Removal of textile dyes from aqueous solutions by adsorption on biodegradable wastes.

The adsorption of the textile dyes Basic Blue 41, Aniline Blue, Reactive Black 5 and Mariposa Blue was studied from model solutions prepared in distilled water in the concentration range up to 2000 mg l(-1). Biodegradable wastes were used and are proposed here as adsorbents due to their abundance and inexpensiveness in the authors' country. The influence of the particle size, pH, presence of an electrolyte in the dye solution, adsorbent activation and competition in ternary dyes mixtures was determined in this study. Adsorption capacity of the adsorbents designated as HOMAP and POMAP with particle diameter less than 3 mm for the Basic Blue 41 dye was found to be 164 and 77 mg g(-1), respectively. The efficiency of the prepared adsorbents for removing basic, acid and reactive dyes with a concentration of 400 mg l(-1) was examined. A comparison of the adsorption capacity and desorption feasibility of the adsorbents was made. The basic dye was adsorbed with efficiencies varying from 87-98%, the reactive dye was removed in the range 60-98% and the add dye, 60-70% by three of the four adsorbents tested in this study. The determination of adsorption equilibrium concentrations was followed by HPLC with diode array detection.