The Experts below are selected from a list of 17475 Experts worldwide ranked by ideXlab platform
Beibei Tang - One of the best experts on this subject based on the ideXlab platform.
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optimization characterization and nanofiltration properties test of mwnts polyester thin film nanocomposite Membrane
Journal of Membrane Science, 2013Co-Authors: Beibei TangAbstract:Abstract MWNTs/polyester thin film nanocomposite (TFN) Membranes were prepared through an improved process by interfacial polymerization of triethanolamine (TEOA) and trimesoyl chloride (TMC) on the polysulfone (PSf) supporting Membrane in the presence of multi-walled carbon nanotubes (MWNTs). The effect of MWNTs concentration and surfactant species in the aqueous phase as well as the reaction time of interfacial polymerization on the Membrane properties were investigated. The water permeability increased as the MWNTs concentration in aqueous phase increased up to 0.5 mg/mL, reaching a maximum which was nearly double that of the thin film Membrane without MWNTs, while the Membrane Rejection kept increasing dramatically. Compared with cationic (CTAB) and non-ionic (Triton X-100) surfactants, anionic (SDS) surfactant was more suitable for the preparation of TFN Membrane. The reaction time determined the extent of interfacial polymerization and the integrality of surface skin layer. Furthermore, the nanofiltration properties of the MWNTs/polyester TFN Membrane were tested by examining the separation performance of different feed solutions, feed concentrations, feed pHs at 0.6 MPa operating pressure. Additionally, the MWNTs/polyester TFN Membrane exhibited a good long-term stability.
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mwnts polyester thin film nanocomposite Membrane an approach to overcome the trade off effect between permeability and selectivity
Journal of Physical Chemistry C, 2010Co-Authors: Beibei TangAbstract:An improved process to prepare MWNTs/polyester thin film nanocomposite Membranes was initiated by interfacial polymerization of trimesoyl chloride (TMC) and triethanolamine (TEOA) solution containing MWNTs. The improved process was facilely done by immersing the support Membrane into the organic phase before the conventional process of interfacial polymerization. The TEM images showed that the MWNTs were embedded throughout the polyester thin film layer. The MWNTs/polyester thin film nanocomposite Membrane prepared via the improved process exhibited both high permeability and excellent selectivity when compared with the thin film composite Membrane without MWNTs and the MWNTs/polyester thin film nanocomposite Membrane prepared via the conventional process. The water permeability increased upon an increase of reaction time of TMC-saturated support Membrane immersed into aqueous phase (step-1), reaching a maximum of 4.7 L/m2 h at 25 min, while the Membrane Rejection rate kept increasing. The role of step-1 ...
Chuyang Y Tang - One of the best experts on this subject based on the ideXlab platform.
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a highly selective surface coating for enhanced Membrane Rejection of endocrine disrupting compounds mechanistic insights and implications
Water Research, 2017Co-Authors: Hao Guo, Yu Deng, Zhikan Yao, Jianqiang Wang, Chuner Lin, Tong Zhang, Baoku Zhu, Zhe Yang, Chuyang Y TangAbstract:Abstract We designed a highly selective surface coating to achieve enhanced Rejection of endocrine disrupting compounds (EDCs) by nanofiltration Membranes. A commercial NF90 Membrane was first coated with polydopamine (PDA) followed by in situ immobilization of silver nanoparticles (AgNPs). This PDA/AgNPs coating greatly improved EDC Rejection at the expense of slight water permeability loss (4–10%). This improvement in Rejection can be attributed to a combination of enhanced size exclusion and suppressed hydrophobic interaction. A resistance-in-series analysis further reveals that the coating was highly permeable to water but highly resistant to EDCs, leading to an EDC selectivity that was an order of magnitude greater than those of the bare PDA coating and the base Membrane NF90. The current study provides important insights into the design of highly selective coatings for effective retention of targeted trace organic contaminants.
