LaY and CeY zeolites. Adsorptive removal of trace amount of 1
1-difluoro-2-chloroethylene (HCFC-1122) from 1
1
1
2-tetrafluoroethane product over NaY
CaY
LaY
and CeY zeolites were investigated. The structure and surface properties of fresh and regenerated adsorbents were characterized by X-ray diffraction
pyridine infrared spectra techniques and temperature programmed desorption of ammonia. Results show that the residual ratio of HCFC-1122 impurity in the eluate can be decreased to 1.0% over CaY,LaY and CeY zeolites via the formation of p-adsorption complexes between HCFC-1122 and Brønsted acid sites. The increase of intensity of Brønsted acid favors the formation of p-adsorption complexes
consequently decreasing adsorption temperature for complete removal of HCFC-1122 (CeY < LaY < CaY). Breakthrough adsorption capacity of HCFC-1122 at 220℃ increases in the order of CaY < LaY < CeY
since lower density of strong Brønsted and weak Lewis acid sites are favorable to lower degree polymerization initiated by p-adsorption complexes. The thermal regeneration of adsorbents is unsatisfactory
attributed to hardly removal of contaminant on the acid sites of saturated adsorbents during the thermal regeneration process.