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Enhanced Arsenate Removal Performance in Aqueous Solution by Yttrium-Based Adsorbents.

Lee SH, Kim KW, Lee BT, Bang S, Kim H, Kang H, Jang A - Int J Environ Res Public Health (2015)

Bottom Line: The present study focuses on the development of the yttrium-based adsorbents, with basic yttrium carbonate (BYC), Ti-loaded basic yttrium carbonate (Ti-loaded BYC) and yttrium hydroxide prepared using a co-precipitation method.The Ti-loaded BYC also displayed the highest adsorption affinity for a wide pH range (3-11) and in the presence of coexisting anionic species such as phosphate, silicate, and bicarbonate.Therefore, it is expected that Ti-loaded BYC can be used as an effective and practical adsorbent for arsenate remediation in drinking water.

View Article: PubMed Central - PubMed

Affiliation: School of Environmental Science and Engineering, Gwangju Institute of Science and Technology, 123, Cheomdangwagi-ro, Buk-gu, Gwangju 61005, Korea. ddlee19@gist.ac.kr.

ABSTRACT
Arsenic contamination in drinking water has become an increasingly important issue due to its high toxicity to humans. The present study focuses on the development of the yttrium-based adsorbents, with basic yttrium carbonate (BYC), Ti-loaded basic yttrium carbonate (Ti-loaded BYC) and yttrium hydroxide prepared using a co-precipitation method. The Langmuir isotherm results confirmed the maximum adsorption capacity of Ti-loaded BYC (348.5 mg/g) was 25% higher than either BYC (289.6 mg/g) or yttrium hydroxide (206.5 mg/g) due to its increased specific surface area (82 m²/g) and surface charge (PZC: 8.4). Pseudo first- and second-order kinetic models further confirmed that the arsenate removal rate of Ti-loaded BYC was faster than for BYC and yttrium hydroxide. It was subsequently posited that the dominant removal mechanism of BYC and Ti-loaded BYC was the carbonate-arsenate ion exchange process, whereas yttrium hydroxide was regarded to be a co-precipitation process. The Ti-loaded BYC also displayed the highest adsorption affinity for a wide pH range (3-11) and in the presence of coexisting anionic species such as phosphate, silicate, and bicarbonate. Therefore, it is expected that Ti-loaded BYC can be used as an effective and practical adsorbent for arsenate remediation in drinking water.

No MeSH data available.


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Variation of Fourier Transform IR spectra in BYC (a), Ti-loaded BYC (b), and yttrium hydroxide (c) by reaction with arsenate (black line: raw materials, dotted line: reaction with arsenate).
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ijerph-12-13523-f005: Variation of Fourier Transform IR spectra in BYC (a), Ti-loaded BYC (b), and yttrium hydroxide (c) by reaction with arsenate (black line: raw materials, dotted line: reaction with arsenate).

Mentions: In order to determine how the functional groups were influenced by the reaction with arsenate ions, variations in the functional groups on the adsorbent surfaces were measured using FT-IR. Figure 5 presents the variation of spectra between the raw materials and materials reacted with arsenate. The band at 3400–3450 cm−1 is assigned to the vibration of O–H stretching in all adsorbents [43]. Figures 5a,b present bands at 1280 cm−1 to 1420 cm−1, which are assigned to the asymmetric stretching vibration of carbonate spectra comprised of aliphatic C=O and C–O [44]. In the BYC and Ti-loaded BYC, O–H and carbonate bands were observed, whereas yttrium hydroxide showed only the O–H band. In samples reacted with arsenate, the bands at hydroxyl (3400 cm−1) decreased and the carbonate (1420 cm−1) bands disappeared, compared to the raw materials. After adsorption, the new band at 813 cm−1 in all materials was observed. The new bands were attributed to As-O vibration of arsenate ion [45]. The equilibrium pH slightly increased to 7.6 after adsorption, with the carbonate-arsenate ion exchange being dominant for the removal process in the case of BYC [31]. However, yttrium hydroxide can remove arsenic by the co-precipitation pathway. Therefore, the reaction for the removal mechanism is assumed to be as follows:(1)Y(OH)CO3 + 2HAsO42− → Y(OH)(HAsO4)2 + CO32− (Chemical adsorption)(2)Y(OH)3 + 3HAsO42− → Y(HAsO4)3 + 3H2O (Co-precipitation)


Enhanced Arsenate Removal Performance in Aqueous Solution by Yttrium-Based Adsorbents.

