The Experts below are selected from a list of 12195 Experts worldwide ranked by ideXlab platform
Hiroaki Ozaki - One of the best experts on this subject based on the ideXlab platform.
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performance of an ultra low pressure Reverse Osmosis Membrane ulprom for separating heavy metal effects of interference parameters
Desalination, 2002Co-Authors: Hiroaki Ozaki, Kusumakar Sharma, Wilasinee SaktaywinAbstract:Abstract An experimental investigation was conducted to study the performance of an aromatic polyamide (ES 20) ultra-low-pressure Reverse Osmosis Membrane (ULPROM) for separating divalent (Cu 2+ , Ni 2+ ) and hexavalent (Cr 6+ ) heavy metals from bulk solution. The influence of operating pressure, feed concentration, pH, and effect of other ions (Ca 2+ and Mg 2+ ) on the ULPROM performance was studied. The investigation was conducted for synthetic wastewater and wastewater from the heavy metal industry. Experimental results show that the rejection increases with increasing feed pressure, it is dependent on feed pH and is higher at higher pH. Increasing concentration of other ions slightly decreased the rejection of heavy metals. Generally, rejection of heavy metal is found to be greater than 95% for the ULPROM tested, which suggests the suitability of such Membranes for industrial application for recovery of heavy metal and reclaiming wastewater.
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rejection of organic compounds by ultra low pressure Reverse Osmosis Membrane
Water Research, 2002Co-Authors: Hiroaki OzakiAbstract:Abstract The introduction of ultra-low pressure Reverse Osmosis (ULPRO) Membrane has widened the horizon of Reverse Osmosis (RO) in purification of surface water and wastewater as well as desalination of brackish water. The ULPRO Membrane chemistry can provide a high water flux at low operating pressure, while maintaining a very good salt and organics rejection. This paper deals with the investigation on the rejection of low molecular weight organic compounds by ULPRO Membrane. Laboratory scale experiments were carried out at a pressure of 3 kg/cm 2 with a feed flow rate of 1.20 l/min. The rejection of undissociated organic compounds did not show a close relationship with the feed pH. The percentage removal of undissociated organic compounds increased linearly with the molecular weight as well as with the molecular width. The removal efficiency can be predicted by these relationships. But neither molecular weight nor molecular width can be considered as an absolute factor for rejection. The feed pH also influenced the removal efficiency of dissociated organic compounds. The efficiency decreased linearly with the increase in the dissociation constant.
Guodong Kang - One of the best experts on this subject based on the ideXlab platform.
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surface modification of a commercial thin film composite polyamide Reverse Osmosis Membrane by carbodiimide induced grafting with poly ethylene glycol derivatives
Desalination, 2011Co-Authors: Guodong Kang, Haijun YuAbstract:Based on the existing carboxylic acid groups on surface of used commercial thin film composite polyamide Reverse Osmosis Membrane, two kinds of poly(ethylene glycol) derivatives with different chains were grafted by carbodiimide-induced method to improve the antifouling property. The Membranes before and after modification were characterized by attenuated total reflectance Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy and static contact angle measurement. Moreover, the water flux, NaCl rejection and fouling experiments were also conducted. The changes of chemical composition and morphology on Membrane surfaces indicated the successful grafting of poly(ethylene glycol) derivatives. Compared to unmodified Membrane, the modified Membranes were more resistant to fouling in protein and cationic surfactant feeding solutions. The method in this study provided a new way for surface modification of commercial polyamide Reverse Osmosis Membranes.
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study on hypochlorite degradation of aromatic polyamide Reverse Osmosis Membrane
Journal of Membrane Science, 2007Co-Authors: Guodong Kang, Weidong Chen, Quan YuanAbstract:A serious limitation of most commercial polyamide Reverse Osmosis (RO) Membranes is their sensitivity to chlorine attack. By studying the hypochlorite degradation of aromatic polyamide RO Membrane, this work was to get some understandings in the prevention of Membrane depreciation and develop Membranes with improved chlorine resistance. Membrane performances, including water flux and salt rejection, were evaluated before and after hypochlorite exposure under different pH and concentration conditions. The results showed that chlorination destroyed hydrogen bonds in polyamide chains, causing a notable decline of Membrane flux especially in acid environment; however, Membrane performance was slightly improved after the treatment of alkaline hypochlorite solution for a certain time, which was probably due to the effect of amine groups in barrier layer. Based on the attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) characterizations and performance measurements, the results indicated that N-chlorination reaction of aromatic polyamide was also reversible, in other words, the N-chlorinated intermediate could be regenerated to initial amide with the alkaline treatment before ring-chlorination reaction. This conclusion provided several relative suggestions for Membrane cleaning procedures. Finally, a method adopting surface coating was proposed to develop Membranes with good chlorine resistance, and the preliminary results showed its potential for applications.
Ali E Anqi - One of the best experts on this subject based on the ideXlab platform.
