野鸭湖湿地土壤对正磷酸盐的吸附特性及机理分析
Adsorption properties and mechanism of orthophosphate adsorption on soils from the Yeyahu Wetland of Beijing.
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摘要: 以北京市野鸭湖湿地为研究对象，对湿地土壤吸附正磷酸盐的吸附动力学、等温吸附特性、吸附影响因素和吸附机理进行了分析。结果表明：湿地土壤对水中正磷酸盐的吸附在5 h后基本达到平衡；Langmuir交叉型吸附等温式可较好地描述土壤对正磷酸盐的等温吸附过程；水体pH值对土壤吸附正磷酸盐具有显著影响，pH值在8左右时，吸附量最大；土壤对正磷酸盐的吸附量随水中有机质浓度的升高而增加，有机质质量浓度为100 mg/L时，吸附量最大，3#、5#和7#土壤样品的吸附量分别比有机质浓度为0时增加了37.81%、35.52%和64.98%。此外，对吸附正磷酸盐前后的土壤样品进行了X射线衍射（XRD）和傅里叶变换红外光谱（FT-IR）分析，结果表明，土壤中的高岭石是影响土壤吸附正磷酸盐的主要成分。Abstract: In this study, the adsorption kinetics, isothermal adsorption model of orthophosphate (P) on soil from the Yeyahu Wetland of Beijing were investigated. The effects of pH and organic matter content on P adsorption were also analyzed. The results showed that the P adsorption equilibrium time was about five hours and Langmuir cross-shaped isothermal adsorption model well fitted the experiment data. pH had a significant influence on P adsorption. The P adsorption capability achieved the maximum value when the initial pH of the incubation solution was 8. Soil P adsorption capability increased with dissolved organic matters (DOM) increasing. When the concentration of DOM was 100 mg/L, the P adsorption capability reached the highest value and increased by 37.81%, 35.52% and 64.98%, respectively, for soil samples No. 3, 5 and 7 when compared with no DOM experiments. The results of XRD and FT-IR analysis of soil samples before and after P adsorption experiments reveal that kaolinite involved in P adsorption process and it is a key clay component for P adsorption on the Yeyahu Wetland soil of Beijing.
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Keywords:
- wetland soil /
- adsorption /
- orthophosphate /
- organic matter /
- Yeyahu Wetland
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