Exploring the Effect of the Number of Characteristic Groups in Melaminebased Polymers on the Photocatalytic Performance

Abstract

: Three polymers containing different numbers of thiophene groups were constructed. Degradation experiments on the aqueous solutions of tetracycline and norfloxacin revealed that the polymer with three thiophene groups in the monomer indicated the best degradation efficiency of 73.7% for tetracycline and 56.9% for norfloxacin. Moreover, this polymer had a relatively stronger ability to separate and transport photocharging carriers under visible light. Therefore, the photocatalytic performance of conjugated polymers could be regulated by changing the number of characteristic groups. Background: Antibiotic residues in the environment are considered as one of the most serious sources of environmental pollution. Although catalyst photodegradation is regarded as the most promising strategy to solve environmental pollution-related problems, it still requires new and advanced photocatalysts. Objective: To design new organic conjugated material structures. Material and Methods: Three polymers (ThME-1, ThME-2, and ThME-3) were prepared by the condensation of melamine with 2, 5-thiophenedicarboxaldehyde, thieno[3, 2-b]thiophene-2, 5-dicarbaldehyde, and dithieno[3, 2-b:2’, 3’-d]thiophene-2, 6-dicarbaldehyde. The photocatalytic performance of these polymers was investigated by testing their diffused light absorption capacity, photocurrent response, AC impedance, specific surface area, fluorescence, and thermal stability. Results: ThME-3, containing three thiophene groups in the monomer, manifested the best degradation efficiency of 73.7% for tetracycline and 56.9% for norfloxacin. Conclusion: The photocatalytic performance of conjugated polymers could be regulated by changing the number of characteristic groups.