DOI: https://doi.org/10.55373/mjchem.v24i2.46

Keywords: Fuzzy Inference System; photocatalysis; reduced graphene oxide; water recovery; zinc oxide

Abstract

In this work, zinc oxide/reduced graphene oxide (ZnO/rGO) composites with different ratios synthesized by a one-pot sol-gel method were tested as photocatalysts for the degradation of methylene blue in aqueous solution. The physicochemical properties of the photocatalysts were characterised by FTIR and SEM-EDX. FTIR analysis showed the existence of various functional groups on the ZnO/rGO surfaces, which indicated strong interactions between the carbonyl, carboxylic, and hydroxyl groups on the rGO with ZnO particles. SEM images revealed a nearly spherical shape for ZnO which was homogeneously distributed on the rGO sheets, while the EDX results confirmed the presence of C, Zn, and O with increasing amounts of rGO. Based on a pseudo first-order kinetic model, the highest degradation rate constant, k, of 2.67 × 10–2 min-1 was obtained with 85% methylene blue degradation using a ZnO/rGO-10 photocatalyst. The relationship between the amount of rGO loadings, degradation percentage and rate constant was discussed using a fuzzy inference system (FIS). The introduction of a fuzzy logic controller (FLC) in this work provides the future direction and prediction for the creation of optimum ZnO/rGO photocatalysts for practical water recovery processes.