Reduced graphene oxide/TiO2(B) immobilized on nylon membrane with enhanced photocatalytic performance.

Abstract

Taking advantage of the unique properties of reduced graphene oxide (rGO) and monoclinic crystalline titanium dioxide (TiO2(B)) nanomaterials, a novel rGO-TiO2(B) composite membrane (MrGO-TiO2(B)) was constructed by UV-light-assisted self-assembly of rGO and TiO2 on a nylon membrane. The structure of MrGO-TiO2(B) was characterized by scanning electron microscopy, transmission electron microscopy, UV-visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction analysis. Through 2D/2D self-assembly, rGO and TiO2(B) were more tightly combined, and then MrGO-TiO2(B) exhibited outstanding photocatalytic activity and an excellent methylene blue (MB) removal rate. MB was completely removed in 60 min at a constant rate of 0.042 min-1 by the MrGO-TiO2(B)/H2O2/MB system upon solar simulating Xe lamp irradiation. The synergistic effect of rGO and TiO2(B) facilitated the photocatalytic degradation of MB. TiO2(B) was excited and generated electrons and holes upon irradiation. Some electrons migrated to the surface of TiO2(B) to react with H2O2 to produce hydroxyl radicals (OH), while the other electrons migrated to the surface of rGO to react with H2O2, producing OH. In addition, a number of superoxide radicals (O2-) was detected. The holes in the valence band of TiO2(B) directly oxidized MB. The catalytic activity of MrGO-TiO2(B) toward MB degradation remained stable after four rounds of reuse. Therefore, the surface modification of a nylon membrane with TiO2(B) and rGO can serve as a promising route to fabricate photocatalytic membranes for use in the water treatment industry.