Solar-Driven Degradation of Malachite Green by Photoenzyme: Mechanisms and Sustainable Water Treatment

Abstract

Malachite Green (MG), a widely used industrial dye and biocide, poses significant environmental and health risks due to its non-biodegradability and toxicity. In this study, we employed a novel solar-driven photoenzyme coupled catalytic system, Lac@PHOF, which combines the enzyme laccase with a porous photoactive hydrogen-bonded organic framework (PHOF; synthesized from H4TBAPy as PFC-1) to efficiently degrade MG under visible light irradiation. The Lac@PHOF system exhibited remarkable photocatalytic performance, achieving 92% MG removal within just 15 minutes under natural sunlight, with an impressive conversion efficiency of 18,300 mg/g/h. The degradation process was primarily driven by singlet oxygen and photogenerated holes, converting MG into non-toxic small molecules. Lac@PHOF exhibited excellent stability, resisting pH extremes (3-11), long-term storage (35 days), and elevated temperatures (up to 80°C), while maintaining degradation efficiency after 10 reuse cycles. The system’s high efficiency, combined with the absence of sacrificial agents, positions Lac@PHOF as a promising candidate for sustainable water treatment applications. These findings underscore the potential of solar-driven photoenzyme systems for environmental remediation, offering a cost-effective and eco-friendly approach to the removal of organic pollutants from aquatic environments.