2017 Fiscal Year Annual Research Report
Design of functionalized adsorbents for simultaneous removal of fluoride and arsenite from waters
| Project/Area Number |
16F16082
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| Research Institution | Kyushu University |
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Principal Investigator |
笹木 圭子 九州大学, 工学研究院, 教授 (30311525)
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| Co-Investigator(Kenkyū-buntansha) |
SUBBAIAH MUTHU PRABHU 九州大学, 工学(系)研究科(研究院), 外国人特別研究員
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| Project Period (FY) |
2016-10-07 – 2019-03-31
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| Keywords | Sucrose-derived carbon . / Oxyhydroxide materials / MOF-like materials / Arsenite / Arsenate / Fluoride / Binary solution / Adsorption |
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| Outline of Annual Research Achievements |
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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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
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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| Strategy for Future Research Activity |
1.Graphene based magnetic nanocomposites for functionalized biopolymer for simultaneous adsorption of F- and AsO33-.
2.Synthesize of ligand-functionalized biopolymer for simultaneous adsorption of both F- and AsO33-.
3.Surfactant assisted mixed oxide onto biochar for simultaneous adsorption of F- and AsO33-.
4.Preparation of magnetic coated ZrO2 @polyamidoamine (PAMAM) dendrimer for F- and AsO33- adsorption from single and binary systems
5.Evaluation of their uptake mechanism, and understanding of the reduction pathways by different analyses such as EXAFS and XPS.
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