Assembly of artificial photo-enzyme coupling nanoreactor for boosting photodegradation of trace bisphenol A pollutant in water

It is a difficult issue to remove the trace persistent organic phenolic pollutants in water. Herein, a new artificial horseradish peroxidase (HRP)/hierarchical carbon nitride (HCN) photo-enzyme coupling nanoreactor is assembled by immobilizing HRP on HCN, which achieves the high-efficiency degradation performance for trace bisphenol A (BPA) in water. Besides the promoted charge separation efficiency as well as visible light harvest capacity, the hollow and abundant pores structure of HCN/HRP can provide a confinement effect and molecular diffusion channels to promote photo-enzyme synergic catalytic effect, thus boosting degradation reaction of BPA. Compared with original HCN, the optimal HCN/HRP-3 sample obtain a higher degradation rate of 0.0575 min⁻¹, which is 3.60 and 125 times as large as that over original HCN (0.016 min⁻¹) and HRP (0.00046 min⁻¹), respectively. Meanwhile, the mineralization ability of the HCN/HRP photo-enzyme coupling nanoreactor is enhanced dramatically owing to the far higher TOC removal efficiency of BPA with 81.05 % within 60 min than original HCN (37.63 %). The photocatalytic reaction mechanism investigations demonstrate that h⁺, •O₂⁻ and •OH all take part in the degradation process of BPA and the importance order of h⁺ > •O₂⁻ > •OH. This work provides an innovative design philosophy for the assembly of photo-enzyme synergic catalytic system to effectively remove the organic pollutants in water.