CHEMOSPHERE
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2020
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IF 5.778
Chao Fang,Tian Ou,Xingyu Wang,Min Rui,Wenhai Chu
Ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) are widely used in drinking water treatment and wastewater recycling. However, limited information was available regarding their performance in removing trihalomethanes (THMs). The present study investigated the effect of feed solution characteristics and membrane fouling on THM removal by UF/NF/RO membranes. The results indicated that THMs were poorly removed by UF membrane, and the removal was dominated by hydrophobic adsorption. In contrast, high removal of THMs was observed for NF/RO membranes, which was contributed by both size exclusion and hydrophobic adsorption. By comparing the adsorption of THMs on NF/RO membranes at different feed concentration, it was found that the role of hydrophobic adsorption was more important at lower feed concentration. The removal of THMs by UF/NF/RO membranes increased with increasing feed concentration, which can be ascribed to the enhanced diffusion at higher concentration gradient. With increasing ionic strength, THM removal was decreased significantly for UF membrane, but the removal by NF/RO membranes remained largely unchanged. By comparing THM removal by clean and fouled membranes, the effect of membrane fouling was examined. The removal of most THMs (except trichloromethane) decreased after fouling for UF membrane, whereas decreased removal was only observed for iodinated THMs for fouled NF/RO membranes.
研究领域:
环境科学
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水处理工程
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产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Yi Wang,Hao Yang,Yvling Yang,Lijing Zhu,Zhixiang Zeng,Shuan Liu,Yiguo Li,Zhiying Liang
Oil droplets can adsorb on the surface or enter the pore channels during membrane separation , causing a decrease in water flux and increasing the number of washing and replacements, thus increasing costs. So, membrane fouling seriously limits the use of the membrane in the purification of wastewater containing oils. Generally, the underwater superoleophobic surface provides better resistance to oils, which can be fabricated by the synergistic effects of the rough structure and hydrophilic groups are required. Here, poly(vinylidene fluoride)/poly(2-hydroxyethyl methacrylate) (PVDF/PHEMA) composite membranes with the continuous sponge-like rough structure were prepared by the vapor-induced phase separation process (VIPS), and then they were furthermore co-deposited by tannic acid (TA) and N-aminoethyl piperazine propane sulfonate (AEPPS). The zwitterionic surfaces with excellent underwater anti-oil adhesion ability can efficiently separate crude oil-in-water having the flux 1056 ± 102 L m −2 h −1 bar −1 and toluene-in-water emulsions having the flux of 1593 ± 163 L m −2 h −1 bar −1 , the separation efficiency is more than 99%. Moreover, they exhibit excellent underwater anti-oil adhesion ability, excellent stability, and reversibility. Our work develops rough and porous surfaces with stable underwater superoleophobicity in an efficient way, which enables the resulting membranes to be used in the continuous purification of oily wastewater.
研究领域:
材料科学
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环境工程
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2017
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IF 3.359
Guosheng Wang,Chuanyang Zhang,Mengjie Sun,Xu Zhang,Cuiming Wu,Yonghui Wu
Porous sulfonated polyethersulfone and polysulfone (SPES and SPSf) cation exchange membranes were prepared by phase inversion process, in which water was used as the coagulation bath at 4 °C or 25 °C. Dense SPES and SPSf cation exchange membranes were also prepared for comparison. Characterizations of the membrane structure, morphology and physico-chemical properties showed that the dense membranes are hydrophobic with large area resistance (>80 Ω cm 2 ), while the porous membranes are hydrophilic with low area resistance (0.35–18.62 Ω cm 2 ). The porous SPSf membranes have lower area resistance (0.35–0.81 Ω cm 2 ) than SPES membranes due to their higher water uptake (289.1–370.1%) and special morphology containing oval-shaped pores in the top skin layer. The membranes are utilized in bipolar membrane electrodialysis (BMED) process to separate the mixed amino acids of l -glutamic acid (Glu) and l -lysine (Lys). Though the dense membranes are unsuitable for electrodialysis experiments due to the large area resistance, the porous membranes have higher recovery ratio and current efficiency than the commercial membrane CMX, for the Lys + can migrate through the porous membranes with lower hindrance. In addition, the SPSf membranes have higher Glu leakage ratio (13.9–15.3%) and lower energy consumption (4.82–6.52 kWh/kg) than the SPES membranes (∼0%, 6.43–9.53 kWh/kg). What’s more, the water permeation can be controlled by membrane materials and pore structures.
