Adsorption of short chain carboxylic acids from aqueous solution by swellable organically modified silica materials

Edmiston, Paul L.; Gilbert, Alyssa R.; Harvey, Zachary H.; Mellor, Noël

doi:10.1007/s10450-017-9923-0

Cited by 16 publications

(8 citation statements)

References 61 publications

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“…The swelling process enhances its surface area, pore volume, and pore size. SOMS returns to its unswollen state upon removal of the swelling agent because the swelling process is reversible. − ,, The fact that SOMS cannot be kept at its swollen state due to the lack of an organic swelling agent during nitrogen physisorption measurement results in measuring the surface area of SOMS at its unswollen-state. The surface area and pores which would be generated upon swelling are inaccessible to nitrogen during N 2 physisorption experiment.…”

Section: Resultsmentioning

confidence: 99%

“…Animated materials are a class of materials whose characteristics exhibit stimuli-induced responses where the stimuli are pH, − temperature, , or exposure to organics in the gas, liquid, or solid phase. − The development of such materials opens opportunities for engineering heterogeneous “smart catalysts” with improved activity, selectivity, and resistance to deactivation. There is a variety of animated materials reported in the literature including hyper-cross-linked polymers, ,,, hydrogels, −,, and swellable organically modified silica (SOMS). − ,− Unlike conventional catalytic supports such as silica, carbon, or alumina, the animated materials do not have an inelastic structure with a constant porosity under working conditions.…”

Section: Introductionmentioning

confidence: 99%

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Swellable Organically Modified Silica (SOMS) as a Catalyst Scaffold for Catalytic Treatment of Water Contaminated with Trichloroethylene

et al. 2018

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The properties of a swellable organically modified silica (SOMS) scaffold allowed us to synthesize "smart" catalysts with tunable accessibility of the active sites induced by organic swelling agents. Pd nanoparticles (NPs) deposited inside the swollen matrix of SOMS were shown to be selectively located on the interior surface, a surface which is only available through swelling. Techniques such as near ambient-pressure X-ray photoelectron spectroscopy (NAP−XPS) and cryogenic scanning electron microscopy (SEM) were employed to characterize Pd/ SOMS in its swollen as well as unswollen state because their conventional counterparts do not preserve the swollen state of Pd/SOMS during spectral acquisition. The results obtained depicted significant differences between the unswollen and swollen state of Pd/SOMS. The most important difference is that Pd NPs became accessible on the surface after exposure to an organic compound. This indicates that the accessibility of the active sites can be controlled by changing the reaction environment, hence allowing a tunable accessibility induced by organic swelling agents. The effects of the extent of swelling on the catalytic activity were investigated by performing catalytic activity experiments in the presence of an organic swelling agent. Hydrodechlorination (HDC) of trichloroethylene (TCE), an important method of catalytic water abatement, was chosen as a model reaction. The catalytic performance was found to be proportional to the concentration of the organic swelling agent, indicating that the accessibility of active sites is related to the concentration of organic compounds. While the unavoidable reaction product HCl inhibited the commonly used HDC catalyst 1%Pd/Al 2 O 3 , 1%Pd/SOMS was able to maintain its rate throughout the reaction under the same conditions, indicating its resistance to the inhibition. Overall, a silica-based catalyst with tunable accessibility of the active sites induced by changes in the reaction environment can have significant implications for heterogeneous catalysis.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Swellable Organically Modified Silica (SOMS) as a Catalyst Scaffold for Catalytic Treatment of Water Contaminated with Trichloroethylene

et al. 2018

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“…We have previously demonstrated the use of a swellable organically modified silica (SOMS) to mitigate the deactivation problems of Pd-based HDC catalytic systems. − SOMS is a novel catalyst scaffold that has unique properties, such as high affinity for adsorbing organic compounds, extreme hydrophobicity, swelling ability upon contact with organics, and high surface area. − By using SOMS as a scaffold, an animated Pd-based catalyst, the characteristics of which change upon exposure to organic compounds, was synthesized. These unique characteristics led us design poison-resistant catalysts by incorporating Pd NPs inside the matrix of a SOMS scaffold. , Pd/SOMS showed remarkable resistance to chloride poisoning and Pd leaching by HCl. , In addition, due to its surface hydroxyl groups and low acidity, Pd/SOMS was also shown to be resistant to coke deposition during gas-phase HDC of TCE .…”

Section: Introductionmentioning

confidence: 99%

Aqueous-Phase Hydrodechlorination of Trichloroethylene over Pd-Based Swellable Organically Modified Silica: Catalyst Deactivation Due to Sulfur Species

Çelik

Ailawar

Gündüz

et al. 2019

Ind. Eng. Chem. Res.

