Abstract
The use of low-cost and eco-friendly adsorbents has been investigated as an ideal alternative to the current expensive methods of removing dyes from wastewater. Orange peel was collected from the local fields of orange trees and converted into a low-cost adsorbent. The present study deals with the removal of textile dyes from artificial textile dye effluent by activated carbons developed from orange peel. Direct Yellow 12 (DY-12) was used as the model compound due to its wide range of applications and high stability in the environment. The maximum removal was 96% for 125 mg l(-1) of DY-12 concentration on 5 g l(-1) carbon concentration. The effect of initial dye concentration (25-125 mg l(-1)), pH, contact time, and concentration of orange peel carbon (2.5-10.0 g l(-1)) have been studied at 27 +/- 2 degrees C. Several isotherm models, Langmuir, Freundlich, Koble-Corrigan, Redlich-Peterson, Tempkin, Dubinin-Radushkevich and generalized isotherm equations, were investigated and all of them were in good agreement with the experimental data except Redlich-Peterson. The results indicate that acidic pH (1.5) supported the adsorption of DY-12 on activated carbon developed from orange peel. Furthermore, adsorption kinetics of DY-12 was studied and the rate of sorption was found to conform to pseudo-second-order kinetics with correlation coefficients equal unity under all studied conditions. The maximum adsorption capacity calculated from the Langmuir isotherm model was 75.76 mg g(-1). The activated carbon obtained from orange peel via acid decomposition has been found to be an efficient material for dye removal from artificial textile dye effluent owing to its very low cost.