The Sorption of Erythrosine E127 Dye onto Commercial Kaolin Thermokinetic Studies

Abstract

In this study, a highly efficient and economical method was used to remove E127 dye using commercial kaolin (CK) as the adsorbent. The optimal pH for adsorption was found to be 4.7, and the maximum surface concentration of the dye was 53.8 mg.g^-1 when 125 mg of adsorbent was used. The Freundlich isotherm was used to describe the adsorption process, which suggested that the active sites in the adsorption process were randomly selected. The adsorption capacity (q_max), enthalpy (?H), and entropy (?S) were calculated to be 74.6 mg.g^-1, -12.3 KJ.mol^-1, and 75.0 J.mol^-1, respectively. Both thermodynamic and kinetic analyses indicated that the adsorption process was spontaneous, involved physical adsorption, and followed the pseudo-second-order (PSO) model. The method was effective in extracting the E127 dye up to four times.