BATCH STUDIES FOR METHYLENE BLUE REMOVAL AND RECOVERY BY UNTREATED COFFEE RESIDUES

This paper reports the practicability of using coffee residues to remove widely used basic dyes like methylene blue from wastewaters. The effect of different batch system parameters, namely stirring speed, pH, initial dye concentration and contact time were studied. Moreover, in continuous fixed-bed column systems, the effects of parameters such as bed-depth, flow rate and initial dye concentration were examined. The experimental batch systems data were simulated using: (a) Freundlich, Langmuir and Sips isotherm models and (b) 1st order, 2nd order, and intra-particle kinetic models. The results revealed that the methylene blue is fairly adsorbed on coffee residues. This process could be a low cost technique for the removal of basic dyes from aqueous systems.