Photoassisted highly efficient activation of persulfate over a single-atom Cu catalyst for tetracycline degradation: Process and mechanism

A single-atomic-site Cu catalyst (SAS-Cu) supported on carbon nitride (CN) material was synthesized by a pyrolyzing coordinated polymer (PCP) strategy. The introduction of a single-atomic Cu site improved the charge transfer and separation efficiency. The reaction rate constant of SAS-Cu-1.0 is 4.5 times higher than that of CN. Under the condition of only 0.1 mM sodium persulfate (PS) and 0.1 g/L catalyst, the removal rate of tetracycline (TC) reached 82.5% after 30 mM of LED illumination, which greatly improved the utilization of oxidant. Mechanistic analysis shows that there are free radical (center dot O-2(-), SO4 center dot(-), center dot OH) and nonradical pathways (O-1(2) and direct electron transfer) in the system, and they have synergistic effect. Density functional theory (DFT) calculations show that SAS-Cu-1.0 can optimize the adsorption and activation of PS. This work illustrates the application value of SAC combined with activated persulfate and the low energy consumption of the LED light in the field of environment, which provides a new strategy for reducing the salinity and treatment cost of treated water.

Automated summary

A single-atomic-site Cu catalyst supported on carbon nitride material was synthesized, which improved charge transfer and separation efficiency; the experimental results showed that the reaction rate constant of this catalyst significantly increased, and the utilization of oxidant was greatly improved under LED illumination.