Binary Adsorption of Two Textile Dyes onto Diatomite: Kinetic and Isotherm Study

Abstract

Nowadays, many studies focus only on the removal of dyes from water in single solution. In real applications the colored effluents contain more than one component to eliminate. In this study, the adsorption of two textile dyes – Red Bemacid-ETL (RB-ETL) and Bezaktiv Turquoise Blue-VG (BTB-VG) – was investigated in a binary mixture. The derivative spectrophotometry was used to determine the specific wavelength for each dye. The effect of pH, contact time and initial dye concentrations was considered. The results show that diatomite has a good potential to eliminate both of dyes simultaneously. The competitive statistical rate theory model fits the adsorption kinetic data of the binary system well. The adsorption isotherm data for both dyes is well described by multicomponent Langmuir isotherm model. A high competition effect was observed, but BTB-VG dye was more selectively adsorbed by heat treated diatomite than RB-ETL dye.