研究领域:
化学工程
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生物技术
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产品关联
DOI
高影响因子
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
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2018
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IF 2.891
Bo Gao,Weiping Chen,Jiadong Liu,Jiajun An,Lei Wang,Ying Zhu,Mika Sillanpää
Based on the concept of dynamic membrane and photocatalytic membrane reactor (PMR), the dynamic photocatalytic membrane reactor is developed via deposition of ZnIn 2 S 4 suspension on polyvinylidene fluoride (PVDF) membrane. Operating with effluent circulating to the photocatalytic membrane reactor, the highest total organic carbon (TOC) removal efficiency of 57% is obtained after 3 h reaction with 1.88 mg cm −2 photocatalyst under the flux of 84.06 L m −2 h −1 and light intensity of 50 mW cm −2 . Operating with continuous influent and effluent mode under the flux of 26.09 L m −2 h −1 and light intensity of 50 mW cm −2 , an average of 50% removal efficiency can be maintained during the 24 h photocatalytic reaction with photocatalyst loading of 1.88 mg cm −2 when the initial concentration of tetracycline is 10 mg L −1 . Under the same operating conditions, more than 92% removal efficiency can be maintained during 36 h photocatalytic reaction when lower initial concentration of 100 μg L −1 is applied. After this reaction, the characterizations show that the surface and structure of PVDF basement membrane are not affected.
研究领域:
环境科学
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化学工程
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产品关联
DOI
高影响因子
Membranes
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2022
·Vol. 12
·期 1
·65
·
IF 4.562
Jun Pan,Kun Chen,Zhaoliang Cui,Omar Bamaga,Mohammed Albeirutty,Abdulmohsen Omar Alsaiari,Francesca Macedonio,Enrico Drioli
Due to the good hydrophobicity and chemical resistance of poly(ethylene trifluoroethylene) (ECTFE), it has been an attractive potential material for microfiltration, membrane distillation and more. However, few porous hydrophobic ECTFE membranes were prepared by thermally induced phase separation (TIPS) for membrane condenser applications. In this work, the diluent, di-n-octyl phthalate (DnOP), was selected to prepare the dope solutions. The calculated Hassen solubility parameter indicated that ECTFE has good compatibility with DnOP. The corresponding thermodynamic phase diagram was established, and it has been mutually verified with the bi-continuous structure observed in the SEM images. At 30 wt% ECTFE, the surface contact angle and liquid entry pressure reach their maximum values of 139.5° and 0.71 MPa, respectively. In addition, some other basic membrane properties, such as pore size, porosity, and mechanical properties, were determined. Finally, the prepared ECTFE membranes were tested using a homemade membrane condenser setup. When the polymer content is 30 wt%, the corresponding results are better; the water recovery and condensed water yield is 17.6% and 1.86 kg m−2h−1, respectively.Keywords:membrane condenser;hydrophobic membrane;ECTFE membrane;thermally induced phase separation
研究领域:
化学工程
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材料科学
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膜技术
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产品关联
DOI
PubMed
高影响因子
COLLOID AND POLYMER SCIENCE
·
2021
·Vol. 300
·期 4
·297-307
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IF 1.931
Hu Yuning,Gong Fangling,Yan Xingran,Li Tong,Chen Jingkun,Wei Wei,Ma Guanghui
The low percentage of pores at which droplets are formed results in lower production efficiency, which is one of the main issues hampering the application of microporous membrane emulsification on a large scale. The effect of microporous membrane pore activation on the droplet’s formation and emulsion performance was systemically investigated by changing both transmembrane pressures and membrane wettability during membrane emulsification. It indicated that the high transmembrane pressure increased the pore activation ratio (the percentage of pores at which droplets are formed) by the growing flux. These induced the enhancements of emulsification efficiency and the degradation of emulsion performance. Different wettability of membrane inflow and outflow influenced the pore activation speed (the speed which droplets are formed at pores). It indicated that the wettability of membrane outflow had a key effect on droplet formation and the high pore activation speed avoided splashing for high emulsion performance.
