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

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 degrees C led to the formation of NiO-ZnO-NZX catalyst. The samples were characterized by XRD, UV/I./is-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). (C) 2017 Published by Elsevier B.V.