Removal of Chromium and Azo Metal-Complex Dyes Using Activated Carbon synthesized from Tannery Wastes

Abstract

Leather industries are one of pollution-intensive industrial complexes generating huge volumes of liquid and high concentration of solid wastes. Tanneries use different harmful chemicals like (chromium, sulphuric acid, dyes, etc) in their processing. They could have a number of adverse impacts on the environmental eco-system as well as on the society living around. In this study, fleshed parts of tannery solid wastes were brought from Bahir Dar leather factory to synthesize an activated carbon used for effective removal of chromium, mordant black-11 and red azo dyes from the aqueous solution. Fleshed tannery waste activated carbon (FTWAC) characterized by FTIR which shows acidic properties, surface area by BET was 535.02 m2/g and different physical and chemical properties were determined. The concentration of Cr(VI) was determined by ICP-OES, but mordant black-11 and red azo dyes were determined by UV-Vis spectroscopy instrument. Freundlich isotherm model is well fitted than Langmuir model for the adsorption. Generally the results showed that the removal efficiency of FTWAC for Cr(VI) over 99%, for mordant black-11 dye over 97% and red azo dye over 93% were achieved. Therefore, using FTWAC for treatments of chromium and dyes in the effluent wastes for leather industry is economical and viable option.