Green synthesis of bimetallic nanocomposite: Efficient use of nanocomposite in the removal of phenol and n-(n-Propyl) thiourea by photo-Fenton-like process

Abstract

The contamination of water bodies with emerging and persistent water contaminants, viz., phenol and n-(n-propyl) thiourea (NNPT) is a severe environmental and health concern. This study aims to obtain the novel bimetallic heterogeneous nanocatalyst supported with natural bentonite using a facile greener route. The in situ nanoparticles, i.e., Fe0 and Ag0, were obtained utilizing natural phytochemicals from leaf extracts of P. guajava. The XPS and XRD analyses inferred the presence of Ag0(NPs) and Fe0(NPs) in the composite material. Moreover, the bandgap energy of nanocomposite material (Ben@(Fe0+Ag0)) was 2.25 eV compared to the pristine bentonite of 3.25 eV. Further, the nanocatalyst was efficiently employed in the photo-Fenton-like process to eliminate of phenol and NNPT in an aqueous medium. The degradation efficiency of the catalyst for targeted pollutants was found to be 73% (for phenol) and 95% (for NNPT) in the photo-Fenton-like process for 2 h of UV-A illumination. Similarly, a significant efficiency (Ca. 60% for phenol and Ca. 90% for NNPT) was achieved utilizing the LED (Visible) light illumination in a similar photo-Fenton-like process. The degradation of these two pollutants has predominantly proceeded through the •OH radicals. The photo-Fenton-like process mineralized these two pollutants significantly. Several parameters optimized the Fenton-like process, including pH, catalyst dose, and H2O2 concentration. The repeated photo-Fenton-like processes for 4 consecutive cycles showed an insignificant decrease in the efficiency of nanocatalyst, at least in the elimination of these two contaminants. The process was further employed to eliminate phenol and NNPT in the natural water samples spiked with known concentrations of these pollutants. The promising approach is excellent for the removal of recalcitrant environmental pollutants.