Laccase-coupled photoelectrocatalytic system for highly efficient degradation of bisphenol A

Spatial nanopores promote laccase degradation of bisphenol A and its analogs

Bisphenol A (BPA) and its analogs are endocrine-disrupting chemicals that are frequently detected in environmental and human samples. However, the effective removal of BPA and its analogs has not yet been extensively studied. Herein, we introduce a novel enzyme reactor for the degradation of BPA and its analogs in water. The influence of pore size on the degradation efficiency of immobilized laccase in the spatial nanopores of hydrogel was investigated using BPA as a representative compound. This showed that nanopores enhance the activity of immobilized laccases in a pore size-dependent manner and increase their stability. Compared with the same amount of free laccase, the 50 mg/L BPA degradation performance of laccase immobilized in 76 nm nanopores increased to 300 %. Taking advantage of magnetic separation, this immobilized laccase can be reused, and its degradation capacity was maintained at over 73.7 % after ten reactions. Moreover, the degradation of seven BPA analogs was 1.03-5.88 times higher using laccase immobilized in nanopores compared with free laccase. Also, the biocatalyst could efficiently degrade BPA analogs in real water matrix. This study opens up a new avenue for the removal of BPA and its analogs by immobilizing laccase in nanopores, overcoming the key limitations introduced by the short enzyme life span and non-reusability.

Highly Efficient Copper Doping LaFeO3 Perovskite for Bisphenol A Removal by Activating Peroxymonosulfate

A series of copper doping LaFeO3 perovskite (LaCuxFe1−xO3, LCFO, x = 0.1, 0.4, 0.5, 0.6, 0.9) are successfully synthesized by the sol-gel method under mild conditions. In this study, it is applied for the activation of peroxymonosulfate (PMS) for bisphenol A (BPA) removal. More than 92.6% of BPA was degraded within 30 min at 0.7 g/L of LCFO and 10.0 mM of PMS over a wide pH range with limited leaching of copper and iron ions. The physical–chemical properties of the catalysts were demonstrated by using X-ray diffraction (XRD), N2 adsorption–desorption isotherms, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Furthermore, the effects of catalyst dosage, PMS concentration, initial pH value, and inorganic anions on the LCFO/PMS system were fully investigated. Quenching experiments were performed to verify the formation of reactive oxidant species, which showed that the radical reaction and mechanisms play a great role in the catalytic degradation of BPA. The perovskite LCFO is considered a stable, easy to synthesize, and efficient catalyst for the activation of PMS for wastewater treatment.