Photocatalytic degradation of atrazine in aqueous solution using hyperbranched polyethyleneimine templated morphologies of BiVO₄fused with Bi₂O₃

Conventional methods have been reported to fail to completely remove contaminants of emerging concern (CECs) during wastewater treatment. Thus, new methods are required to improve wastewater treatment to completely remove the CECs from water. In this paper, we present the degradation of atrazine in aqueous solution using heterojunctions of BiVO4 and Bi2O3 that were synthesized from different morphologies of BiVO4 (truncated octahedron, plate-like, and platelet-like). The nanoparticles (NPs) were characterized using a scanning electron microscope, X-ray diffraction, UV-vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, electrochemical impedance spectroscopy, and X-ray photoelectron spectroscopy. It was observed that the heterojunctions were successfully synthesized and the observed morphologies for the BiVO4 were truncated octahedron, plate-like and platelet-like. The most effective heterojunction in the removal of atrazine was 0.5NaCl-BiVO4-Bi2O3. The 0.15HPEI-0.5NaCl-BiVO4-Bi2O3 had a reduced reaction rate compared to 0.5NaCl-BiVO4-Bi2O3, even though characterization showed that it was expected to be the most effective of all the NPs. The degradation of atrazine proceeded through dehalogenation, followed by the dealkylation and further deamination into cyanuric acid, a stable and less toxic compound. Data from LCMS/MS showed the formation of hydroxyatrazine, desethylhydroxyatrazine, and ammeline as intermediates. The degradation of several concentrations of atrazine revealed that the heterojunction efficiently removed >90 % of atrazine.