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does hydrophilic polydopamine coating enhance Membrane Rejection of hydrophobic endocrine disrupting compounds
Environmental Science and Technology Letters, 2016Co-Authors: Hao Guo, Yu Deng, Zhijia Tao, Zhikan Yao, Jianqiang Wang, Chuner Lin, Tong Zhang, Baoku Zhu, Chuyang Y TangAbstract:Endocrine-disrupting compounds (EDCs), an important class of micropollutants with potent adverse health effects, are generally poorly rejected by traditional thin film composite polyamide Membranes and thus pose significant risks in Membrane-based water reclamation. We hypothesize that Membrane Rejection of hydrophobic EDCs can be enhanced by a hydrophilic surface coating. Using polydoamine (PDA) as a model hydrophilic coating layer, the PDA-coated NF90 Membrane experienced an up to 75% reduction in the passage of bisphenol A compared to the control (NF90 without coating). Meanwhile, we also observed a systematic increase in the level of Rejection of three hydrophobic parabens with an increase in PDA coating time. In contrast, there were no systematic changes in the Rejection of neutral hydrophilic polyethylene glycol, which suggests that the enhanced Rejection of EDCs was due to weakened EDC–Membrane hydrophobic interaction. Further sorption tests revealed that the hydrophilic PDA coating could effective...
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mesoporous silica gel based mixed matrix Membranes for improving mass transfer in forward osmosis effect of pore size of filler
Scientific Reports, 2015Co-Authors: Yining Wang, Chuyang Y TangAbstract:The efficiency of forward osmosis (FO) process is generally limited by the internal concentration polarization (ICP) of solutes inside its porous substrate. In this study, mesoporous silica gel (SG) with nominal pore size ranging from 4–30 nm was used as fillers to prepare SG-based mixed matrix substrates. The resulting mixed matrix Membranes had significantly reduced structural parameter and enhanced Membrane water permeability as a result of the improved surface porosity of the substrates. An optimal filler pore size of ~9 nm was observed. This is in direct contrast to the case of thin film nanocomposite Membranes, where microporous nanoparticle fillers are loaded to the Membrane Rejection layer and are designed in such a way that these fillers are able to retain solutes while allowing water to permeate through them. In the current study, the mesoporous fillers are designed as channels to both water and solute molecules. FO performance was enhanced at increasing filler pore size up to 9 nm due to the lower hydraulic resistance of the fillers. Nevertheless, further increasing filler pore size to 30 nm was accompanied with reduced FO efficiency, which can be attributed to the intrusion of polymer dope into the filler pores.
Xia Huang - One of the best experts on this subject based on the ideXlab platform.
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direct concentration of municipal sewage by forward osmosis and Membrane fouling behavior
Bioresource Technology, 2018Co-Authors: Zhou Fang, Peng Liang, Xia HuangAbstract:Abstract Forward osmosis (FO) draws attention due to its advantages compares to traditional pressure-driven Membrane processes. In this study, a FO Membrane concentrating system was built for sewage concentration to investigate Membrane Rejection, concentrating effect, Membrane fouling behavior. Sewage could be concentrated to 1/10 original volume by FO Membrane, while pollutants concentrating multiple could not reach 10. The FO Membrane had excellent rejecting effect, with effluent COD, ammonia nitrogen, total nitrogen, total phosphorus concentration of 18, 2.5, 2.8, 0.4 mg/L, respectively. The FO Membrane flux was mainly associated with the draw solution (DS) concentration, which increased with DS concentration but more severe Membrane fouling engendered in the meantime. Scanning electronic microscope and fourier transform infrared spectroscopy analysis indicated the formation and constitution of the fouling layer, which included humic acid, protein, and polysaccharide. After concentration, fouled FO Membrane was remitted by physical and chemical cleaning, with recovery of 90% and 96%.
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indigenous somatic coliphage removal from a real municipal wastewater by a submerged Membrane bioreactor
Water Research, 2010Co-Authors: Xia HuangAbstract:Abstract The Membrane bioreactor (MBR) features many advantages, such as its excellent effluent quality and compactness. Moreover, the MBR is well known for its disinfectant capacity. This paper investigates virus removal performance for municipal wastewater using a submerged MBR and the operational conditions affecting the virus removal using indigenous somatic coliphages (SC) as an indicator for viruses. The results revealed that the municipal wastewater acquired by the Qinghe Municipal Wastewater Treatment Plant, Beijing, contained an SC concentration of (2.81 ± 1.51) × 10 4 PFU ml −1 , which varies seasonally due to spontaneous decay. In the MBR system, the biomass process dominates SC removal. Membrane Rejection is an essential supplement of biomass process for SC removal. In this paper, the relative contributions of biomass process and Membrane Rejection during the start-up and steady operational periods are discussed in detail. The major factors affecting SC removal are biodegradation, Membrane pore size, and gel layer formation on the Membrane. During long-term experiments, it was demonstrated that high inoculated sludge concentration, long hydraulic retention time, moderate fouling layer, and non-frequent chemical cleaning are favorable for high SC removal in MBR systems.
