Single and competitive adsorption between Indigo Carmine and Methyl orange dyes on quaternized kapok fiber adsorbent prepared by radiation technique

Since industrial effluents contain several dye species, investigation on the competitive adsorption and selective adsorption mechanism is quite necessary. In this paper, single and competitive adsorption of Indigo Carmine (IC) and Methyl Orange (MO) dyes using methacryloxyethyltrimethyl ammonium chloride functionalized kapok fiber (DKF) were investigated. The maximum adsorption capacity of individual adsorption was 1011.3 mg/g and 1079.9 mg/g for MO and IC, respectively. However, IC has significant inhibitory effect on MO uptake but IC adsorption almost not change in binary system, which is in contrast to the reported results that competitive adsorption capacity was greatly reduced for each dye in binary system. The separation factor of IC/MO could reach 129.53 when the concentration of IC and MO equal 0.2 mol/L, indicating good selectivity toward IC. The selective adsorption mechanism between MO and IC was attributed to the displacement impact. Therefore, this work provided a potential adsorbent for selectively removing dye from industrial effluents and give a new sight to the competitive adsorption mechanism among dyes.