Ultrasonic-assisted preparation of amidoxime functionalized silica framework via oil-water emulsion method for selective uranium adsorption
writer：Mudasir Ahmad, Jiqi Wang, Zuoting Yang, Qiuyu Zhang, Baoliang Zhang
keywords：amidoxime functionalized SiO2， Uranium adsorption， Environmental remediation， Porous materials， Click reaction
source：期刊
specific source：Chemical Engineering Journal
Issue time：2020年
The demand for low-cost adsorbent and method for efficient adsorption of metal ions for environmental and energy applications is highly required. The novel amidoxime functionalized silica framework (SiO2-AO) is prepared through a step by step process including ultrasonic-assisted oil–water emulsion method, surface sulfhydrylation, click reaction and modification of amidoxime. The hexane/water emulsion system in the presence of hexadecyltrimethylammonium bromide (CTAB) gives a large specific surface area of the precursor (SiO2-OH) and final products. The spectroscopic characterization combined with kinetics and isothermal studies reveals that the interaction between U(VI) and SiO2-AO is usually through coordination complexation. The adsorption behavior of SiO2-AO for U(VI) adsorption is explored through various batch methods including the effect of U(VI) concentration, pH, contact time and adsorbent dosage. It is revealed 99.9 ± 0.5% U(VI) adsorption occurs at pH = 8, which is close to the pH of seawater. The highest U(VI) adsorption capacity obtained from the Langmuir adsorption model is 955.8 mg g?1 at room temperature. The high removal rate (above 85%) at low U(VI) initial concentration (3 μg L-1), excellent selectivity of U(VI) in presence of coexisting ions and high adsorption efficiency of regenerated adsorbent in sixth cycle refer SiO2-AO as a potential adsorbent for U(VI) adsorption in the practical field.