Mechanism and Kinetic Study on the Degradation of Typical Biomass Tar Components (Toluene, Phenol and Naphthalene) by Ozone

The detailed reaction mechanisms for degrading typical biomass tar components (toluene, phenol and naphthalene) by ozone were investigated by employing Density Functional Theory and ab-initio methods. Results showed that toluene, phenol and naphthalene were degraded by ozone in a similar way by destroying C=C bonds and aromatic ring. For toluene and phenol, ozone preferentially destroys C=C bonds at the 1,2-position because of the activation of methyl and hydroxy groups. Relatively, for naphthalene, ozone preferentially destroys C=C bonds at the 2,3-position because of the activation of the middle sharing C=C bond. Based on the mechanism study, the kinetic parameters of the reactions were also calculated by Transition State Theory. The calculated rate constant for degrading toluene by ozone was in good agreement with the literature experimental result. The theoretical calculation was reasonable and reliable. The rate constant for degrading naphthalene by ozone was larger than that for degrading phenol, and the rate constants for degrading phenol by ozone were larger than that for degrading toluene. The degradation sequence of typical biomass tar components by ozone was that naphthalene > phenol > toluene.