Submerged microfiltration membrane coupled with alum coagulation/powdered activated carbon adsorption for complete decolorization of reactive dyes

Even the presence of very low concentrations of dyes (1mgL(-1)) in the effluent is highly visible and is considered aesthetically undesirable. it must be removed from wastewater completely. This study systematically evaluates the performance of adsorption (three kinds of powdered activated carbons), coagulation (AlCl(3)(.)6H(2)O) and membrane (submerged hollow fiber microfiltration) processes individually in treating two kinds of reactive dyes (Orange 16 and Black 5) and then using a hybrid process with combined coagulation-adsorption-membrane treatment system. Adsorption capacity and kinetics of Orange 16 were much higher and faster than those of Black 5. The dye removal efficiency by coagulation was highly dependent on dye concentration and solution pH. The hybrid process performance was far more superior that individual process in removing both kinds of dyes. It was evident that the combined coagulation-adsorption-membrane process has a great potential application for complete reactive dye removal, production of high-quality treated water and allows the reduction in the use of coagulant and adsorbent. (c) 2005 Elsevier Ltd. All rights reserved.