Adsorption and release of phosphorus from sediments from the main branches of the Three-Gorges Reservoir

被引：0

作者：

Wang, Ying ^{[1
,2
]}

Shen, Zhenyao ^{[1
]}

Hu, Lijuan ^{[1
]}

Niu, Junfeng ^{[1
]}

机构：

[1] State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China

[2] Key Laboratory of Environmental Remediation and Ecological Health, College of Natural Resources and Environmental Science, Zhejiang University, Hangzhou 310029, China

来源：

Huanjing Kexue Xuebao / Acta Scientiae Circumstantiae | 2008年 / 28卷 / 08期

关键词：

Calcium compounds - Reservoirs (water) - Phosphorus - Eutrophication - Alkalinity - Sediments - Iron oxides - Chemical analysis;

D O I：

暂无

中图分类号：

学科分类号：

摘要：

The effects of pH and temperature on adsorption and release of phosphorus (P) from sediments from the main branches (Cuntan, Xiaojiang, Daning and Xiangxi) of the Three-Gorges Reservoir (China) were investigated. The contents and fractions of P in the sediments were analyzed by sequential chemical extraction. The results showed that inorganic P was the major fraction of total P (accounting for 59.29%-78.82% of total P) for all the samples in this study. The content of calcium-bound P (Ca-P) was higher than that of Fe/Al oxides-bound P (Fe/Al-P). The pH of the overlying water influenced P release from the sediments. The least amount of P was released under neutral conditions. Higher P release was observed in acid than in alkaline conditions due to the dissolution of Ca-P at lower pH. Thus acidification of the overlying water increases the risk of eutrophication in the main branches of the Three-Gorges Reservoir. Adsorption of P on the sediments also varied with the pH. The maximum P adsorption capacity of various sediments occurred at pH values between 6 and 8. The adsorption capacity followed the order: Xiaojiang > Daning > Cuntan > Xiangxi. At pH + to trap soluble reactive P (SRP), whereas at pH > 8, high concentrations of free OH-could prevent adsorption of SRP onto sediment surfaces. So the adsorption of P decreased rapidly when pH 8. Moreover, the adsorption of P on the sediments was endothermic. A modified Larigmuir model may describe the P adsorption well for all the samples at different temperatures (278K, 293K, 303K). The standard heat of adsorption (ΔH0) of P on the sediments ranged from 18.92 to 46.63 kjmol-1, and the highest value was observed in the Daning sediment.

引用

页码：1654 / 1661