Ion-exchange in natural zeolite stilbite and significance in defluoridation ability

Gómez‐Hortigüela, Luis; Pinar, Ana B.; Pérez‐Pariente, Joaquín; Sani, Taju; Chebude, Yonas; Dı́az, Isabel

doi:10.1016/j.micromeso.2014.03.014

Cited by 51 publications

(18 citation statements)

References 18 publications

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“…Based on the above specific structure, zeolites exhibit high cation exchange property, polarity, and hydrophilicity and thus make them particularly suitable for removing NH 4 + , kinds of heave metal ions such as Hg, Pb, Ag, Cu, Cd, Cr, Zn, Ni, Co, Mn, etc., and polar organic contaminations such as phenol and tetrahydrofuran . The modifications of zeolites, such as ion exchange, surfactant/organosilane modification, acid treatment, and heat treatment, are applied to change the property of zeolites, which greatly influence the practical applications.…”

Section: Introductionmentioning

confidence: 99%

Influences of acid and heat treatments on the structure and water vapor adsorption property of natural zeolite

Wang

Cao

Huang

2017

Surface & Interface Analysis

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Natural zeolite was first acid treated and then heat treated. The influences of acid and heat treatments on the structure and water vapor adsorption property of natural zeolite were investigated. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), thermogravimetric analysis (TG), and Brunauer-Emmett-Teller (BET) surface areas were employed to investigate the structure changes of the zeolite samples. Water vapor adsorption property of the samples was investigated in order to determine wettability of the samples. The results showed that nitric acid treatment could remove Al from the structure, decrease relative crystallinity, and significantly increase specific surface area of the zeolite samples. Heat treatment could change or even destroy the structure, effectively remove water molecules from the surface/structure, and decrease the specific surface area of the zeolite samples. Water vapor adsorptions on the acid-treated zeolite samples were significantly lower than that for the zeolite sample, and the adsorptions further reduced for the heat-treated zeolite samples. The increase of Si/Al ratio, decreases of silanol groups, and specific surface area of the samples were major reasons related to the reductions of water vapor adsorptions on the zeolite samples.

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Section: Introductionmentioning

confidence: 99%

Influences of acid and heat treatments on the structure and water vapor adsorption property of natural zeolite

Wang

Cao

Huang

2017

Surface & Interface Analysis

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“…The introduction of sulfur into zeolite networks modifies remarkably the charge equilibrium into the zeolite lattice [27]. It is not surprising, then, that if the cations of stilbite are fully exchanged to calcium, the performance of the sample in fluoride retention is increased not only because connectivity defects are generated during the exchange treatments [21], but because the calcium ions are divalent and highly charged; and, thus, the performance of stilbite previously mentionned as not depending on Si/Al ratio may be explained. If stilbite contains exchangeable cations, which only balance the charge network and do not create zones highly charged, fluoride is not retained.…”

Section: Discussionmentioning

confidence: 99%

“…The idea lying behind the choice of zeolites is to use cheap natural minerals that may be exploited in the vicinity of the fluorosis affected area. Zeolites (clinoptilolite, stilbite and analcime) are potential candidates and thus they have been tested for fluoride removal from drinking water in Ethiopia and in Mexico [19][20][21]. In this work we compare the previously tested Ethiopian zeolites (stilbite and analcime [19]) with Mexican zeolites, namely clinoptilolite and heulandite, in order to rationalize the influence of the structure and Si/Al ratio in the fluoride removal mechanism.…”

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confidence: 99%

Comparison of the defluoridation capacity of zeolites from Ethiopia and Mexico

Adem¹,

Sani²,

Chebude³

et al. 2015

Bull. Chem. Soc. Eth.

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ABSTRACT. Fluorosis, either dental or skeleton, is often due to the high fluoride content of well waters. In this work, using solutions which contain different amounts of fluoride, natural zeolites from Ethiopia and Mexico were tested. It is shown that, although zeolites are known to be cationic exchangers, their extra-framework aluminum and their high calcium contents determine their performance. A mechanism involving adsorption and ion exchange is proposed.

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“…Recent researches indicate that modifications of zeolites, such as ion exchange [7], surfactant/organosilane modification [8][9][10], and acid treatment [11,12] can significantly change the properties of zeolites, which greatly influence practical applications. Barquist and Larsen [13,14] successively functionalized silicate-1 and magnetic zeolite with 3-aminopropyltriethoxysilane (NH 2 (CH 2 ) 3 Si(OC 2 H 5 ) 3 , APTES) and found that the APTES functionalization increased negatively charged chromate adsorption due to its positively charged amino functional groups.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Amino Functionalized Hydrophobic Zeolite and Its Adsorption Properties for Chromate and Naphthalene

Wang

Leng

et al. 2018

Minerals

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Amino functionalized hydrophobic zeolite was prepared by modification of natural zeolite with 3-aminopropyltrimethoxysilane. X-ray diffraction, Fourier transform infrared analysis, thermal gravimetric analysis, Brunauer-Emmett-Teller surface areas, and element analysis were employed to investigate the structures of the samples. The water vapor adsorption method was used to determine the hydrophobicity of the samples. The adsorption properties of the samples for chromate and naphthalene were then investigated. The results showed that the silane modification had a negligible effect on the crystalline structure of zeolite while significantly decreasing the specific surface area and increasing the hydrophobicity of the zeolite sample. The functionalized zeolite samples exhibit higher adsorption capacity and removal rate on chromate and naphthalene as compared with the unmodified zeolite sample due to their specific amino functional group and hydrophobicity property.

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Ion-exchange in natural zeolite stilbite and significance in defluoridation ability

Cited by 51 publications

References 18 publications

Influences of acid and heat treatments on the structure and water vapor adsorption property of natural zeolite

Influences of acid and heat treatments on the structure and water vapor adsorption property of natural zeolite

Comparison of the defluoridation capacity of zeolites from Ethiopia and Mexico

Preparation of Amino Functionalized Hydrophobic Zeolite and Its Adsorption Properties for Chromate and Naphthalene

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