Preparation of polysulfone based rubidium ion imprinted membrane and its selective adsorption and separation performance

A novel Rb + imprinted membrane was fabricated via non-solvent inversion phase separation method by blending template RbCl, poly(styrene- co -4-hydroxylstyrene) (P(S-co-VPh)) and polysulfone, where the phenolic hydroxyl groups of P(S- co -VPh)) spontaneously coordinated with template Rb + in the casting solution to form an imprinted Rb + site. Gel permeation chromatography , FTIR and 1 H NMR results indicated that the (P(S-co-VPh) had been synthesized successfully. The characterization of water contact angle, scanning electron microscope and membrane performance tests indicated that the blending membranes had better hydrophilicity , more porous structure and higher pure water flux. The adsorption behaviors of Rb + on the blending membranes were investigated depending on the parameters of solution pH , temperature, ions interference, Rb + concentration and contact time. The results indicated that the maximum Rb + adsorption capacity can be obtained when the solution pH is 9.0, and low temperature is favorable for adsorption because it is an exothermic process . As compared to Na + , Ca 2+ , and Mg 2+ , K + has the greatest ion interference effect, causing up to 58.1% decline in Rb + adsorption capacity for non-imprinted membranes but only 7.4% for imprinted membranes. The adsorption process conforms to Langmuir isothermal model and pseudo-second-order kinetic model , and the theoretical maximum adsorption of Rb + is 70.12 mg/g. Furthermore, the Rb + imprinted membrane can be reused at least five times using 0.1 M HCl solution as the eluent , indicating that membrane has potential application value in the separation and extraction of rubidium.