title: pH-dependent phosphatization of ZnO nanoparticles and its influence on subsequent lead sorption.
abstract: Phosphatization of ZnO nanoparticles (ZNPs) at various pHs and its influence on subsequent lead sorption were investigated. Results showed that, in presence of phosphate, both the chemical speciation and crystalline phase of ZNPs were pH dependent that most of them were converted to crystalline Zn3(PO4)2 at acidic pHs, but only little amorphous hopeites can be formed under alkaline condition. Phosphatization process significantly enhanced subsequent lead sorption with the order of acidic process > alkaline > pristine ZNPs. Spectroscopic analysis including ATR-FTIR and XPS revealed main mechanisms of lead phosphate precipitation and inner-sphere complexes for lead sorption on acidic and alkaline treatment products, respectively. The potential toxicity of ZNPs and heavy metals in eutrophic aquatic ecosystems would thus be reduced due to the ubiquitous phosphatization process. This study highlights the importance of environmental variables in exploring the environmental behavior and fate of heavy metals as well as nanoparticles in natural waters.
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China. Electronic address: hcxu@niglas.ac.cn.
authors.forename: Huacheng
authors.initials: H
authors.lastname: Xu
authors.affiliation: Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 20104, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Li
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; College of Materials Science and Engineering, Nanjing Forestry University, Nanjing 210037, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Lv
authors.affiliation: College of Materials Science and Engineering, Nanjing Forestry University, Nanjing 210037, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Helong
authors.initials: H
authors.lastname: Jiang
mesh_terms: D000327:Adsorption; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000032:analysis / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D014961:X-Ray Diffraction; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D010710:Phosphates; D014874:Water Pollutants, Chemical; D007854:Lead; D015034:Zinc Oxide
keywords: Lead sorption; Phosphatization; Potential toxicity; Structural transformation; ZnO nanoparticles