Adsorption of Arsenic on Conditioned Layered Double Hydroxides: Column Experiments and Modeling
Adsorption of Arsenic on Conditioned Layered Double Hydroxides: Column Experiments and Modeling
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DOI：
10.1021/ie800878n
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发表时间：
2009-02-18
影响因子：
4.2
通讯作者：
Tsotsis, Theodore T.
中科院分区：
文献类型：
--
作者：
Dadwhal, Megha;Ostwal, Mayur M.;Tsotsis, Theodore T.
在连续流动填充床柱中研究了经调理、煅烧的层状双氢氧化物（LDH）吸附剂对As（V）的去除，以研究重要操作参数（如进水As浓度、pH值、吸附剂粒径和流速）的影响。在较高的流速和进水浓度下，观察到较早的床饱和和突破。另一方面，在吸附剂的粒径和进水pH值的减少导致在突破的床体积的数量增加。一个列模型，占外部，液膜传质和扩散和吸附剂颗粒中的吸附。采用两种不同的吸附模型，这是以前被证明是能够预测的LDH吸附剂的As（V）的吸收。它们是常规的均相表面扩散模型和双分散孔模型，后者将LDH颗粒视为微粒的集合，并考虑到颗粒内孔空间中的体扩散和微粒本身内的表面扩散。这两种模型被发现能够预测流柱实验结果。
The removal of As(V) by conditioned, calcined layered double hydroxide (LDH) adsorbents is investigated in continuous-flow, packed-bed columns, in order to study the effect of important operating parameters, such as the influent As concentration, the pH, the adsorbent particle size, and the flow rate. Earlier bed saturation and breakthrough were observed at higher flow rates and influent concentrations. On the other hand, a decrease in the adsorbent particle size and the influent pH resulted in an increase in the number of bed volumes at breakthrough. A column model which accounts for external, liquid-film mass transport and for diffusion and adsorption in the adsorbent particles is utilized. Two different adsorption models are employed, which were shown previously to be capable of predicting the As(V) uptake by LDH adsorbents. They are a conventional homogeneous surface diffusion model and a bidisperse pore model, the latter viewing the LDH particles as assemblages of microparticles and taking into account bulk diffusion in the intraparticle pore space, and surface diffusion within the microparticles themselves. Both models are found capable of predicting the flow-column experimental results.