title: Combination of forward osmosis (FO) process with coagulation/flocculation (CF) for potential treatment of textile wastewater.
abstract: A novel combination of forward osmosis (FO) process with coagulation/flocculation (CF) (FO-CF) has been experimentally conceived for the treatment and reuse of textile wastewater. FO is employed to spontaneously recover water from the wastewater via osmosis and thus effectively reduces its volume with a dramatically enhanced dye concentration. CF is then applied to precipitate and remove dyes from the FO concentrated stream with much improved efficiency and reduced chemical dosage. The FO-CF hybrid system exhibits unique advantages of high water flux and recovery rate, well controlled membrane fouling, high efficiency, and minimal environmental impact. Using a lab-made thin-film composite (TFC) FO membrane, an initial water flux (Jw) of 36.0 L m(-2) h(-1) with a dye rejection of 99.9% has been demonstrated by using 2 M NaCl as the draw solution and synthetic textile wastewater containing multiple textile dyes, inorganic salts and organic additives as the feed under the FO mode. The Jw could be maintained at a high value of 12.0 L m(-2) h(-1) even when the recovery rate of the wastewater reaches 90%. Remarkable reverse fouling behavior has also been observed where the Jw of the fouled membrane can be almost fully restored to the initial value by physical flushing without using any chemicals. Due to the great dye concentration in the FO concentrated wastewater stream, the CF process could achieve more than 95% dye removal with a small dosage of coagulants and flocculants at 500-1000 ppm. The newly developed FO-CF hybrid process may open up new exploration of alternative technologies for the effective treatment and reuse of textile effluents.
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore.
authors.forename: Gang
authors.initials: G
authors.lastname: Han
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore.
authors.forename: Can-Zeng
authors.initials: CZ
authors.lastname: Liang
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore. Electronic address: chencts@nus.edu.sg.
authors.forename: Tai-Shung
authors.initials: TS
authors.lastname: Chung
authors.affiliation: Advanced Materials & Systems Research, BASF SE, GM-B001, 67056 Ludwigshafen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Weber
authors.affiliation: Advanced Materials & Systems Research, BASF SE, GM-B001, 67056 Ludwigshafen, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Staudt
authors.affiliation: Performance Materials, BASF SE, G-PM/PU-F206, 67056 Ludwigshafen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Maletzko
mesh_terms: D004396:Coloring Agents / Q000737:chemistry*; D005374:Filtration / Q000295:instrumentation / Q000379:methods*; D005427:Flocculation; D008567:Membranes, Artificial; D009995:Osmosis; D013783:Textile Industry; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*; D062065:Wastewater / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D004396:Coloring Agents; D008567:Membranes, Artificial; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Coagulation and flocculation; Forward osmosis; TFC membrane; Textile wastewater treatment; Water reuse