Phenol adsorption properties and microstructural changes of organically modified bentonite

Abstract

Phenolic compounds are prevalent organic contaminants in aquatic and soil environments. To address the issue of phenolic waste water treatment, bentonite can be utilised as an effective adsorbent through organic modification. The present study focuses on using sodium bentonite, which was modified with cetyltrimethylammonium bromide (CTMAB), to remove phenol from an aqueous solution. The influence of various factors such as adsorption time, initial phenol concentration and CTMAB–bentonite dosage on phenol adsorption was thoroughly investigated. In addition, the microstructural changes during the adsorption process, adsorption kinetics and adsorption isotherms of the organically modified bentonite (OMB) were analysed. The results indicated that the adsorption equilibrium time of OMB was longer compared with that of sodium bentonite. The amount of phenol adsorbed by OMB was found to be positively correlated with the initial phenol concentration and CTMAB–bentonite dosage. The maximum phenol adsorption capacity and removal rate achieved were 3.00 mg/g and 43.74%, respectively. The study also revealed that a quasi-second-order kinetic model was appropriate for describing the phenol adsorption process of OMB, and the adsorption isotherm was found to conform with the Freundlich isotherm model. These findings demonstrate the potential of OMB as an efficient and effective adsorbent for phenolic waste water treatment.