Wang Shengrui, Jin Xiangcan, Pang Yan, Zhao Haichao, Zhou Xiaoning
Research Center of Lake Environment, Chinese Research Academy of Environment Sciences, Chaoyang District, Beijing 100012, People's Republic of China.
J Colloid Interface Sci. 2005 May 15;285(2):448-57. doi: 10.1016/j.jcis.2004.08.039.
This paper studies the effect of pH on phosphate sorption by the sediments of different trophic lakes, including sorption isotherms with different pH values, their effect on sorption rate, their impact on the kinetics of sorption and desorption. The following conclusions are drawn. (1) The phosphate sorption capacity of lake sediment is correlated with pH, but not with its trophic level; that is, pH at 7.0>5.5>9.0. The three isotherms models cannot well describe phosphate sorption by different trophic sediments with different pH, and its applicability seems irregular. (2) The power function equation is one of the best kinetic models, which can provide satisfactory fitting of the kinetic data of phosphate sorption by different trophic sediments, and there is no obvious difference between them. The quick phosphate sorption by the sediment takes place mainly at 0-0.5 h, the pH value has a remarkable effect on the rate of phosphate sorption by the sediment, and sediments in different trophic states tend to have similar trends of change, with pH 5.5>7.0>9.0. (3) The effect of pH on phosphate sorption shows a similar trend for different trophic sediments; namely, as pH increases phosphate sorption rate tends to increases sharply at first and then drop suddenly. After a while it increases slightly, and finally a slight decrease follows as the pH increases. The maximum and minimum of phosphate sorption capacity may be attributed to the rate of phosphate release. (4) Phosphate sorption by lake sediments is not completely reversible and strong bonding occurs between sediment particles and sorbed phosphate. This makes it difficult for the sorbed phosphate to be desorbed from the sediments. The amounts of desorbed phosphate are almost the same in different trophic sediments with different initial pH values; that is, the effect of pH on phosphate desorption is small.
本文研究了pH值对不同营养状态湖泊沉积物磷吸附的影响，包括不同pH值下的吸附等温线、其对吸附速率的影响、对吸附和解吸动力学的影响。得出以下结论：（1）湖泊沉积物的磷吸附能力与pH值相关，而与其营养水平无关；即pH值为7.0时>5.5时>9.0时。三种等温线模型不能很好地描述不同营养状态沉积物在不同pH值下的磷吸附情况，其适用性似乎没有规律。（2）幂函数方程是最佳动力学模型之一，能对不同营养状态沉积物的磷吸附动力学数据提供满意的拟合，且它们之间没有明显差异。沉积物对磷的快速吸附主要发生在0 - 0.5小时，pH值对沉积物磷吸附速率有显著影响，不同营养状态的沉积物变化趋势相似，即pH值5.5时>7.0时>9.0时。（3）不同营养状态沉积物中pH值对磷吸附的影响呈现相似趋势；即随着pH值升高，磷吸附速率起初趋于急剧增加，然后突然下降。一段时间后略有增加，最终随着pH值升高略有下降。磷吸附容量的最大值和最小值可能归因于磷的释放速率。（4）湖泊沉积物对磷的吸附并非完全可逆，沉积物颗粒与吸附的磷之间会发生强结合。这使得吸附的磷难以从沉积物中解吸出来。在不同初始pH值的不同营养状态沉积物中，解吸的磷量几乎相同；即pH值对磷解吸的影响较小。
