Preparation of Ice-Templated MOF–Polymer Composite Monoliths and Their Application for Wastewater Treatment with High Capacity and Easy Recycling

Fu, Qingshan; Wen, Lang; Zhang, Lei; Chen, Xuedan; Pun, Daniel; Ahmed, Adham; Yang, Yonghong; Zhang, Haifei

doi:10.1021/acsami.7b10872

Cited by 92 publications

(62 citation statements)

References 45 publications

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“…The freeze-dried chitosan beads were also characterized by other techniques. Based on the PXRD analysis, the beads generated were amorphous, consistent with the previous finding of freeze-dried chitosan [36]. While the macroporous structure was revealed by SEM imaging (Fig.…”

Section: Characterization and Morphology Of Chitosan And Crosslinked supporting

confidence: 89%

Porous chitosan by crosslinking with tricarboxylic acid and tuneable release

et al. 2020

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Chitosan hydrogels crosslinked with 1,3,5-benzene tricarboxylic acid (BTC) are readily prepared at room temperature by adding aqueous chitosan solution dropwise into BTC-ethanol solution. Highly interconnected porous chitosan materials are subsequently prepared by freeze-drying the chitosan hydrogels. These chitosan materials show porous structures with smaller pores than conventionally prepared chitosan hydrogels via crosslinking with NaOH, genipin or sodium triphosphate. This method of forming chitosan hydrogels with BTC provides the advantage of facile encapsulation of both hydrophobic and hydrophilic compounds, as demonstrated with the model dyes (Oil Red O and Rhodamine B). The release of the hydrophilic dye from the chitosan hydrogels is demonstrated and can be tuned by BTC/chitosan concentrations and the hydrogel drying methods. However, the release of encapsulated hydrophobic dye is negligible.

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Section: Characterization and Morphology Of Chitosan And Crosslinked supporting

confidence: 89%

Porous chitosan by crosslinking with tricarboxylic acid and tuneable release

et al. 2020

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“…Therefore, many resources are directed towards improving and developing water treatment technologies [1,2]. A large number of studies have aimed to develop new sorbents for pollutant removal [3–6], such as organically modified clay minerals, termed organoclays [7,8]. More recently, adsorbed polymer clay composites have often exceeded the performance of commercial sorbents and have therefore drawn attention as sorbents for water treatment [9–11].…”

Section: Introductionmentioning

confidence: 99%

Designing a regenerable stimuli-responsive grafted polymer-clay sorbent for filtration of water pollutants

Gardi

Mishael

2018

Science and Technology of Advanced Materials

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A novel, stimuli-responsive composite, based on poly(4-vinylpyridine) (PVP) brushes, end-grafted to montmorillonite clay (GPC), was designed as a regenerable sorbent for efficient removal of pollutants from water. We characterized the novel composite sorbent and its response to pH, employing Fourier transform infrared, X-ray photoelectron spectroscopy, X-ray diffraction, thermogravimetry analysis and zeta potential measurements. In comparison with conventional, electrostatically adsorbed PVP composites (APC), the GPC presented superior characteristics: higher polymer loading without polymer release, higher zeta potential and lower pH/charge dependency. These superior characteristics explained the significantly higher removal of organic and inorganic anionic pollutants by this composite, in comparison with the removal by APC and by many reported sorbents. For example, the filtration (20 pore volumes) of selenate by GPC, APC and a commercial resin column was complete (100%), negligible (0%) and reached 90% removal, respectively. At low–moderate pH, the grafted polymer undergoes protonation, promoting pollutant adsorption, whereas at high pH, the polymer deprotonates, promoting pollutant desorption. Indeed, ‘in-column’ regeneration of the GPC sorbents was achieved by increasing pH, and upon a second filtration cycle, no reduction in filter capacity was observed. These findings suggest the possible applicability of this stimuli-responsive sorbent for water treatment.

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“…One of the water-stable MOFs is UiO-66, a zirconium-based MOF made up of twelve Zr6 clusters, connected via terephthalate linkers [11]. As such, UiO-66 has been used for water remediation [12,13], including the adsorption of methylchlorophenoxypropionic acid (MCPP), a phenoxy acid commonly used in agriculture as an herbicide [14,15].…”

Section: Introductionmentioning

confidence: 99%

“…However, the disadvantages of using this procedure include tedious collection & recycling of MOF nanoparticles and the difficulty in upscaling. To address this issue, MOF monoliths [16,17], and more commonly MOF/polymer composites have been fabricated and used [14]. Among various methods of making nanoparticles/polymer composites [18,19], freeze-casting is a highly versatile and efficient process to make a wide range of porous materials, including polymer, ceramics, and composites [20,21].…”

Section: Introductionmentioning

confidence: 99%

Fabricating MOF/Polymer Composites via Freeze Casting for Water Remediation

Rogers

Pun

et al. 2018

Ceramics

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Various porous materials have been used as adsorbents for water remediation. Among them, metal-organic framework (MOF) particles have been explored intensively, due to their size-controlled micropores and high surface areas. MOF nanoparticles are often used because of high external surface area and easy access to the micropores. However, recovering MOF nanoparticles, usually by filtration or centrifugation, is time-consuming and is difficult to scale up. We report here the preparation of porous MOF/polymer monoliths by freeze casting for water remediation. Chitosan and UiO-66 (Universitetet i Oslo) nanoparticles (including different surface functional groups) are used to prepare such monoliths. In order to improve the mechanical stability and the tendency of disintegrating in water, the freeze-dried UiO-66/chitosan monoliths are further treated by heating, washing with aqueous NaOH solution, or chemical crosslinking with glutaraldehyde. All these treated monoliths are used for adsorption of a herbicide methylchlorophenoxypropionic acid (MCPP) from aqueous solution. Particularly, the crosslinked chitosan/UiO-66 monolith achieves an adsorption capacity of 47.67 mg g−1, with a 60 ppm MCPP solution. It is superior to that presented by the sole UiO-66 nanoparticles, exhibiting over a 30% increase in the adsorption capacity. The monoliths can be easily removed using tweezers, providing facile recyclability, which is advantageous for upscaling. The recycled monolith upheld approximately 75% of the adsorption capacity compared to the original monolith after three reuse cycles.

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Preparation of Ice-Templated MOF–Polymer Composite Monoliths and Their Application for Wastewater Treatment with High Capacity and Easy Recycling

Cited by 92 publications

References 45 publications

Porous chitosan by crosslinking with tricarboxylic acid and tuneable release

Porous chitosan by crosslinking with tricarboxylic acid and tuneable release

Designing a regenerable stimuli-responsive grafted polymer-clay sorbent for filtration of water pollutants

Fabricating MOF/Polymer Composites via Freeze Casting for Water Remediation

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