Bio-inspired synthesis of thermo-responsive imprinted composite membranes for selective recognition and separation of ReO4−

Abstract

A novel thermo-sensitive imprinted composite membranes (TSICMs) was developed. Different from other TSICMs, poly N,N-diethylacrylamide (PDEA) as a block part was grafted onto the imprinted polymeric separation layer matrix to obtain highly adjustable imprinted site, which could ensure imprinted site more excellent selectivity and separation performance. The morphology and structure of this polymer membrane were characterized by scanning electron microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results showed that TSICMs of ReO4− (Re-TSICMs) possessed Thermo-responsive recognition sites and exhibited excellent performance for selective separation and purification of the ReO4− through adjusting the structure of imprinted cavities under different temperature. The maximum adsorption capacity was 0.1163 mmol/g at 35 °C, and the adsorption equilibrium was reached in 2 h. Meanwhile, the Re-TSICMs could not only presented an outstanding selectivity (adsorption selectivity coefficient ReO4−/MnO4− was 19.3), but also showed excellent desorption property (the desorption rate was 78.3%). What’s more, excellent cyclic adsorption-desorption performance was also observed. Conducting the adsorption at 35 °C and desorption at 25 °C aqueous solution, it could still remained 61.3% of the original adsorption capacity with the adsorption selectivity coefficient of 13.3 after ten adsorption/desorption cycles.