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As a clean and efficient renewable energy source, solar energy has been rapidly applied worldwide. The growth rate of China's installed capacity ranks first in the world. However, the life span of photovoltaic (PV) modules is 25 to 30 years, and the rapid development of installed capacity indicates that a large number of PV modules will be decommissioned in the future. Therefore, the ongoing treatment of the scrapped PV waste cells in the near future requires urgent plans and countermeasures. Proper recycling and disposal of decommissioned PV modules is a practical requirement for the sustainable development of the country and industry. Crystalline silicon (c-Si) solar cells currently occupy 85%–90% of the market share, and some scholars have begun to seek the utilization pathways of the waste Si in and outside the PV industry. In this paper, the research status of the separation and recycling process of crystalline Si PV modules is reviewed, and the recycling ways of crystalline silicon are particularly focused on. In addition, the current bottlenecks in the PV recycling industry in China are analyzed and some suggestions on the sustainable development of the PV industry are proposed. [ABSTRACT FROM AUTHOR]

The exceptional photoelectromagnetic characteristics of rare-earth elements contribute significantly to their indispensable position in the high-tech industry. The exponential expansion of the demand for high-purity rare earth and related compounds can be attributed to the swift advancement of contemporary technology. Nevertheless, rare-earth elements are finite and limited resources, and their excessive mining unavoidably results in resource depletion and environmental degradation. Hence, it is crucial to establish a highly effective approach for the extraction and reclamation of rare-earth elements. Adsorption is regarded as a promising technique for the recovery of rare-earth elements owing to its simplicity, environmentally friendly nature, and cost-effectiveness. The efficacy of adsorption is contingent upon the performance characteristics of the adsorbent material. Presently, there is a prevalent utilization of porous adsorbent materials with substantial specific surface areas and plentiful surface functional groups in the realm of selectively separating and recovering rare-earth elements. This paper presents a thorough examination of porous inorganic carbon materials, porous inorganic silicon materials, porous organic polymers, and metal–organic framework materials. The adsorption performance and processes for rare-earth elements are the focal points of discussion about these materials. Furthermore, this work investigates the potential applications of porous materials in the domain of the adsorption of rare-earth elements. [ABSTRACT FROM AUTHOR]

The separation and recovery of valuable metals from the Huayangchuan uranium polymetallic ore was investigated based on mineralogical research and mineral processing experiments. The most promising valuable elements in the ore, according to mineralogical studies, are U, Nb, and Pb. 95.75% of U and 93.00% of Nb are found in betafite, 46.85% of Pb is present in galena, 52.01% of Pb occurs in cerussite, and associated Ag exists primarily in galena. The beneficiation process involving gravity concentration, magnetic separation, and flotation was determined based on the mineralogical characteristics of the ore. The U-Nb concentrate with U grade of 3578 ppm and recovery of 83.18 %, Nb2O5 grade of 4391 ppm and recovery of 74.55 % can be obtained, and five elements including U, Nb, Pb, Ag, and Fe are recovered. Compared with the previous beneficiation experimental process, the flowsheet is greatly simplified and the beneficiation recovery efficiency has been improved. The results of this investigation can help to address the gaps in the processing of low-grade uranium deposits with similar mineralogical properties. [ABSTRACT FROM AUTHOR]

The exceptional photoelectromagnetic characteristics of rare-earth elements contribute significantly to their indispensable position in the high-tech industry. The exponential expansion of the demand for high-purity rare earth and related compounds can be attributed to the swift advancement of contemporary technology. Nevertheless, rare-earth elements are finite and limited resources, and their excessive mining unavoidably results in resource depletion and environmental degradation. Hence, it is crucial to establish a highly effective approach for the extraction and reclamation of rare-earth elements. Adsorption is regarded as a promising technique for the recovery of rare-earth elements owing to its simplicity, environmentally friendly nature, and cost-effectiveness. The efficacy of adsorption is contingent upon the performance characteristics of the adsorbent material. Presently, there is a prevalent utilization of porous adsorbent materials with substantial specific surface areas and plentiful surface functional groups in the realm of selectively separating and recovering rare-earth elements. This paper presents a thorough examination of porous inorganic carbon materials, porous inorganic silicon materials, porous organic polymers, and metal–organic framework materials. The adsorption performance and processes for rare-earth elements are the focal points of discussion about these materials. Furthermore, this work investigates the potential applications of porous materials in the domain of the adsorption of rare-earth elements.

