Gravimetric adsorption energy distribution (GAED) full characterization
GAED software provides a cornucopia of information about specific activated carbons for gas- or aqueous-phase physical adsorption application opportunities. Besides isotherms, GAED offers: Pore size distribution, BET surface area, trace-capacity number, mid-capacity number, pore or adsorption space volume as a function of adsorption energy density and total pore volume for individual sample and much more.
GAED is the best AC characterization test available. We have provided over 5,000 samples, using GAED. GAED provides full characterization of vapor-, aqueous- or solvent-phases.carbon pellets manufacturer
Received and dry American Society for Testing (ASTM) apparent densities for AC test material are determined. This enables presenting AC adsorption data on a volume basis. Most clients fill a container with granular activated carbon (GAC), so volume comparisons are more useful than weight-based comparisons. The dried material is placed in GAED instrument sample compartment. It is heated to 250o C with a flowing inert argon gas stream, to take away any volatiles and clean the sample. After the sample is cleaned, weight lost at 250o C is reported as a measure of sample cleanliness — two percent or less weight lost is good. When comparing multiple samples, they need to all be cleaned and you must know the starting amount of contamination before adding the challenge adsorbate gas.
TFE, or 1,1,1,2-Tetrafluoroethane, was chosen as the challenge gas because TFE outer shell electrons are tightly held with a RI measurement of 1.200 and thus has an exceptionally low polarizability. After a 250o C sample cleaning, TFE is added by flowing through the sample; then a temperature program cools the sample to above the TFE condensation temperature at minus 21o C. This avoids sample weight gain from TFE condensation on the tested sample. About 700 sample weight gain values during cool down, due to physical adsorption, are acquired. Then the temperature program is reversed back to 250o C to obtain a loaded sample desorption curve. Out of some 1,400 data points for adsorption and desorption, software selects 30 representative data points from quasi-equilibrium weights. This provides a data table and graphical presentation, called Characteristic Curve, for the specific AC sample that was run.
From the Characteristic Curve, the Y-axis is pore volume, in cc of TFE adsorbate per 100 cc of material, versus adsorption energy density on the X-axis, in calories per cc adsorption space or pore volume. Software determines the polynomial equation from the Characteristic Curve distribution. This equation enables isotherm determinations for any compounds of interest at any process temperature. The pore size distribution, BET surface area and more are calculated.ningxia yongruida carbon Co., Ltd
Standard sorbents are used as benchmark controls for comparison and to prove that the GAED instrument is performing within statistical performance limits. Three standard compound isotherms are provided: Methyl-tertiary-butyl-ether (MTBE), benzene and phenol. These three compounds cover the range from weak-, medium- and strong-adsorption capacities in water. Once a specific sorbent adsorption space is mapped with TFE- GAED full characterization, we can supply isotherms for any compounds of interest at any temperature desired. We only need to ratio the molar volume of the compound of interest to TFE molar volume in order to get a specific compound’s Characteristic Curve and thus its isotherms. Also, relative refractive indices can be used to re-map adsorption space distribution for specific compounds outside of the three standards given.