Removal of Carbon Tetrachloride from Contaminated Groundwater Environment by Adsorption Method

This study describes the removal of carbon tetrachloride (CT) in simulated groundwater sample by an adsorption method using quaternary ammonium salt modified bentonite as adsorbent. The morphology of bentonite before and after modification was observed through scanning electron microscope (SEM). Moreover, the effects of bentonite dosage, adsorption time and temperature on removal rate of CT were investigated. The SEM results showed that, after natural calcium-benonite is modified by quaternary ammonium salt, the particle clearance of the modified bentonite obviously increased and the surface property changed from originally hydrophilic to hydrophobic, enabling it to effectively adsorb and remove CT from water. The optimal adsorption conditions obtained were bentonite dosage 5.0 g/L, adsorption time 2 hours and temperature 30°C. Under these optimized conditions, the removal efficiency of CT reached above 70% when modified bentonite was used in treating a real groundwater polluted by CT.