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One of the problems of catalytic water treatment systems is that sulfur-containing species present in contaminated water have a detrimental effect on the catalytic performance because of strong interactions of sulfur species with active metal sites. In order to address these problems, our research has focused on developing a poison-resistant catalytic system by using a novel material, namely, swellable organically modified silica (SOMS), as a catalyst scaffold. Our previous investigations demonstrated that the developed system was resistant to chloride poisoning, active metal leaching, and carbon deposition under reaction conditions. This study examines the sulfur tolerance of the developed catalytic system for hydrodechlorination (HDC) of trichloroethylene (TCE) by subjecting Pd-incorporated samples to different sulfur species, including sulfates (SO 4 2− ), bisulfides (HS − ), and hydrogen sulfide (H 2 S). The pristine and sulfur-treated catalysts were then tested for aqueous-and gas-phase HDC of TCE and characterized by several techniques, including N 2 physisorption, X-ray photoelectron spectroscopy (XPS), extended X-ray absorption fine structure spectroscopy (EXAFS), and temperatureprogrammed reaction (TP rxn ) with H 2 . The investigations were also performed on Pd/Al 2 O 3 , a commercially used HDC catalyst, to have a basis for comparison. The activity and characterization results revealed that Pd/Al 2 O 3 underwent deactivation due to exposure to sulfur-containing compounds. Pd/SOMS, however, exhibited better resistance to aqueous sulfates, bisulfides, and gas-phase H 2 S. In addition, the removal of sulfur species from completely poisoned catalysts was found to be more facile in Pd/SOMS than Pd/Al 2 O 3 . The tolerance of Pd/SOMS to sulfur poisoning was attributed to stem from the novel characteristics of SOMS, such as swelling ability and extreme hydrophobicity.

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“…Zero-valent iron in the nano size is very reactive because of its large surface area and high reducing capability and it finds application in soil remediation contaminated with pollutants (Irshad et al 2019). TiO 2 NPs have immense uses in the treatment of wastewater (Edmiston et al 2018). Therefore, TiO 2 NPs are a certainly safe material having enormous photocatalytic activity in UV light, but very less photocatalytic activity in visible light (Hamedani et al 2019).…”

Section: Titanium Dioxide Nanomaterialsmentioning

confidence: 99%

“…TiO 2 NPs have immense uses in the treatment of wastewater (Edmiston et al . 2018). Therefore, TiO 2 NPs are a certainly safe material having enormous photocatalytic activity in UV light, but very less photocatalytic activity in visible light (Hamedani et al .…”

Section: Introductionmentioning

confidence: 99%

Applications of metallic nanomaterials for the treatment of water

Tabassum

Ahmad

2022

Letters in Applied Microbiology

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Water scarcity is not a novel issue. It has already affected almost every continent in this blue planet. It is driven by two primary sources: increasing demand for fresh water due to the increase in population and overexhaustion of the available freshwater resources. During the past decade, stress has been given to extract fresh, clean and safe potable elixir of life from the bountiful stores of sea water by exploiting various technologies. As nanomaterials are providing promising solutions to almost all our problems, they are again being accessed in order to combat the problem of global freshwater scarcity. Desalination methods have marvellously improved under the impact of nanomaterials. Different metallic nanomaterials are being used to serve this purpose; for example, silver, iron, zinc, titanium dioxide in addition to natural and synthetically derived polymeric bionanomaterials. In the present paper, a brief account of all the metallic nanomaterials which are being used for treatment of water has been provided by thorough investigation on the research done till now. It strives to throw light on various materials and methods which are based on the exploitation of nanotechnology for the treatment of water.

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Adsorption of short chain carboxylic acids from aqueous solution by swellable organically modified silica materials

Cited by 16 publications

References 61 publications

Swellable Organically Modified Silica (SOMS) as a Catalyst Scaffold for Catalytic Treatment of Water Contaminated with Trichloroethylene

Swellable Organically Modified Silica (SOMS) as a Catalyst Scaffold for Catalytic Treatment of Water Contaminated with Trichloroethylene

Aqueous-Phase Hydrodechlorination of Trichloroethylene over Pd-Based Swellable Organically Modified Silica: Catalyst Deactivation Due to Sulfur Species

Applications of metallic nanomaterials for the treatment of water

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