Hydrothermal synthesis of surface-modified copper oxide-doped zinc oxide nanoparticles for degradation of acid black 1: Modeling and optimization by response surface methodology

Dyes are widely used in various industries most of them are not readily biodegradable and are consisted of number of toxic, mutagenic, and carcinogenic compounds. Therefore, it is essential to remove them from effluent before their discharge to the environment. The objective of this investigation was to synthesize copper oxide (CuO) doped zinc oxide (ZnO) nanoparticles under mild hydrothermal conditions using CuO as dopant and triethylamine as surface modifier to remove acid black 1 from aqueous solutions. Synthesized nanoparticles were characterized using powder X-ray diffractometer, Fourier transform infrared spectroscopy, scanning electron microscopy, and ultra violet-visible spectroscopy. The central composite design matrix and response surface methodology (RSM) were applied for designing the experiment, evaluating the effect of variable and modeling the degradation of acid black 1 dye. The results obtained from analyses of variance indicated that our experiments were fit with quadratic model. Moreover, the optimization R2 and R2 adjusted correlation coefficients for model were evaluated as 0.94 and 0.89, respectively. The optimal conditions for high efficiency (100% dye removal) was found to be at catalyst dosage of 1g/l, dye concentration of 50 mg/l, and pH = 6. This investigation introduced the RSM as an appropriate method to model and optimizes the best operating condition for maximizing dye removal. In conclusion, the results showed that nanoparticals dosage plays crucial role in this regard.