Extraction of Sc from Sc-rich limonitic laterite without interfering with the main nickel-cobalt production circuit will significantly enhance the economic value of laterite. A process for separation and recovery of Sc from high pressure acid leach (HPAL) liquor of limonitic laterite was proposed in this paper. Based on the chemical composition of the leach liquor, precipitation thermodynamic analysis and experiments were conducted. The results indicated that after a first step to precipitate Fe3+ at pH = 2.5 and 90 °C, Sc could be enriched through a second step precipitate at pH = 4.8 and 60 °C to 267 g/t in Sc-containing precipitate. Then, Sc was re-leached from the Sc-containing precipitate via 1 mol/L sulfuric acid at L:S ratio of 5 mL/g, 80 °C, and 40 min. Meanwhile, gypsum in the Sc-containing precipitate transformed into calcium sulfate hemihydrate during leaching. After that, Sc was synergistically extracted from the leach solution via 5% P204 and 2.5% TBP. Moreover, impurities extracted into the organic phase during the extraction of Sc were scrubbed by HCl. Finally, Sc was stripped by NaOH. By using this process, Sc could be efficiently recovered from limonitic laterite in a facile way. [ABSTRACT FROM AUTHOR]

• A clean and efficient method for recovering Ag from Ag-Sn alloy is proposed, and the feasibility of this method is studied through theory and experiment. • The migration modes of Ag and Sn metal vapours were discussed. • The purity of crude Ag is more than 95 wt%, which can be directly electrolysed to produce electro-silver, with short process flow and high efficiency. The recycling of waste lead-free solder and the tin refining process generates large quantities of silver-tin alloys, which have a very high potential for recovery but for which there is no clean and efficient means of recovery. This study examined the saturation vapour pressure, separation coefficients, prediction of the T - x (y) phase diagram of the silver-tin alloys, and condensation rate to explore the feasibility of using vacuum evaporation-multistage condensation as a method for separating silver-tin alloys. The results suggest that in the process of vacuum evaporation, both silver and tin will evaporate, and the evaporability of silver is slightly greater than that of tin. In the process of multistage condensation, tin condenses before silver. Furthermore, the vacuum evaporation-multistage condensation method was experimentally validated. The results suggest that the TF consists of crude silver, with a silver content of 98.17 wt% and a silver distribution rate of 43.60%. The MP consists of a silver-tin alloy with 7.87 wt% silver content and exhibits a silver distribution rate of 53.06%. The RE is crude tin containing 0.27 wt% of silver content and a silver distribution rate of 5.14%. The separation rate of Ag is 96.64%. This study provides a clean and efficient method that is instructive for the recovery of Ag-Sn alloys. [ABSTRACT FROM AUTHOR]

In this paper, the parameters affecting the adsorption of CuII and NiII by PAN‐NHx fiber and PAN‐COONa fiber were discussed firstly, such as initial ion concentration, pH, and temperature. Secondly, influence factors toward the separation of CuII and NiII by PAN‐NHx fiber were systematically evaluated by single‐column experiments. The results showed that the PAN‐NHx fiber had good separation of CuII and NiII; NiII accounts for more than 99.00 % of total metal ion content in the initial 1000 mL effluent, while CuII is less than 1 %. With the changed from CCuII: CNiII=90 %:10 % to 95 %:5 %, the ratio of CCuII: CNiII in the treated effluent changed from 6 %: 94 % to 2 %: 98 % (fed flow rate: 0.42 BV min−1). The adsorption capacity of PAN‐NHx adsorption column was well maintained after six cycles. Finally, based on the above laboratory results, a multi‐column process was designed to separate and recover CuII and NiII from wastewater. [ABSTRACT FROM AUTHOR]

