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采用室内模拟试验研究了氧化还原条件对盘锦天然湿地土壤磷吸附与解吸特性的影响,并对磷的吸附与解吸过程进行拟合。结果表明,氧化或还原条件下Langmuir模型和Freundlich模型均能较好地拟合磷的等温吸附曲线,且Langmuir方程的拟合效果好于Freundlich方程。淹水还原条件下,湿地土壤对磷的最大吸附量和解吸率比淹水前分别降低了9.5%和16.3%;吸附解吸平衡浓度升高,平均增加158.8%。淹水后土壤活性铁含量明显升高,淹水前后活性铁变化与吸附解吸平衡浓度变化之间的相关性达到了显著水平,与土壤中磷的最大吸附量和解吸率变化的相关性不显著,表明活性铁含量的变化是淹水还原条件下影响土壤磷吸附解吸平衡浓度变化的主要因素。
The effects of redox conditions on P adsorption and desorption characteristics of soils in Panjin wetland were studied using laboratory simulation experiments. The adsorption and desorption processes of phosphorus were fitted. The results show that both Langmuir model and Freundlich model fit the isothermal adsorption curve of P well, and the fitting effect of Langmuir equation is better than Freundlich equation. Under the conditions of flooding and reduction, the maximum adsorption and desorption rates of phosphorus in wetland decreased by 9.5% and 16.3%, respectively, compared with those before flooding. The adsorption and desorption equilibrium concentrations increased by an average of 158.8%. The content of active iron in soil increased significantly after flooding, the correlation between the change of active iron before and after flooding and the change of equilibrium concentration of adsorption and desorption reached a significant level, which was not significantly related to the change of the maximum adsorption amount of phosphorus and desorption rate in soil , Indicating that the change of active iron content is the main factor that affects the change of equilibrium concentration of phosphorus adsorption-desorption under flooding conditions.