Recent advances of CO2-responsive materials in separations

Yang, Ziqi; He, Changqing; Sui, Hong; He, Lin; Li, Xingang

doi:10.1016/j.jcou.2019.01.004

Cited by 75 publications

(20 citation statements)

References 167 publications

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“…Consequently, many of the identified switchable solvents only work under ultra-dry conditions [19,20]. The water sensitivity of these systems [21] makes them difficult to work with for the preparation of metal oxide precursors, especially if the initial metal salt contains water.…”

Section: Introductionmentioning

confidence: 99%

“…There are a wide variety of switchable systems that have been applied, using switchable hydrophilicity [18,21], switchable surfactants [22] and switchable water [23]; where the additive increases its ionic strength under different atmospheres and can be used to precipitate out compounds. The switching of the solvent properties is relatively slow using low pressure gases, although in theory this could be used as a way of precipitating a dissolved component from solution.…”

Section: Introductionmentioning

confidence: 99%

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Triethylamine–Water as a Switchable Solvent for the Synthesis of Cu/ZnO Catalysts for Carbon Dioxide Hydrogenation to Methanol

Wallace

Hayward

et al. 2021

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Cu/ZnO catalyst precursors for industrial methanol synthesis catalysts are traditionally synthesised by coprecipitation. In this study, a new precipitation route has been investigated based on anti-solvent precipitation using a switchable solvent system of triethylamine and water. This system forms a biphasic system under a nitrogen atmosphere and can be switched to an ionic liquid single phase under a carbon dioxide atmosphere. When metal nitrate solutions were precipitated from water using triethylamine–water as the anti-solvent a hydroxynitrate phase, gerhardite, was formed, rather than the hydroxycarbonate, malachite, formed by coprecipitation. When calcined and reduced, the gerhardite precursors formed Cu/ZnO catalysts which showed better productivity for methanol synthesis from CO2 hydrogenation than a traditional malachite precursor, despite their larger CuO crystallite size determined by X-ray diffraction. The solvents could be recovered by switching to the biphasic system after precipitation, to allow solvent recycling in the process, reducing waste associated with the catalyst synthesis.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Triethylamine–Water as a Switchable Solvent for the Synthesis of Cu/ZnO Catalysts for Carbon Dioxide Hydrogenation to Methanol

Wallace

Hayward

et al. 2021

Top Catal

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“…However, these surfactant‐stabilized emulsions are often undesired to the downstream operations, such as oil–water separation and wastewater treatment. These emulsions could contain valuable oil products (e.g., enhanced oil recovery), cause environmental pollution (e.g., wastewater of industrial laundry and soil remediation), or accumulate surfactants in the eco‐system if untreated 19 . Hence, a subsequent stage of oil–water separation is usually required to break down these stable emulsions.…”

Section: Introductionmentioning

confidence: 99%

“…The tunability of the switching pH permits the customization of surfactants regarding specific chemical processes, such that a suitable reagent could be readily selected according to process requirements 23 . Furthermore, the external stimulus, CO 2 gas, is also inexpensive, abundant in nature, and usually available onsite in the flue gas 19,26,28 . We therefore hypothesize that this series of MEA‐LCFAs surfactants are promising chemical aids to the commercial separation applications to resolve the IFT conflicts between the oil‐solid and oil–water separation stages.…”

Section: Introductionmentioning

confidence: 99%

Enhancing oil–solid and oil–water separation in heavy oil recovery by CO₂‐responsive surfactants

Manica

et al. 2020

AIChE Journal

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Interfacial properties are of critical importance to various separation applications. In heavy oil recovery, for example, a low oil–water interfacial tension (IFT) benefits the separation of heavy oil from their host rocks, which becomes problematic in the later stage of oil–water separation. CO2‐responsive surfactants were investigated to enhance the overall heavy oil recovery by switching their interfacial activity to the desired state in each stage. The surfactants at interfacially active state greatly enhanced the separation of heavy oil from hosting solids, as demonstrated by measuring contact angle and oil liberation using a custom‐designed on‐line visualization system. Meanwhile, the resulting heavy oil‐in‐water emulsions could also be easily demulsified by the bubbling of CO2 gas, which switched off the interfacial activity of the surfactants. Furthermore, CO2‐responsive surfactants could be partially recycled in process water to improve sustainability, making CO2‐responsive surfactants to be promising chemical aids in heavy oil production and many other vital industries.

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“…Different applications have been proposed for these solvents in the ME context for different matrices, biological [26], environmental [27], or food and drinks [28]. In general, SHS-based procedures are simple, fast paced (allowing an increased sample throughput), and compatible with a variety of instrumental techniques for a wide range of analytes [29]. The demand of new chemicals for pharmaceutical [30], cosmetic [31], or industrial [32] purposes has a major global impact on water quality in the developed societies.…”

Section: Introductionmentioning

confidence: 99%

Application of Switchable Hydrophobicity Solvents for Extraction of Emerging Contaminants in Wastewater Samples

et al. 2019

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In the present work, the effectiveness of switchable hydrophobicity solvents (SHSs) as extraction solvent (N,N-Dimethylcyclohexylamine (DMCA), N,N-Diethylethanamine (TEA), and N,N-Benzyldimethylamine (DMBA)) for a variety of emerging pollutants was evaluated. Different pharmaceutical products (nonsteroidal anti-inflammatory drugs (NSAIDs), hormones, and triclosan) were selected as target analytes, covering a range of hydrophobicity (LogP) of 3.1 to 5.2. The optimized procedure was used for the determination of the target pharmaceutical analytes in wastewater samples as model analytical problem. Absolute extraction recoveries were in the range of 51% to 103%. The presented method permits the determination of the target analytes at the low ng mL−1 level, ranging from 0.8 to 5.9 (except for Triclosan, 106 ng mL−1) with good precision (relative standard deviation lower than 6%) using high-pressure liquid chromatography (HPLC) combined with ultraviolet (DAD) and fluorescence (FLR) detection. The microextraction alternative resulted in a fast, simple, and green method for a wide variety of analytes in environmental water sample. The results suggest that this type of solvent turns out to be a great alternative for the determination of different analytes in relatively complex water samples.

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Recent advances of CO2-responsive materials in separations

Cited by 75 publications

References 167 publications

Triethylamine–Water as a Switchable Solvent for the Synthesis of Cu/ZnO Catalysts for Carbon Dioxide Hydrogenation to Methanol

Triethylamine–Water as a Switchable Solvent for the Synthesis of Cu/ZnO Catalysts for Carbon Dioxide Hydrogenation to Methanol

Enhancing oil–solid and oil–water separation in heavy oil recovery by CO₂‐responsive surfactants

Application of Switchable Hydrophobicity Solvents for Extraction of Emerging Contaminants in Wastewater Samples

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Recent advances of CO2-responsive materials in separations

Cited by 75 publications

References 167 publications

Triethylamine–Water as a Switchable Solvent for the Synthesis of Cu/ZnO Catalysts for Carbon Dioxide Hydrogenation to Methanol

Triethylamine–Water as a Switchable Solvent for the Synthesis of Cu/ZnO Catalysts for Carbon Dioxide Hydrogenation to Methanol

Enhancing oil–solid and oil–water separation in heavy oil recovery by CO2‐responsive surfactants

Application of Switchable Hydrophobicity Solvents for Extraction of Emerging Contaminants in Wastewater Samples

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Enhancing oil–solid and oil–water separation in heavy oil recovery by CO₂‐responsive surfactants