The solubilization laws of pollutants in micelles and their separation efficiency are very important in the successfully efficient application of micellar enhanced ultrafiltration (MEUF). The solubilization behavior of o-toluidine (OT) and tricyclazole (TC) into sodium dodecyl sulfate (SDS) micelles in MEUF was studied using nonlinear equation sets for concentration analysis, which resolved the issue on the overlap of absorption spectra of multicomponent compounds restricting the application of conventional ultraviolet (UV) spectroscopic method. The solubilization isotherms for both pollutants could be best explained by the Langmuir-Freudlich model (R2>0.99) followed by the modes of Langmuir and Freudlich, inferring the complexity of solubilization mechanism and solubilization advantage of monolayer over multilayer. The calculated thermodynamic parameters (ΔG0, ΔH0 and ΔS0) indicated that this process was endothermic and spontaneous. The solubilization of OT and TC well followed the pseudo second-order and pseudo first-order kinetics, respectively. The separation and recovery of SDS solubilizing these two pollutants were also investigated through lowering solution temperature to 2 °C followed by centrifugation. The best recovery rate of about 66% for SDS was achieved containing 10 and 5% of each initial amount of OT and TC, respectively, at near-neutral solution pH value. The recovery of SDS could decrease to some extent under alkaline and acidic conditions. [ABSTRACT FROM AUTHOR]

A new type of alkali-soluble polyester/cotton blended yams was used to knit a compact knitted fabric on a drcular weft knitting machine, treated with 5 g/L NaOH solution for 60 min at a temperature of 100 °C, and the polyester was completely dissolved. The dissolved polyester could be polymerized again by a polycondensation reaction. After the cotton fibers were opened and combed,the length and mechanical properties of the cotton fibers were tested. The physical and mechanical properties of the separated cotton fibers were good. The chemical structure and crystallinity were analyzed by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis. It could be seen that the chemical structure of cotton fibers was almost unchanged after treatment,and the crystallinity decreased slightly. It provides some reference for the separation and recycling of waste polyester/cotton fabrics. [ABSTRACT FROM AUTHOR]

Since the discovery of microemulsions, they have attracted great attention due to its unique properties, such as ultra-low interfacial tension and nanoscale droplets. During the past several decades, microemulsions have shown unparalleled advantages in critical metal separation and recovery, e.g., high separation rate, high recovery efficiency, and good selectivity. Therefore, fundamental understandings of such metal recovery behavior are of great significance for the continuous development of microemulsion-based separation technology in this field. Herein, we first systematically reviewed the application of regular microemulsion in the separation and recovery process of critical metals focusing on their separation mechanisms. Then, we summarized the recent progress of CO 2 -responsive microemulsions and highlighted their potential application in critical metal separation and recovery, aiming to provide some insights into alleviating the difficulties in demulsification during the stripping stage using regular microemulsions. In this section, the latest development of CO 2 -responsive microemulsions is introduced, and the relationship between their composition, microstructure and macroscopic properties is discussed. Discussion and future perspectives are provided highlighting the design of new microemulsions and potential application of CO 2 -responsive microemulsions for metal separation and recovery in the future. [Display omitted] • Microemulsions for critical metal recovery were summarized focusing on mechanisms. • The latest development of CO 2 -responsive microemulsions was introduced. • Future perspectives of microemulsions for metal recovery were discussed. • Potential use of CO 2 -responsive microemulsions for metal recovery was explored. [ABSTRACT FROM AUTHOR]

In this work, a clean technology is introduced to separate and recover vanadium and chromium from vanadium-containing chromate solution. It was found that vanadium can be precipitated from vanadium-containing chromate solution by hydrolysis. The hydrolysate is the mixture of polyvanadic acid and sodium polyvanadate. The concentration of V in the solution can be decreased to 0.76 g/L under pH 2.0 at 95 °C. The Na in the mixture can be effectively removed by washing with (NH 4 ) 2 SO 4 solution as the bind of NH 4 -VO 3 is stronger than that of Na-VO 3 . The V 2 O 5 with purity 98.6% was acquired by calcining the washed mixture. The vanadium residue in precipitated solution can be completely removed by adding Fe 2+ or Fe 3+ to form iron vanadate under pH 3.8–4.5. The chromium in the V free solution was reduced from Cr(VI) to Cr(III) with Na 2 SO 3 , and then the precipitate of Cr 2 O 3 ∙ x H 2 O was formed under pH above 8.5 at 90 °C. At last, the Cr 2 O 3 with purity 98.7% was obtained by the treatment of the chromic oxide hydrate. Using the process above, the generation of V-Cr-bearing reducing slag and the mixture of Na 2 SO 4 and (NH 4 ) 2 SO 4 can be avoided in vanadium pentoxide production from vanadium-containing chromate solution. [ABSTRACT FROM AUTHOR]

