Preparation and evaluation of a novel Fe-Mn binary oxide adsorbent for effective arsenite removal.
Preparation and evaluation of a novel Fe-Mn binary oxide adsorbent for effective arsenite removal.
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DOI：
10.1016/j.watres.2007.02.009
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发表时间：
2007-05
期刊：
影响因子：
12.8
通讯作者：
Gaosheng Zhang;J. Qu;Huijuan Liu;Ruiping Liu;Rong-cheng Wu
中科院分区：
文献类型：
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作者：
Gaosheng Zhang;J. Qu;Huijuan Liu;Ruiping Liu;Rong-cheng Wu
亚砷酸盐（As（III））比砷酸盐（As（V））毒性更大，更难从水中去除。由于没有简单的处理方法来有效去除As（III），因此氧化步骤总是必要的，以实现更高的去除率。然而，这导致复杂的操作并且不具有成本效益。为了克服这些缺点，本研究采用同时氧化共沉淀的方法，以低成本原料为原料，结合二氧化锰的氧化性能和铁氧化物对As（V）的高吸附性能，制备了一种新型的Fe-Mn二元氧化物材料。采用BET比表面积测定、粉末XRD、SEM、XPS等手段对吸附剂进行了表征。结果表明，所制备的Fe-Mn二元氧化物为非晶态，具有较高的比表面积（265 m2 g-1）。铁和锰主要存在于氧化态+III和IV，分别。通过室内实验研究了该吸附剂的吸附动力学、吸附容量以及溶液pH值对除砷效果的影响。批实验结果表明，该吸附剂能将As（III）完全氧化为As（V），对As（V）和As（III）均有较好的去除效果，尤其是As（III）。As（V）和As（III）的最大吸附容量分别为0.93mmolg-1和1.77mmolg-1。结果与使用其他吸附剂所获得的结果相比是有利的。研究了天然水体中可能存在的SO 42-、PO 43-、SiO 32-、CO 32-和腐殖酸（HA）等阴离子对As（III）去除效果的影响。结果表明，磷酸盐是砷在吸附剂上吸附位的最大竞争者。硫酸盐和HA的存在对砷的去除没有显著影响。Fe-Mn二元氧化物的高吸收能力使其成为从水溶液中去除As（III）的潜在有吸引力的吸附剂。
Arsenite (As(III)) is more toxic and more difficult to remove from water than arsenate (As(V)). As there is no simple treatment for the efficient removal of As(III), an oxidation step is always necessary to achieve higher removal. However, this leads to a complicated operation and is not cost-effective. To overcome these disadvantage, a novel Fe–Mn binary oxide material which combined the oxidation property of manganese dioxide and the high adsorption features to As(V) of iron oxides, were developed from low cost materials using a simultaneous oxidation and coprecipitation method. The adsorbent was characterized by BET surface areas measurement, powder XRD, SEM, and XPS. The results showed that prepared Fe–Mn binary oxide with a high surface area (265m2g-1) was amorphous. Iron and manganese existed mainly in the oxidation state +III and IV, respectively. Laboratory experiments were carried out to investigate adsorption kinetics, adsorption capacity of the adsorbent and the effect of solution pH values on arsenic removal. Batch experimental results showed that the adsorbent could completely oxidize As(III) to As(V) and was effective for both As(V) and As(III) removal, particularly the As(III). The maximal adsorption capacities of As(V) and As(III) were 0.93mmolg-1and 1.77mmolg-1, respectively. The results compare favorably with those obtained using other adsorbent. The effects of anions such as SO42-, PO43-, SiO32-, CO32-and humic acid (HA), which possibly exist in natural water, on As(III) removal were also investigated. The results indicated that phosphate was the greatest competitor with arsenic for adsorptive sites on the adsorbent. The presence of sulfate and HA had no significant effect on arsenic removal. The high uptake capability of the Fe–Mn binary oxide makes it potentially attractive adsorbent for the removal of As(III) from aqueous solution.