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研究了大孔交联聚甲基丙烯酸酯树脂(相当于 Amberlite-XAD-7)吸附和解吸 AuCl_4~-的动力学.结果表明,两种过程均由液膜扩散转向粒内扩散主控.HCl 浓度对吸附 AuCl_4~-过程影响甚微,25℃时的■_(AuCl_4~-)=4.4×10~(-8)cm~2·s~(-1),扩散活化能△E_a=-13.0kJ·mol~(-1);研究了 HCl-硫脲为解吸剂时的动力学,表明液膜扩散常数 R 和粒内扩散常数 B 对树脂半径γ_0的关系服从 Boyd 方程.
The kinetics of adsorption and desorption of AuCl_4 ~ on macroporous cross-linked polymethacrylate resin (equivalent to Amberlite-XAD-7) was studied. The results show that both of the two processes are dominated by the diffusion of liquid film to the main control of intragranular diffusion. The concentration of AuCl_4 ~ - has little effect on AuCl_4 ~ (superscript ~) adsorption process. The Au_ (AuCl_4 ~) = 4.4 × 10 -8 cm ~ 2 · s -1 at 25 ℃ and the activation energy △ E_a = -13.0 kJ · mol ~ (-1). The kinetics of HCl-thiourea as a desorbent was investigated. It is shown that the relationship between the diffusion constant R and the diffusion constant B of the liquid film obeys the Boyd equation.