Highly efficient sorbent utilizing regenerated cellulose as an eco-friendly template for humic acid removal and oil-water separation processes

Abstract

In this study, a novel and environmentally friendly sorbent was developed utilizing regenerated cellulose (RC) as a renewable resource. The preparation process of the regenerated cellulose hydrogel, following a bottom-up strategy, occurs in an aqueous system and offers the added benefits of temperature-induced gelation and solvent recyclability. The RC/PEI aerogel was prepared through a polyethyleneimine (PEI) modification and diepoxide crosslinking process, which improves the gel's elastic recovery for the squeezing process and concurrently provides excellent ability to remove humic acid (HA) contaminants. As a result of the HA removal experiment using the RC/PEI aerogel in an aqueous environment, the gel showed an experimental HA adsorption capacity of 124.9 mg/g and qm value of 196.7 mg/g. Furthermore, the prepared RC hydrogel template was successfully transformed into a highly effective oil-water separation sorbent through a hydrophobic alkylated graphene oxide (AGO) coating process. Oil-water separation was carried out using AGO-RC/PEI gel, and it was possible to successfully adsorb the oil and then recover it through the squeezing process. In addition, long-term usability has been validated by demonstrating an oil adsorption capacity of over 84 %, even after ten consecutive reuses.