2020 Fiscal Year Annual Research Report
Removal of arsenic from groundwater using a composite of cationic hydrogel and iron hydroxide
| Project/Area Number |
19J22780
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| Research Institution | Hiroshima University |
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Principal Investigator |
Safi SyedRagib 広島大学, 工学研究科, 特別研究員(DC1)
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| Project Period (FY) |
2019-04-25 – 2022-03-31
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| Keywords | Polymer / Adsorption / Manganese / Arsenic / Cationic |
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| Outline of Annual Research Achievements |
My research aims to remove both forms of arsenic using cationic polymer gel. There are primarily two forms of arsenic in the environment, As(V) and As(III). Because As(V) remains in an ionic form, it is easier for adsorbents to remove than As(III). As (III), on the other hand, exists in a non-ionic form. As a result, ionic contact with As (III) ion is impossible. Though theoretically impossible, I was able to efficiently remove both types of arsenic using the same adsorbent, DMAPAAQ+FeOOH, in my research. The gel's γ-FeOOH particles oxidized As(III) to As(V), and subsequently arsenic was adsorbed in the gel. After my gel had removed both types of As, I elected to remove Mn because it is another dangerous pollutant typically present in surface and groundwater. According to my research, Mn was successfully removed by DMAPAAQ+FeOOH. Despite the fact that Mn is a cation and my adsorbent is cationic, Mn ions formed complexes with the hydroxyl group and subsequently created binding with the amino group of DMAPAAQ as well as the iron particles due to the existence of -FeOOH particles. High Mn adsorption was also seen at neutral pH values. DMAPAAQ + FeOOH achieved the maximum Mn adsorption of 39.02 mg/g. As a result, the DMAPAAQ + FeOOH gel eliminates Mn more efficiently than the other adsorbents.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
Originally, I intended to remove only arsenic. Because As(III) exists in a non-ionic form, it is more difficult to remove. In theory, removing As(III) with my developed gel, DMAPAAQ+FeOOH, is difficult since ionic contact between the gel surface and arsenic is not conceivable. However, the results indicated that the gel could remove As (III) because the gel's γ-FeOOH particles first oxidized As(III) into As(V), and then arsenic was adsorbed in the gel. In addition, another goal of mine was to get As adsorption at neutral pH levels. The quantity of As(III) adsorption was found to be greatest at pH 7. These findings are significant because no other researcher has reported them. I continued my research after acquiring the initial plan for removing arsenic and moved on to remove other components such as manganese. Because Mn is a cation and my gel is cationic, it is theoretically impossible to remove Mn using my gel. Surprisingly, my gel was able to eliminate Mn. Mn elimination was greatest at neutral pH levels.
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| Strategy for Future Research Activity |
Mn is one of the most regularly discovered contaminants in Bangladesh's rivers and groundwater, second only to arsenic (As). In addition, the coexistence of As and Mn in groundwater has previously been described. Furthermore, As and Mn are two of the most serious contaminants in South African drinking water. As a result, the simultaneous removal of As and Mn must be investigated. There have been several research on the removal of As, but just a few on the removal of Mn. However, research on the simultaneous removal of As and Mn are uncommon since removing anionic and cationic components with a single adsorbent is difficult. Although As and Mn have been removed separately or solely, there has yet to be a study of their simultaneous adsorption. As a result, I aim to conduct a ground-breaking research on the simultaneous removal of total As and Mn using a single polymer-based adsorbent without the need for any additional separation processes.
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