An economic and environmentally benign approach for the preparation of monolithic silica aerogels

Zhang, Yuanyuan; Peng, Junxia; Du, Guanqun; Zhang, Hongxia; Fang, Yu

doi:10.1039/c6ra21050c

Cited by 12 publications

(15 citation statements)

References 59 publications

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“…(d). The contact angle of silica xerogel was 60° that indicated hydrophilic surface of silica xerogel due to Si‐OH and ‐OH groups …”

Section: Resultsmentioning

confidence: 99%

“…The contact angle of silica xerogel was 60 ∘ that indicated hydrophilic surface of silica xerogel due to Si-OH and -OH groups. 51 Optimization studies for MB removal The values of RE and S/N ratio for each experiment are given in Table 2. Maximum value of average RE and S/N ratio were obtained wileyonlinelibrary.com/jctb Table 4.…”

Section: Characterization Of Silica Xerogelmentioning

confidence: 99%

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A novel silica xerogel synthesized from volcanic tuff as an adsorbent for high‐efficient removal of methylene blue: parameter optimization using Taguchi experimental design

Kaya

Yılmaz

Deveci

2019

J of Chemical Tech & Biotech

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BACKGROUND: In this study, silica xerogel was synthesized using volcanic tuff instead of expensive silica precursors at ambient pressure drying. The mesoporous silica xerogel with unique structural and textural properties was evaluated as an adsorbent for methylene blue (MB) removal from aqueous solution. Taguchi method was applied to optimize controllable factors (contact time, initial MB concentration, silica xerogel dose, temperature and pH) for MB removal. RESULTS:The temperature was determined as the most significant factor with percentage contribution of 54.50%. MB removal efficiency was 96.18% at optimum conditions (contact time: 60 min, initial MB concentration: 20 ppm, silica xerogel dose: 0.0016 g mL −1 , temperature: 40 ∘ C, pH: 5). The experimental data fitted with the Langmuir isotherm, yielding a maximum adsorption capacity of 51.967 mg g −1 . MB desorption process was performed depending on eluent concentration and contact time. Maximum desorption efficiency was specified as 88% using 1 M hydrochloric acid for 4 h. The silica xerogel was easily recycled with retaining approximately 70% of adsorption efficiency after five cycles. CONCLUSION: In the light of the promising results, the silica xerogel can be used as an effective adsorbent in many environmental applications. MB desorption process and reusabilityThe simple regeneration and reusability of adsorbent are important factors in adsorption processes in terms of economy. Desorption efficiency of MB adsorbed silica xerogel depending on HCl concentration and contact time is shown in Fig. 5. Desorption

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“…(d). The contact angle of silica xerogel was 60° that indicated hydrophilic surface of silica xerogel due to Si‐OH and ‐OH groups …”

Section: Resultsmentioning

confidence: 99%

Section: Characterization Of Silica Xerogelmentioning

confidence: 99%

A novel silica xerogel synthesized from volcanic tuff as an adsorbent for high‐efficient removal of methylene blue: parameter optimization using Taguchi experimental design

Kaya

Yılmaz

Deveci

2019

J of Chemical Tech & Biotech

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“…The amphiphilic compound, Chol-OH, was synthesized according to our previous work. 41 Two immiscible phases were emulsified into stable Pickering emulsions using a homogenizer (IKA T10) at 11400 rpm for about 5 min. Moreover, the effects of the COP nanoparticle content (ranging from 0 to 0.05 g•mL −1 ), water content (ranging from 30 to 75%), PVA content (ranging from 0 to 3 wt %), and Chol-OH content (ranging from 0 to 0.04 g•mL −1 ) on the stability were systematically investigated, and the selected dosages in all tests are summarized in Table S1.…”

Section: Acs Appliedmentioning

confidence: 99%

“…The interfacial activity enables COP nanoparticles to adsorb and accumulate at the oil−water interface, forming a nanoparticle film, which is strengthened with the help of the amphiphilic molecule Chol-OH. 41 As a result, a series of Pickering emulsions containing COP nanoparticles were formed, and the stable starting emulsion droplets were used as templates for the successful preparation of COP monolithic foams. It has been demonstrated that the as-prepared COP monolith materials not only have good porosity and thermal stability but also exhibit compressibility and cuttability.…”

Section: Introductionmentioning

confidence: 99%

Covalent Organic Polymer Nanoparticle-Supported Monolithic Foams for Separation of Nitrotoluene Isomers

Lyu

Song

et al. 2021

ACS Appl. Nano Mater.

