SU1469322A1 - Method of determining porosity of adsorbents - Google Patents

Abstract

This invention relates to an instrumentation technique, namely a method for determining the porosity of adsorbents. The purpose of the invention is to expand the field of application of the method by ensuring that the parameters of pores available for sorption of a given substance are determined. The method consists of passing a monochromatic x-ray beam (X-ray) through the sample, measuring the angular dependences of the x-ray scattering intensity and measuring the pore parameters dependencies. To achieve the goal, the angular dependence of the X-ray scattering intensity on the sample, using the material, is additionally measured, and the pore sizes available for sorption of this substance, and the proportion of their volume of the total pore volume is calculated from the angular dependence of the X-ray scattering intensity difference on the original and unsaturated samples. (P

Description

one

 . The invention relates to instrumentation, technology, and specifically to methods for determining the parameters of porous materials, and can be used in the chemical, petroleum, metallurgical and other industries in the development of adsorbents and filters.

The aim of the invention is to expand the field of application of the method of pu- re: to ensure the determination of the parameters of pores available for sorption of a given substance.

Fig. 1 shows the X-ray scattering intensity of a porous sample as a function of the scattering angle; Fig. 2 shows the differential curves of the pore volume distribution.

Example. Determined the size and proportion of the total pore volume of the samples of the adsorbent Polysorb-capable of sorption of tributyl phosphate molecules. The sample was irradiated and the angular dependences of the x-ray scattering intensity were measured using a CRM-1 installation on a CuK-A radiation monochromatized with a nickel filter, with radiation being recorded by a scintillator counter with an amplitude analyzer. Sorbent. It was filled into a 1 mm thick flat cell with windows sealed with a 1-dimensional film transparent to X-rays. The survey was carried out both on the initial adsorbent and on Polysorb-1 saturated with tributyl phosphate (TBP). The mass of sorbent in the cuvee ate

with

with you

those in its cases were the same. The scattering intensity was also measured on pure TBP, which turned out to be negligible compared to the scattering intensity on pure (original) Polysorb-1 and on an adsorbent saturated with tributyl phosphate. The obtained small-angle scattering curves are shown in Fig. 1 (curve 1 — intensity of scattering of a pure sorbent as a function of scattering angle; curve 2 — scattering intensity of a sorbent saturated with TBP). The scattering intensity of polysorb-1 saturated with TBP (1 (f)) is given taking into account the attenuation coefficient. The calculation was carried out using the formula

I, (H) I

, Kc, V)

CO 20

where Ig (h) scatter intensity - NIN adsorbent, kasyKo)

and ex,

schenny TBP;

1 - respectively, in- (o) intensity of the direct. the beam weakened when passing through a pure and saturated TBP adsorbent. Differential distribution curve: - laziness of pore volume in size (radius of inertia R) for a clean sample and f (R) was calculated by the formulas

f (R)

Ш11-1АИ-;

(2)

i

one

1 + 0.5 e

-C / v

(3)

. l. s de h -i- sin

40

A ° 2

I (Y) intensity, dissipated for a clean sample as a function of 45 angle V;

y "0,4431-0,212rarctg 1;

- V / c + c /

with 108.5 angular min.- parameter, vertical characterization of 50

the divergence of the incident beam, x-ray radiation; 0.154 nm - wavelength X-ray,

new radiation; 55

0

5 o

five

0

45

50

55U is the scattering of the adsorbent material (without pores), which was determined from the tail of the scattering curve of the clean sample, where the intensity did not vary with the angle f (Fig. 1, curve 1, section AB).

The resulting distribution curve f (R), which characterizes a clean sample, is shown in Figure 2 (curve 1),

The differential curve of the distribution of pore volume filled with tribu-tilphosphate (Fig. 2, curve 2) was calculated using the formula:

f (R) .1 JifiLtf, (, 5

In the calculation, in this case, the values of K-f) and 1 (v) were used in the area from the time to the intersection point of curves 1 and 2 in figure 1. .

From curve 2 in FIG. 2, it follows that TBP is absorbed by pores having inertia radii of at least 0.8-0.9 nm. From the ratio of the areas under curves 1 and 2 of FIG. 2, we find that about 90% of the total pore volume absorbs tributyl phosphate.

Claims (1)

 Invention Formula A method for determining the porosity of adsorbents, which involves transmitting a monochromatized x-ray beam through a sample, measuring the angular dependences of the x-ray scattering intensity and calculating pore parameters from the measured dependence, in order to widen the field of application of the method by ensuring that parameters are determined the pores available for sorption of a given substance, additionally measure the angular dependence of the intensity of x-ray scattering on a sample saturated with The pores available for sorption of a given substance, and the proportion of their volume in the total pore volume, are calculated from the angular dependence of the difference in the x-ray scattering intensities on the original and n-saturated samples. A B. 4t O u Js g o FIG. one Editor T. Parfenova Compiled by A. Koscheev Tehred M. Khodanych Order 1347/45 Circulation 788 BNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 4/5, Moscow, Zh-35, Raushsk nab. 113035 ( -eight tStg (f Proofreader V.Girn to Subscription