Photoactive Graphene Aerogel from Biomass for the Visible-Light-Induced Degradation of Pharmaceutical Residues

Abstract

Currently, telmisartan (TEL) is globally employed to reduce high blood pressure and in the treatment of hypertension. Unused TEL from hospitals and pharmaceutical industries and its metabolic products are present in wastewater, which are posing a critical menace to the environment and modern society. As a result, development of a durable and high-performance TEL removal method is needed. The design of a sustainable and robust visible light photocatalyst is a key concern in the degradation of pharmaceuticals. Herein, a low-cost and green N-doped graphene aerogel (N-GA) was synthesized using glucose as the carbon source and ammonium chloride as a nitrogen source via a one-step pyrolysis technique for the photocatalytic degradation of TEL. N-GA exhibits a significant photocatalytic activity toward the visible-light-induced degradation of TEL. Notably, 99.8% of TEL was removed from water within a time period of 70 min with high recyclability. Moreover, after the treatment, N-GA is easy to recover without any extra effort or chemical/physical treatment. The possible photocatalytic mechanism has been elaborately explained by using radical trap experiments. The driving force for the ease of formation of radicals or reactive oxygen species is governed by heteroatoms, and herein, the superoxide is a major ROS for photocatalytic activity. N-GA can provide new insights into the photocatalytic removal of emerging pollutants.