Kinetics of Ozone Decomposition by Granular Activated Carbon

详细信息    查看全文

• 作者：Pedro M. Á ; lvarez ; F. Javier Masa ; Josefa Jaramillo ; Fernando J. Beltrá ; n ; Vicente Gó ; mez-Serrano
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2008
• 出版时间：April 16, 2008
• 年：2008
• 卷：47
• 期：8
• 页码：2545 - 2553
• 全文大小：184K
• 年卷期：v.47,no.8(April 16, 2008)
• ISSN：1520-5045

文摘

The kinetics of the removal of ozone from air by granular activated carbon (GAC) has been investigated.Twenty GACs with different textural and chemical surface properties were used in this study. The kineticexperiments were carried out in an expanded bed reactor (EBR) and in a packed bed reactor (PBR). A rateequation that takes into account thermal ozone decomposition and removal of ozone by GAC due tochemisorption and catalytic decomposition has been proposed. Deactivation kinetics has also been consideredin the reaction model. Intrinsic rate constants for thermal ozone removal (k_T), chemisorption of ozone (k₁),and GAC-catalyzed decomposition of ozone (k₂), as well as deactivation rate constants (k_d1 and k_d2) havebeen evaluated from dynamic modeling. At the conditions used in this work, ozone was thermally stable onlybelow 323 K. Above this temperature, ozone partially decomposed even in the absence of GAC. Temperaturefavored the rate of ozone removal by GAC following Arrhenius behavior while air humidity had a negativeeffect, likely attributed to the blockage of GAC active sites by water. A relationship between k₁ and surfacearea, volume of pores larger than 3.5 nm, concentration of surface oxygen complexes (SOC), and ash contenthas been found, while k₂ depends mainly on surface area, basic SOC concentration, and metal content. Theactivity of the all the GAC samples used decreased with the ozone exposure time. The formation of acidicSOC due to chemisorption of ozone onto GAC has been pointed to as a major reason for the processdeactivation. Effective GAC regeneration has been achieved by thermal treatment at 1123 K.