title: Size-dependent sorption of myo-inositol hexakisphosphate and orthophosphate on nano-γ-Al2O3.
abstract: The effects of particle size (5, 35 and 70nm) on the sorption of myo-inositol hexakisphosphate (IHP) and inorganic phosphate (KH2PO4, Pi) on γ-Al2O3 nanoparticles were investigated using batch sorption experiments, zeta potential measurements and solid-state nuclear magnetic resonance spectroscopy (NMR). The results show that the maximum sorption densities (μmolm(-2)) for IHP and Pi increase with decreasing γ-Al2O3 particle size. The sorption affinity of γ-Al2O3 for IHP and Pi generally increases with decreasing particle size, and the sorption affinity for IHP is approximately one order of magnitude greater than that for Pi. In our experimental time scale, surface complexation is the main mechanism for IHP and Pi sorption on large size γ-Al2O3. While an additional surface precipitation mechanism, indicated by solid-state (31)P and (27)Al NMR data, is partly responsible for the greater sorption density on very small size γ-Al2O3. Compared with Pi, the effect of particle size on the sorption of IHP is more pronounced. The results suggest a size-dependent surface reactivity of Al2O3 nanoparticles with Pi/IHP. The underlying mechanism will also be relevant for other small nanosize (hydr)oxide particles and is important for our understanding of the role of small nanoparticles in controlling the mobility and fate of organic and inorganic phosphates in the environment.
authors.affiliation: Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
authors.forename: Yupeng
authors.initials: Y
authors.lastname: Yan
authors.affiliation: Physical Chemistry and Soft Matter, Wageningen University and Research, Dreijenplein 6, 6703 H B Wageningen, Netherlands.
authors.forename: Luuk K
authors.initials: LK
authors.lastname: Koopal
authors.affiliation: Key Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210093, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China.
authors.forename: Anmin
authors.initials: A
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China.
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
authors.affiliation: Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
authors.forename: Fan
authors.initials: F
authors.lastname: Liu
authors.affiliation: Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, People's Republic of China. Electronic address: fxh73@mail.hzau.edu.cn.
authors.forename: Xionghan
authors.initials: X
authors.lastname: Feng
keywords: Nano-γ-Al(2)O(3); Orthophosphate; Particle size; Sorption; Surface precipitation; myo-Inositol hexakisphosphate