新型功能化吸附剂G-PA-SBA-15对U（VI）的吸附机理

摘要

采用啤酒酵母菌为生物大孔模板，三嵌段聚合物(P123)为介孔相模板制备合成介孔氧化硅SBA-15。再采用Fe3O4为铁源，二乙基磷酰乙基三乙氧基硅烷(PTS)和氨丙基三乙氧基硅烷(APS)为有机改性基团，通过后嫁接法使有机改性基团对介孔氧化硅SBA-15进行功能化改性，得到新型功能化吸附剂G-PA-SBA-15，并通过扫描电镜、粉末X射线衍射和比表面分析仪分别表征吸附剂G-PA-SBA-15和SBA-15的结构。考察溶液pH值、吸附时间、铀初始浓度和温度等因素对吸附剂G-PA-SBA-15和SBA-15吸附铀的影响。结果表明：吸附剂G-PA-SBA-15直径均匀分布、孔径均一，吸附铀的最佳条件是pH值为6.0、吸附时间为1.0 h、铀初始浓度为20 mg/L和吸附反应温度为25℃。对吸附动力学模型和吸附等温模型进行分析，G-PA-SBA-15对铀的吸附动力学过程符合准二级动力学模型(相关系数R2均大于0.99)，吸附等温线符合BET等温线模型，说明该吸附体系是一个多层吸附过程。%Mesoporous silica SBA-15 was synthesized usingSaccharomyces Cerevisiae as the biological macroporous templet, and using P123 as the mesoporous phase templet. The novel functional adsorbent G-PA-SBA-15 was prepared using Fe3O4as the iron source, and using PTS and APS as the organic modification group by the functional modification of mesoporous silica SBA-15 after grafting. SEM, XRD and BET were used to characterize the structures of G-PA-SBA-15 and SBA-15, and the effects of pH value, adsorption time, initial concentration of uranium ions and temperature on the adsorption of G-PA-SBA-15 and SBA-15 on uranium were investigated. The results show that the optimal uranium adsorption conditions are as follows: the pH of the solution is 6.0; the adsorption time is 1.0 h; the initial concentration of uranium ions is 20 mg/L and the adsorption temperature is 25℃. The adsorption kinetic models and the adsorption isotherm models of G-PA-SBA-15 on uranium were studied. The kinetic models of G-PA-SBA-15 can be described by the pseudo-second-order model well, its correlation coefficient are all above 0.99 (R2>0.99), and isotherm models are fitted to BET adsorption models, indicating that the adsorption process is a multilayer adsorption process.