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Research Project: Increasing the Value of Cottonseed

Location: Commodity Utilization Research

Title: Adsorption of phosphate by sediments in a eutrophic lake: Isotherms, kinetics, thermodynamics and their influence of dissolved organic matter

Author
item XIE, FAZHI - Anhui Jianzhu University
item DAI, ZHILI - Anhui Jianzhu University
item ZHU, YUANRONG - Chinese Research Academy Of Environmental Sciences
item LI, GUOLIAN - Anhui Jianzhu University
item LI, HAIBIN - Anhui Jianzhu University
item He, Zhongqi
item GENG, SHIXIONG - Anhui Jianzhu University
item WU, FENGCHANG - Chinese Research Academy Of Environmental Sciences

Submitted to: Colloids and Surfaces A: Physicochemical and Engineering Aspects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/11/2018
Publication Date: 2/1/2019
Citation: Xie, F., Dai, Z., Zhu, Y., Li, G., Li, H., He, Z., Geng, S., Wu, F. 2019. Adsorption of phosphate by sediments in a eutrophic lake: Isotherms, kinetics, thermodynamics and their influence of dissolved organic matter. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 562:16-25. https://doi.org/10.1016/j.colsurfa.2018.11.009.
DOI: https://doi.org/10.1016/j.colsurfa.2018.11.009

Interpretive Summary: Adsorption and desorption of phosphorus (P) at sediment-water interface is one of the key processes of biogeochemical cycling of P in lakes. Thus, typical sediments from Lake Dianchi, a eutrophic lake in China, were selected to study the isotherms, kinetics and thermodynamic parameters of phosphate adsorption and desorption at sediment-water interface. A typical dissolved organic matter (DOM) component, fulvic acid (FA), was selected to investigate the influence of DOM on isotherms, kinetics and thermodynamic parameters of phosphate adsorption and desorption at sediment-water interface. Our observations demonstrated that adsorption of phosphate on sediments was a spontaneous endothermic reaction process which was a chemical-physical process rather than a simple physical adsorption. The influence of FA on the adsorption of phosphate by sediments was closely related with characteristics of sediments such as contents of Fe-Al oxides and organic matter. This investigation would be important for understanding release of internal loading of P when bioavailable P and DOM changed in the period of algal blooming.

Technical Abstract: Adsorption and desorption of phosphorus (P) at sediment-water interface is one of the key processes of biogeochemical cycling of P in lakes. Thus, adsorption of phosphate by sediments from Lake Dianchi, a eutrophic lake, was investigated in this study. Importantly, the influence of dissolved organic matte (DOM) with fulvic acid (FA) as a representative example on this process was further studied. The results showed that the presence of FA in the solution did not change the tendency of phosphate adsorption by sediments from Lake Dianchi.Compared with Freundlich equation, Langmuir model fitted better in describing the adsorption isotherm, and its pseudo-second-order kinetic model predicated well the adsorption kinetics for adsorption of phosphate by sediments. Under low concentrations of phosphate, FA promoted desorption of phosphate adsorbed on the sediments. However, adsorption behaviors including capacity and efficiency would be enhanced by presence of FA under high concentrations of phosphate. Based on adsorption thermodynamics, temperature and DOM (FA in this study) were two most important factors for adsorption of phosphate by sediments. Adsorption of phosphate on sediments was a spontaneous endothermic reaction process which was a chemical-physical process rather than a simple physical adsorption. The influence of FA on the adsorption of phosphate by sediments was closely related with characteristics of sediments such as contents of Fe-Al oxides and organic matter.