研究领域:
化学工程
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材料科学
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胶体与界面科学
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产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2024
·
IF 8.4
Jiaojiao Zhang,Xin Yang,Na Zhang,Zhimin Tao,Linxin Han,Bing Wei,Ruiyao Qi,Yunke Fu,Zhining Wang
Thermally driven membrane distillation (MD) has garnered significant attention in hypersaline solution treatment. However, MD membranes suffer from inevitable membrane fouling and wetting owing to its inherent hydrophobicity and the complex composition of wastewater. Herein, dense polyamide (PA) Janus membranes based on both polyvinyl alcohol (PVA) and aramid nanofiber (ANF) intermediate layers are fabricated atop the hydrophobic polytetrafluoroethylene (PTFE) substrate via a coating-assisted interfacial polymerization (IP) method. The PVA and ANF hydrophilic coatings provide a favorable interface condition for the IP process to facilitate the introduction of a complete and dense PA layer. While treating the oily saline feed, both PA Janus membranes can significantly resist fouling owing to hydrophilic PA composite layers. When treating saline feed containing a high sodium dodecyl sulfate (SDS) surfactant, the PA/PVA PTFE membrane might experience progressive wetting with a prolonged operation time caused by SDS penetrating through the PA/PVA composite layer, while the PA/ANF PTFE membrane exhibits robust wetting resistance. Benefiting from ANF coating with superior swelling resistance and thermal stability conducive to maintain a denser and more complete PA layer compare to PVA coating, the PA/ANF PTFE membrane simultaneously resists wetting and fouling when dealing with a complex saline solution containing both oil and SDS surfactant, which is confirmed by its stable flux and low permeate conductivity in the continuous MD operation for 100 h. Scalable fabrication process and robust performance of the composite membrane endow it with great potential in saline wastewater desalination practicability.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2018
·
IF 3.927
Yanni Liu,Zhi Wang,Song Zhao,Xiaochang Cao,Nan Li,Jixiao Wang,Shichang Wang
Impacts of substrate membrane storage conditions, which might have special significance in the industry and laboratory research of composite membranes, are rarely reported. Herein, the polysulfone ultrafiltration membrane was chosen as a typical substrate membrane and differences between substrate membranes stored in wet and dry conditions were discussed. An easy-operational hydrothermal pretreatment method was therefore proposed to regenerate the dry substrate membranes. The substrate membranes were heated in deionized water, and the pore morphology was significantly improved after the pretreatment. Three types of additives were applied to improve the effects of pretreatment and the effects of the hydrothermal pretreatment turned to be stronger as the concentration of the additive increased. Membrane structure parameters were investigated and the dry support membranes pretreated with 3.0% or 6.0% molar fraction ethanol displayed approaching structure parameters with wet membranes pretreated with the same conditions, which means the dry substrate membranes were successfully regenerated. Poly(vinylamine)-polysulfone composite membranes were prepared with polysulfone substrates before and after pretreatment, and tested by using CO 2 /N 2 (15/85 by volume) mixed gas. Composite membranes prepared with wet and dry polysulfone substrates pretreated with 3.0% molar fraction ethanol exhibited similar CO 2 permeance, which confirmed that the dry substrate membranes were effectively regenerated.
研究领域:
材料科学
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环境工程
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产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2022
·
IF 10.53
Dejun Feng,Xianhui Li,Zhangxin Wang
Membrane wetting, fouling, and scaling are three prominent challenges that limit membrane distillation (MD) applications. To overcome these challenges, novel MD membranes including omniphobic membranes and Janus membranes with a dense hydrophilic surface layer have been developed. In this study, we fabricated an omniphobic membrane and a Janus membrane composed of a dense polyvinyl alcohol (PVA) surface layer and a polyvinylidene fluoride (PVDF) substrate. The two membranes have been compared in MD experiments with different feeds. Furthermore, the working mechanisms of the two membranes have been elucidated. As a result, neither the omniphobic MD membrane nor the Janus MD membrane can resolve all three challenges at the same time. Specifically, both the omniphobic MD membrane and Janus MD membrane can resist wetting but via different working mechanisms. From breakthrough pressure (BP) determinations with an ethanol-water mixture (i.e., a low-surface-tension liquid), the omniphobic MD membrane resists wetting as its LEP (82.0 ± 9.2 kPa) is larger than the transmembrane pressure in the MD operation, while the Janus MD membrane resists wetting because the huge capillary pressure (550 ± 50 kPa) in the dense hydrophilic surface layer retains the wetting solution. The omniphobic MD membrane is prone to oil fouling because of the strong underwater hydrophobic attraction between the membrane surface and the mineral oil droplets, while the Janus MD membrane can substantially mitigate fouling due to the lack of attraction between the mineral oil droplets and the hydrophilic membrane surface. The omniphobic MD membrane exhibits outstanding scaling resistance because minerals can hardly precipitate and/or crystalize on the membrane surface, while the Janus MD membrane was susceptible to scaling due to the precipitation and/or crystallization of minerals inside the hydrophilic surface layer. Therefore, the selection of MD membranes should depend on the feed constituents. Overall, our study provides important guidelines for the future development of robust MD membranes.
