Photocatalytic Degradation of Emtricitabine, Lamivudine, and Tenofovir in Water Using the UV/TiO2/H2O2 Hybrid System
Pauline Ncube, Caliphs Zvinowanda, Freeman Ntuli
Abstract
Abstract This study was aimed at investigating the removal of antiretroviral (ARV) drug residues of emtricitabine (FTC), lamivudine (LVD) and Tenofovir (TFV) from water using the UV–Vis/TiO 2 /H 2 O 2 hybrid system. Evaluations of operational factors, degradation kinetics, scavenger effects, degradation pathways, and reusability of the catalyst were the key objectives of the study. The central composite design (CCD) of the response surface methodology (RSM) was used for process optimization. Five variables (pH, pollutant concentration, TiO 2 loading, H 2 O 2 dosage and time) were optimized. The removal realized was 92.56% (FTC), 91.67% (LVD) and 94.83% (TFV) respectively under optimum conditions. The degradations obeyed the pseudo-first-order model with the rate constant (k 1 ) of 0.10773 min −1 (FTC), 0.0513 min −1 (TFV,) and 0.04756 min −1 (LVD). pH and H 2 O 2 had a positive influence on pollutant removals up to optimum conditions. The ·OH and h + were the major contributors to pollutant degradations. The synthesized TiO 2 could be reused in four successive cycles for the effective degradation of all the ARVs. The research shows that the UV–Vis/TiO 2 /H 2 O 2 hybrid system may provide an alternative treatment method for the ARVs in water. Graphical Abstract