Volatile fatty acids (VFAs) are attractive compounds in renewable based bio-refinery industries and can be produced through anaerobic digestion of organic wastes. Nevertheless, the recovery of VFAs from anaerobically digested organic wastes is the bottleneck of the resource recovery. In this study, VFA recovery from synthetic VFA solutions and fermented organic wastes via air-filled and tertiary amine extractant-filled PTFE membranes through vapor pressure membrane contactors (VPMC) was investigated. Acetic acid was recovered with greater than 45% efficiency in all the fermented wastes. Recovery of propionic, butyric, valeric, and caproic acids through trioctylamine-filled PTFE membrane was greater than 86% and 95% from landfill leachate and fermentation broth of anaerobically digested organic waste, respectively. This study reveals that VFA separation can be effectively achieved via economic and environmental friendly VPMC system and the process is implementable as it can be coupled to a fermentation process to prevent inhibition and to recover VFAs. [ABSTRACT FROM AUTHOR]

To comprehensively utilize the laterite resources, the present study focused on the selective recovery of valuable metals Ni, Co or Al, Cr, and concurrent synthesis of spinel ferrites from saprolite-limonite laterite leach liquors by a one-step selective precipitation method. The precipitation behaviors were investigated in detail, as were factors such as precipitant reagent, pH value, precipitation method, and initial metal ion concentration. In optimal conditions, about 93.0% Ni and 92.0% Co could be enriched in the filtrate by using ammonia (aqueous NH 3 ) solution as precipitant reagent while the recoveries of Al and Cr were 92.0% and 90.0% by using sodium hydroxide (NaOH) solution. After the separation and selective precipitation processes, the precipitates were utilized to synthesize spinel ferrites and the effects of saprolite to limonite laterite mass ratio (M S/L ) and calcination temperature on the product purity are discussed. Single phase multi-metal doped magnesium ferrites with high purity could be synthesized when the precipitates were obtained using M S/L ratio of 9:1 and 7:3 by using aqueous NH 3 and NaOH solutions as precipitant reagents, and then calcined at 1000 °C for 2 h, respectively. The overall metal recoveries from laterite blends using aqueous NH 3 and NaOH precipitant reagents were 89.2% and 85.4%, respectively. [ABSTRACT FROM AUTHOR]

Separation and recovery of V(IV) from the synthetic sulfuric acid solutions containing Fe(III) and Al(III) were investigated using the bis(2-ethylhexyl)phosphoric acid (D2EHPA)-impregnated resin (DIR). It is confirmed that D2EHPA was incorporated to the support by comparing the characteristics of the support resin and DIR using thermogravimetric analysis (TGA) and Fourier transform infrared spectra (FT-IR), respectively. Batch experiments proved that the adsorption capacity of Fe(III) on the DIR was by far higher than that of V(IV) and Al(III), and the separation factor of Fe(III) to V(IV) reached the plateau at the pH ranging from 1.0 to 1.2, which provided feasibility for the V(IV) separation from the solutions by column mode. During the preferential removal of Fe(III) by the DIR, it was shown that effective Fe(III) removal can be achieved at feed flow rate of 1.0 mL/min, column height of 18 cm and solutions pH 1.0. Subsequently, 1.5 mol/L H 2 SO 4 and 30 g/L H 2 C 2 O 4 was appropriate for the stepwise elution of partial loaded V(IV) and Fe(III), respectively. The iron-removed effluent was combined with the following eluted vanadium-bearing solutions and then was further processed by the DIR. Finally, the vanadium-rich solutions were obtained by stripping with 1.0 mol/L H 2 SO 4 . The total recovery of vanadium was 91.47% and it was concentrated almost 5 times. This study provides potential method for the separation and recovery of V(IV) from acid aqueous solutions by solvent impregnated resins. [ABSTRACT FROM AUTHOR]

