Abstract

Catalytic ozonation process (COP) is a new method of single ozonation process that has recently received considerable attention in air pollution control industry. The present study aimed to evaluate the efficiency of catalytic ozonation using carbosieve in xylene removal from the waste air stream. An experimental-laboratory study was conducted at the pilot scale, and the performance of carbosieve adsorbent system, simple ozonation, and catalytic ozonation was studied. A lab-scale pilot was designed and launched at the chemical laboratory of the Faculty of Health, Hamadan. Xylene liquid with purity of 99.5 was prepared from Merck (German) and carbosieve from Aldrich Co. (USA). The specific surface rate and the used catalyst size in this study were 972 m(2)/g and 1.8-2.3 mm, respectively. Results showed that by increasing xylene concentration in the beginning of the system, the time of bed saturation and adsorbent breakpoint decreased, and removal efficiency by ozone gas declined by increasing xylene concentrations in the reactor inlet from 20 to 200 ppm. The findings showed that the carbosieve breakpoint and saturation in catalytic ozonation can happen later from the absorbent carbosieve system alone. It seems that the catalytic ozonation was more efficient in xylene removal compared with absorbent carbosieve system and simple ozonation. The COP by carbosieve could be a promising alternative to conventional volatile organic compounds; removal systems are particularly toxic compounds from waste air stream.