title: Dye removal from textile dye wastewater using recycled alum sludge.
abstract: The removal of dyes from textile dying wastewater by recycled alum sludge (RAS) generated by the coagulation process itself was studied and optimized. One hydrophobic and one hydrophilic dye were used as probes to examine the performance of this process. It was found that RAS is a good way of removing hydrophobic dye in wastewater, while simultaneously reducing the fresh alum dosage, of which one third of the fresh alum can be saved. The back-diffusion of residued dye from the recycling sludge is detected but is easily controlled as long as a small amount of fresh alum is added to the system. The use of RAS is not recommended for the removal of hydrophilic dyes, since the high solubility characteristics of such dyes can cause deterioration in the water quality during recycling.
authors.affiliation: Department of Civil and Structural Engineering, Research Centre for Urban Environmental Technology and Management, The Hong Kong Polytechnic University, Hung-Hom, Kowloon. chu@polyu.edu.hk
authors.forename: W
authors.initials: W
authors.lastname: Chu
mesh_terms: D000534:Alum Compounds / Q000737:chemistry / Q000378:metabolism*; D004396:Coloring Agents / Q000302:isolation & purification*; D003247:Conservation of Natural Resources / Q000379:methods*; D012722:Sewage / Q000737:chemistry*; D013783:Textile Industry; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D000534:Alum Compounds; D004396:Coloring Agents; D012722:Sewage; D014874:Water Pollutants, Chemical; C041524:aluminum sulfate