Geopolymers as a New Class of High pH Stable Supports with Different Chromatographic Selectivity

Wimalasinghe, Rasangi M.; Weatherly, Choyce A.; Wahab, M. Farooq; Thakur, Nimisha; Armstrong, Daniel W.

doi:10.1021/acs.analchem.8b01426

Cited by 20 publications

(11 citation statements)

References 58 publications

(126 reference statements)

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“…-Well cementing in hydrocarbon and geothermal industries [285][286][287] -Chromatographic substrates [288] -Manufacture of composites [289,290], including strain-hardening and/or ductile "engineered composite" materials [291][292][293] -Repair mortars [294] -Materials for additive manufacturing or "3D printing" through various extrusion-based and powder bed processes (Fig.13 [295]) [296][297][298] -Moderate-temperature refractories or fire-resistant construction materials [299][300][301][302]…”

Section: Applications Of Alkali-activated Materialsmentioning

confidence: 99%

Recent progress in low-carbon binders

Shi

Provis

2019

Cement and Concrete Research

466

131

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The development of low-carbon binders has been recognized as a means of reducing the carbon footprint of the Portland cement industry, in response to growing global concerns over CO2 emissions from the construction sector. This paper reviews recent progress in the three most attractive low-carbon binders: alkali-activated, carbonate, and belite-ye'elimite-based binders. Alkali-activated binders/materials were reviewed at the past two ICCC congresses, so this paper focuses on some key developments of alkali-activated binders/materials since the last keynote paper was published in 2015. Recent progress on carbonate and belite-ye'elimite-based binders are also reviewed and discussed, as they are attracting more and more attention as essential alternative low-carbon cementitious materials. These classes of binders have a clear role to play in providing a sustainable future for global construction, as part of the available toolkit of cements.

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Section: Applications Of Alkali-activated Materialsmentioning

confidence: 99%

Recent progress in low-carbon binders

Shi

Provis

2019

Cement and Concrete Research

466

131

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“…The increase in total pore volume is more prominent implying larger increase in macroporosity than mesoporosity. The high permeability of these geopolymer monoliths has been shown by using them as monolithic chromatographic solid supports . The geopolymers synthesized using bulk geopolymerization or using a reactive emulsion template technique could not be used as chromatographic monolithic columns because of the lack of macropores and the predominant closed pores and hence exerted back pressures of more than 400 MPa (column dimensions: 5 cm × 4.6 mm id, mobile phase: methanol, flow rate: 1 mL/min), which is an upper limit for back pressure for most of the modern HPLC instruments.…”

Section: Resultsmentioning

confidence: 99%

“…The drastic dip in back pressure indicates the presence of a more permeable structure for the geopolymers. The chromatographic evaluation using columns made of GS4‐3 has been discussed in a previous paper …”

Section: Resultsmentioning

confidence: 99%

“…Geopolymers are ceramic‐like inorganic polymers synthesized from reactive aluminosilicate precursors (eg, metakaolin, fly ash, etc) and alkali solutions . Geopolymers are finding various applications as construction materials, adsorbents for heavy metals, in catalysis, separation science, etc. Intrinsically, geopolymers are mesoporous, but they are highly dense structures exhibiting low permeability .…”

Section: Introductionmentioning

confidence: 99%

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Fabrication of interconnected macroporosity in geopolymers via inverse suspension polymerization

et al. 2019

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A new approach to fabricate geopolymer monoliths with interconnected macroporosity and a permeable structure is presented. This was achieved using an unconventional route of inverse suspension polymerization in which the aqueous geopolymer slurry consisting of potassium hydroxide, fumed silica, and natural metakaolin was dispersed in a continuous phase of soybean oil. The geopolymer monolith was synthesized by taking advantage of the so-called "sticky period" that occurs during inverse suspension polymerization. During this period, individual droplets can coalesce but cannot re-divide because of the partially polymerized matrix. We deliberately brought the partially polymerized geopolymer particles in proximity during the sticky period to fuse the particles. Hence this method, termed as "sticky period particle fusion," helped to form a monolithic structure with inter-particle spacing as macropores which resulted in high permeability. The sticky period was observed to depend on synthesis conditions such as stirring speed, temperature, and viscosity of continuous phase which in turn helped to tune the surface and pore properties of geopolymer monoliths. The BET surface area up to 67 m 2 /g and total pore volumes of 0.4 cm 3 /g from pycnometry were obtained. K E Y W O R D Saluminosilicates, geopolymers, pores/porosity

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“…The Armstrong research group investigated geopolymers as a new class of high pH stable chromatographic supports, which were previously introduced in the field of chromatography by Alzeer et al (24)(25) (26) These amorphous poly-condensed aluminosilicate ceramic solids have a high mechanical strength, chemical stability in basic conditions, and are water insoluble, making them a unique solid support material that can be turned into porous spherical particles with high surface area amenable for chromatographic purposes. (25) Their chromatographic selectivity shows a strong hydrophilic and electrostatic character, and in the HILIC mode a different selectivity than that in silica columns is found, with excellent peak shapes. The produced particles had an average particle size of 6.1 μm, a D90/D10 of 2.9 and the RSD of the geopolymer PSD was 7.6%.…”

Section: Fully Porous Particlesmentioning

confidence: 99%