Microwave-assisted synthesis of three dimensional superhydrophilicity ion imprinted polymer based on POSS/SBA-15 for copper ion adsorption in environmental water

Abstract

The research developed a three-dimensional super-hydrophilic Cu(II)-imprinted polymer(Cu(II)-IIP) utilizing Polyhedral oligomeric silsesquioxane(POSS) and Santa Barbara Amorphous-15(SBA-15) as the matrix material, in conjunction with surface imprinting and microwave-assisted techniques. SBA-15 improved the dispersion of the three-dimensional cage-like POSS structure, thus facilitating a more uniform distribution of imprinting sites. Microwave-induced polymerization markedly decreases the reaction duration to about 60 min-one-sixth of the time needed for traditional heat-induced techniques-highlighting its good efficiency and the time-saving benefits of microwave-assisted synthesis in polymer fabrication. The Cu(II)-IIP based on POSS/SBA-15 composite achieved a maximum adsorption capacity of 163.87 mg/g within 60 min under optimal conditions (pH 5, adsorbent dosage of 0.5 g/L, and a POSS mass fraction of 52.94 %), which was almost four times greater than that of the non-ion-imprinted polymer (NIIP), which only showed an adsorption capacity of 41.99 mg/g, the result was further analyzed using Langmuir isotherms and Pseudo-second order kinetics. The Cu(II)-IIP exhibited excellent adsorption–desorption efficacy during five successive cycles, with stable repeatability measurements, signifying remarkable stability and reusability of the material. The Cu(II)-IIP demonstrates significant selectivity for Cu(II) at pH 5.0, attributed to the development of specific recognition sites that correspond to the size and coordination environment of Cu(II). Additionally, the elevated surface area and mesoporous structure of SBA-15 improve ion accessibility in both binary and multi-component systems. The synthesized Cu(II)-IIP demonstrated effective application for analyzing two distinct concentrations (25.0 and 50.0 µg/L) in Yudai River and Yangtze River water, achieving satisfactory recoveries between 97.90 % and 103.24 %. Density functional theory and frontier molecular orbital calculations indicate that the adsorption of Cu(II) in Cu(II)-IIP is primarily due to the coordination between the nitrogen atom on 4-VP and Cu(II).