功能化磁性载体固定耐辐射奇球菌及其对铀的吸附行为与机理

Adsorption behavior and mechanism of uranium(Ⅵ) on Deinococcus radiodurans immobilized functionalization magnetic carrier

为了解决耐辐射奇球菌(DR)容易以悬浮态生长,菌体与水的密度差较小,吸附铀后难以分离等问题,首先使用氯化亚砜对羧基化磁性纳米Fe_3O_4粒子进行酰氯功能化,以此作为DR菌固定载体,再与二乙烯三胺化学修饰的DR菌进行固定化,得到一种新型功能化磁性耐辐射奇球菌吸附剂NFGDR,并通过红外光谱仪和扫描电镜分别表征吸附剂NFGDR的结构。考察溶液pH值、吸附时间、铀初始浓度和吸附剂投加量等因素对吸附剂NFGDR吸附铀的影响,对吸附动力学模型和吸附等温模型进行分析。结果表明:吸附剂NFGDR表面具有大量吸附铀的基团,吸附铀后表面形态发生变化;吸附铀的最佳条件是pH值为5、吸附时间为80 min、铀初始浓度为10 mg/L和吸附剂投加量为5 mg。吸附剂NFGDR对铀的吸附动力学过程符合准二级动力学模型,吸附等温线符合Langmuir等温线模型,说明该吸附体系是一个单层吸附过程。同时,使用3种不同的解析剂对吸附剂NFGDR解析再生6次后,其对铀的吸附率均在80%以上,说明其具有良好的再生性能。

In order to solve the problems such as Deinococcus radiodurans（DR） growing in a suspended state, the small difference between the bacteria density and the water density, and the hard separation after uranium adsorption, the novel functional magnetic Deinococcus radiodurans adsorbent NFGDR was prepared. At first, the carboxylation magnetic Fe_3O_4 nanoparticle was chloride functionalization using sulfoxide chloride, and it was immobilized with the chemical modification DR using Diethylenetriamine as the magnetic carrier. FT-IR and SEM were used to characterize NFGDR, and the effects of pH value, adsorption time, initial concentration of uranium and the adsorbent dosage on the adsorption of NFGDR on uranium were investigated. The adsorption kinetic models and the adsorption isotherm models of NFGDR on uranium were studied. The results show that a lot of functional groups are found on the cell wall of NFGDR for adsorbing uranium, and its surface form changes because of adsorbing uranium. The optimal uranium adsorption conditions are as follows： the pH of the solution is 5; the adsorption time is 80 min; the initial concentration of uranium is 10 mg/L and the adsorbent dosage is 5 mg. The kinetic model of NFGDR can be described by the pseudo-second-order model well, and the isotherm model is fitted to Langmuir adsorption model, indicating that the adsorption process is a monolayer cover adsorption process. At the same time, the uranium adsorption percents are over 80% after NFGDR was regenerated 6 times using 3 different analytical agents. It shows that NFGDR has good regeneration performance.