Study on the preparation and performances of temperature-sensitive ion-imprinted composite membrane modified with TiO2 for selective adsorption of ReO4−

Abstract

A new type of temperature-sensitive imprinting composite membrane was prepared by introducing TiO2 in this work. As follows, Firstly, membrane of PVDF/PET was coated by poly dopamine (PDA) and TiO2, and then it was RAFT modified by grafting reaction. After that, temperature-sensitive polymer, Poly(N,N-diethylacrylamide) (PDEA), were grafted onto the membrane surface by graft from reaction and polymerization strategy to give the surface of the imprinted composite membrane a certain "flexibility". Finally, the ReO4− temperature-sensitive ion-imprinted composite membrane (Ti-Re-TIICM) was made. Comprehensive properties of Ti-Re-TIICM were tested and evaluated. Results showed that Ti-Re-TIICM possessed a thermal recognition site, and the structure of the imprinted cavity could be adjusted by changing the temperature. The maximum adsorption capacity was 0.0669 mmol/g at 35 °C. In the presence of interfering ion MnO4−, the separation degree of Ti-Re-TIICM was 3.05, and the desorption rate was 65.64 %. After 9 cycles of adsorption/desorption, the adsorption capacity of Ti-Re-TIICM remained at 62.8 % of the original adsorption capacity, the degree of separation decreased to 1.27, and the desorption rate decreased to 56.53 %. When Ti-Re-TIICM was applied to the secondary leach solution of the high temperature alloy, the purity of rhenium in the solution increased from 38.719 % to 61.220 %.