A growing number of persistent and emerging organic micropollutants and pathogens are frequently observed in natural and treated water. These contaminants attract significant attention because they may pose risks to human health and ecological system even at very low concentrations. Solar-energy-enabled photocatalysis is a sustainable advanced oxidation process (AOP) to destruct organic micropollutants via the attack of photogenerated reactive oxygen species (ROS, e.g., ●OH, O2-●/HO2●, H2O2, 1O2) and holes (also known as electron vacancies). Graphitic carbon nitride (g-C3N4) has emerged as a promising polymeric photocatalyst for water purification, because of its capability of using more solar energy in the visible spectrum, low-cost, excellent stability, and no reported toxicity. In our study, we designed and fabricated a series of g-C3N4 samples with improved surface area and charge separation via a supramolecular approach and elemental doping, and evaluated their performance for the degradation of phenol, atrazine, sulfamethoxazole, and carbamazepine under simulated visible sunlight. Density functional theory simulations suggested that carbon doping but not phosphorus doping could improve the photocatalytic activity, which was verified in the experimental evaluation. The mechanism for contaminant transformation was further evaluated, by determining the ROS production, interaction between ROS and contaminants, and hole oxidation of contaminants via an integrated experimental and simulation approach. The photocatalytic performance of g-C3N4 was evaluated in both a model buffer system and complex water matrices, and the presence of water constituents (e.g., hardness, alkalinity, organic matter, scavenges, foulants) did not inhibit the reactivity for contaminant degradation. Our study demonstrates that g-C3N4 holds promise for sustainable water purification, and it provides guidelines for rational design of reactive materials for water purification.

Tailored graphitic carbon nitride: Smart design of visible-light-responsive photocatalyst to achieve sustainable water treatment

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.