title: Immobilization of phosphorus from water and sediment using zirconium-modified zeolites.
abstract: Adding sorbents to sediments has been suggested as an effective technology for contaminated sediment remediation. In this study, a zirconium-modified zeolite (ZrMZ) was prepared, characterized, and used as a sediment amendment to control phosphorus (P) release from eutrophic lake sediments. The efficiency of ZrMZ in immobilizing P from water and sediments was investigated through a series of experiments. The phosphate adsorption capacity for ZrMZ decreased with increasing water pH. The adsorption of phosphate on ZrMZ followed a pseudo-second-order kinetic model. The equilibrium adsorption data of phosphate on ZrMZ could be well described by the Langmuir isotherm model with a maximum monolayer adsorption capacity of 10.2 mg P/g at pH 7 and 25 °C. Sequential extraction of P from the phosphate-adsorbed ZrMZ suggested that most of P bound by ZrMZ existed as the NaOH extractable P (NaOH-P) and residual P (Res-P) and was unlikely to be released under natural pH and reducing conditions. The addition of ZrMZ into sediments reduced the inorganic P activity in the sediments by transforming bicarbonate-dithionite extractable P (BD-P) to NaOH-P and Res-P. The contents of bioavailable P such as water-soluble P (WS-P), NaHCO3 extractable P (Olsen-P), and algal available P (AAP) in sediments reduced after the sediments were mixed with ZrMZ, making P in the sediments more stable. The addition of ZrMZ into sediments significantly reduced the releasing flux of P from the sediments to the water column under different conditions. Results of this study indicate that the ZrMZ is a promising sediment amendment for controlling the internal P loading of lake sediments.
authors.affiliation: College of Marine Science, Shanghai Ocean University, No. 999 Hucheng Huan Road, , Pudong District, 201306, Shanghai, China.
authors.forename: Mengjuan
authors.initials: M
authors.lastname: Yang
authors.forename: Jianwei
authors.initials: J
authors.lastname: Lin
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Zhan
authors.forename: Zhiliang
authors.initials: Z
authors.lastname: Zhu
authors.forename: Honghua
authors.initials: H
authors.lastname: Zhang
mesh_terms: D000327:Adsorption; D001682:Biological Availability; D005591:Chemical Fractionation; D002681:China; D005068:Eutrophication / Q000502:physiology; D019015:Geologic Sediments / Q000737:chemistry*; D060106:Lakes / Q000737:chemistry*; D010710:Phosphates; D010758:Phosphorus / Q000032:analysis / Q000302:isolation & purification* / Q000493:pharmacokinetics; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*; D017641:Zeolites / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry
chemical_list: D010710:Phosphates; D014874:Water Pollutants, Chemical; D017641:Zeolites; D010758:Phosphorus; D015040:Zirconium