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Abstract: The selective separation mechanisms of three textile dyes with NaCl solution by nanofiltration membranes during brine recovery at three different pH values were investigated. Tests were performed with the purpose of relating flux decline, brine recovery, and dye rejection behavior to membrane characteristics, like molecular weight cutoff, contact angle, and zeta potential, charge of the dye molecules, and solution chemistry. The salt‐organic separation factor was estimated in order to rank and choose the most suitable nanofiltration membranes for brine recovery with high degree of flux. [ABSTRACT FROM AUTHOR]

The textile industry generates large volumes of effluents on a daily basis, which contains substantial loads of organic compounds, inorganic salts, and suspended impurities. Membrane filtration has become an essential part of advanced treatment plants for dye wastewater treatment. Prevention of membrane fouling is one of the critical objectives for making the overall treatment process commercially viable. Development in this area during the past decade is critically evaluated in this review. Recent developments in the primary, secondary, and tertiary treatment steps in textile wastewater treatment are outlined. The methods employed for measuring, modeling, and understanding membrane fouling processes are discussed. Specific efforts toward fouling control by (a) pretreatment stages of textile wastewater and (b) modifying and optimizing the membrane separation process parameters such as feed composition, hydrodynamic conditions, and membrane properties are then assessed. Fouling related investigations for microfiltration/ultrafiltration membranes, membrane bioreactors, reverse osmosis, and nanofiltration membranes with special focus on textile wastewater treatment are discussed. Recent efforts toward developing new membranes and cleaning processes for fouled membrane activation are also discussed. Pilot plant studies involving membrane separation in combination with other treatment processes are also summarized. Strategies evolved and experiences gained from the industrial scale textile wastewater treatment plants in India are discussed. The authors also summarize the opportunities and the challenges remaining at different stages of industrial textile wastewater treatment units. [ABSTRACT FROM AUTHOR]

• A rapid & eco-friendly surface mineralization approach was applied on NF membrane. • BaSO 4 -mineralized membrane showed excellent flux & rejection.. • The mineralized membrane also displayed better antifouling ability with higher FRR. • The rejection of mineralized membrane was very stable for multiple filtration cycles. In this study, an environmentally friendly and rapid surface modification method known as surface mineralization was adopted to alter the polyamide (PA) layer of commercial NF270 thin film composite (TFC) membrane, aiming to improve its characteristics for enhanced desalination process. An alternate soaking process was applied on the membrane surface by using barium chloride solution and sodium sulfate solution at varying concentrations (0.01 M, 0.05 M and 0.1 M). The reaction of these two salts can form a layer of barium sulfate (BaSO 4) minerals atop the PA layer via an ionic interaction. Our result revealed that the best-performing membrane could be developed using salt solutions at 0.05 M with its water contact angle descended to 33.5° compared to the pristine membrane of 46.4°. Furthermore, the surface roughness of the BaSO 4 -mineralized membrane was reported to be higher than the pristine membrane. The increase in surface roughness together with improved surface hydrophilicity yielded the BaSO 4 -mineralized membrane to exhibit 12% higher water flux than the pristine membrane. Nonetheless, the difference in Na 2 SO 4 rejection before and after surface mineralization was not found to be statistically significant owing to the high Na 2 SO 4 rejection of the control membrane. The BaSO 4 -mineralized membrane also achieved excellent performance in filtering solutions containing sodium alginate and showed very stable salt rejection for multiple cycle of combined chemical cleaning and water filtration process. These results highlighted the potential of the surface mineralization process in overcoming the trade-off effect between water flux and selectivity of TFC membrane. [ABSTRACT FROM AUTHOR]