Enhancement of photocatalytic performance of cu-decorated bifunctional g-C3N4-laccase ICPB system

Printing and dyeing wastewater contains high concentrations of dyes which have been released into the environment and lead serious threat to the ecological environment and human health. This article uses a covalent grafting method to immobilize laccase onto mesoporous g-C3N4 (CN) and Cu is doped to improve the degradation performance of intimate coupling photocatalysis and biodegradation (ICPB) system. The crystal structure of the CN is no changed after the immobilization of laccase. In addition, more oxygen-containing functional groups of the immobilized carrier is increased that improve the separation efficiency of photogenerated electron hole pairs of the original carrier. Compared to free enzymes, mesoporous g-C3N4 immobilized laccase (CN-LC) and copper doped mesoporous g-C3N4 immobilized laccase (Cu-CN-LC) both have a wider adaptation range and better stability. Because the addition of Cu, the PL of Cu-CN-LC becomes significantly weaker, and the bandgap is decreased. The removal efficiency of Cu-CN-LC for methyl orange and active blue is 1.34 times and 1.66 times higher than of CN and possessed good reusability. A novel technical contribution of ICPB proposed in this work is a feasible solution for printing and dyeing wastewater.