Zeolitic water content and adsorptive capacity for ammonia of microporous sepiolite

Dandy, A. J.

doi:10.1039/j19710002383

Cited by 25 publications

(8 citation statements)

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“…In the work of Molina-Sabio et al (2004), the activated carbon-sepiollite was employed as the adsorbent for ammonia gas removal. Sepiollite has special affinity towards NH 3 (Dandy 1971), specific interactions between ammonia with the acid groups of the sepiollite surface produces very strong adsorption energy (Molina-Sabio et al 2004). Sepiollite has special affinity towards NH 3 (Dandy 1971), specific interactions between ammonia with the acid groups of the sepiollite surface produces very strong adsorption energy (Molina-Sabio et al 2004).…”

Section: Selective Pollutant Gas Adsorption By Clay Mineralsmentioning

confidence: 99%

Clay Materials for Environmental Remediation

Ismadji

Soetaredjo

Ayucitra

2015

SpringerBriefs in Molecular Science

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Section: Selective Pollutant Gas Adsorption By Clay Mineralsmentioning

confidence: 99%

Clay Materials for Environmental Remediation

Ismadji

Soetaredjo

Ayucitra

2015

SpringerBriefs in Molecular Science

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“…Although the channel structure has been studied by X-ray powder diffraction (Brauner & Preisinger, 1956) and electron microscopy (R autureau& Tchoubar^ a /., 1973), the adsorption properties of the channel have not yet been clarified fully. Many studies have been carried out on the adsorption properties of sepiolite, e.g., adsorption selectivity Serna & Fernandez-Alvarez, 1974,1975, the effect of acid treatment on the surface area (Jimenez-L o p c z e ta l., 1978;Lopez-Gonzalez^a/., 1981) and the effect of heating on the microporosity (Dandy, 1968(Dandy, , 1971Dandy & Nadiye-Tabbiruka, 1982). But distinction between the adsorption in the channel and that on the outer surface was ambiguous.…”

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confidence: 99%

Pore size distribution and adsorption selectivity of sepiolite

et al. 1990

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: Micropore distribution and effective size of the channels of natural sepiolite from Turkey were measured by the BET method. Before the BET measurement, the samples were treated under a water vapour atmosphere at various pressures to fill progressively the sepiolite micropores with water. The surface areas measured by means of N 2 adsorption decreased with increased vapour pressures of water. The outer surface area was estimated by comparison of the surface area of the vacuum-dried sepiolite with that filled with adsorbed water. The total surface area was ~290 m2/g, and the outer surface area was 170 m2/g, the difference being attributed to the structural micropores of the sepiolite. The ratio of the surface areas possessed by the channels and that of the outer surface suggest that the mean thickness of the sepiolite fibre was ~ 12 nm. The effective size of the channels was estimated from the number of various-sized molecules sorbed by the sepiolite, the results showing that molecules larger than benzene could not migrate into the channels.

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“…Actually, the location of the "micropores" (Sing et al, 1985) responsible for sepiolite's adsorption capacity is somewhat controversial. Barrer and Mackenzie (1954) and Dandy (1968Dandy ( , 1971 suggested that the availability of these structural channels to the nitrogen molecules is limited. The loss in BET-N2 surface area observed on outgassing at >200~ has been attributed to a sintering of the external fiber surface (Dandy and Nadiye-Tabbiruka, 1975).…”

Section: Introductionmentioning

confidence: 99%

Modification of the Porous Structure and Surface Area of Sepiolite under Vacuum Thermal Treatment

Grillet

1988

Clays and clay miner.

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Abstract--Modifications of the external surface area and the two types of microporosity of sepiolite (structural microporosity and inter-fiber porosity) were examined as a function of the temperature of a vacuum thermal treatment to 500~ The methods used included: reciprocal thermal analysis, N 2 and Ar low-temperature adsorption microcalorimetry, gas adsorption volumetry (for N2, mr, and Kr at 77 K and CO2 at 273 and 293 K), water-vapor adsorption gravimetry, and immersion microcalorimetry into liquid water at 303 K. If the sample was not heated > 100~ only 20% of the structural microporosity was available to N2, whereas 52% was available to CO: at 293 K. In both experiments, the channels filled at very low relative pressures. At > 350~ the structure transformed to anhydrous sepiolite, which showed no structural microporosity. The inter-fiber microporosity decreased from 0.031 to 0.025 cmVg (as seen with N2), and the external specific surface area decreased from 120 to 48 m2/g. The water adsorption isotherms showed a lower and lower affinity of the external surface of fibers for water as the temperature of thermal treatment increased. The thickness of the bound water on the external surface was estimated to be -<3.5 monolayers, i.e., less than l0/~.

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Zeolitic water content and adsorptive capacity for ammonia of microporous sepiolite

Cited by 25 publications

References 0 publications

Clay Materials for Environmental Remediation

Clay Materials for Environmental Remediation

Pore size distribution and adsorption selectivity of sepiolite

Modification of the Porous Structure and Surface Area of Sepiolite under Vacuum Thermal Treatment

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