Adsorptive Removal of 2,4-Dichlorophenoxyacetic Acid (2,4-D) from Aqueous Solutions Using MIEX Resin

Abstract

Batch experiments are carried out to evaluate the adsorption performances of 2,4-D from aqueous solutions by MIEX resin. The initial 2,4-D concentration, adsorption time, adsorbent dosage, inorganic ions, natural organic matter, and initial pH of solution have considerable effect on the removal of 2,4-D, but temperature has less effect. The isotherm experiments show the Redlich–Peterson and Sips models are the most appropriate models to simulate the equilibrium data at 293 K. The kinetic study demonstrates the pseudo-second-order model gives a best fitting to the adsorption of 2,4-D on the resin and the intraparticle diffusion is not the only rate-controlling step. The thermodynamic parameters are calculated. The results show that the adsorption of 2,4-D on the resin is a thermodynamically spontaneous and endothermic process. Accordingly, it can be concluded that MIEX resin can potentially be employed as an adsorbent for removing 2,4-D from raw water.