NMP-induced surface self-corrosion-assisted rapid spin-coating method for synthesizing imprinted heterojunction photocatalyst anchored membrane towards high-efficiency selective degradation tetracycline

The membrane immobilization of imprinted photocatalysts is a good cooperative model, which not only gives self-cleaning and selectivity to the membrane but also solves the problem of difficult recycling and reuse of powder catalysts. Nevertheless, the problem of catalyst encapsulation and pore blockage limits its practical application. Herein, 1-methyl-2-pyrrolidone (NMP)-induced surface self-corrosion-assisted rapid spin-coating method was first proposed to prepare imprinted perylene diimide/poly-3,4-ethylenedioxythiophene heterojunction photocatalyst anchored membrane (I-PDI/PEDOT-M) with high stability and permeability. NMP can corrode polyvinylidene fluoride (PVDF) membrane and cause pore wall collapse on PVDF surface. The collapse of the pore wall firmly anchored the imprinted PDI/PEDOT heterojunction photocatalyst (I-PDI/PEDOT) into the surface pore of the PVDF membrane, effectively enhancing the stability. More importantly, this method did not produce a dense layer of traditional spin-coating solution, and I-PDI/PEDOT was fully exposed in the surface pores of the membrane to contact pollutants, thus maintaining high water flux and photodegradation activity. Besides, the construction of heterojunction structure and the introduction of imprinted cavities resulted in the good self-cleaning performance, excellent photocatalytic performance and significant specific degradation ability of I-PDI/PEDOT-M. The degradation activity of tetracycline (TC) with I-PDI/PEDOT-M was 11.05 times that of ciprofloxacin, and the selectivity coefficients of I-PDI/PEDOT-M were 2.51and 1.63 relative to PDI-M and non-imprinted PDI/PEDOT heterojunction photocatalyst, respectively. Additionally, the theoretical calculation and toxicity experiment proved that the toxicity was significantly reduced after degrading TC by I-PDI/PEDOT-M. This work provides an interesting idea for the design of highly stable and permeable photocatalytic membrane and highly selective degradation of specific pollutant.