Pharmaceutical emerging pollutants photodegradation by the action of g-C3N4/BiVO4 heterojunctions

Abstract

Emerging contaminants are increasingly common in natural resources causing adverse health effects on humans, animals, and the environment. Thus, recently, a significant need for research to develop sustainable purification approaches to remove these pollutants from wastewater plants is required. Heterogenous photocatalysis represents a promising approach to remove traces of these pollutants from wastewater using semiconductor oxides. Some of the most promising materials for this purpose are g-C₃N₄ and BiVO₄, which when combined in a heterojunction favor high efficiencies to remove water trace pollutants, e.g., pharmaceuticals. Therefore, this work proposes the optimization of the synthesis of the g-C₃N₄/BiVO₄ heterojunction by microwave-hydrothermal method (MW-H) with an orthogonal L₉ Taguchi design of experiments. During the synthesis, four factors were changed: load of BiVO₄, power, temperature, and time of the MW-H method, to find the optimal conditions to obtain g-C₃N₄/BiVO₄ heterojunctions with outstanding efficiencies to remove trace drugs of acetaminophen and tetracycline, contributing to proposes solutions for water purification. The g-C₃N₄/BiVO₄ heterojunction promoted efficiencies to remove both drugs up to 74 % for acetaminophen and 87 % for tetracycline, confirming mineralization degree of 21 and 35 %, respectively. A mechanism for the decomposition of the organic molecules was proposed through the study of oxidant species.