A simple and rapid method for the separation and recovery of osmium [Os(IV)] was investigated in a packed column with γ-nano-AlO. The influence of flow rate, initial Os(IV) concentration, and column height on column adsorption were also analyzed in this study. The experimental breakthrough curves were modeled using Bohart-Adams, Thomas, and Yoon-Nelson models, respectively, and the parameters for all of these models were calculated. Sequential adsorption/desorption experiments confirmed that the adsorption column can be readily regenerated and reused. Under the optimized experimental conditions, it is expected that this dynamic adsorption process can be a candidate for the effective separation and recovery of Os(IV) from the simulated industrial leach liquor. Graphical abstract: A simple method for the rapid separation and recovery of osmium was successfully established using AlO in a packed column, and it is probable that the column is suitable for a continuous system for large-scale applications in industry.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Traditional methods of vanadium recovery from vanadium slag suffer from serious environmental pollution due to the residue and wastewater containing highly toxic V(V) and Cr(VI). To avoid this, a complexation method based on sodium diethyldithiocarbamate (DDTC) complexing agent was proposed to separate and recover V(IV), Fe(II), Cr(III) in the leaching solution directly prepared from vanadium slag. Firstly, the recovery effect of DDTC on metal ions was studied in the imitated solution containing V (IV), Fe (II) and Cr (III), 97.67% vanadium, 99.51% iron and 98.99% chromium were recovered, respectively. In addition, DDTC was recycled in the complexation process. After four cycles, the regeneration rate of DDTC remained above 86%. Then, this method was applied to the leaching solution of vanadium slag, and 97.38% Cr, 97.69% V, 99.66% Fe and 97.64% Mn were recovered, respectively. Chromium was recovered as Cr 2 O 3 with purity of 97.1%. Most iron was recovered as (NH 4) 2 Fe(SO 4) 2 ·6H 2 O with purity of 99.23%. Manganese and a small amount of iron were enriched in the slag, which could be used to produce manganese alloy. Vanadium was recovered as calcium salt, which could be used to produce VOSO 4 electrolyte with purity greater than 99.8%. Without waste water and residue containing highly toxic V(V) and Cr(VI) produced in this new method, which provides a new strategy for cleaner comprehensive utilization of vanadium slag. A novel method for deep separation and recovery of V(IV), Fe(II) and Cr(III) in solution. [Display omitted] [ABSTRACT FROM AUTHOR]

Volatile fatty acids (VFA) are organic compounds of great importance for various industries and environmental processes. Fermentation and anaerobic digestion of organic wastes are promising alternative technologies for VFA production. However, one of the major challenges is development of sustainable downstream technologies for VFA recovery. In this study, an innovative microbial bipolar electrodialysis cell (MBEDC) was developed to meet the challenge of waste-derived VFA recovery, produce hydrogen and alkali, and potentially treat wastewater. The MBEDC was operated in fed-batch mode. At an applied voltage of 1.2 V, a VFA recovery efficiency of 98.3%, H 2 of 18.4 mL and alkali production presented as pH of 12.64 were obtained using synthetic fermentation broth. The applied voltage, initial VFA concentrations and composition were affecting the VFA recovery. The energy balance revealed that net energy (5.20–6.86 kWh/kg-VFA recovered) was produced at all the applied voltages (0.8–1.4 V). The coexistence of other anionic species had no negative effect on VFA transportation. The VFA concentration was increased 2.96 times after three consecutive batches. Furthermore, the applicability of MBEDC was successfully verified with digestate. These results demonstrate for the first time the possibility of a new method for waste-derived VFA recovery and valuable products production that uses wastewater as fuel and bacteria as catalyst. [ABSTRACT FROM AUTHOR]

In recent years, the rapid development of copper indium gallium selenide (GIGS) solar cells makes it necessary to recycle spent CIGS in order to realize circular economy. In this work, a novel and efficient method for comprehensive recovery valuable metals in spent CIGS materials was investigated, mainly including three steps: (1) leaching of spent CIGS with nitric acid to separate indium; (2) precipitating to obtain copper gallium selenite mixture with magnesium oxide as precipitant; (3) calcination of the residue and the precipitation to recover selenium. X-ray photoelectron spectroscopy (XPS) analysis indicates that the valence state of selenium was converted from negative divalent to positive tetravalent after oxidative leaching. In addition, the results of X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR) and scanning electron microscope/energy dispersive spectrometer (SEM/EDS) shows that the dissolution of metals in CIGS during leaching were significantly different. Copper and gallium were almost completely leached, while indium entered the slag phase as indium selenite, which achieved the separation of indium. Moreover, the reaction mechanism of leaching was analyzed from the perspective of thermodynamics. After leaching, copper, gallium and selenium can be completely recovered from the leach liquor using magnesium oxide as precipitant. Subsequently, the separation of Se in the residue and precipitates can be achieved at 800 °C for 90 min. Finally, the recovery yields of Cu, In, Ga and Se were 99.23%, 96.82, 98.08% and 96.38% respectively. This research represents an important innovation from the perspective of circular economy and provides a new idea for comprehensive utilization of secondary solar cells. [Display omitted] • An innovative technology for treating spent CIGS via HNO 3 leaching was proposed. • Leaching agent (HNO 3) and precipitation agent (MgO) were regenerated and recycled. • Indium was efficiently separated by one-step leaching. • The recovery of selenium was completed quickly at much lower temperatures. [ABSTRACT FROM AUTHOR]

