The anion exchange kinetics between NO3− and benzoate (BA) in layered double hydroxides (LDHs) have been studied. The experimental conditions were selected to favour a particle diffusion rate-controlling mechanism, subsequently confirmed by the variation of the exchange rate with temperature, resin bead size and stirring speed. Furthermore, the parallel diffusion model is successfully validated in this anion exchange process. Intraparticle effective diffusivities (Deff) of BA in these NO3-LDHs macroparticles were determined from the homogeneous Fickian diffusion model at various temperatures. Crystallites diffusion is the rate-controlling step, in which the anion exchange in the interlayer is much slower than the anion diffusion in the pores between the crystallites.

中文翻译：

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层状双氢氧化物阴离子交换动力学分析

已经研究了层状双氢氧化物 (LDH) 中 NO3- 和苯甲酸盐 (BA) 之间的阴离子交换动力学。选择的实验条件有利于粒子扩散速率控制机制，随后通过交换速率随温度、树脂珠粒尺寸和搅拌速度的变化来证实。此外，在此阴离子交换过程中成功验证了并行扩散模型。这些 NO3-LDHs 大粒子中 BA 的粒子内有效扩散率 (Deff) 由不同温度下的均匀 Fickian 扩散模型确定。微晶扩散是速率控制步骤，其中夹层中的阴离子交换比微晶之间孔隙中的阴离子扩散慢得多。