Insights into molecular imprinting polydopamine in-situ activating peroxydisulfate for targeted removal of refractory organic pollutants: Overlooked N site

This study proposed a simple and green method to develop a molecular imprinting polymer for in-situ activating peroxydisulfate (PDS) without metal active sites and then targeted degrading pollutants. The molecularly imprinted polydopamine (MI-PDA) can selectively re-bonded target pollutant (sulfamethoxazole, SMX) by nitrogenous and oxygenated functional groups. On this basis, the N site of nitrogenous groups can efficiently in-situ activate PDS to generate singlet oxygen (1O2). The detailed mechanism is that PDS adsorbed on the electron-deficient N site of MI-PDA would transfer the electron to the N atom in MI-PDA, shorting the O-O bond length and resulting in the cleavage of S-O bond of PDS, which induced more 1O2 generation. Tow functions, selective enrichment and in-situ activation, endowed MI-PDA/PDS system with over 95% removal efficiency of SMX and 9.23-fold enhancement of degradation rate constants. This work provided novel insights into the selective removal of target pollutants in complicated water matrix.