Optimisation and kinetic modelling of atenolol degradation by ZnO under solar irradiation

Abstract

ABSTRACT The aim of this study is to investigate the atenolol (ATL) degradation in aqueous suspension using commercial ZnO photocatalysts under solar irradiation. Effects of various operating parameters such as the ZnO dosage (0.025 to 0.075 g L−1), as well as pH ranges (3–12), and the ATL concentration (5–30 mg L−1) were also studied in a batch system. Results show that alkaline medium favoured the photocatalytic degradation of ATL (pH~7) and the best value of ZnO dosage occurred in 0.075 g L−1. Also, the removal rate increased with increasing ATL concentration. Kinetic data indicated that the photocatalytic kinetics followed the second-order model at high concentration of ATL, third-order model at low concentration, and first order model when adjusted pH. The second-order rate constant (k2) increases from 0.064 to 0.13 L mg−1 mn−1 when ZnO dosage increases from 0.025 to 0.2 g L,−1 respectively. As well, the pH rises from 3 to 7 the first-order rate constant (k1) increases from 0.35 to 1.56 mn−1. Then, at pH = 12 the rate constant (k1) decreases to 0.74 mn−1. The biodegradability, based on the BOD5 to COD ratio, increased with the increased photocatalysis time.