Optimization of Influential Parameters for the Degradation of Metronidazole Contained in Aquaculture Effluent via Sonocatalytic Process: Kinetics and Mechanism

Abstract

This study examined the synthesis of a viable catalyst for the degradation of metronidazole contained in aquaculture effluent. Zinc oxide nanoparticles (n-ZnO) were synthesized via the precipitation method and calcined at 500oC in a muffle furnace to enhance the degradability properties. The morphology showed a hexagonal structure with an average particle size of 71.48 nm and the elemental composition showed a higher weight percent of 59.15% for zinc and 21.65% for oxygen. The FTIR confirms the vibrational characteristic mode of the Zn-O band at 427.21cm-1. The XRD showed a good crystallinity and the BET surface area was 8.58 m2.g-1 which showed that the n-ZnO possesses more active sites that can remove pollutants from wastewater. However, no studies have been done on the removal of MNZ in aquaculture effluent. The kinetics followed pseudo-second-order kinetics and the Langmuir-Hinshelwood model best fit the degradation process with R2, Kc, and KLH values of 0.96781, 1.486 × 10-1 mg. Lmin-1) and 8.790 × 10-2 (L.mg-1). Under the influential parameters, the percentage COD removal achieved for MNZ in aquaculture effluent was 62.6%, 89.8%, and 98.5% of MNZ at 20% ultrasonic amplitude, 5 mL 2% H2O2 and 0.02g n-ZnO within 60 min sonication time for US only, US/n-ZnO and US/n-ZnO/H2O2 systems. Hence, MNZ contained in aquaculture effluent can best be degraded with the synergetic effect of the US/n-ZnO/ H2O2 system.

Keywords

• ultrasound, sonocatalytic process, aquaculture effluent, metronidazole, advanced oxidation process