Color Removal from Tannery Wastewater Using Activated Carbon Generated from Rice Husk

Color of the waste water is one of the most important indicators of water pollution as it is aesthetically displeasing and can greatly damage the receiving water bodies. Tannery wastewater contains organic and inorganic complex constituents and exhibit high color concentrations which are not typically reduced through conventional treatment technologies. The objective of this research is to study the possibilities of using a low-cost activated carbon for the elimination of dyes from tannery waste water. Activated carbon generated from rice husk has been used as an adsorbent in laboratory batch studies with tannery effluent and methylene blue. The maximum color removal was found to be 94.13% and 77% for methylene blue and tannery waste water respectively. Both Langmuir and Freundlich isotherms were found to represent the observed adsorption process reasonably well, but Langmuir model fitted better suggesting that monolayer adsorption maybe taking place. The adsorption process has been found to be generally favorable. Kinetic studies showed that pseudo second-order kinetic model fitted better (R-2 > 0.99) than the first-order model over the whole range of contact times and initial color concentrations indicating that the adsorption process may be controlled by chemisorption. Being an abundant and a low-cost agricultural by-product in Bangladesh and at the same time being an efficient adsorbent, rice husk has good prospects for being utilized for color treatment of tannery wastewater and thereby