Photothermal catalytic activation of peroxydisulfate with porphyrin-based metal-organic framework for removal of organic pollutants

Abstract

Metal-organic frameworks (MOFs) have been proved to be one of the most promising photocatalysts for removing organic pollutants. However, the disadvantages, such as fast recombination of photogenerated carrier and low light utilization, significantly hinder the practical applications of MOFs. In this paper, porphyrin groups with wide light absorption range and high light-to-thermal conversion efficiency were introduced into MOFs to enhance their photocatalytic performance. These porphyrin-based MOFs can convert red and near-infrared light to heat to improve the utilization of solar energy. In particular, PCN-224-Co, which has a large specific surface area and high stability, was selected, as a proof-of-concept, to investigate the effect of photothermal effect in peroxydisulfate (PDS) activation. The results showed that PCN-224-Co could remove 92 % tetracycline hydrochloride (TC) in 15 min under photothermal condition, giving a high-rate constant of 0.11 min⁻¹, which is much higher than that obtained without photothermal effect. PCN-224-Co/PDS system is capable of removing pollutants from different water bodies, indicating that the system has excellent prospects for practical application. In addition, the catalytic mechanism was also investigated by both experimental methods and theoretical simulations.