Solar-light-harvesting degradation of aqueous ammonia by CuO/ZnO immobilized on pottery plate: Linear kinetic modeling for adsorption and photocatalysis process

•Photocatalytic degradation of ammonia by CuO/ZnO photocatalyst was investigated.•The photocatalyst was coated over pottery plate and studied in a thin film photoreactor.•The photocatalyst with 5%wt. CuO loading exhibited the highest photocatalytic efficiency.•In optimum conditions, 77.2% ammonia removal from synthetic wastewater was achieved.•A linear model was applied in relation between adsorption and photocatalytic process.

The present study involves the photocatalytic degradation of ammonia by CuO/ZnO photocatalyst. The CuO/ZnO photocatalyst was prepared by an economical and easy method and immobilized over rough surface of pottery plate. The photocatalytic activity of this photocatalyst was investigated under solar irradiation. Also, the morphology and microstructure properties of the prepared photocatalyts have been characterized by FESEM, FT-IR, UV–vis and PL analyses. The characterization results revealed that the CuO particles sufficiently loaded over ZnO. It also was found that an appropriate amount of CuO loading (5 wt.%) could greatly increase the photocatalytic activity. According to the optimum conditions, 77.2% ammonia removal from synthetic wastewater was achieved within 240 min solar irradiation time. Additionally, the photocatalytic activity of the CuO-ZnO/pottery plate decreased with increasing initial ammonia concentration from 85 to 510 mg/L. Linear model was applied to explain relation between adsorption and photocatalytic process in ammonia removal. This model was able to predict adsorption and photocatalytic data with non-significant differences with experimental results.