilize colloids at much smaller doses, were herein investigated as a potential alternative to alum. Experimentation was conducted within a single-stage dissolved air flotation column. Out of the eight cationic polymers tested, only one was capable of outperforming alum. This polymer, poly(dimethylamine-co-epichlorohydrin), sold by the product name Superfloc C-572, yielded the greatest removal efficiencies when compared to alum and the seven other cationic polymers tested. Under optimal conditions, a C-572 dose of 0.10 mg L-1 was able to remove up to 87% of the oil and 90% of the turbidity from the wastewater samples. The removal efficiencies were further increased when the polymer and alum were used together. A C-572 dose of 0.10 mg L-1 with an alum dose of 200 mg L-1 yielded removal efficiencies of 95.6%, 94.6%, 73.0%, and 94.4% for oil, turbidity, chemical oxygen demand, and 5-day biochemical oxygen demand, respectively. However, the combined use of alum and polymer produced inconsistent results when treating a range of wastewaters that varied in strength. The C-572 polymer was less sensitive to the effects of dilution and produced more consistent results when treating these wastewaters. The C-572 polymer was also able to operate at a much higher pH range which eliminated the need to adjust the pH of the wastewater prior to treatment. The pH adjustment step was required when using alum. On balance, it was determined that C-572 was a suitable alternative to alum for the demulsification of commercial dishwasher wastewater.

    更新日期:2017-12-14
  • Steady-state and Transient Transport Studies of Gas Permeation Through Dense Membranes Using On-line Mass Spectrometry
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-13
    Sofia C. Fraga, Maria A. Azevedo, Isabel M. Coelhoso, Carla Brazinha, João G. Crespo
    更新日期:2017-12-14
  • Correlating Vapour-Liquid Equilibria of Binary HI+H2O Mixtures using Pitzer’s Model of Electrolyte Solutions
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-13
    Chaitanya R. Sampat, Amogh Joshi, Sadhana Mohan, Vilas G Gaikar

    The need to produce Hydrogen in an environmentally friendly manner has increased as the transportation industry has started to employ cleaner sources of energy. One of the cleaner ways to produce H2, is to use the Bunsen S-I cycle. This includes the separation of the H2 from an ionic mixture of Hydrogen Iodide and water using distillation. In this work, the Pitzer’s model for electrolyte solutions has been employed to represent the vapour-liquid equilibrium (VLE) of the binary system of HI and H2O. The activity coefficient (γ) is calculated from the equation which indicated the non-ideal nature of the system and aided the calculation of the vapour phase mole fraction. The experimental VLE data was obtained from a recirculating still at 101.3 kPa pressure for the binary system. This experimental data and data from literature was used to estimate the parameters of the Pitzer’s model to represent the activity coefficient of HI in this mixture. These optimized parameters could explain all the variations in the data with more that 90% accuracy for most of the data, with an average standard deviation of about 0.04. Furthermore, the temperature dependent form of the Pitzer’s equation was used to predict the VLE data at higher pressures of 3 and 5.7 bars and higher temperature conditions.

    更新日期:2017-12-13
  • Surface functionalized biomass for adsorption and recovery of gold from electronic scrap and refinery wastewater
    Sep. Purif. Technol. (IF 3.359) Pub Date : 2017-12-13
    Bharat C. Choudhary, Debajyoti Paul, Amulrao U. Borse, Dipak J. Garole
    更新日期:2017-12-13
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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