Adsorption Kinetics of Uranium(Ⅵ) from Aqueous Solution by Amino Modified Rice Husk Biochar 氨基修饰稻壳生物炭对水溶液中铀的吸附动力学特性

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, pH 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 (Q(NBC)=69.63 mg/g>Q(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 pH 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 the Pseudo Second-Order Kinetic model (R=0.999) and Sipisisotherm model (R>0.914), respectively. The results showed that the modified biochar had high adsorption capacity, good environmental tolerance and better application potential.