Heterogeneous Photocatalytic degradation of Nevirapine in wastewater using the UV/TiO2/H2O2 process

Abstract

This work sought to study the elimination of NVP from simulated wastewater using the UV/TiO2/H2O2 system. The main objectives were to evaluate the influence of operating parameters, reaction kinetics, contributing reactive species, degradation pathway, and catalyst reusability. The research surface methodology (RSM) was utilized for optimizing process variables and for statistical analysis. Five process variables (pH, NVP concentration, TiO2 dosage, H2O2 concentration, and irradiation time) were optimized with the responses set as NVP and Total organic carbon (TOC) removals (%), respectively. 89.23% (NVP) and 85.71% (TOC) removals were achieved under optimum conditions. All the experimental factors were significant for NVP removal. pH was the most dominant factor, with the highest removals obtained under acidic conditions (pH 3). NVP removal conformed to the pseudo-first-order model with a rate constant (k1) of 0.03676 min-1. Increasing pH reduced the rate constant by 75.38%, while there was an increase of 43.55% with H2O2. NVP degradation was largely driven by the •OH and h+VB. The photocatalyst demonstrated good stability against NVP loss over four cycles. Although the UV/TiO2/H2O2 process has shown promising results in the removal of pharmaceuticals and dyes in wastewater, its application for the degradation of ARVs remains limited. As far as the authors know, the UV/TiO2/H2O2 process and RSM have not yet been reported for the degradation and optimization of NVP in wastewater, respectively. The findings of this work illustrate that the UV/TiO2/H2O2 system, applied with RSM can effectively degrade and mineralize NVP in wastewater.