Composition and structural effects on the adsorption of ionic liquids onto activated carbon

Lemus, Jesús; Neves, Catarina M. S. S.; Marques, Carolina S.; Freire, Mara G.; Coutinho, João A. P.; Palomar, José

doi:10.1039/c3em00230f

Cited by 25 publications

(17 citation statements)

References 36 publications

(78 reference statements)

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“…As expected, the chemical structure of the tested ILs, more specifically the size of the cation of the IL, length of the alkyl chain, and nature of the core significantly influence the adsorption efficiency. The results indicate that ILs derived from heterocyclic aromatic cations are more highly adsorbed onto ACs than the corresponding aliphatic derivatives (pyridinium>imidazolium>pyrrolidinium>piperidinium) . The data are in accordance with the data assembled by Farooq regarding the sorption rates of pyridinium and imidazolium cores.…”

Section: Degradation Of Ionic Liquidssupporting

confidence: 86%

“…The data are in accordance with the data assembled by Farooq regarding the sorption rates of pyridinium and imidazolium cores. The nature of the anion also contributes to the adsorption ability of ILs, and hydrophobic anions, such as bistriflimide and hexafluorophosphate, present the highest adsorption rates (NTf 2 >PF 6 >OTf>BF 4 >TFA>Cl; OTf=trifluoromethanesulfonate, TFA=trifluoroacetate) . A study conducted by Hassan et al .…”

Section: Degradation Of Ionic Liquidsmentioning

confidence: 99%

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Environmental Impact of Ionic Liquids: Recent Advances in (Eco)toxicology and (Bio)degradability

et al. 2017

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This Review aims to integrate the most recent and pertinent data available on the (bio)degradability and toxicity of ionic liquids for global and critical analysis and on the conscious use of these compounds on a large scale thereafter. The integrated data will enable focus on the recognition of toxicophores and on the way the community has been dealing with them, with the aim to obtain greener and safer ionic liquids. Also, an update of the most recent biotic and abiotic methods developed to overcome some of these challenging issues will be presented. The review structure aims to present a potential sequence of events that can occur upon discharging ionic liquids into the environment and the potential long-term consequences.

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Section: Degradation Of Ionic Liquidssupporting

confidence: 86%

Section: Degradation Of Ionic Liquidsmentioning

confidence: 99%

Environmental Impact of Ionic Liquids: Recent Advances in (Eco)toxicology and (Bio)degradability

et al. 2017

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“…Adsorption with activated carbon or other materials and the ‘salting‐out’ of ILs with aluminium salts has been investigated as potential solutions for their recovery or non‐destructive removal. However, in the case of the imidazolium‐based ILs, important limitations have been found regarding the length of the alkyl chain and the nature of the counter anion, since both issues affect the hydrophobicity of the molecule and consequently, their affinity for the carbon surface .…”

Section: Introductionmentioning

confidence: 99%

Degradation of imidazolium‐based ionic liquids in aqueous solution by Fenton oxidation

Domı́nguez

Muñoz

Quintanilla

et al. 2014

J of Chemical Tech & Biotech

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BACKGROUND: The breakdown of imidazolium ionic liquids (ILs) by Fenton oxidation has been demonstrated, but using unaffordable doses of hydrogen peroxide (H 2 O 2 ). The literature studies so far do not report on the evolution of total organic carbon (TOC) and ecotoxicity. Therefore, the potential application of the process for the degradation of ILs still remains an open question. This work investigates the feasibility of the Fenton process for the treatment of aqueous effluents containing imidazolium-based ILs of different structures, represented by the length of the alkyl chain and the nature of the anion. Special attention is paid to the evolution of the ecotoxicity and the consumption of H 2 O 2 as a critical issue for the economy of the process. The experiments were performed at 70 ∘ C. RESULTS: With the stoichiometric H 2 O 2 dose, the complete conversion of the starting imidazolium-based ILs was achieved in less than 5 min, at 70 ∘ C, with 60% of TOC reduction after 4 h, except in the [C 4 mim][CH 3 CO 2 ] case, where iron precipitation was observed, thus inhibiting its catalytic action. Low ecotoxicity effluents were obtained at the stoichiometric H 2 O 2 dose, even in the cases of the highly ecotoxic ILs of long alkyl chain with chloride anion. CONCLUSION: Fenton oxidation is shown to be a promising solution for the degradation of imidazolium-based ILs in water, allowing deep detoxification with the stoichiometric H 2 O 2 dose.

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“…Therefore, the search of novel methods/techniques to remove ILs from aqueous environments is of outmost importance. There are some previous studies regarding the removal of ILs from aqueous streams [11-31]. Amongst those, some of them use destructive methods such as advanced oxidation [11-13] or biological treatments [14,21,22].…”

Section: Introductionmentioning

confidence: 99%

Enhancing the adsorption of ionic liquids onto activated carbon by the addition of inorganic salts

Neves

Lemus

Freire

et al. 2014

Chemical Engineering Journal

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Most ionic liquids (ILs) are either water soluble or present a non-negligible miscibility with water that may cause some harmful effects upon their release into the environment. Among other methods, adsorption of ILs onto activated carbon (AC) has shown to be an effective technique to remove these compounds from aqueous solutions. However, this method has proved to be viable only for hydrophobic ILs rather than for the hydrophilic that, being water soluble, have a larger tendency for contamination. In this context, an alternative approach using the salting-out ability of inorganic salts is here proposed to enhance the adsorption of hydrophilic ILs onto activated carbon. The effect of the concentrations of Na2SO4 on the adsorption of five ILs onto AC was investigated. A wide range of ILs that allow the inspection of the IL cation family (imidazolium- and pyridinium-based) and the anion nature (accounting for its hydrophilicity and fluorination) through the adsorption onto AC was studied. In general, it is shown that the use of Na2SO4 enhances the adsorption of ILs onto AC. In particular, this effect is highly relevant when dealing with hydrophilic ILs that are those that are actually poorly removed by AC. Furthermore, the COnductor like Screening MOdel for Real Solvents (COSMO-RS) was used aiming at complementing the experimental data obtained. This work contributes with the development of novel methods to remove ILs from water streams aiming at creating "greener" processesThe authors acknowledge FCT- Fundação para a Ciência e a Tecnologia, through the projects Pest-C/CTM/LA0011/2013 and PTDC/AAC-AMB/119172/2010. Catarina M.S.S. Neves also acknowledges FCT for the doctoral Grant SFRH/BD/70641/2010.The authors are also grateful to the Spanish “Ministerio de Ciencia e Innovación (MICINN)” and “Comunidad de Madrid” for financial support (projects CTQ2011-26758 and S2009/PPQ-1545). M.G. Freire acknowledges the European Research Council (ERC) for the Starting Grant ERC-2013-StG-33775

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Composition and structural effects on the adsorption of ionic liquids onto activated carbon

Cited by 25 publications

References 36 publications

Environmental Impact of Ionic Liquids: Recent Advances in (Eco)toxicology and (Bio)degradability

Environmental Impact of Ionic Liquids: Recent Advances in (Eco)toxicology and (Bio)degradability

Degradation of imidazolium‐based ionic liquids in aqueous solution by Fenton oxidation

Enhancing the adsorption of ionic liquids onto activated carbon by the addition of inorganic salts

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