Response Surface Optimization of CuS Photocatalytic Process Using UV-vis Irradiation for Wastewater Treatment

Abstract

Optimizing the overall efficiency of current wastewater treatment technologies is a global challenge to achieving sufficient wastewater remediation. Thus, this study aimed to optimize the operating parameters of the photocatalytic degradation process using copper sulphide (CuS) and UV-visible irradiation via response surface methodology (RSM) to determine the relationship that exists between the most significant factors and the water quality parameters. The efficiency of the CuS photocatalyst was evaluated as a function of three input variables viz. (A) catalyst load (1–2 g/L), (B) mixing speed (60–120 rpm), and (C) exposure time (10–60 min) by using Box–Behnken design (BBD) adapted from RSM. Using chemical oxygen demand (COD), turbidity and colour removal as responses, a 15-run experiment matrix was generated by the BBD to investigate the interactive effects of the three abovementioned input factors. The correlation coefficients (R2) [0.9332, 0.9948, 0.9805] and their corresponding Adjusted R2 [0.8663, 0.9878 and 0.9545] values were near 1, suggested that a good fit existed between the developed statistical model and the collected data. For the use of CuS, the optimal solution suggested a COD (47.2%), turbidity (75.1%) and colour (48.3%) at a catalyst load (2 g/L), mixing speed (120 rpm), and exposure time (30 min), and maximum desirability of 96% removal efficiency. CuS was shown to be a viable photocatalyst for wastewater treatment under UV-vis irradiation under specific operating conditions.