Sorption on natural solids for arsenic removal

Elizalde-González, Marı́a P.; Mattusch, Jürgen; Einicke, Wolf‐Dietrich; Wennrich, Rainer

doi:10.1016/s1385-8947(00)00201-1

Cited by 195 publications

(103 citation statements)

References 14 publications

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“…4). Natural smectite (S) shows two main peaks at -110 and -105 ppm and these are assigned to Q 3 [(SiO) 3 SiOH] and Q 4 [(SiOH)4Si] framework silanol site. Q 4 is clearly the dominant peak in both spectra because it is the most abundant sites.…”

Section: Characterization Of Materialsmentioning

confidence: 99%

“…Q 4 is clearly the dominant peak in both spectra because it is the most abundant sites. In the functionalized smectite two peaks appeared at -52 and -60 ppm, which are assigned to T 2 [(SiO) 2 SiOH-R] and T 3 [(SiO) 3 Si-R] sites, respectively [14].…”

Section: Characterization Of Materialsmentioning

confidence: 99%

“…Different technologies have been developed to remove arsenic from both water and wastewater. Technologies include the conventional process of oxidation, co-precipitation and adsorption onto coagulated flocs, adsorption onto lamellar materials, ion exchange and ceramic membrane techniques [1][2][3]. Due to its high toxicity and the epidemiological evidence of arsenic carcinogenicity [4,5], drinking water regulations only permit the presence of extremely low concentrations of As (V).…”

Section: Introductionmentioning

confidence: 99%

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Performance of natural and modified smectite: kinetic and thermodynamics involving arsenic (V) adsorption

2010

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A natural smectite sample has been modified by organofunctionalization process using synthetic route involved the reaction of 2-mercaptopyrimidine with 3-chloropropyltriethoxysilane. The resulting material (S MPY ) was characterized by SEM, FTIR, textural analysis and 29 Si MAS-NMR. The ability of this material to removed As (V) from aqueous solution was followed by series of adsorption isotherms adjusted to the Langmuir equation at room temperature and pH 2.0. The kinetic parameters analyzed by Lagergren and Elovich models gave a good fit for a pseudo-second order reaction with k 2 in the 4.9 to 14.0 mmol -1 min -1 range for S MPY . The adsorption process was exothermic (D int H = -4.09 to -5.79 kJ.mol -1 ) accompanied by increase in entropy (D int S = 41.29 to 61.80 JK -1 .mol -1 ) and Gibbs energy (D int G = -22.34 to -24.19 kJmol -1 ). The energetic effect caused by arsenic cation adsorption was determined through calorimetric titration at the solid-liquid interface and gave a net thermal effect that enabled the calculation of the exothermic values and the equilibrium constant. Keywords: adsorption, smectite, kinetic, thermodynamic, arsenic. Resumo Uma amostra de esmectita natural foi modificada por processo de organofuncionalização usando rota sintética, envolvendo a reação de 2-mercaptopirimidina com 3-cloropropiltrietoxisilano. O material resultante (S MPY)

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Section: Characterization Of Materialsmentioning

confidence: 99%

Section: Characterization Of Materialsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Performance of natural and modified smectite: kinetic and thermodynamics involving arsenic (V) adsorption

2010

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“…Adsorption, chemical coagulation-precipitation and membrane separation have been established as the broad technology options in the purification of arsenic contaminated drinking water. In adsorption-based studies (Kazuo and Toshio 1998;Balaji et al 2000;Elizalde-Gonzalez et al 2001;Grafe et al 2001;Xu et al 2002;Morgada et al 2009) several adsorbents have been examined for assessing the effectiveness of arsenic separation from water in small scale. Physico-chemical separation through chemical coagulation and precipitation has been demonstrated by several researchers (Edwards and Benjamin 1989;Brewster 1992;Cheng et al 1994;Edwards 1994;Hering et al 1996;Hering 1997;Hatice et al 2004;Wickramasinghe et al 2004).…”

Section: Available Purification Optionsmentioning

confidence: 99%

Contamination of groundwater by arsenic: a review of occurrence, causes, impacts, remedies and membrane-based purification

Pal¹,

Sen²,

Manna³

et al. 2009

Journal of Integrative Environmental Sciences

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The contamination of groundwater by leached out arsenic has assumed an alarming proportion in several countries. Continued and prolonged ingestion even at a very low level can lead to serious arsenic-related diseases. Strong epidemiological evidence of arsenic carcinogenicity has forced the World Health Organization (WHO) to lower the maximum permissible contaminant limit (MCL) in drinking water to 10 ppb from earlier limit of 50 ppb. This has thrown a big challenge to the scientific community to devise efficient methods to purify contaminated water to such a high level. Though literature abounds in occurrence of groundwater contamination by arsenic and its removal from drinking water by laboratory techniques, millions of people continue to suffer, particularly in the developing countries like India (Bangladesh, West Bengal). Through a comprehensive review of the existing literature on the occurrence, causes, impacts and remedial measures, this article finds out what has gone wrong and what is to be done with special emphasis on membrane-based separation that seems to be highly promising in purifying arsenic-contaminated groundwater to a WHOprescribed level.

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“…Most often, more trivalent arsenic than pentavalent arsenic is found in reducing groundwater conditions, whereas the converse is true in oxidizing groundwater conditions. The stabilities of arsenic species under different pH and redox conditions are shown in Table 1 (11). Unlike other toxic trace metals whose solubilities tend to decrease as pH increases, most oxyanions, including arsenate (As 5+ ), tend to become more soluble as pH increases (Fig.…”

Section: Effects Of Ph and Redox Potentialmentioning

confidence: 99%