COMPARATIVE STUDY OF SORPTIVE PROPERTIES OF VARIOUS LOW-COST SORBENT MATERIALS FOR BEMACID BLUE (ACID DYE) REMOVAL FROM SYNTHETIC AQUEOUS SOLUTIONS.

Abstract

This work explores the possibility of using three agricultural wastes namely: orange (Tomson and Clementine varieties) peel and grenada peel, as inexpensive sorbents for the removal of an acid dye: bemacid blue, as a model of acid dyes, from synthetic aqueous solutions. These materials are abundantly available in Algeria, hence cost effective sorbents. Dyes sorption equilibrium and kinetics tests were performed at acid pH of solutions (2.20) in batch conditions. The effect of some parameters such as: contact time and initial dye concentration on dye sorption kinetics, has been studied. For each sorbent, the quantity of dye sorbed at equilibrium depends on initial dye concentration: it increased with its increasing. Two simplified kinetic models including a first-order and pseudo second-order models were selected to analyse the dye sorption kinetics. The sorption kinetics of bemacid blue by each sorbent tested was well described by a pseudo-second order rate model. In order to describe the dye sorption isotherms mathematically and to obtain information about the maximum dye sorption capacity of each sorbent tested, the equilibrium data were analysed using only the Langmuir model which has shown an acceptable fitting in all the range of dye initial concentrations studied. Under the investigated experimental conditions, the maximum dye sorption capacities obtained by the sorbents followed the order: 31.39 mg/g (clementine peel)  30.71 (Thomson peel)  27.35 mg/g (grenade peel). As results, the present study shows these wastes tested can be acceptably used as sorbent materials for the removal of acid dyes from synthetic aqueous solutions but in acidic medium.