Combining Carbon Materials and Ionic Liquid Gels to Boost Simultaneous Removal of Emerging Pollutants from Wastewaters

Abstract

Water bodies contamination is a pressing issue of modern society, exacerbated by the large structural variety of contaminants. This explains the interest toward developing systems able to remove from wastewater different contaminants, with different susceptibility to removal methods. Consequently, herein hybrid ionic liquid gels, based on 1,3:2,4-dibenzylidene-D-sorbitol (DBS), doped with graphite, carbon nanotubes, graphene, and graphene oxide, are described. First, the gel–sol transition temperatures (Tgel), rheological and self-healing properties are determined. These gels are then used as sorbent materials and, for the first time, for removing mixtures of pollutants of different classes, namely the dyes rhodamine B and methyl orange, the drugs diclofenac and carbamazepine, or the endocrine disruptor bisphenol A, to simulate real wastewaters. Interestingly, hybrid gels prove efficient in removing single and mixed pollutants. The best performing gel is reusable for at least 12 consecutive cycles, without any intermediate washing. It can also be embedded in adsorption columns or dialysis membranes, to treat larger volumes of wastewater. Here, this gel achieves an adsorption capacity of 117 and 66 mg g−1 for rhodamine B and bisphenol A in mixture, with a distinct preference toward cationic contaminants, exhibiting competitive performance with most systems previously reported.