| 研究実績の概要 |
The adsorbents, ZrOOH, LaOOH, ZrxLa1-xOOH and sucrose-derived porous carbon (PSC) doped PSC-ZrxLa1-xOOH were prepared by chemical co-precipitation method and utilized for adsorption of F- and AsO33- from single/binary solutions. The mechanism of adsorption can be interpreted based on the HSAB principle, where the bimetallic oxyhydroxides become “soft acids”, while La3+ and Zr4+ are categorized as “hard acids”. Moreover, the PSC-ZrxLa1-xOOH adsorbent demonstrated high selectivity for AsO33- in the co-existence of other ions in a triple component system. Instead of PSC, a biopolymer, namely chitosan (CS) was used as a supporting material which possesses surface rich O- and N-containing functional groups such as -OH and -NH2, useful for bonding transition metal ions through a chelation mechanism which helps to enhance the adsorption capacity of several toxic ions. Chemical precipitation method was employed to synthesize ZrOOH, AlOOH, ZrxAl1-xOOH and CS@ ZrxAl1-xOOH and the resulting material showed high removal efficiency of simultaneous adsorption of AsO33- and F-. Also, the SPC@La-oxalate complex was prepared, where oxalate has been used as an organic ligand, and the carbonaceous biomass has been used as a doping material that is naturally carboxylate rich functional groups derived from sucrose biomass. The mechanism of AsO43- uptake was by ligand-exchange, chelation and electrostatic interaction between AsO43- and SPC@La-oxalate. The presence of other ions did not significantly affect the adsorption of AsO43-, which indicates the high selectivity.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
MOF-like compounds have been synthesized including Zr and La as central metals, and their adsorption characteristics of arsenate, arsenite and fluoride have been revealed. The results can be well interpreted by HSAB theory. But their chemical stability in water, especially when they are utilized for adsorption of arsenate and fluoride, should be much improved. This is an action assignment to overcome.
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