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Ionic liquid-modified silica particles with a large pore size were synthesized and used as the stationary phase for size exclusion chromatography coupled with a refractive index detector for the determination of polysaccharides, such as fucoidan, alginic acid, and laminarin from Undaria pinnatifida (seaweed). The molecular weight of polysaccharide was determined by a dextran standard curve (5-1100 kDa). The ionic liquid-modified silica column exhibited excellent size exclusion properties in separating laminarin from other components. The 1-butyl-3-methyl-imidazolium bis-(trifluoromethylsulfonyl)-amino silica column has superior resolution in laminarin separation than the other columns because the amino-group in ionic liquid provide π-π interactions due to aromaticity of the ring structure, which enhances the effect of the hydroxyl group in the target compound separation. The concentrations of polysaccharides were calculated using a standard linear equation to be 0.332-0.484 mg/g of fucoidan, 0.207-0.301 mg/g of alginic acid, and 0.154-0.297 mg/g of laminarin. [ABSTRACT FROM AUTHOR]

Large quantities of fly ash are discharged as a by-product from coal power plants. Therefore, an effective method to recycle this waste material is necessary. In this regard, the high silica content of fly ash makes it a potential useful source for the synthesis of nanoporous materials, such as zeolites, mesoporous silica or silica aerogels. In this mini review, zeolite synthesis from fly ash was examined by considering the ash composition, pretreatment procedures, and hydrothermal synthesis conditions (substrate composition and synthesis temperature/time) to identify an optimal set of synthesis conditions. These zeolites can be used as adsorbents and ion-exchangers for environmentally hazardous materials including those present in the fly ash itself. The synthesis of mesoporous silica materials with a high surface area and large pore volume derived from fly ash was next assessed for their use as a support and as a surface-functionalized host for capturing the global warming CO 2 and rare earth metal ions. Lastly, the utilization of fly ash for the preparation of silica aerogels or adiabatic foams, which are being considered as a potential building insulation materials, was briefly examined. Cases of synthesizing these nanoporous materials using other solid wastes as silica and/or alumina sources were also examined. The synthesis of diverse porous materials utilizing the waste sources would enable a high level of recycling for a sustainable society with a low environmental burden. [ABSTRACT FROM AUTHOR]

A zeolitic imidazolate framework, ZIF-8, was prepared via a variety of synthesis routes: solvothermal, microwave-assisted, sonochemical, mechanochemical, dry-gel, and microfluidic methods. Their textural properties and morphology were examined by surface area measurements and scanning electron microscopy, and compared with those of commercial ZIF-8. Although the BET surface areas fell within a range of 1250–1600 m 2 g − 1 , the particle size of the samples prepared by dry-gel and sonochemical routes were significantly smaller than the others, which led to superior performance in the Knoevenagel condensation reaction. The effective incorporation of magnetic Fe 3 O 4 nanoparticles into the ZIF-8 structure for easy particle separation in the liquid phase was feasible using solvothermal, dry-gel and mechanochemical synthesis methods. Dry-gel and mechanochemical synthesis produced a higher ZIF-8 yield. [ABSTRACT FROM AUTHOR]

Thiol-functionalized ZIF-90 (ZIF-90-SH) was prepared via condensation of the free aldehyde group of ZIF-90 with 2-mercaptoethylamine to an imine through a one-step post-synthesis route. A subsequent reaction with manganese(ii) acetate resulted in the formation of a new Mn(ii)-immobilized hybrid material (ZIF-90-S[Mn]). This material was characterized by chemical analysis, X-ray diffraction, N2 adsorption–desorption, thermogravimetric analysis and Fourier transform infrared spectroscopy, which confirmed the successful functionalization of the as-synthesized ZIF-90. ZIF-90-SH employed as an adsorbent for the removal of Hg(ii) ions from an aqueous solution at room temperature exhibited an adsorption capacity of ca. 22.4 mg g−1. The material showed 96–98% removal of Hg(ii) ions in a low concentration range (0.1 to 10.0 mg L−1). ZIF-90-S[Mn] showed good catalytic activity and selectivity in the epoxidation of several important alkenes using molecular oxygen under atmospheric pressure. Recycling and hot filtration experiments coupled with a blank test showed that epoxidation proceeded over ZIF-90-S[Mn] on the external surface of the ZIF-90 matrices, where the active Mn(ii) sites were located. The catalyst could be recycled up to four times without significant loss of efficiency. [ABSTRACT FROM AUTHOR]

A dry gel conversion synthesis aided by fine-grinding of the synthesis precursors produces a MIL-101 product with a high surface area greater than 4100 m2 g−1 and a product yield approaching 90% in a very reproducible manner after only simple water washing. [ABSTRACT FROM AUTHOR]