Muñiz G, Fierro V, Celzard A, Furdin G, Gonzalez-Sánchez G, Ballinas M L
Laboratoire de Chimie du Solide Minéral, Nancy-Université, UMR CNRS 7555, Vandoeuvre-lès Nancy, France.
J Hazard Mater. 2009 Jun 15;165(1-3):893-902. doi: 10.1016/j.jhazmat.2008.10.074. Epub 2008 Oct 28.
Arsenic removal from natural well water from the state of Chihuahua (Mexico) is investigated by adsorption using a commercial activated carbon (AC). The latter is used as such, or after oxidation by several chemicals in aqueous solution: nitric acid, hydrogen peroxide, and ammonium persulphate. Raw and oxidised activated carbons are fully characterised (elementary analysis, surface chemistry, pore texture parameters, pH(ZC), and TEM observation). Adsorption of As is measured in the aforementioned water, containing ca. 300 ppb of arsenic: removal of As is poor with the raw AC, and only the most oxidised carbons exhibit higher performances. By contrast, iron-doped ACs are much more efficient for that purpose, though their As uptake strongly depends on their preparation conditions: a number of samples were synthesised by impregnation of raw and oxidised ACs with HCl aqueous solutions of either FeCl(3) or FeCl(2) at various concentrations and various pH. It is shown that iron(II) chloride is better for obtaining high iron contents in the resultant ACs (up to 8.34 wt.%), leading to high As uptake, close to 0.036 mg As/g C. In these conditions, 100% of the As initially present in the natural well water is removed, as soon as the Fe content of the adsorbent is higher than 2 wt.%.
采用商用活性炭（AC）通过吸附法对墨西哥奇瓦瓦州天然井水的除砷情况进行了研究。活性炭可直接使用，也可在水溶液中经几种化学物质氧化后使用：硝酸、过氧化氢和过硫酸铵。对原始活性炭和氧化后的活性炭进行了全面表征（元素分析、表面化学、孔隙结构参数、零电荷点pH值以及透射电镜观察）。在上述含砷量约为300 ppb的水中测定了砷的吸附情况：原始活性炭对砷的去除效果较差，只有氧化程度最高的活性炭表现出较高的性能。相比之下，铁掺杂活性炭在此方面效率更高，不过它们对砷的吸附量很大程度上取决于其制备条件：通过用不同浓度和不同pH值的FeCl₃或FeCl₂盐酸水溶液浸渍原始活性炭和氧化后的活性炭合成了多个样品。结果表明，氯化亚铁更有利于在所得活性炭中获得高铁含量（高达8.34 wt.%），从而实现高砷吸附量，接近0.036 mg As/g C。在这些条件下，一旦吸附剂中的铁含量高于2 wt.%，天然井水中最初存在的100%的砷就能被去除。