Application of power ultrasound in chemical processes is recognized as an effective tool to solve many industrial problems encountered in processes involved in nuclear industry, particularly, digestion and leaching steps. In addition, problems related to radiological safety are the most important factors to be considered, when handling radioactive materials. Sonochemical processes, due to relatively low temperature operations, are attractive in this regards. Further they are eco-friendly and economical as well. Hence, sonochemical studies were taken up for the removal of uranium from fluoride containing matrix. Dissolution studies were carried out in nitric acid medium, in a 5 L capacity tank type sono-reactor, operating at frequency and power of 22 ± 3 kHz and 150 W respectively. The parameters studied were concentration of HNO, temperature of water-bath, choice of purged gas (air/oxygen) and flow rate of purged gas passed. Experiments were also carried out to study the amount of fluoride matrix dissolved. Enhancement with US was 76 to 91 % for U removal from MgF slag in 2 M HNO. The prime advantage achieved is the reduction in the reaction time. Other advantages are minimizing labor, remotisation of operations to reduce radiation exposure, use of less acid and accordingly lesser effluent for treatment before disposal. [ABSTRACT FROM AUTHOR]

Abstract: The metals in waste mobile-phone batteries may cause environmental pollution. In this paper, leaching with H2SO4+H2O2, P507 extraction, and sedimentation with oxalic acid and carbonic acid were used to deal with waste batteries and obtain cobalt and lithium salts by separation, which shows an easy and feasible method with less waste water disposal. The effects of sulphuric acid concentration, pH value, and lithium ions on the recovery were investigated. When the sulphuric acid concentration was over 0.4mol/L, the loss of cobalt increased significantly. If pH value of 3.5 was used, it was easy for cobalt and lithium separation with a low cobalt loss. Over several recycles, the recovery of lithium could reach the maximum with the lithium ion concentration of 27.3g/L. The recovery efficiencies for cobalt and lithium were 90.02% and 86.04%, respectively. [Copyright &y& Elsevier]

BACKGROUND: Lactic acid has many different applications in a variety of industries including the food, cosmetics, packaging, leather and chemical industries. Current methodologies for lactic acid production are lengthy and complicated and more efficient methods are being sought. Some organic wastes contain lactic acid and our work investigates the use of ionic liquids (ILs) in the efficient and selective extraction of lactic acid from organic waste using wine as a model system. The ionic liquid was chosen based on its ability to selectively solvate and separate lactic acid from the remaining bulk waste material. RESULTS: Several ILs including 1-hexyl-3-methylimidazolium chloride (hmimCl), 1-hexyl-3-methylimidazolium bromide (hmimBr), 1-hexyl-3-methylimidazolium iodide (hmimI) and N-hexylpyridinium iodide (hpyrI) have been synthesized in high yield (68-95%) using microwave technology. Lactic acid is soluble in each of the ILs synthesized with optimum results achieved with hmimBr where lactic acid is miscible in all proportions. HmimBr has been used to successfully separate and extract lactic acid from wine as confirmed by FTIR spectroscopy. Furthermore, it has been possible to recover the IL for recycle in subsequent extraction cycles where the efficiency for the extraction process increases with each recycle. CONCLUSION: HmimBr has been used for the first time in a novel process for the separation and recovery of lactic acid from wine, as confirmed by FTIR spectroscopy. This work demonstrates a novel process which can be applied to the recovery of lactic acid from organic waste. Copyright © 2012 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Experiments were carried out on clindamycin''s separation and recovery from clindamycin fermentation wastewater with nanofiltration (NF) membranes. Four types of flat-sheet NF membranes, DLNF-1, NTR-7250, XCNF-1 and MPF-44, were tested under different dynamic operating conditions. It was found that the operating pressure and solute concentration had great influence on membrane performance while flow rates (or velocities) had little influence on membrane performance. Experiments on SO42− rejection were conducted with such four flat-sheet NF membranes because SO42− had bad influence on microbes in biochemical process following the NF process. The results indicated that DLNF-1 and MPF-44 membranes had higher SO42− rejection among four membranes. Two spiral membranes, MPS-44 (1.4 m2) and DLNF2-30 (0.24 m2), were adopted in a concentrating process for clindamycin''s separation and recovery from clindamycin fermentation wastewater under laboratory conditions. After being operated for 60 h, clindamycin wastewater was concentrated from 266 to 26 L, and the clindamycin was concentrated from 220 to 1940 mg/L, which met the demand of reuse. This research may widen the application of NF membranes in disposal of pharmaceutical wastewater. [Copyright &y& Elsevier]

