Activated carbon adsorption coupled with ozonation regeneration for efficient removal of chlorobenzene

Chlorobenzene is a typical toxic and persistent organic pollutant in wastewater and site polluted groundwater. In this study, powdered activated carbon (AC) was used for the adsorption of chlorobenzene from simulated wastewater, and it showed high adsorption capacity in a wide range of pH. Pseudo-second-order kinetic model and Langmuir isothermal adsorption model are suitable to describe the adsorption process. Furthermore, the adsorption mechanism is clarified by correlating the adsorption rate constants with the molecular descriptor by theory calculating. Chlorobenzene adsorption on AC was mainly controlled by π-π interaction and hydrophobicity, external mass transfer and intraparticle diffusion. Ozonation was adopted to regenerate the adsorption saturated AC and simultaneously avoid secondary solid waste. After three cycles of adsorption-ozonation, the adsorption capacity of AC even increased from 80 to 215 mg/g due to the increase of oxygen-containing functional groups on the AC surface. This mode can also be used for granular AC column adsorption, and ozonation partially restored the adsorption capacity. The work provides a better alternative way to deal with chlorobenzene polluted wastewater and groundwater. • Activated carbon showed a good adsorption capacity for chlorobenzene. • π-π interaction and hydrophobic interaction play an important role in chlorobenzene adsorption. • Ozone can effectively regenerate the activated carbon adsorbed with chlorobenzene.