The clay used in this study was the bentonite from Mostagnem, Algeria. This material is used in many fields such as drilling, foundry, painting, ceramics, etc. It can also be applied in the treatment of wastewaters from chemical industries by means of adsorption. In this chapter the physicochemical properties of bentonite were determined by using several analyses techniques such as chemical composition, XRD, FTIR and SBET. The bentonite was intercalated by aluminum poly-cations solution and cethytrimethyl ammonium bromide. The acid activation of natural bentonite was performed by treatment with hydrochloric acid at different concentrations. The surface water pollutants removed by the modified bentonites are bemacid yellow E-4G and reactive MX-4R dyes, and fungicide chlorothalinil. The Langmuir and Freundlich adsorption models were applied to describe the related isotherms. The pseudo-first order and pseudo-second order kinetic models were used to describe the kinetic data. The changes of enthalpy, entropy and Gibbs free energy of adsorption process were also calculated.

Bentonite samples collected from M'Zila of Mostaganem (Algeria) were treated in first protocol with sulfuric acid at concentrations 1, 3 and 6N. The second protocol concerns the acid attack of bentonite combined with thermal treatment at temperatures 100 and 200 °C. The obtained adsorbents were characterized by different analyses techniques such as Chemical composition, XRD, Specific surface area and pHPZC. The modified bentonites were used for removal of Chlorothalonil (Chl) from aqueous solution. The adsorption behavior of the pesticide was studied at different experimental conditions of pH, contact time, concentration of Chl and temperature solution. The adsorption of Chl followed pseudo-second order kinetics and described by Freundlich equation. Thermodynamic study revealed that Chl adsorption was endothermic and physic in nature.

The adsorption of Chlorothalonil fungicide from aqueous solution onto raw and activated bentonite samples was investigated as a function of parameters such as pH, contact time, and temperature. The acid activation of natural bentonite was performed by treatment with hydrochloric solution of different concentrations. The high adsorption capacity of chlorothalonil was obtained by activated bentonite at 323 K in the range of pH 3-4 for 60 min of contact time. It was be 32.01 and 42.88 mg/g for raw and bentonite activated by 1N hydrochloric acid, respectively. The Langmuir and Freundlich adsorption models were applied to describe the related isotherms. Freundlich equation has shown the best fitting with the experimental data. The pseudo-first order and pseudo-second order kinetic models were used to describe the kinetic data. The changes of enthalpy, entropy and Gibbs free energy of adsorption process were determined. The results indicated that the adsorption of chlorothalonil occurs spontaneously as an endothermic process.