Organoclay Sorption of Benzene as a Function of Total Organic Carbon Content

Abstract:Montmorillonies separated from the bentonites SAz-1 (Cheto, AZ, USA), and Cressfield (New South Wales, Australia) were used as starting materials. Reduced charge montmorillonites (RCMs) were prepared from these chemically different and Li-saturated montmorillonites via heating at temperatures in the range of 120-300°C. The residual exchangeable Li + cations were then replaced with tetramethylammonium (TMA + ) or hexadecyltrimethylammonium (HDTMA + ) cations and the ability of the modified montmorillonites to adsorb biphenyl was investigated. Lower adsorption was observed for Li-montmorillonites than for the organoclays. The extent of adsorption was dependent on both the layer charge of montmorillonite and the size of alkylammonium cations. HDTMA-forms prepared from unheated Li-montmorillonites adsorbed biphenyl better than the organoclays prepared from RCMs. In contrast, the TMA-samples prepared from the Li-montmorillonites that were not heated showed low uptake of biphenyl probably due to high content of TMA + cations. Reduction of the layer charge, resulting in lower content of TMA + cations, increased sorption efficiency of both TMAmontmorillonites. The best adsorbents of biphenyl were HDTMA-SAz-1 prepared from the unheated Li-SAz-1 and TMA-Cressfield prepared from the Li-form heated at 180°C. These samples removed about 80% of biphenyl from its aqueous solutions © Versita Warsaw and Springer-Verlag Berlin Heidelberg.

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“…[17][18][19][20]. Layer charge affects most properties of smectites among which the adsorption ability is of great importance.…”

Section: Introductionmentioning

confidence: 99%

The effect of layer charge and exchangeable cations on sorption of biphenyl on montmorillonites

2009

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“…Argilas modificadas com sais monoquaternários de amônio de comprimentos de cadeia variados têm sido investigadas quanto às suas capacidades na remoção de diversos tipos de poluentes orgânicos, tais como, organoclorados [1,2] , óleo e graxa [3] , dodecilbenzeno sulfonato de sódio [4] , gasolina [5] , benzeno [6] , 2-naftol [7] e naftaleno [8,9] . Os cátions orgânicos pequenos (tetrametilamônio) geram superfícies apolares relativamente rígidas, responsáveis pela remoção, por adsorção, de solutos não-iônicos.…”

Section: Introductionunclassified

Preparação e caracterização de organobentonita modificada com ionenos alifáticos

2005

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A preparação de complexos bentonita-ionenos a partir da adsorção de tetrametil-[x,y]-ionenos, onde x= 2 e y= 4,6,10 ou 12, e o 2-hidróxi-3-cloro-ioneno, EPI-DMA, foi realizada com a finalidade de observar o comportamento do tamanho do espaçador do ioneno na expansão basal (d001) das camadas de uma bentonita comercial do Brasil. Os complexos foram caracterizados por espectrometria de absorção na região do infravermelho, termogravimetria, fluorescência e difração de raios X. A partir das análises por fluorescência e difração de raios X dos complexos, foi observado que os poli-quaternários de amônio são adsorvidos nas superfícies internas e externas da argila delaminada, acima da capacidade de troca catiônica, CTC = 91 meq/100g de argila (calculada a partir de dados de fluorescência de raios X). A expansão basal das camadas da argila com os diferentes policátions revelou que o tamanho do espaçador é o fator mais importante, independentemente das massas molares dos ionenos, tal como foi observado principalmente entre os complexos Bt-2,10- e Bt-2,12-ioneno, com massas molares de 12000 e 5000 g/mol, respectivamente.

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“…Many studies have been done on the effect of organic carbon loading on the sorption capacity of sorbents surface of sorbents has higher affinity to interact with organic compounds. As a result, unmodified bentonites and silty clay presented a negligible sorption capacity to organic contaminants because they have limited percentage of natural occurring carbon in their structure (Redding et al 2002). However, organobentonites exhibited significant sorption capacity to organic contaminants because the intercalated modifier cations increase the carbon loading on the surface of organobentonites Smith and Jaffe 1994).The effect of TOC on the partitioning coefficient of studied sorbents has been shown in Figure 2-8.…”

Section: Effect Of Molecular Characteristics Of Sorbents On Sorption mentioning

confidence: 98%

“…The proposed materials are: mixture of bentonite and fly ash, surfactant modified soils, activated carbon, paper industry sludge, organo-sand, zeolite, organo-zeolite, and many other commercial additives. Recently, the surface modification of clay minerals has received a great attention because it can produce a strong and stable sorbent media with favorable sorption of common environmental pollutants (Redding et al 2002;Richards and Bouazza 2007;Zhao and Burns 2012).…”

Section: Engineering Applicationsmentioning

confidence: 99%

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Engineering applications of organic surfactant modified bentonite in sorptive soil barriers.

Javadi¹

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Organoclay Sorption of Benzene as a Function of Total Organic Carbon Content

Cited by 89 publications

References 27 publications

The effect of layer charge and exchangeable cations on sorption of biphenyl on montmorillonites

The effect of layer charge and exchangeable cations on sorption of biphenyl on montmorillonites

Preparação e caracterização de organobentonita modificada com ionenos alifáticos

Engineering applications of organic surfactant modified bentonite in sorptive soil barriers.

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