Peroxydisulfate bridged photocatalysis of covalent triazine framework for carbamazepine degradation

Covalent triazine frameworks (CTFs) are appealing photocatalysts for environmental remediation. However, high recombination rate of photogenerated electrons and holes is the key limitation for its application. Notably, peroxydisulfate (PDS) can potentially act as electron withdrawing center to efficiently prevent the recombination. Herein, the photocatalysis of CTF under visible light (VL) coupled with PDS shows great potential for pollutants removal, taking carbamazepine (CBZ) as a case, in which the observed rate constant of CBZ degradation in VL/CTF/PDS process is 9.0 and 4.5 times to that in CTF/PDS and VL/CTF processes, respectively. PDS can construct a bridge to enhance the charge separation and transfer efficiency of CTF to prevent the recombination of electrons and holes, thus significantly improving the oxidation ability of the VL/CTF/PDS process. Moreover, the accepted electrons can initiate the PDS activation to generate more reactive species, thus contributing to higher oxidation capacity of the VL/CTF/PDS process. Furthermore, the VL/CTF/PDS process tends to attack the 1 N and 12C-15C atoms of CBZ to induce the cleavage of N-C bond and oxidation of C--C bond, thus decomposing CBZ into lower molecules and finally being mineralized. This study will promote the development on applying photocatalysis of CTF materials and PDS activation in practical environmental remediation.

Automated summary

Covalent triazine frameworks (CTFs) are promising photocatalysts for environmental remediation, but their high recombination rate of photogenerated electrons and holes limits their application. In this study, peroxydisulfate (PDS) was found to effectively prevent recombination and enhance charge separation in CTF, leading to improved oxidation ability under visible light. The combined VL/CTF/PDS process showed higher efficiency in degrading pollutants, such as carbamazepine (CBZ), by attacking specific atoms and bonds in the molecule. This research demonstrates the potential of utilizing CTF materials and PDS activation for practical environmental remediation.