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The combination of micron-scale macropores with meso-/micropores into three-dimensional (3D) macroscopic architectures could give increasing attention to both fast diffusion and mass transfer and exposure of the intrinsic micropores, thereby improving the performance and realizing the real-world applicability of nanoscale functionalized materials. In this report, the emulsion-droplet-templated method was used for the preparation of a hierarchically porous macroscopic covalent organic polymer (COP) monolithic foam, showing compressibility, high mass transfer, and excellent chromatographic separation capacity. The as-synthesized COP nanoparticles with the size of about 40 nm possessed good crystallization and high chemical and thermal stability. More importantly, the resulting COP nanoparticles showed interfacial activity, absorbing and accumulating the water/mesitylene interface, thus producing the COP nanoparticle film. As a result, a series of Pickering emulsions stabilized by COP nanoparticles were formed. Emulsion droplets of approximately 4.90 μm could serve as templates, producing hierarchically porous COP monolithic foams via freeze-drying of the starting Pickering emulsions. In view of the effective merging of macropores with meso-/micropores, the very thin disklike COP monolith (1 mm height × 10 mm i.d.) can serve as a separation column, which is highly efficient in differentiating the isomers of p-< o-< mnitrotoluenes and chloronitrobenzenes. Clearly, the macropores guarantee high mass transfer, while the micropores provide many active sites. Therefore, the resulting COP foam shows excellent chromatographic separation capacity. Finally, the as-prepared COP monolithic foam has great potential as a prospective chromatographic column for highly efficient separation of isomers.

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“…This property can be attributed to the three‐dimensional network structures that are built up through noncovalent interactions, such as hydrogen bonding, electrostatic interactions, van der Waals interactions and π – π interactions. Although several gelators are already used as hardeners for spilled fluids, cooking oils, cosmetic materials and paint thickeners, recent research on gelators has focused on their application to drug delivery and drug release in the field of biomaterials, scaffold materials for cells in tissue engineering, sensors, templates for the synthesis of inorganic nanostructures, auxiliary agents for producing organic electronics, electrolytes that prevent liquid leakage and detectors for explosives …”

Section: Introductionmentioning

confidence: 99%

Preparation of porous polymer materials using water‐in‐oil gel emulsions as templates

Hori

Sano

Suzuki

et al. 2018

Polymer International

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Water-in-oil gel emulsions consisting of water and n-butyl acrylate were successfully prepared using N-3-hydroxybutylcarbonyl-L-isoleucylaminooctadecane and sorbitan monooleate (Span 80) as gelator and surfactant, respectively. Stable gel emulsions were formed using aqueous phase fractions (APFs) ranging from 10 to 90 vol%. Creaming, flocculation and coalescence were not observed. Low-temperature polymerization of the gel emulsions with a redox initiator gave the corresponding low-density, highly porous poly(n-butyl acrylate)s (PBAs). The microstructures of the PBAs were observed using scanning electron microscopy. All the porous PBAs comprised numerous spherical structures whose sizes could be controlled by adjusting the gel emulsion APF. The densities and porosities of the porous PBAs decreased and increased, respectively, with increasing APF. The absorption capacities of the porous PBAs in organic solvents were studied. The porous PBAs selectively absorbed kerosene from water instantly and the kerosene could then be recovered by physical compression of the PBAs. Further porous polymers were prepared from gel emulsions containing styrene, methyl methacrylate (MMA) or 2-ethylhexyl acrylate (EHA) as continuous oil phases. The order of absorption capacity and swelling ratio in kerosene was poly(EHA) > PBA ≫ poly(MMA). Porous copolymers were also prepared from gel emulsions containing a mixture of EHA and MMA as the oil phase. Their absorption and swelling in liquids could be controlled by changing the ratio of EHA and MMA in the gel emulsions. poly(EHA-co-MMA) (6:4) was the best polymer when absorption capacity, swelling ratio and durability were simultaneously considered.

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An economic and environmentally benign approach for the preparation of monolithic silica aerogels

Abstract: One step sol–gel reaction, followed by solvent exchange free ambient pressure drying resulted in various monolithic silica aerogels from super-hydrophobic to hydrophilic with densities as low as 0.026 g cm−3 and thermal conductivities lower than air.

Cited by 12 publications

References 59 publications

A novel silica xerogel synthesized from volcanic tuff as an adsorbent for high‐efficient removal of methylene blue: parameter optimization using Taguchi experimental design

A novel silica xerogel synthesized from volcanic tuff as an adsorbent for high‐efficient removal of methylene blue: parameter optimization using Taguchi experimental design

Covalent Organic Polymer Nanoparticle-Supported Monolithic Foams for Separation of Nitrotoluene Isomers

Preparation of porous polymer materials using water‐in‐oil gel emulsions as templates

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