Strelko Vladimir, Malik Danish J
Department of Chemical Engineering, Loughborough University, Loughborough, LE11 3TU, United Kingdom.
J Colloid Interface Sci. 2002 Jun 1;250(1):213-20. doi: 10.1006/jcis.2002.8313.
A commercial activated carbon Chemviron F 400 has been oxidized using nitric acid in order to introduce a variety of acidic surface functional groups. Both unoxidized and oxidized carbon samples were characterized using nitrogen porosimetry, elemental analysis, pH titration, Boehm's titration, and electrophoretic mobility measurements. Results show that oxidation treatment reduced surface area and pore volume. However, the carbon surface acquires an acidic character with carboxylic groups being the dominant surface functional groups. The modified sample displays cation-exchange properties over a wide range of pH values and exhibits polyfunctional nature. Both carbon samples were challenged for the removal of transition metals such as copper(II), nickel(II), cobalt(II), zinc(II), and manganese(II). The affinity series Mn2+<Co2+<Ni2+<Cu2+>Zn2+ has been found to coincide with the general stability sequence of metal complexes (the Irving-Williams series). The higher preference displayed by carbons toward copper(II) is a consequence of the fact that copper(II) often forms distorted and more stable octahedral complexes.
一种商用活性炭Chemviron F 400已用硝酸进行氧化，以引入各种酸性表面官能团。使用氮气孔隙率测定法、元素分析、pH滴定、 Boehm滴定和电泳迁移率测量对未氧化和氧化后的碳样品进行了表征。结果表明，氧化处理降低了表面积和孔体积。然而，碳表面具有酸性特征，羧基是主要的表面官能团。改性样品在很宽的pH值范围内显示出阳离子交换特性，并表现出多官能性质。对两种碳样品去除过渡金属如铜（II）、镍（II）、钴（II）、锌（II）和锰（II）的能力进行了测试。发现亲和力顺序Mn2+<Co2+<Ni2+<Cu2+>Zn2+与金属配合物的一般稳定性顺序（欧文-威廉姆斯序列）一致。碳对铜（II）表现出更高的偏好是因为铜（II）通常形成扭曲且更稳定的八面体配合物。
