One-Step Fabrication of Graphene Oxide Enhanced Magnetic Composite Gel for Highly Efficient Dye Adsorption and Catalysis

Abstract

Graphene oxide (GO) is emerging as a potential adsorbent for environmental cleanup due to its attractive attributes associated with high removal efficiency toward water pollutants. However, it is difficult to separate GO from water after adsorption. Until now, the development of an effective approach that can simultaneously take advantage of the adsorption feature of GO and overcome the separation problem is still a challenge. Herein, we demonstrate a simple one-step approach to fabricate magnetic GO/poly(vinyl alcohol) (PVA) composite gels (mGO/PVA CGs), which not only exhibit convenient magnetic separation capability but also show remarkably enhanced adsorption capacity for cationic methylene blue (MB) and methyl violet (MV) dyes as compared with the one without GO (e.g., the adsorption capacities of mGO/PVA-50% and mGO/PVA-0% for MB are 231.12 and 85.64 mg/g, respectively). Detailed adsorption studies reveal that the adsorption kinetics and isotherms can be well-described by pseudo-second-order model and Langmuir isotherm model, respectively. Moreover, the adsorbent could be well regenerated in an acid solution without obvious compromise of removal efficiency. Considering the facile fabrication process and robust adsorption performance of the mGO/PVA CG, this work opens up enormous opportunities to bring GO from experimental research to practical water treatment applications. In addition, the mGO/PVA CG can act as a magnetic support for in situ growth of noble metal nanocatalyst with excellent catalytic performance, as exemplified by the synthesis of mGO/PVA-Pt catalyst in this paper.