Efficiently enhancing photocatalytic activity of NiO-ZnO doped onto nanozeoliteX by synergistic effects of p-n heterojunction, supporting and zeolite nanoparticles in photo-degradation of Eriochrome Black T and Methyl Orange

Abstract

Abstract The goal of this work is to use the photo-catalyst NiO-ZnO doped onto nano zeolite X (NZX) with a p-n heterojunction semiconductor structure in the photo-catalytic degradation of Eriochrome Black T (EBT) and Methyl Orange (MO) under UV-light irradiation. Nano-zeolite crystals were synthesized by hydrothermal crystallization. Ion exchanging of the prepared Nano zeolite in an aqueous solution containing Ni(II) and Zn(II) cations and calcinations of the ion-exchanged material at 450 °C led to the formation of NiO-ZnO-NZX catalyst. The samples were characterized by XRD, UV/vis-DRS, FT-IR, TEM and BET. The composites exhibited significantly enhanced photo-degradation activity for the degradation of (EBT) and (MO). A synergistic effect of mixed p–type NiO and n–type ZnO oxides incorporated in NZX has been noticed on the photo-degradation process. Several influencing process parameters, such as the NiO-ZnO ratio, pH, initial dyes concentrations, dosage of photo-catalyst, were also investigated. The extent of degradation was estimated from the residual concentration by spectrophotometrically and it was confirmed by the reduction of chemical oxygen demand (COD).