Adsorbents comprising ferric hydroxide loaded on a variety of support materials are commonly used to remove arsenic from potable water. Although several studies have investigated the effects of support properties on arsenic adsorption, there have been no investigations of their effects on adsorbent regeneration. Furthermore, the effect of regenerant solution composition and the kinetics of regeneration have not been investigated. This research investigated the effects of adsorbent and regenerant solution properties on the kinetics and efficiency of regeneration of arsenate-loaded ferric hydroxide-based adsorbents. Solutions containing only 0.10–5.0 M NaOH or 0.10–1.0 M NaCl, as well as solutions containing both compounds, were used as regenerants. On all media, >99% of arsenate was adsorbed through complexation with ferric hydroxide. Arsenate recovery was controlled by both equilibrium and kinetic limitations. Adsorbents containing support material with weak base anion-exchange functionality or no anion-exchange functionality could be regenerated with NaOH solutions alone. Regeneration of media containing strong base anion (SBA)-exchange functionality was greatly enhanced by addition of 0.10 M NaCl to the NaOH regenerant solutions. Adsorbed silica had a significant effect on NaOH regeneration of media containing type I SBA-exchange functionality, but on other media, adsorbed silica had little impact on regeneration. On all media, 5–25% of arsenate was resistant to desorption in 1.0 M NaOH solutions. However, the use of 2.5–5.0 M NaOH solutions significantly reduced the desorption-resistant fraction.
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机译：包含负载在多种载体材料上的包含氢氧化铁的吸附剂通常用于从饮用水中去除砷。尽管一些研究已经研究了载体性质对砷吸附的影响，但是还没有研究其对吸附剂再生的影响。此外，还没有研究再生溶液组成的影响和再生动力学。这项研究调查了吸附剂和再生溶液性质对负载砷酸氢氧化铁基吸附剂的动力学和再生效率的影响。仅含有0.10–5.0 M NaOH或0.10–1.0 M NaCl的溶液以及含有两种化合物的溶液均用作再生剂。在所有介质上，> 99％的砷酸盐通过与氢氧化铁络合而被吸附。砷的回收率受平衡和动力学限制的控制。包含具有弱碱性阴离子交换功能或没有阴离子交换功能的载体材料的吸附剂可以仅通过NaOH溶液进行再生。通过向NaOH再生溶液中添加0.10 M NaCl，大大增强了包含强碱阴离子交换功能的培养基的再生。吸附的二氧化硅对含有I型SBA交换功能的介质的NaOH再生有显着影响，但在其他介质上，吸附的二氧化硅对再生几乎没有影响。在所有介质上，5–25％的砷酸盐在1.0 M NaOH溶液中均具有抗解吸性。但是，使用2.5–5.0μM NaOH溶液会显着降低抗脱附率。
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