The Experts below are selected from a list of 7890 Experts worldwide ranked by ideXlab platform
Xihui Zhang - One of the best experts on this subject based on the ideXlab platform.
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effect of pre ozonation on mitigation of ceramic uf membrane fouling caused by algal extracellular organic matters
Chemical Engineering Journal, 2016Co-Authors: Zhenghua Zhang, Xihui ZhangAbstract:Abstract Soluble extracellular organic matters (EOM) resulting from algal blooms in water sources can cause severe membrane fouling in water treatment. The effect of pre-ozonation on mitigation of ceramic UF membrane fouling caused by EOM released from Microcystis aeruginosa and the associated fouling mitigation mechanism were investigated through the characterization of hydraulic performance, dissolved organic carbon (DOC), fluorescence excitation–emission matrix (EEM) spectra, molecular weight (MW) distribution, hydrophilicity and model fit of five combined fouling models. Pre-ozonation achieved a remarkable effect of hydraulically reversible fouling mitigation as a result of the selective oxidation of the very high MW hydrophobic biopolymers (⩾20 kDa) to lower MW and more hydrophilic compounds. However, pre-ozonation had a very limited effect on mitigation of hydraulically irreversible fouling dominated by the high MW (1–10 kDa) hydrophilic organics. Modeling results indicated that the EOM-related membrane fouling mitigation by pre-ozonation was more likely ascribed to the alleviation of cake layer and standard Pore Blocking with standard Pore Blocking playing a more important role.
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effect of pre ozonation on mitigation of ceramic uf membrane fouling caused by algal extracellular organic matters
Chemical Engineering Journal, 2016Co-Authors: Dequan Wei, Zhenghua Zhang, Yi Tao, Xihui ZhangAbstract:Abstract Soluble extracellular organic matters (EOM) resulting from algal blooms in water sources can cause severe membrane fouling in water treatment. The effect of pre-ozonation on mitigation of ceramic UF membrane fouling caused by EOM released from Microcystis aeruginosa and the associated fouling mitigation mechanism were investigated through the characterization of hydraulic performance, dissolved organic carbon (DOC), fluorescence excitation–emission matrix (EEM) spectra, molecular weight (MW) distribution, hydrophilicity and model fit of five combined fouling models. Pre-ozonation achieved a remarkable effect of hydraulically reversible fouling mitigation as a result of the selective oxidation of the very high MW hydrophobic biopolymers (⩾20 kDa) to lower MW and more hydrophilic compounds. However, pre-ozonation had a very limited effect on mitigation of hydraulically irreversible fouling dominated by the high MW (1–10 kDa) hydrophilic organics. Modeling results indicated that the EOM-related membrane fouling mitigation by pre-ozonation was more likely ascribed to the alleviation of cake layer and standard Pore Blocking with standard Pore Blocking playing a more important role.
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effect of in situ ozonation on ceramic uf membrane fouling mitigation in algal rich water treatment
Journal of Membrane Science, 2016Co-Authors: Zhenghua Zhang, Xihui ZhangAbstract:Abstract The presence of seasonal algal blooms with harmful algae-derived organic matters threatens the performance of ultrafiltration in drinking water treatment. The hybrid process of in-situ ozonation with ceramic ultrafiltration membrane was proposed for the treatment of algal-rich water with effective removal of algal cells and mitigation of membrane fouling. The mechanism of membrane fouling mitigation with in-situ ozonation was systematically investigated from the perspective of cake layer, gel layer and membrane Pore Blocking. The results showed that in-situ ozonation treatment can effectively mitigate membrane fouling. For instance, transmembrane pressure was reduced by 75.8% with in-situ ozonation at 1 mg/L. In-situ ozonation resulted in the formation of a more porous and thinner cake layer due to the disintegration of extracellular organic matters that attached on the algal surface. Besides, the portion of very high molecular weight biopolymers (around 100 kDa) and the hydrophobic fraction of algae-derived organic matters, the main component intercepted by the ceramic membrane, were reduced with in-situ ozonation and thus leaded to less severe gel layer fouling. Furthermore, in-situ ozonation induced the accelerated organics degradation within the ceramic membrane Pores, alleviating the membrane Pore Blocking.
Zhenghua Zhang - One of the best experts on this subject based on the ideXlab platform.
