Microwave-assisted synthesis of reduced graphene oxide/titania nanocomposites as an adsorbent for methylene blue adsorption

In this study microwave-assisted reduction (MrGO) and direct reduction of graphene oxide (rGO) by Ti powders were established, and the effect of the reaction conditions on the reduction were discussed. The results showed that GO can be effectively reduced by both methods, however, microwave assistance can greatly shorten the reduction time. The produced Ti ions from the reaction of Ti powder with GO were transferred to TiO2 by hydrolysis and formed MrGO/TiO2 and rGO/TiO2. They were used as adsorbents for the removal of methylene blue (MB). MrGO/TiO2 showed a higher adsorption capacity (q(max), 845.6 mg/g) than rGO/TiO2 (q(max), 467.6 mg/g). Investigation on the adsorption MB onto MrGO/TiO2 was conducted and demonstrated that adsorption kinetics followed the pseudo second-order kinetics model and the adsorption isotherm was well described by the Langmuir isotherm model. The recycling of MrGO/TiO2 was achieved by photocatalytic degradation of MB catalyzed by MrGO/TiO2 itself. (C) 2015 Elsevier B.V. All rights reserved.