Preparation and adsorption performance of CTMAB-bentonite on landfill leachate

Abstract

The toxic organic pollutant with high concentration in landfill leachate is increasingly harmful to human health. In order to treat landfill leachate more efficiently, a novel cheap organobentonite (CTMAB-bentonite) was successfully prepared from Na-bentonite modified with cetyltrimethylam-monium bromide (CTMAB) as intercalation agent. The CTMAB-bentonite were characterized by X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy, and the effects of contact time, CTMAB concentration, temperature and pH on the adsorption performance were investigated. XRD analysis results showed that CTMAB with concentration of 4 mmol/5 g was successfully intercalated into bentonite, and the layer spacing of CTMAB-bentonite increased by 6 Å than larger that before modification. The adsorption experiment results indicated that the best adsorption time is 60 min, pH and temperature have little effect on the adsorption performance. The adsorption process of landfill leachate conforms to the Freundlich and pseudo-second-order kinetic model, which indicated a multimolecular layer and chemical adsorption, respectively. Thermodynamic parameters confirmed that adsorption process was spontaneous and exothermic. Bentonite modified by CTMAB has a satisfactory adsorption effect on leachate and satisfactory adsorption capacity. CTMAB-bentonite was an excellent adsorbent for removal of landfill leachate which was promising in the field of wastewater treatment.