ADSORPTION OF DYES AND HEAVY METAL IONS BY CHITOSAN COMPOSITES: A REVIEW

Various adsorbents have been used to remove different types of dyes from wastewater such as anionic azo dye, methylene blue, etc. Activatedcarbons, plant or lignocellulosic wastes, clays andclay minerals, bottom ash, zeolite , silica gel, oil palm trunk fiber , cellulose powder ,rattan sawdust , ricehusk , tea waste , various resins , microorganisms, and biopolymers are among the common adsorbents used. Chitosan a type of biopolymer is a goodadsorbent to remove various kinds of anionic and cationic dyes. Chemical modifications that lead to the formation of chitosan derivatives, grafting chitosanand chitosan composites have gained much attention, extensively studied and widely reported in the literatures. This review provides relevant literature ofthe past tow years on the application of chitosan composites for removing dyes activation. The dye adsorption capacities of chitosancomposites adsorbents vary, depending on the pH of solution, initial dye concentration, adsorbent dosage and process temperature. This review also includesDesorption and reusability, kinetic models and adsorption isotherms