Removal of tetramethyl thiuram disulphide from aqueous solution by chemically modified bentonite

Abstract

Abstract The adsorption of tetramethyl thiuram disulphide (thiram) on bentonite, acid‐treated with H 2 SO 4 (over a concentration range between 0.25 mol dm −3 and 2.00 mol dm −3 ), and heat‐treated at 110°C or at 200°C, from aqueous solution at 20°C has been studied. In general, the adsorption isotherms may be classified as L type of the Giles classification which suggests that there is no strong competition from the solvent for adsorption sites. The experimental data points have been fitted to the Freundlich equation in order to calculate the adsorption capacities (K) of the samples; K values range from 230 μg g −1 for the sample acid‐treated with 0.25 mol dm −3 H 2 SO 4 and heat‐treated at 110°C up to 2010 μg g −1 for the sample acid‐treated with 1.00 mol dm −3 H 2 SO 4 and heat‐treated at 200°C. In all cases the K values for samples heat‐treated at 200°C were higher than those heat‐treated at 110°C. The removal efficiency (R) has also been calculated for all the samples; R values range from 42.8% up to 89.9%.