研究领域:
材料科学
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环境工程
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产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2023
·
IF 9.5
Hailan Wang,Ya Xu,Bozhan Ma,Wenxuan Zou,Jin Zeng,Ruobin Dai,Zhiwei Wang
Environmental and economic concerns necessitate the recycle of end-of-life (EOL) reverse osmosis (RO) membranes. Controlled downcycling of EOL RO membrane to nanofiltration (NF)-like or ultrafiltration (UF)-like membrane through regulating sodium hypochlorite (NaClO) exposure doses has been developed in recent years. However, the impact of foulants on the chlorination-based membrane downcycling is often overlooked. An alkaline-NaClO treatment strategy was employed to downcycle Si-Al complex-fouled EOL RO membrane. Alkaline cleaning not only partially removed Si-Al complex foulants via dissolution, but also converted Al 2 O 3 ·SiO 2 to Al-O-Si amorphous oxides . Subsequent NaClO treatment gradually deconstructed the Si-Al complex fouling layer by dissolving Al contained in Al-O-Si amorphous oxides and degraded the polyamide (PA) layer with extended exposure time, resulting in membrane with loose NF-like characteristic. Moreover, the conversion of Al-contained component with alkaline pre-treatment prevented Al 3+ -catalyzed degradation of PA layer and ensure controlled downcycling. For the downcycling to UF-like membrane, complete removal of PA layer with sufficient chlorine oxidation was essential while alkaline pre-treatment process was optional. Both downcycled loose NF-like and UF-like membranes exhibited satisfactory filtration and antifouling performance. Our study presents an effective and robust protocol for controllable downcycling of EOL RO membrane with alkaline pre-treatment based on their fouling characteristic.
研究领域:
环境科学
·
材料科学
·
水处理工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Water Process Engineering
·
2022
·
IF 7.34
Lin Chen,Fangqing Li,Longjie Jiang,Fudong He,Yufei Wei
Polytetrafluoroethylene (PTFE) hydrophobic membranes used in direct contact membrane distillation (DCMD) processes were prone to fouling and wetting by oil and surfactants, which hampered their broad industrial application. In this work, a new Janus composite membrane was developed by modifying UiO-66-NH 2 with polyvinyl alcohol (PVA) as a cross-linking agent and immobilizing the modified UiO-66-NH 2 on the PTFE membrane by vacuum filtration. By tuning the ratio of PVA to MOF , an optimally proportioned Janus membrane was obtained, and its performance was tested in DCMD experiments through the use of a sodium chloride feed solution containing hexadecane and sodium dodecyl sulfate. The top layer of this Janus membrane exhibited underwater oleophobicity (130.1 ± 0.96°) and hydrophilicity in the air (54.0 ± 0.92°), while the bottom layer is hydrophobic (132.3 ± 0.97°). Compared to the pristine PTFE membrane, the modified Janus membrane demonstrated promising resistance to both membrane fouling and wetting of oils and surfactants. The desalination rate of 99.99% was still achieved within 24 h with the conductivity remaining lower than 10 μS/cm and the flux maintained at 21.3 L/(m 2 ·h). As a result, the Janus composite membrane developed in this study was shown to be a prospective alternative for treating wastewater containing oily substances and surfactants in a resourceful manner.
研究领域:
材料科学
·
环境工程
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产品关联
DOI
高影响因子
Membranes
·
2020
·Vol. 10
·期 1
·12
·
IF 3.094
Xi Yang
The interfacial polymerization (IP) of piperazine (PIP) and trimesoyl chloride (TMC) has been extensively utilized to synthesize nanofiltration (NF) membranes. However, it is still a huge challenge to monitor the IP reaction, because of the fast reaction rate and the formed ultra-thin film. Herein, two effective strategies were applied to reduce the IP reaction rate: (1) the introduction of hydrophilic interlayers between the porous substrate and the formed polyamide layer, and (2) the addition of macromolecular additives in the aqueous solution of PIP. As a result, in situ Fourier transform infrared (FT-IR) spectroscopy was firstly used to monitor the IP reaction of PIP/TMC with hydrophilic interlayers or macromolecular additives in the aqueous solution of PIP. Moreover, the formed polyamide layer growth on the substrate was studied in a real-time manner. The in situ FT-IR experimental results confirmed that the IP reaction rates were effectively suppressed and that the formed polyamide thickness was reduced from 138 ± 24 nm to 46 ± 2 nm according to TEM observation. Furthermore, an optimized NF membrane with excellent performance was consequently obtained, which included boosted water permeation of about 141–238 (L/m2·h·MPa) and superior salt rejection of Na2SO4> 98.4%.Keywords:interfacial polymerization;in situ FT-IR spectroscopy;thin-film composite membrane;nanofiltration membrane
研究领域:
材料科学
·
化学工程
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产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）