THE METHOD OF DETERMINATION OF THE SORPTION CAPACITY OF ACTIVATED CARBON BY GAS CHROMATOGRAPHY

The article analyzes the possibility of gas chromatography use for determination of sorption capacity of adsorbents on the example of activated carbon BAC-A. The offered method provides the use of gas chromatograph with flame-ionizing detector and with nozzle geyser that is filled with studied adsorbent. At that the isotherms of absorption of substance are constructed by manifestation curve – desorption branch of substance peak on chromatogram. As a result the isotherms of absorption of isoamylol and camphor on activated carbon were constructed and the values of specific sorption capacity for these substances were calculated. This method allows receive fast and precisely the data about absorption characteristics of adsorbent and also adapt the conditions of the study using gas chromatography to the real conditions of adsorption of substances by studied adsorbent (temperature, adsorbent concentration in vapor phase and so on).

Synthesis and Characterizations of MCM-41 Silica with Thick Pore Wall

Nano-structured mesoporous silica with highly ordered 2D hexagonal topology has been synthesized using novel surfactant cetyltrimethylammonium tosylate (CTATos) as template via directly hydrothermal treatment at high temperature of 175 °C and varied crystallization time. The maximum pore wall thickness is up to 2.2 nm calculated by BdB method from desorption branch. The enlargement of pore wall thickness and unit-lattice of currently synthesized MCM-41 silica is attributed to the migration and subsequent deposition of the silicate species in the inner pore channel.

THE PORE STRUCTURE AND ADSORPTIVE PROPERTIES OF SOME ACTIVATED CHARCOALS: III. THE APPARENT DENSITY OF WATER ADSORBED ON ACTIVE CHARCOAL

The apparent density of water adsorbed on four different charcoals at 20 °C. has been measured by a method of helium displacement. At low relative pressures the density is appreciably higher than that of liquid water, but falls rapidly to nearly the normal density as the amount adsorbed increases. A very sharp drop in density occurs close to saturation, and is attributed to the blocking of the very small porous spaces through the advent of capillary condensation in this region. It is suggested that the apparent high initial density is due to the size of the molecules of the measuring fluid rather than to the compression of the adsorbed film.The apparent density of the adsorbed water on the desorption branch of the isotherm differs from that on the adsorption branch, which suggests that the mechanisms of adsorption and desorption differ. An attempt has been made to evaluate the constants Vm and C of the multimolecular adsorption theory from one of the adsorption isotherms.