| 研究実績の概要 |
(1) Sorption of Co2+, Ni2+ and Cu2+ on LDH nanosheets.
The presence of amino acid on the surface of LDH proved by FT-IR, 1H MAS-NMR and TEM EDS analyses. The colloidal LDH nanosheets was utilized for the removal of Co2+, Ni2+ and Cu2+ from aqueous solution. It depicted that the maximum adsorption capacity of 0.598, 0.601, 0.030 mmol/g for Co2+, Ni2+ and Cu2+ respectively in the single solution. The selectivity of Co2+ was high in both the binary mixed solution. The selectivity of metal cations are in the order of Co2+ > Ni2+ >and Cu2+. The mechanism of Co2+ adsorption on the amino acid anchored LDH occurs due to the diamine- like coordination. On the other hand, the Cu2+ adsorption occurs by glycine-like coordination with amino acid, rendering very poor sorption capacity of Cu2+.
(2) Sorption of halides and oxyhalides on LDH nanosheets.
The amino acid functionalized colloidal LDH nanosheets was sorption of halides (F-, Cl- , Br- and I- ) and oxy halides (IO3-, BrO3- and ClO4-) on colloidal LDH nanosheets and discussed the mechanism of sorption based on equilibrium pH, zeta potential, hydrated ionic radius and hydration free energy of corresponding anions. The sorption of halides on colloidal LDHs indicates that sorption followed Hofmeister ionic series of ionic activity except nitrate (F- > NO3- > Cl- > Br- > I-). However, in the case of oxyalides the sorption of anion followed the reverse order of corresponding halides, (IO3- > BrO3- > NO3- > ClO4-). Simulation studies indicated that the order of halide adsorption is directly related to the free energy of adsorption.
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