Saccharin copolymerization-modified metal-free graphite carbon nitride for efficient photocatalytic removal of tetracycline hydrochloride in actual water samples: Process and mechanism

Abstract

Nowadays, photocatalytic degradation of organic pollutants is considered an ideal solution for environmental remediation. Graphite carbon nitride (g-C3N4) is one of the most promising visible light-responsive photocatalysts. However, g-C3N4-based photocatalysts are constrained by the drawbacks of inadequate light absorption ability and easy recombination of electron-hole pairs. To overcome the above-mentioned shortcomings, metal-free g-C3N4 (GCN-S-75) was successfully synthesized by a one-step saccharin copolymerization approach and applied to the photodegradation of tetracycline. Overall, the prepared GCN-S-75 exhibited a significant improvement in light trapping capacity, charge separation, and degradation efficiency. Meanwhile, free radical trapping experiments were conducted to confirm the •O2- the primary active species. The effects of photocatalyst dosage, tetracycline initial concentration, solution pH, and inorganic anions (HCO3-, CO32-, Cl-, NO3-, SO42-), and in actual water samples on photocatalytic activity were examined. The degradation pathways of tetracycline (TC) were explored. This work might serve as fresh inspiration for the development of high-performance, low-cost photocatalysts for environmental remediation.