Structure and thermal stability of organo-vermiculite

Su, Xiaoli; Ma, Longlong; Wei, Jingming

doi:10.1016/j.clay.2016.06.011

Cited by 32 publications

(15 citation statements)

References 40 publications

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“…The results, which coincide with others described in the literature, confirm that the modification of vermiculite using HDTMA was successful. Various mineral-organic complexes capable of adsorbing different anions have been designed [18,24,30]. evolved gaseous products will be analyzed with the Aeolos QMS 403 C mass spectrometer (Netzsch, Chennai, India).…”

Section: Xrdmentioning

confidence: 99%

“…The adsorption of HDTMA on vermiculite in the analyzed samples is evidenced by the presence of additional bands that are derived from vibrations of surfactant molecules (occurring at the positions 2918, 2850, 1487, and 1473 cm −1 ), which were found to be absent in VER [39,40]. Bands occurring in the 2920-2850 cm −1 range are the result of symmetrical and asymmetric C-H stretching vibrations occurring within the methylene groups of HDTMA [18,39,41]. The characteristic bands observed at around 1470 cm −1 are derived from bending vibrations of C-H within the methyl groups of the surfactant [26,[42][43][44].…”

Section: Ftirmentioning

confidence: 99%

“…For removal by adsorption technique, activated carbon, metal-organic frameworks, zeolites, bog iron ores, water treatment residuals, and activated alumina have been proven to be promising adsorbents for arsenic removal [13][14][15][16][17].Clay minerals are low-cost and nontoxic sorbents. Raw clays are able to sorb cations owing to their negatively charged surface; however, they display low sorption efficiency for negatively charged contaminants such as arsenic [18]. Nevertheless, clays can be chemically modified by organic surfactants, which change the charge on the clay surface from negative to positive [19].…”

mentioning

confidence: 99%

“…Clay minerals are low-cost and nontoxic sorbents. Raw clays are able to sorb cations owing to their negatively charged surface; however, they display low sorption efficiency for negatively charged contaminants such as arsenic [18]. Nevertheless, clays can be chemically modified by organic surfactants, which change the charge on the clay surface from negative to positive [19].…”

mentioning

confidence: 99%

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Organo-Modified Vermiculite: Preparation, Characterization, and Sorption of Arsenic Compounds

et al. 2019

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Among the various technologies tested for removing the anionic species resulting from arsenic contamination, sorption methods have received unflagging interest. Being potential sorbent materials, clay minerals modified by cationic surfactants are often examined for this purpose. Among the clay minerals tested, information regarding sorption properties of expanded vermiculite modified with surfactants is scarce. Therefore, the present study aims to prepare organo-vermiculites modified with hexadecyltrimethylammonium (HDTMA) and benzyldimethylhexadecylammonium (HDBA) at surfactant concentrations of 0.5, 1.0, and 2.0 cation exchange capacity. Modified sorbents were identified and characterized using the analytical methods that can determine phase composition and textural properties of the samples. The sorption of As(III) and As(V) as a function of initial pH value, initial concentration of As(III, V), and initial dosage of sorbent was investigated. The results show that HDTMA and HDBA affect the properties of raw vermiculite. For instance, increase in the concentration of surfactants is often accompanied by a change in interlayer space or textural properties of vermiculite. It was observed that tested organo-minerals adsorbed As(V) to a greater extent compared to As(III). Various analytical studies were carried out and the results revealed the successful synthesis of organo-vermiculite. Moreover, the study also showed that the structure of organo-vermiculite has a significant impact on the uptake of As(III) and As(V) anions.In the last decades, various technologies for removing As from contaminated water have been investigated, such as oxidation, coagulation, ion exchange, precipitation, membrane filtration, biological treatment, and sorption [9][10][11]. However, most of these methods have drawbacks, including high costs, deficient removal, generation of waste products, or high reagent and energy requirement. Among the methods mentioned earlier, adsorption seems to be the most effective method [1,12]. For removal by adsorption technique, activated carbon, metal-organic frameworks, zeolites, bog iron ores, water treatment residuals, and activated alumina have been proven to be promising adsorbents for arsenic removal [13][14][15][16][17].Clay minerals are low-cost and nontoxic sorbents. Raw clays are able to sorb cations owing to their negatively charged surface; however, they display low sorption efficiency for negatively charged contaminants such as arsenic [18]. Nevertheless, clays can be chemically modified by organic surfactants, which change the charge on the clay surface from negative to positive [19]. The organo-clays are hydrophobic materials that can effectively sorb anions and organic compounds. Modified kaolinite, montmorillonite, and illite are the most popular clay minerals that are used as sorbents [20][21][22]. However, only a few studies have focused on using organo-vermiculites to sorb anions [23,24].Vermiculite is a 2:1 phyllosilicate mineral having a sandwiched structure with two tetrahedral shee...

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Section: Xrdmentioning

confidence: 99%

Section: Ftirmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Organo-Modified Vermiculite: Preparation, Characterization, and Sorption of Arsenic Compounds

et al. 2019

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“…The interlayer cations are exchangeable with each other and they are also exchangeable with organic cations such as primary, secondary and quaternary ammonium compounds. 18,19 Cation exchange capacity (CEC) is an important characteristic of the MMT minerals, which represents the degree to which hydrophilicity of MMT can be converted into hydrophobicity or organophilicity, where the organic cations are exchanged with interlayer cations. 20 After modification, the interlayer spacing of MMT is enlarged, which can provide suitable reaction space for the dimerization of unsaturated fatty acids and effectively prevent polyreaction.…”

Section: Introductionmentioning

confidence: 99%

Effects of the Structure and Composition of Montmorillonite on the Dimerization of Unsaturated Fatty Acids

Huang¹,

Yin²,

Zhang³

et al. 2018

J. Braz. Chem. Soc.

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The effects of structure and composition of different montmorillonites on their catalytic performance in the dimerization of unsaturated fatty acids were investigated. The dimerization reaction was performed at 240 °C for 3 h, with montmorillonite as catalyst, and LiCl as the co-catalyst. The results showed that the specific surface areas of the different montmorillonites did not have a major effect on their catalytic performance, but the interlayer spacing and surface acidity of montmorillonite show significant effects on the product yield. After the organic modification through hexadecyl trimethyl ammonium bromide (CTAB) intercalation, the microenvironment of the montmorillonite layer changes. Moreover, the inner and outer surfaces change from being hydrophilic to lipophilic, which improves the dispersibility of montmorillonite in fatty acids. The x Al /x Si molar ratios of the three samples are similar and lie within the range of 0.4306-0.5010, thus the x Al /x Si molar ratio has little effect on the dimerization reaction.

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Vermiculite modified with alkylammonium salts: characterization and sorption of ibuprofen and paracetamol

et al. 2021

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Structure and thermal stability of organo-vermiculite

Cited by 32 publications

References 40 publications

Organo-Modified Vermiculite: Preparation, Characterization, and Sorption of Arsenic Compounds

Organo-Modified Vermiculite: Preparation, Characterization, and Sorption of Arsenic Compounds

Effects of the Structure and Composition of Montmorillonite on the Dimerization of Unsaturated Fatty Acids

Vermiculite modified with alkylammonium salts: characterization and sorption of ibuprofen and paracetamol

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