The influence of turbulence on sediment phosphorus sorption

Xian Zhu; Yongping Chen; Chunyang Xu; Perran L.M. Cook; Bismark Odum; Min Gan; Changkuan Zhang

Ecotoxicology and Environmental Safety (Jun 2023)

The influence of turbulence on sediment phosphorus sorption

Xian Zhu,
Yongping Chen,
Chunyang Xu,
Perran L.M. Cook,
Bismark Odum,
Min Gan,
Changkuan Zhang

Affiliations

Xian Zhu: State Key Laboratory of Hydrology-Water Resource and Hydraulic Engineering, Hohai University, Nanjing 210098, PR China; College of Harbour, Coastal and Offshore Engineering, Hohai University, Nanjing 210098, PR China
Yongping Chen: State Key Laboratory of Hydrology-Water Resource and Hydraulic Engineering, Hohai University, Nanjing 210098, PR China; College of Harbour, Coastal and Offshore Engineering, Hohai University, Nanjing 210098, PR China; Corresponding author at: State Key Laboratory of Hydrology-Water Resource and Hydraulic Engineering, Hohai University, Nanjing 210098, PR China.
Chunyang Xu: State Key Laboratory of Hydrology-Water Resource and Hydraulic Engineering, Hohai University, Nanjing 210098, PR China; College of Harbour, Coastal and Offshore Engineering, Hohai University, Nanjing 210098, PR China
Perran L.M. Cook: School of Chemistry, Monash University, Clayton, VIC 3800, Australia
Bismark Odum: State Key Laboratory of Hydrology-Water Resource and Hydraulic Engineering, Hohai University, Nanjing 210098, PR China; College of Harbour, Coastal and Offshore Engineering, Hohai University, Nanjing 210098, PR China
Min Gan: Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
Changkuan Zhang: State Key Laboratory of Hydrology-Water Resource and Hydraulic Engineering, Hohai University, Nanjing 210098, PR China; College of Harbour, Coastal and Offshore Engineering, Hohai University, Nanjing 210098, PR China

Journal volume & issue: Vol. 258
p. 114955

Abstract

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The effect of mean flow velocity on phosphorus (P) partitioning between water and sediment has received much attention in recent decades. However, the impact of turbulence on the efficiency and capability of sediment adsorbing and desorbing dissolved inorganic phosphorus (DIP) is still unclear. A series of contrasting experiments on the sediment sorption and desorption of DIP with the flow turbulence kinetic energy (TKE) ranging from 1.95 to 2.93 pa have been conducted. It was found that the adsorbed P onto unit mass of sediment increases with the increase in TKE. It is because an increase in TKE results in a rise in the effective adsorption capacity of sediment (bm) by 20–30% during the adsorption process. The bm shows the maximum rise from 0.18 to 0.25 mg/g when TKE increases from 1.95 to 2.93 pa with a fixed sediment concentration of 0.5 g/L. To account for the direct effect of TKE on P adsorption, the Langmuir model is modified by introducing a newly defined coefficient (fA−TKE). The fA−TKE shows a good linear relationship with TKE. Comparison between the modified model and the classic model shows that the amount of adsorbed P could be overestimated by over 50% if the direct effect of turbulence intensity is ignored. The experimental data show that the increase in TKE also enhances the desorption process, with the degree of P desorption (Ddes) increased by 44%. The relation between Ddes and TKE can be well represented using a logarithmic function to quantify the direct effect of turbulence intensity on desorption of P.

Published in Ecotoxicology and Environmental Safety

ISSN: 0147-6513 (Print); 1090-2414 (Online)
Publisher: Elsevier
Country of publisher: United States
LCC subjects: Technology: Environmental technology. Sanitary engineering: Environmental pollution; Geography. Anthropology. Recreation: Environmental sciences
Website: https://www.journals.elsevier.com/ecotoxicology-and-environmental-safety

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