Removal of Arsenic and Selenium Using Layer Structure Inorganic Ion Exchanger-Hydrotalcite-Like Compounds-

Murakami, Takayuki; Oshima, Hisamitsu; Kuwabara, Tomoyuki; Sato, Takaya; Kawamoto, Ariumi

doi:10.2965/jswe.28.269

Cited by 4 publications

(1 citation statement)

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“…7) in this study. Table 4 summarizes the reported adsorption capacities of various As(III) adsorbents documented in the literature 11,20,48,49) for comparison with that of Fe-HT (The range of equilibrium concentration: 0.1-100 mg/L). Fe-HT exhibits the highest adsorption capability (the data (67.9 mg/g) obtained from the adsorption isotherm in Fig.…”

Section: Mechanism Of As(iii) Adsorption On Fe-htmentioning

confidence: 99%

Adsorption of As(III) from Aqueous Solutions by Novel Fe–Mg Type Hydrotalcite

Ogata

Kawasaki

2015

CHEMICAL & PHARMACEUTICAL BULLETIN

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Morphological and chemical evaluation of Fe-Mg hydrotalcite (Fe-HT) was performed using scanning electron microscopy, X-ray diffraction analysis, and electron microanalysis for application as an adsorbent for water treatment. The adsorption of arsenic III (As(III)) on Fe-HT was evaluated via examination of the effect of the contact time and analysis of the adsorption isotherm. The amount of As(III) adsorbed increased slightly with increasing temperature. The results of the adsorption isotherm studies suggested that As(III) adsorption can be well described by both the Freundlich and Langmuir equations. The adsorption of As(III) on Fe-HT reached equilibrium within 24 h, and the adsorption kinetic data fit the pseudo-second-order kinetic model better than the pseudo-first-order model. The amount of As(III) present on the surface of Fe-HT increased after As(III) adsorption, and the crystalline structure of Fe-HT was maintained after adsorption of As(III). The (003) and (006) peaks in the X-ray diffraction patterns were attributed to basal reflections, and these peaks shifted from respective 2θ values of 10.86 and 21.94° to 11.12 and 22.52°, indicating exchange of As(III) with chloride ions in Fe-HT with consequent narrowing of the inter-layer spacing. Collectively, these results suggest that Fe-HT is prospectively useful for the adsorption of As(III) from aqueous solutions. Key words Fe-Mg hydrotalcite; arsenic(III); adsorptionHeavy metals are potentially hazardous to human health and aquatic flora and fauna at concentrations exceeding the allowable limits. At concentrations below these limits, long-term heavy metal contamination is still possible because heavy metals are known to accumulate within biological systems. 1)Arsenic (As) is one of the most toxic metal ions and poses a serious health risk in many countries of the world, being associated with increased risk of skin, lung, and kidney cancer.2,3) The presence of As in groundwater in different parts of the world has recently been extensively reported, including countries in North America and Latin America, Australia, and South Asia. [4][5][6][7][8][9][10] Therefore, the Environmental Protection Agency (EPA) lowered the maximum concentration level of arsenic in water systems from 50 to 10 µg/L. In addition, As(III) is more toxic and difficult to treat than As(V) species. As(III) and As(V) are highly toxic agents that exert mutagenic effects on living organisms.11-13) Compliance with this strict As standard in drinking water requires the development of inexpensive and effective technologies for better removal of As.Among these methods, the adsorption technique is gaining popularity due to its simplicity, potential for regeneration, and sludge-free operation.14) Furthermore, the potential of adsorption as an attractive technology can be further enhanced if the adsorbent can be made cheaply and ready for use. Many kinds of adsorbents such as modified red mud, aluminum compounds, and synthetic goethite have been developed for the removal arsenic. [15][16][17][18] ...

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Section: Mechanism Of As(iii) Adsorption On Fe-htmentioning

confidence: 99%