title: [Effect of Zirconium Modified Kaolin-Based Cap on Migration and Transformation of Phosphorus Between Sediment and Overlying Water].
abstract: In this study, microcosm incubation experiments were conducted to investigate the effect of zirconium modified kaolin (ZrMK)-based cap on the migration and transformation of phosphorus (P) between sediments collected from a heavily polluted river and overlying waters under anaerobic conditions. The results showed that a large amount of P was released from the sediments into the overlying water column under anaerobic conditions, and the overwhelming majority of P in the overlying water existed in the form of phosphate. The flux of P from the anaerobic sediments was slightly reduced by the kaolin-based cap, while significantly reduced by the ZrMK-based cap. Sequential extraction of P from the kaolin-based cap at the end of incubation experiments suggested that 29% of P adsorbed by kaolin existed as the bicarbonate-dithionite extracted P (BD-P), and 63% of adsorbed P existed as the residual P (Res-P). Sequential extraction of P from the ZrMK-based cap at the end of incubation experiments suggested that 90% of P adsorbed by ZrMK existed as the NaOH extractable P (NaOH-P) and Res-P, which were unlikely to be released under anaerobic conditions. Compared with no capping, sediments capping with ZrMK did not promote BD-P release from the sediments under anaerobic conditions, but promoted the formation of NaOH-P in the sediments. X-ray photoelectron spectroscopy (XPS) and solid state ³¹P nuclear magnetic resonance (NMR) analyses of ZrMK-based caps before and after sediment incubation experiments indicated that the adsorption of P by the ZrMK-based caps followed the ligand exchange and inner-sphere complexing mechanism. Results of this work indicate that ZrMK is a promising active capping material for controlling P release from sediments in heavily polluted rivers.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Zhang
authors.forename: Jian-wei
authors.initials: JW
authors.lastname: Lin
authors.forename: Yan-hui
authors.initials: YH
authors.lastname: Zhan
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
mesh_terms: D000327:Adsorption; D019015:Geologic Sediments / Q000737:chemistry*; D007616:Kaolin / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry; D010758:Phosphorus / Q000737:chemistry*; D045483:Rivers / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry; D018508:Water Purification / Q000379:methods; D015040:Zirconium / Q000737:chemistry*
chemical_list: D010710:Phosphates; D014874:Water Pollutants, Chemical; D007616:Kaolin; D010758:Phosphorus; D015040:Zirconium