Efficient removal of phenol from wastewater by β-CD modified carboxy expanded graphite

In this study, β-cyclodextrin (β-CD)-modified carboxylated expanded graphite composites (EG-CD) were successfully prepared and systematically evaluated for their adsorption performance of phenol in wastewater. The successful grafting of β-CD was confirmed by various physical and chemical characterisation means, indicating that the surface of EG-CD was enriched with more functional groups, which provided a good basis for its adsorption application. The results of the adsorption experiments showed that the adsorption process of EG-CD on phenol was in accordance with the Langmuir monolayer adsorption model and the quasi-secondary kinetic model, which indicated that its efficient removal of phenol was mainly achieved by chemisorption. The maximum adsorption of phenol by EG-CD could reach 287.8 mg/g at 293 K, and the adsorption process was spontaneous and exothermic. In addition, EG-CD exhibited more than 90% phenol removal in different aqueous environments (including deionised water, tap water, river water and industrial wastewater) and maintained 86.4% of the initial adsorption capacity after seven cycles, which showed excellent recycling performance and potential for practical applications. Therefore, EG-CD, as a new type of adsorbent, has a broad application prospect in the treatment of phenol-containing wastewater.