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effect of pre ozonation on mitigation of ceramic uf membrane fouling caused by algal extracellular organic matters
Chemical Engineering Journal, 2016Co-Authors: Zhenghua Zhang, Xihui ZhangAbstract:Abstract Soluble extracellular organic matters (EOM) resulting from algal blooms in water sources can cause severe membrane fouling in water treatment. The effect of pre-ozonation on mitigation of ceramic UF membrane fouling caused by EOM released from Microcystis aeruginosa and the associated fouling mitigation mechanism were investigated through the characterization of hydraulic performance, dissolved organic carbon (DOC), fluorescence excitation–emission matrix (EEM) spectra, molecular weight (MW) distribution, hydrophilicity and model fit of five combined fouling models. Pre-ozonation achieved a remarkable effect of hydraulically reversible fouling mitigation as a result of the selective oxidation of the very high MW hydrophobic biopolymers (⩾20 kDa) to lower MW and more hydrophilic compounds. However, pre-ozonation had a very limited effect on mitigation of hydraulically irreversible fouling dominated by the high MW (1–10 kDa) hydrophilic organics. Modeling results indicated that the EOM-related membrane fouling mitigation by pre-ozonation was more likely ascribed to the alleviation of cake layer and standard Pore Blocking with standard Pore Blocking playing a more important role.
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effect of pre ozonation on mitigation of ceramic uf membrane fouling caused by algal extracellular organic matters
Chemical Engineering Journal, 2016Co-Authors: Dequan Wei, Zhenghua Zhang, Yi Tao, Xihui ZhangAbstract:Abstract Soluble extracellular organic matters (EOM) resulting from algal blooms in water sources can cause severe membrane fouling in water treatment. The effect of pre-ozonation on mitigation of ceramic UF membrane fouling caused by EOM released from Microcystis aeruginosa and the associated fouling mitigation mechanism were investigated through the characterization of hydraulic performance, dissolved organic carbon (DOC), fluorescence excitation–emission matrix (EEM) spectra, molecular weight (MW) distribution, hydrophilicity and model fit of five combined fouling models. Pre-ozonation achieved a remarkable effect of hydraulically reversible fouling mitigation as a result of the selective oxidation of the very high MW hydrophobic biopolymers (⩾20 kDa) to lower MW and more hydrophilic compounds. However, pre-ozonation had a very limited effect on mitigation of hydraulically irreversible fouling dominated by the high MW (1–10 kDa) hydrophilic organics. Modeling results indicated that the EOM-related membrane fouling mitigation by pre-ozonation was more likely ascribed to the alleviation of cake layer and standard Pore Blocking with standard Pore Blocking playing a more important role.
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effect of in situ ozonation on ceramic uf membrane fouling mitigation in algal rich water treatment
Journal of Membrane Science, 2016Co-Authors: Zhenghua Zhang, Xihui ZhangAbstract:Abstract The presence of seasonal algal blooms with harmful algae-derived organic matters threatens the performance of ultrafiltration in drinking water treatment. The hybrid process of in-situ ozonation with ceramic ultrafiltration membrane was proposed for the treatment of algal-rich water with effective removal of algal cells and mitigation of membrane fouling. The mechanism of membrane fouling mitigation with in-situ ozonation was systematically investigated from the perspective of cake layer, gel layer and membrane Pore Blocking. The results showed that in-situ ozonation treatment can effectively mitigate membrane fouling. For instance, transmembrane pressure was reduced by 75.8% with in-situ ozonation at 1 mg/L. In-situ ozonation resulted in the formation of a more porous and thinner cake layer due to the disintegration of extracellular organic matters that attached on the algal surface. Besides, the portion of very high molecular weight biopolymers (around 100 kDa) and the hydrophobic fraction of algae-derived organic matters, the main component intercepted by the ceramic membrane, were reduced with in-situ ozonation and thus leaded to less severe gel layer fouling. Furthermore, in-situ ozonation induced the accelerated organics degradation within the ceramic membrane Pores, alleviating the membrane Pore Blocking.
Shane A Snyder - One of the best experts on this subject based on the ideXlab platform.
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reducing ultrafiltration membrane fouling during potable water reuse using pre ozonation
Water Research, 2017Co-Authors: Hui Wang, Heng Liang, Shane A Snyder, Minkyu Park, Israel J LopezAbstract:Abstract Wastewater reclamation has increasingly become popular to secure potable water supply. Low-pressure membrane processes such as microfiltration (MF) and ultrafiltration (UF) play imperative roles as a barrier of macromolecules for such purpose, but are often limited by membrane fouling. Effluent organic matter (EfOM), including biopolymers and particulates, in secondary wastewater effluents have been known to be major foulants in low-pressure membrane processes. Hence, the primary aim of this study was to investigate the effects of pre-ozonation as a pre-treatment for UF on the membrane fouling caused by EfOM in secondary wastewater effluents for hydrophilic regenerated cellulose (RC) and hydrophobic polyethersulfone (PES) UF membranes. It was found that greater fouling reduction was achieved by pre-ozonation for the hydrophilic RC membrane than the hydrophobic PES membrane at increasing ozone doses. In addition, the physicochemical property changes of EfOM, including biopolymer fractions, by pre-ozonation were systemically investigated. The classical Pore Blocking model and the extended Derjaguin−Landau−Verwey−Overbeek (XDLVO) theories were employed to scrutinize the fouling alleviation mechanism by pre-ozonation. As a result, the overarching mechanisms of fouling reduction were attributed to the following key reasons: (1) Ozone degraded macromolecules such as biopolymers like proteins and polysaccharides into smaller fractions, thereby increasing free energy of cohesion of EfOM and rendering them more hydrophilic and stable; (2) pre-ozonation augmented the interfacial free energy of adhesion between foulants and the RC/PES membranes, leading to the increase of repulsions and/or the decrease of attractions; and (3) pre-ozonation prolonged the transition from Pore Blocking to cake filtration that was a dominant fouling mechanism, thereby reducing fouling.