Lee SH, Kim KW, Lee BT, Bang S, Kim H, Kang H, Jang A - Int J Environ Res Public Health (2015)

Variation of Fourier Transform IR spectra in BYC (a), Ti-loaded BYC (b), and yttrium hydroxide (c) by reaction with arsenate (black line: raw materials, dotted line: reaction with arsenate).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4627047&req=5

ijerph-12-13523-f005: Variation of Fourier Transform IR spectra in BYC (a), Ti-loaded BYC (b), and yttrium hydroxide (c) by reaction with arsenate (black line: raw materials, dotted line: reaction with arsenate).
Mentions: In order to determine how the functional groups were influenced by the reaction with arsenate ions, variations in the functional groups on the adsorbent surfaces were measured using FT-IR. Figure 5 presents the variation of spectra between the raw materials and materials reacted with arsenate. The band at 3400–3450 cm−1 is assigned to the vibration of O–H stretching in all adsorbents [43]. Figures 5a,b present bands at 1280 cm−1 to 1420 cm−1, which are assigned to the asymmetric stretching vibration of carbonate spectra comprised of aliphatic C=O and C–O [44]. In the BYC and Ti-loaded BYC, O–H and carbonate bands were observed, whereas yttrium hydroxide showed only the O–H band. In samples reacted with arsenate, the bands at hydroxyl (3400 cm−1) decreased and the carbonate (1420 cm−1) bands disappeared, compared to the raw materials. After adsorption, the new band at 813 cm−1 in all materials was observed. The new bands were attributed to As-O vibration of arsenate ion [45]. The equilibrium pH slightly increased to 7.6 after adsorption, with the carbonate-arsenate ion exchange being dominant for the removal process in the case of BYC [31]. However, yttrium hydroxide can remove arsenic by the co-precipitation pathway. Therefore, the reaction for the removal mechanism is assumed to be as follows:(1)Y(OH)CO3 + 2HAsO42− → Y(OH)(HAsO4)2 + CO32− (Chemical adsorption)(2)Y(OH)3 + 3HAsO42− → Y(HAsO4)3 + 3H2O (Co-precipitation)

Bottom Line: The present study focuses on the development of the yttrium-based adsorbents, with basic yttrium carbonate (BYC), Ti-loaded basic yttrium carbonate (Ti-loaded BYC) and yttrium hydroxide prepared using a co-precipitation method.The Ti-loaded BYC also displayed the highest adsorption affinity for a wide pH range (3-11) and in the presence of coexisting anionic species such as phosphate, silicate, and bicarbonate.Therefore, it is expected that Ti-loaded BYC can be used as an effective and practical adsorbent for arsenate remediation in drinking water.

View Article: PubMed Central - PubMed

Affiliation: School of Environmental Science and Engineering, Gwangju Institute of Science and Technology, 123, Cheomdangwagi-ro, Buk-gu, Gwangju 61005, Korea. ddlee19@gist.ac.kr.

ABSTRACT
Arsenic contamination in drinking water has become an increasingly important issue due to its high toxicity to humans. The present study focuses on the development of the yttrium-based adsorbents, with basic yttrium carbonate (BYC), Ti-loaded basic yttrium carbonate (Ti-loaded BYC) and yttrium hydroxide prepared using a co-precipitation method. The Langmuir isotherm results confirmed the maximum adsorption capacity of Ti-loaded BYC (348.5 mg/g) was 25% higher than either BYC (289.6 mg/g) or yttrium hydroxide (206.5 mg/g) due to its increased specific surface area (82 m²/g) and surface charge (PZC: 8.4). Pseudo first- and second-order kinetic models further confirmed that the arsenate removal rate of Ti-loaded BYC was faster than for BYC and yttrium hydroxide. It was subsequently posited that the dominant removal mechanism of BYC and Ti-loaded BYC was the carbonate-arsenate ion exchange process, whereas yttrium hydroxide was regarded to be a co-precipitation process. The Ti-loaded BYC also displayed the highest adsorption affinity for a wide pH range (3-11) and in the presence of coexisting anionic species such as phosphate, silicate, and bicarbonate. Therefore, it is expected that Ti-loaded BYC can be used as an effective and practical adsorbent for arsenate remediation in drinking water.

No MeSH data available.


Related in: MedlinePlus