Arsenic removal using mesoporous alumina prepared via a templating method.
Arsenic removal using mesoporous alumina prepared via a templating method.
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DOI：
10.1021/es0403864
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发表时间：
2004-02
影响因子：
11.4
通讯作者：
Younghun Kim;Changmook Kim;Inhee Choi;S. Rengaraj;J. Yi
中科院分区：
文献类型：
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作者：
Younghun Kim;Changmook Kim;Inhee Choi;S. Rengaraj;J. Yi
砷对健康的威胁是众所周知的，美国环保署建议饮用水中砷的最大污染物水平为0.01 ppm或更低。因此，需要对成品水进行深度处理以满足所需的法规。吸附被认为是一种较便宜的方法，比沉淀、离子交换和膜过滤更安全。活性氧化铝（AA）是最常用的用于从水溶液中去除砷的吸附剂。然而，包括AA的常规多孔固体具有不明确的孔结构，并且通常具有低吸附容量，并且以动力学缓慢的方式起作用。理想的吸附剂应具有均匀可进入的孔、互连的孔系统、高表面积和物理和/或化学稳定性。为了满足这一要求，中孔氧化铝（MA）具有宽的比表面积（307 m2/g）和均匀的孔径（3.5 nm）的制备，并通过后水解方法开发了海绵状互连孔系统。所得MA在pH 3-7范围内不溶且稳定。MA对As（V）的最大吸附量是常规AA的7倍[121 mg As（V）/g和47 mg As（III）/ g]，吸附动力学也很快，与常规AA相比（约2 d达到平衡值的一半）在5 h内完全吸附。使用氢氧化钠溶液（0.01-1 M）进行解吸研究，发现0.05 M NaOH是最合适的解吸剂。吸附在MA上的砷85%以上在1 h内被解吸。还测试了具有不同孔性质的几种其它活化氧化铝。结果表明，吸附剂的比表面积对吸附量的影响不大。事实上，关键因素是均匀的孔径和互连的孔系统。这些研究表明，MA具有宽的比表面积，均匀的孔径和互连的孔系统，可以作为一个有效的吸附剂用于去除砷。
The health threat of arsenic is well-known, and the U.S. EPA recommends the maximum contaminant level to be 0.01 ppm or less for arsenic in drinking water. Therefore, advanced treatment processes are needed for finished water to meet the required regulations. Adsorption is considered to be a less expensive procedure that is safer to handle than precipitation, ion exchange, and membrane filtration. Activated alumina (AA) is the most commonly used adsorbent for the removal of arsenic from aqueous solutions. However, conventional porous solids including AA have ill-defined pore structures and, typically, low adsorption capacities and act in a kinetically slow manner. An ideal adsorbent should have uniformly accessible pores, an interlinked pore system, a high surface area, and physical and/or chemical stability. To meet this requirement, mesoprous alumina (MA) with a wide surface area (307 m2/g) and uniform pore size (3.5 nm) was prepared, and a spongelike interlinked pore system was developed through a post-hydrolysis method. The resulting MA was insoluble and stable within the range of pH 3-7. The maximum uptake of As(V) by MA was found to be 7 times higher [121 mg of As(V)/g and 47 mg of As(III)/ g] than that of conventional AA, and the kinetics of adsorption were also rapid with complete adsorption in less than 5 h as compared to the conventional AA (about 2 d to reach half of the equilibrium value). A desorption study using sodium hydroxide solutions (0.01-1 M) was conducted, and 0.05 M NaOH was found to be the most suitable desorption agent. More than 85% of the arsenic adsorbed to the MA was desorbed in less than 1 h. Several other activated aluminas with different pore properties were also tested. The results show that the surface area of the adsorbents does not greatly influence on the adsorption capacity. In fact, the key factor is a uniform pore size and an interlinked pore system. These studies show that MA with a wide surface area, uniform pore size, and interlinked pore system can be used as an efficient adsorbent for the removal of arsenic.