Kinetics and isotherms of glyphosate removal from effluents using ion exchange resin

Removal of glyphosate from aqueous solutions by using gel basic anion exchange resin N201 was investigated in the paper. The effects of solution initial concentration, temperature, and contact time were studied. Adsorption isotherms were determined using Langmuir and Freundich equations. The results clearly showed that the adsorption of glyphosate onto N201 followed Freundich model and the adsorption was favorable of high temperature. The thermodynamic parameters such as ΔH, ΔS, and ΔG were also calculated for t this adsorption reaction and it indicated that the adsorption was spontaneous and endothermic. At 323 K, the saturated adsorption capacities of glyphosate on N201 was 1.0215 mmol/g. Experimental data were analyzed by pseudo-first and pseudo-second order model equations and it was found that the pseudo-second order model best fitted the adsorption data. Its rate constant of the adsorption reaction was 6.7297 g · (mmol·h)^-1.