Novel graphene oxide sponge synthesized by freeze-drying process for the removal of 2,4,6-trichlorophenol

Abstract

Graphene oxide (GO) spongy materials as environmental pollutant scavengers have drawn great attention owing to their ultralarge surface area, unique spongy structure and hydrogen-bonding interactions. Herein, a novel GO sponge was synthesized by an improved Hummer's method followed by a freeze-drying process and its adsorption capacity of 2,4,6-trichlorophenol (TCP) was investigated. The structural features of GO sheets and GO sponge have been characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM) and scanning electron microscopy (SEM). Specific surface area assessment and pore distribution measurements were analyzed by Micromeritics ASAP 2020. The adsorption mechanism and kinetics study of TCP on GO sheets and GO sponge were studied using a batch equilibration method. The results suggest that the GO sponge presented a higher adsorption capacity than GO sheets due to its large specific surface area and TCP had an optimum adsorption capacity on both GO sheets and GO sponge at pH 2.0–6.0. Adsorption isotherms and kinetics curves of TCP on GO sheets and GO sponge were nonlinear, indicating a homogeneous monolayer chemical adsorption process.