Acid leaching wastewater, produced in the acid pre-leaching process of gold-bearing dust, contains a lot of iron (Fe) and arsenic (As). If these wastewater are discharged directly without proper treatment, massive destruction on the environment will be caused, and a large amount of arsenic and iron resources will be wasted. In this study, Fe(III) reduction by pyrite, recovery and purification of crude green-vitriol and crude As 2 O 3 , and disposal of arsenic-bearing solid waste were studied. Based on those studies, a novel process containing Fe(III) reduction with pyrite, iron recovery after Fe(III) reduction, and arsenic recovery from the solution after iron recovery was proposed to separate and recover Fe and As from an acid leaching wastewater. Results showed that reduction efficiency of Fe(III) in acid leaching wastewater achieved 96.43% under the optimal conditions (80 °C, L S−1 5:1, 3 h). Recovery efficiency of iron in crude green-vitriol achieved 82.37%; moreover, 73.32% As remained in the solution after iron recovery. Through purification, purified green-vitriol reached the national standard of class-I green-vitriol (GB 10531-2006), and the direct recovery efficiency of iron was 51.46%. Through neutralization, SO 2 reduction, recovery and purification of crude As 2 O 3 , purified As 2 O 3 reached the national standard of As 2 O 3 -3 (GB 26721-2011), and the direct recovery efficiency of arsenic achieved 74.89%. This process realized the efficient recovery of iron and arsenic from acid leaching wastewater, and also realized the harmless disposal of arsenic-containing solid waste. [Display omitted] • A novel process was proposed to separate and recover Fe and As from wastewater. • The efficient separation and recovery of Fe and As was achieved. • Purified green-vitriol reached the national standard of I product (GB 10531-2006). • Purified As 2 O 3 reached the As 2 O 3 -3 product standard in GB 26721-2011. • The direct recovery efficiency of Fe and As achieved 51.46% and 74.98%, respectively. [ABSTRACT FROM AUTHOR]

Oil-refinery alkali residue wastewater (ORARW) contains large amounts of phenol and its derivatives, which are highly toxic and valuable but difficult to biodegrade. In this study, using vegetable oil as the liquid membrane phase, a green polypropylene-hollow-fiber supported liquid membrane (SLM) system was constructed to simultaneously separate and recover phenol, m -cresol and o -cresol from aqueous solutions. After screening several types of vegetable oil, linseed oil was selected as the liquid membrane phase. Based on a single SLM module and using a NaOH solution as the stripping reagent with feed phase and stripping phase hydraulic retention times (HRTs) of 7.8 and 6.9 min, respectively, the phenol separation and recovery rates were 92.9% and 88.8%, respectively. The separation rates for m -cresol and o -cresol were both greater than 96%, their recovery rates were approximately 92%, and the membrane separation flux of every phenolic compound exceeded 0.40 g/m2·h. When two SLM modules were operated in series at room temperature for 3 h, the separation efficiency for phenols increased by approximately 9% compared with that obtained with a single SLM module. After applying two SLM modules in series to treat ORARW with an initial concentration of phenols of 4800–5200 mg/L, the simultaneous separation and recovery rates of phenols were near 95% and 92%, respectively. This work concluded that vegetable oil can be used as a nontoxic and renewable green liquid membrane phase and that two SLM modules in series efficiently separated and recovered phenols from aqueous solutions. Image 10784 • Vegetable oil was used as an SLM liquid membrane to separate and recover phenols. • The order of the phenol extraction was linseed oil > sunflower oil > rapeseed oil. • Two membrane modules in series were more effective for the separation of phenols. • The separation and recovery rates for phenols reached 95% and 92%, respectively. • The SLM system can be used in an oil refinery as a cleaner production process. [ABSTRACT FROM AUTHOR]