Study on synthesis and adsorption properties of ReO4− ion imprinted polymer

Abstract

Water solution polymerization was adopted to prepare perrhenate ion imprinted polymers in this work, and preparation conditions, such as molar ratio of acrylic acid, N,N - methylene double acrylamide, hydrogen peroxide and ascorbic acid to N-vinyl pyrrolidone, polymerization time and temperature on adsorption separation property were investigated and optimized using adsorption quantities and separation degree as indexes. To enhance the adsorption selectivity, adsorption properties of samples prepared under different conditions were conducted in a mixture aqueous solution of ammonium perrhenate and potassium permanganate with the molar ratio of 1:1. Results showed that as the molar ratio of N,N - methylene double acrylamide, acrylic acid, hydrogen peroxide, ascorbic acid to N-vinyl pyrrolidone were 2.0, 1.9, 0.03, and 0.003 respectively, the reaction temperature and time were 35 °C and 24 h, adsorption quantities and separation degree arrived at 0.037 mmol/g and 2.31, respectively, while the adsorption capacities and separation degree of non-imprinted polymers were only 0.009 mmol/g and 0.22. Besides, study was also discovered that the prepared samples presented an exciting reusable stability. Based on samples prepared under optimal conditions, the structure was characterized by Fourier transform infrared spectroscopy, scanning electron microscope, transmission electron microscope, BET surface area and thermogravimetric analysis using non-imprinted polymer prepared under the same conditions as a control. Finally, the adsorption thermodynamics and kinetics were studied, and the kinetics documented that the adsorption of perrhenate ion imprinted polymers was a zero-order model process. The thermodynamics presented the adsorption was more suitable to be expressed by Langmuir model, and Scatchard analysis revealed that heterogeneous binding sites were formed in IIP.