为了探究NBC(氨基修饰生物炭)对U(Ⅵ)的吸附性能,通过在BC(未修饰生物炭)上负载氨基的方法得到氨基修饰生物炭,研究BC、NBC对水溶液中U(Ⅵ)的吸附特征,分析生物炭添加量、溶液p H、溶液中阴离子、初始ρ[U(Ⅵ)]、吸附时间和吸附体系温度等因素对U(Ⅵ)吸附的影响,筛选最优的吸附条件,并利用SEM(扫描电镜)、FT-IR(傅里叶红外光谱)、XRD(X-射线衍射)、XPS(X-射线能谱)、BET比表面积、元素分析、零点电位(Zeta电势)测定等手段表征BC、NBC的结构特征,并进一步探讨其对U(Ⅵ)的吸附机理.结果表明:(1)NBC的比表面积和吸附位点显著增加,对U(Ⅵ)的吸附速率和吸附量明显增加,NBC的最大吸附量(69.63 mg/g)大于BC(53.95 mg/g).(2)NBC对U(Ⅵ)吸附的最佳条件为生物炭添加量0.4 g/L、p H 6、初始ρ[U(Ⅵ)]20 mg/L、吸附时间1 h、吸附体系温度328 K.(3)BC、NBC对U(Ⅵ)的吸附动力学均符合伪二级动力学方程,R2均为0.999;等温吸附过程均符合Sips等温吸附模型,R2均大于0.914.研究显示,NBC的吸附能力强、环境耐受性好,具有很好的应用潜力.%Amino modified biochars were obtained by loading amino onto rice husk biochar, and adsorption capacities of U (Ⅵ) by these biochars were investigated to reveal the potential use of the modified biochars for U (Ⅵ) adsorption from aqueous solution. The optimal conditions of U (Ⅵ) adsorption such as biochar dosages, p H value of solution, the anion in the solution, initial concentration, adsorption time and temperature were determined. The SEM, FT-IR, XRD, XPS, BET, SA and Zeta potential were used to characterize the properties of biochars and the mechanisms of U (Ⅵ) adsorption. The results showed that: (1) The specific surface area and adsorption sites of the modified biochar (NBC) were significantly higher than the original biochar (BC), which improves the U (Ⅵ) adsorption capacity of the biochar (Qmax (NBC) = 69. 63 mg/g＞Qmax (BC) = 53. 95 mg/g). (2) The amino modified rice husk biochar had very good removal of U (Ⅵ) when the biochar content was 0. 4 g/L, the initial U (Ⅵ) concentration was 20 mg/L, solution p H was 6, the temperature was 328 K, and the contact time was 1 h. (3) U (Ⅵ) adsorption kinetics onto the original and modified biochars followed thePseudo Second-Order Kinetic model (R2= 0. 999) and Sipisisotherm model (R2＞ 0. 914), respectively. The results showed that the modified biochar had high adsorption capacity, good environmental tolerance and better application potential.
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