(374e) Catalytic Oxidation of Total Reduced Sulfur Compounds from Pulp and Paper Industries with Ozone as an Oxidant

Pulp and paper industry generates more than 144 million lb of VOCs per year including a range of reduced sulfur compounds (TRS) such as dimethyl sulfide (DMS), dimethyl disulfide (DMDS), methane thiol (MT) and H2S that are odorous, toxic and contribute to smog formation. Thermal oxidation methods commonly used to are costly and energy intensive. Ozone is a clean oxidant with high thermodynamic oxidation potential and thus offers the advantage of performing the reactions at low temperatures. The objective of our research is the combined use of ozone and catalysis for the oxidation of reduced sulfur compounds from paper and pulp mills at low reaction temperatures. Oxidation of DMS with ozone using V2O5/TiO2 as a catalyst was conducted at mild temperatures ranging from 100 200 ºC and O3/DMS mole ratios from 0.7 to 3. Excellent conversions of DMS were observed to complete oxidation products viz. CO2 and SO2 with small amounts of DMS partial oxidation products such as dimethyl disulfide (DMDS), dimethyl sulfoxide (DMSO) and dimethyl sulfone (DMSO2). Conversion of DMS increased with increasing the reaction temperature from 100-200 ºC and also with the increase of O3/DMS mole ratio. A plausible reaction mechanism has been proposed based on the distribution of products. Time-on-stream study indicated that the catalytic activity decreased with the reaction time due to the poisoning of the catalyst active sites by sulfur. Further studies are in progress to improve the catalyst performance by either adding the suitable promoter or different supports.