【摘要】 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.更多还原

【Abstract】 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.更多还原