Guangdong Industrial Contaminated Site Remediation Technology and Equipment, Engineering Research Center, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China.
Guangdong Industrial Contaminated Site Remediation Technology and Equipment, Engineering Research Center, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China.
Chemosphere. 2019 May;222:556-563. doi: 10.1016/j.chemosphere.2019.01.171. Epub 2019 Jan 31.
The coprecipitation of organic matter (OM) and minerals is a relatively common phenomenon in soil, and it has a significant influence on the surface properties and reactivity of minerals. In turn, the fate of pollutants in soil is greatly affected by the organic-mineral composites. In this study, goethite-fulvic acid (Ge-FA) composites with varying FA mass ratios in the range of 0-15% were synthesized by coprecipitation. The sample properties were studied using XRD, FTIR, SEM-EDS and N gas adsorption techniques. The influence of Ge-FA on the mobility of Pb/Cd in soil was investigated. The crystal forms of Ge-FA changed from goethite (FA≤4%) to hematite (FA≥5%), and the FA affected the FeO bond vibrations. These results demonstrated that FA was successfully introduced into the iron oxide. Ge-FA changed from a filamental morphology to an aggregate as the FA ratio increased. The coprecipitation resulted in blockages of iron oxides, thereby decreasing the specific surface area and pore volume. The adsorption amount of Pb(II) on Ge-FA increased as the FA ratio increased, but no significant change was observed for Cd(II). With the application of Ge-FA, the exchangeable concentrations of Pb and Cd in contaminated soil decreased by 42.4%-93.6% and 15.8%-43.7%, respectively. The exchangeable and carbonate bound fractions of Pb and Cd decreased and were transformed into the FeMn bound and residual fractions.
有机质（OM）与矿物质共沉淀是土壤中较为常见的现象，它对矿物质的表面性质和反应性有重要影响。反过来，污染物在土壤中的归宿也受到有机-矿物质复合物的极大影响。本研究采用共沉淀法合成了 FA 质量比在 0-15%范围内变化的针铁矿-富里酸（Ge-FA）复合物。采用 XRD、FTIR、SEM-EDS 和 N 气体吸附技术研究了样品性质。研究了 Ge-FA 对土壤中 Pb/Cd 迁移性的影响。Ge-FA 的晶体形态由针铁矿（FA≤4%）变为赤铁矿（FA≥5%），FA 影响了 FeO 键的振动。结果表明 FA 成功地引入了氧化铁。随着 FA 比例的增加，Ge-FA 从丝状形态变为聚集态。共沉淀导致铁氧化物堵塞，从而降低了比表面积和孔体积。Pb(II)在 Ge-FA 上的吸附量随 FA 比例的增加而增加，但 Cd(II)没有明显变化。施加 Ge-FA 后，污染土壤中 Pb 和 Cd 的可交换态浓度分别降低了 42.4%-93.6%和 15.8%-43.7%。Pb 和 Cd 的可交换态和碳酸盐结合态减少，并转化为 FeMn 结合态和残留态。