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numerical simulation of brackish water desalination by a Reverse Osmosis Membrane
Desalination, 2015Co-Authors: Nawaf Alkhamis, Ali E Anqi, Alparslan OztekinAbstract:Abstract The brackish water desalination by Reverse Osmosis Membranes has been widely used to purify water. This study focuses on how the momentum mixing in the feed flow affects the Membrane performance. Steady and transient two dimensional flows in a channel containing circular shaped spacers are investigated. Different arrangements and the spacing of cylinders are considered for the Reynolds number of 400, 800, and 4000. The feed channel is bounded by Membranes. The velocity, the pressure, and the concentration fields are obtained by solving the Navier–Stokes and the mass transport equations. Laminar and turbulent flow models are employed in this study. The Shear Stress Transport (SST) k-ω turbulence model is utilized when the flow is turbulent. The Membrane is treated as a permeable wall, and it is modeled as a functional surface. The water permeate is calculated based on the local osmotic pressure and the concentration at the Membrane surface. Momentum mixing promoted by spacers enhances the Membrane performance significantly.
Wilasinee Saktaywin - One of the best experts on this subject based on the ideXlab platform.
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performance of an ultra low pressure Reverse Osmosis Membrane ulprom for separating heavy metal effects of interference parameters
Desalination, 2002Co-Authors: Hiroaki Ozaki, Kusumakar Sharma, Wilasinee SaktaywinAbstract:Abstract An experimental investigation was conducted to study the performance of an aromatic polyamide (ES 20) ultra-low-pressure Reverse Osmosis Membrane (ULPROM) for separating divalent (Cu 2+ , Ni 2+ ) and hexavalent (Cr 6+ ) heavy metals from bulk solution. The influence of operating pressure, feed concentration, pH, and effect of other ions (Ca 2+ and Mg 2+ ) on the ULPROM performance was studied. The investigation was conducted for synthetic wastewater and wastewater from the heavy metal industry. Experimental results show that the rejection increases with increasing feed pressure, it is dependent on feed pH and is higher at higher pH. Increasing concentration of other ions slightly decreased the rejection of heavy metals. Generally, rejection of heavy metal is found to be greater than 95% for the ULPROM tested, which suggests the suitability of such Membranes for industrial application for recovery of heavy metal and reclaiming wastewater.
Sanchuan Yu - One of the best experts on this subject based on the ideXlab platform.
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In situ modification of polyamide Reverse Osmosis Membrane module for improved fouling resistance
Chemical Engineering Research & Design, 2018Co-Authors: Chuang Yu, Yiyang Wu, Zhenhua Lu, Sanchuan YuAbstract:Abstract In situ improvement of fouling resistance of the state-of-the-art polyamide Reverse Osmosis Membrane module on the basis of the fouling characteristic of the fluid to be treated is of great practical significance. In this work, in situ modification was performed with the spiral wound polyamide Reverse Osmosis Membrane module for improved fouling resistance to specific foulant. Small molecular monomers of amidosulfonic acid (ASA), diethanolamine (DEA) and piperazine (PIP) were grafted onto the surface of the flat-sheet polyamide-based thin-film composite Membrane within the module separately through 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-activated amidation of carboxyl groups. The results of fouling experiments indicated that the fouling resistance of the polyamide Reverse Osmosis Membrane module to the model foulants of bovine serum protein (BSA), sodium alginate (SA) and dodecyl trimethyl ammonium bromide (DTAB) could be effectively improved through grafting monomers ASA, DEA and PIP, respectively, showing significant reduction in declines of Membrane flux to aqueous BSA, SA and DTAB solutions by 47.2%, 41.3% and 34.4%. The changes of Membrane surface hydrophilicity and negative charge were in charge of the improved antifouling property. The in-situ modification was also found to slightly enhance Membrane salt rejection and have nearly no influence on Membrane water flux.
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improving fouling resistance of thin film composite polyamide Reverse Osmosis Membrane by coating natural hydrophilic polymer sericin
Separation and Purification Technology, 2013Co-Authors: Sanchuan Yu, Bingyan Dong, Xiangyang PengAbstract:Abstract In this study, a commercial thin-film composite aromatic polyamide Reverse Osmosis Membrane was modified through coating a surface layer of natural polymer sericin for improved antifouling property. The deposition of sericin on the Membrane was carried out through dip-coating followed by in situ cross-linking and was confirmed by ATR-FTIR spectroscopy. The changes of surface charge, hydrophilicity and roughness that resulted from the sericin application were analyzed using zeta-potential analysis, contact angle measurement and atomic force microscopy, respectively. The separation performance was evaluated through cross-flow permeation tests. It was found that the sericin-coated Membrane showed improved surface hydrophilicity, enhanced surface negative charge, smoothed surface morphology, and decreased pure water permeability and salt permeability coefficient. The results of fouling experiments with bovine serum albumin aqueous solution revealed that the fouling resistance of the reveres Osmosis Membrane could be effectively improved by coating sericin surface layer. Although the initial flux of the modified Membrane was lower than that of the unmodified Membrane under the same operating pressure due to the additional hydraulic resistance, the rate of flux decline slowed after modification due to the mitigation of foulant deposition on the Membrane surface and compensated for the initial flux decline within 40 h.