Facile construction of pH-responsive graphene oxide-based aerogel and its efficient and selective adsorption performance toward methylene blue

In regard to serious environmental pollution by methylene blue (MB) dye, it was crucial to design an efficacious adsorbent for the elimination of MB. Utilizing tannic acid (TA) to functionalize graphene oxide (GO) and employing acrylic acid (AA) and sodium p-styrenesulfonate (SSS) as the monomers, a pH-responsive TGO/P(SSS-co-AA) aerogel (where TGO represented TA-modified GO, and P(SSS-co-AA) denoted the copolymer of SSS and AA) was synthesized by a facile and green one-pot method. The resulting aerogel was subjected to a variety of characterizations, and its adsorption behaviors were systematically explored with MB as the model dye. The results indicated the pH-responsive TGO/P(SSS-co-AA) aerogel possessed the maximum theoretical adsorption capacity of 1782.5 mg/g, and the adsorption process could be accurately described by quasi-second order kinetics model and Langmuir model. The adsorption thermodynamics revealed that the adsorption was a spontaneous, endothermic, and entropy-increasing process. TGO/P(SSS-co-AA) aerogel exhibited highly selective adsorption property and excellent regeneration performance. Even following five regeneration cycles, adsorption capacity of the aerogel could still maintain 936.09 mg/g. In conclusion, TGO/P(SSS-co-AA) aerogel exhibited exceptional performance as an adsorbent for removing MB, providing an inspiration for the construction of GO-based composite aerogel and its actual application in efficient and selective wastewater treatment.