G Pugazhenthi - One of the best experts on this subject based on the ideXlab platform.
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dairy wastewater treatment using a novel low cost tubular ceramic membrane and membrane fouling mechanism using Pore Blocking models
Journal of water process engineering, 2016Co-Authors: Vinoth R Kumar, Lalit N Goswami, Kannan Pakshirajan, G PugazhenthiAbstract:Abstract This study investigated the potential application of a novel low cost tubular ceramic membrane in treating wastewater generated by a local dairy industry. The low cost tubular membrane ($0.5) with 0.309 μm Pore size, 53% porosity and 5.93 × 10−7 m3/m2s kPa water permeability was fabricated from natural clay materials by extrusion technique. The capability of the membrane for treating real dairy industry wastewater was tested in tangential mode of microfiltration operation at different applied pressure (207–414 kPa) and cross flow rate (5.55 × 10−7–2.22 × 10−6 m3/s). An increase in applied pressure and cross flow rate on the microfiltration process resulted in a decrease in percentage removal of chemical oxygen demand (COD). The novel membrane achieved a maximum reduction in COD up to 91% (135 mg/L) in the permeate stream with a flux of 2.59 × 10−6 m3/m2s, which is well within the permissible limit for wastewater discharge into the environment. These investigations affirmed the potential suitability of the membrane in dairy wastewater treatment to attain acceptable limit (
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elaboration of novel tubular ceramic membrane from inexpensive raw materials by extrusion method and its performance in microfiltration of synthetic oily wastewater treatment
Journal of Membrane Science, 2015Co-Authors: Vinoth R Kumar, Aloke Kumar Ghoshal, G PugazhenthiAbstract:Abstract A tubular ceramic microfiltration membrane was prepared by an extrusion technique using inexpensive clay mixtures namely, ball clay, kaolin, feldspar, quartz, pyrophyllite and calcium carbonate. The mixture of clay powders extruded to form a porous tubular membrane without the addition of any organic additives. The dimensions, such as outer and inner diameters, wall thickness and length of the tube are 11.5, 5.5, 3 and 100 mm, respectively. The sintered membrane possesses the porosity of 53%, water permeability of 5.93×10−7 m/s kPa, an average Pore size of 0.309 μm and mechanical strength of 12 MPa with very good corrosion resistance in acidic and basic conditions. The fabricated membrane is expected to have potential applications in the pretreatment and also can be used as support for ultrafiltration membranes. With this intention, the membrane is subjected to microfiltration of synthetic oily wastewater emulsion experiments at various combinations of applied pressures (69–345 kPa), feed concentrations (50–200 ppm) and cross flow rates (5.55×10−7–1.66×10−6 m3/s). An increase in the applied pressure and flow rate of oily wastewater emulsion result a decreased oil rejection while, an increase in the oil concentration results in enhanced rejection. The applied pressure of 69 kPa offers the highest rejection of oily wastewater (99.98%) with permeate flux of 3.16×10−5 m/s. Additionally, the membrane fouling mechanisms are investigated using diverse Pore Blocking models (complete, standard, intermediate Pore Blocking and cake filtration model) with obtained experimental data. It is found that the experimental results are well described by the cake filtration model. Finally, the rejection potential of the membrane is compared with other membranes reported in the literature.
Stefan Kaskel - One of the best experts on this subject based on the ideXlab platform.
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insights into the redistribution of sulfur species during cycling in lithium sulfur batteries using physisorption methods
Nano Energy, 2017Co-Authors: Patrick Strubel, Soren Thieme, Christine Weller, Holger Althues, Stefan KaskelAbstract:Abstract Nitrogen physisorption was used to analyze textural transformations in lithium-sulfur cathodes during cycling for two alternate electrolyte systems. Significant impact of the electrolyte type on the accessible cathode porosity in the charged vs. discharged state was detected, providing important insights in the cells conversion mechanism and the role of polysulfide solubility. The main advantage of the method lies in the resolution of Pore accessibility and size distributions. Thus, depending on the state of charge (SoC), the C-rate used for cycling as well as electrolyte properties (i.e. polysulfide solvation), significant differences in the redistribution of active sulfur species as well as Pore Blocking effects can be identified. This methodology might facilitate interpretation and further optimization to achieve long-term stable lithium-sulfur batteries.