Zhiwei Wang - One of the best experts on this subject based on the ideXlab platform.
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Applications of Membrane bioreactors for water reclamation: Micropollutant removal, mechanisms and perspectives.
Bioresource technology, 2018Co-Authors: Ruobin Dai, Mei Chen, Stuart J. Khan, Zhiwei WangAbstract:Abstract Membrane bioreactors (MBRs) have attracted attention in water reclamation as a result of the recent technical advances and cost reduction in Membranes. However, the increasing occurrence of micropollutants in wastewaters has posed new challenges. Therefore, we reviewed the current state of research to identify the outstanding needs in this field. In general, the fate of micropollutants in MBRs relates to sorption, biodegradation and Membrane separation processes. Hydrophobic, nonionized micropollutants are favorable in sorption, and the biological degradation shows higher efficiency at relatively long SRTs (30–40 days) and HRTs (20–30 h), as a result of co-metabolism, metabolism and/or ion trapping. Although the Membrane Rejection rates for micropollutants are generally minor, final water quality can be improved via combination with other technologies. This review highlights the challenges and perspectives that should be addressed to facilitate the extended use of MBRs for the removal of micropollutants in water reclamation.
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role of dissolved organic matters dom in Membrane fouling of Membrane bioreactors for municipal wastewater treatment
Journal of Hazardous Materials, 2010Co-Authors: Shujuan Tang, Zhiwei Wang, Qi ZhouAbstract:Two Membrane bioreactors (MBRs) with different operation conditions were employed to investigate the role of dissolved organic matter (DOM) in Membrane fouling. DOM characteristics and their correlations with Membrane fouling in the MBR systems were studied by using three-dimensional excitation-emission matrix (EEM) fluorescence technology, gel filtration chromatography (GFC) analysis, and column chromatographic method for DOM fractionation, etc. The three-dimensional EEM fluorescence spectroscopy analysis indicated that the fluorescence intensity of protein-like peaks in DOM samples collected from the MBR zones showed positive correlations with Membrane fouling. The fluorescence spectra of Membrane foulants also exhibited two protein-like peaks, confirming that proteins played an important role in Membrane fouling. The DOM samples collected from MBR zones were fractionated into four components, i.e., hydrophobic (HPO), transphilic (TPI), charged hydrophilic (HPI-C) and neutral hydrophilic fractions (HPI-N). It was found that HPI-N was the most abundant fraction in all the samples, accounting for 42.0-48.9% of the total DOM. Test results also showed that HPI-N had the highest fouling potential, which could be attributed to the high molecular weight (MW) distribution and the high Membrane Rejection rate of macromolecules.
Qi Zhou - One of the best experts on this subject based on the ideXlab platform.
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role of dissolved organic matters dom in Membrane fouling of Membrane bioreactors for municipal wastewater treatment
Journal of Hazardous Materials, 2010Co-Authors: Shujuan Tang, Zhiwei Wang, Qi ZhouAbstract:Two Membrane bioreactors (MBRs) with different operation conditions were employed to investigate the role of dissolved organic matter (DOM) in Membrane fouling. DOM characteristics and their correlations with Membrane fouling in the MBR systems were studied by using three-dimensional excitation-emission matrix (EEM) fluorescence technology, gel filtration chromatography (GFC) analysis, and column chromatographic method for DOM fractionation, etc. The three-dimensional EEM fluorescence spectroscopy analysis indicated that the fluorescence intensity of protein-like peaks in DOM samples collected from the MBR zones showed positive correlations with Membrane fouling. The fluorescence spectra of Membrane foulants also exhibited two protein-like peaks, confirming that proteins played an important role in Membrane fouling. The DOM samples collected from MBR zones were fractionated into four components, i.e., hydrophobic (HPO), transphilic (TPI), charged hydrophilic (HPI-C) and neutral hydrophilic fractions (HPI-N). It was found that HPI-N was the most abundant fraction in all the samples, accounting for 42.0-48.9% of the total DOM. Test results also showed that HPI-N had the highest fouling potential, which could be attributed to the high molecular weight (MW) distribution and the high Membrane Rejection rate of macromolecules.