Lai Chin-Hsing, Chen Chih-Yu, Wei Bai-Luh, Yeh Shu-Hsing
Department of Environmental Engineering and Sanitation, Fooyin Institute of Technology, Ta-Liao Hsiang, Kao-Hsiung Hsien, Taiwan.
Water Res. 2002 Dec;36(20):4943-50. doi: 10.1016/s0043-1354(02)00009-x.
Heat was employed to coat crystalline goethite onto a quartz sand surface so that the adsorbent properties of the coating could be utilized. The adsorption characteristics of cadmium and humic acid onto goethite-coated sand were examined. Results show that the goethite-coated sand surface had a higher specific surface area and more mesopores than the uncoated sand. The adsorption of both cadmium and humic acid was highly pH-dependent: cadmium adsorption increased with pH, but humic acid adsorption decreased as pH increased. The presence of humic acid resulted in increasing cadmium adsorption in a specific pH range. The order of reacting humic acid with cadmium was found to have a noticeable effect on the final adsorption capacity. The adsorption capacity of cadmium for humic acid that is adsorbed onto goethite-coated sand before reacting with a cadmium system, exceeds that of humic acid that is mixed with cadmium ions before goethite-coated sand is added.
采用加热的方法将结晶针铁矿包覆在石英砂表面，以便利用包覆层的吸附性能。研究了镉和腐殖酸在针铁矿包覆砂上的吸附特性。结果表明，与未包覆砂相比，针铁矿包覆砂表面具有更高的比表面积和更多的中孔。镉和腐殖酸的吸附都高度依赖于pH值：镉的吸附量随pH值升高而增加，而腐殖酸的吸附量随pH值升高而降低。在特定pH范围内，腐殖酸的存在导致镉的吸附量增加。发现腐殖酸与镉的反应顺序对最终吸附容量有显著影响。在与镉体系反应之前吸附在针铁矿包覆砂上的腐殖酸对镉的吸附容量，超过了在添加针铁矿包覆砂之前与镉离子混合的腐殖酸的吸附容量。
