Subcritical Water Extraction of Banana Peel Derived ZnO for Photodegradation of Paracetamol

Abstract

Rapid industrialization and growth have led to the emergence of pharmaceutical compounds in water sources. Therefore, a photocatalytic degradation of paracetamol (PCM) was studied using green catalyst i.e. banana peel extract-based zinc oxide (BZnO) photocatalyst. The catalysts were synthesized by incorporating ZnO with banana peels extract (BPE) extracted using subcritical water (SCW) process at various temperature range between 140-180°C and residence time from 15–45 mins. The produced BZnO photocatalysts were tested for photocatalytic degradation at fixed conditions of 10 ppm of PCM, photocatalyst dosage of 0.1 g for 120 min. The degradation percentage of PCM was determined using Ultraviolet-Visible Spectroscopy (UV-Vis). The photocatalyst with the highest PCM degradation was then characterized using X-ray Diffraction (XRD) and Brunauer–Emmett–Teller (BET) surface area and pore analyser. Results showed that the highest percentage of PCM photodegradation was 28.20 % using ZnO incorporated with SCW extracted BPE at 140°C for 30 mins. The energy band gap of pure ZnO is calculated to be 3.370 eV, while the energy band gap of the BZnO drops down to 3.290 eV proving that BPE could act as a reducing agent. Further analysis of this BZnO showed the formation of pure nanoparticles with a hexagonal wurtzite crystal structure from its XRD patterns. Additionally, the BET surface area and total pore volume recorded were 20.5702 m2/g and 0.73188 cm3/g, respectively. Hence, green catalyst synthesized by incorporating ZnO and BPE has the potential to be utilized for pharmaceutical wastewater treatment.