Decomposition Of Dimethyl Sulfide Research Articles

Oxidation of Dimethyl Sulfide in Air Using Electron-Beam Irradiation, and Enhancement of its Oxidation Via an MnO2 Catalyst

The decomposition of dimethyl sulfide (DMS) at initial concentrations of 4.5–18.0 ppmv in air was studied under electron-beam (EB) irradiation. Doses to decompose 90% of input DMS were 2.5 kGy for 4.5 ppmv, 3.4 kGy for 10.6 ppmv, and 3.9 kGy for 18.0 ppmv. HCOOH, (CH3)2SO, and trace CH3OH and (CH3)2SO2 were produced as irradiation products in addition to CO2 and CO. Application of an O3 decomposition catalyst to an irradiated sample gas led to an enhancement in the oxidation of DMS and its products into CO2 and the decomposition of O3. For 10.6 ppmv DMS/air, the mineralization ratio increased from 41% via only EB irradiation to 100% via the combination treatment at 6.3 kGy. The yield of CO2 to COx increased from 5.3 to 87.6% by combination with catalytic oxidation. This combination treatment enables the irradiation energy used to deodorize gas streams containing DMS to be reduced.

Influence of balance gas mixture on decomposition of dimethyl sulfide in a wire-cylinder pulse corona reactor

The influence of balance gas mixture on decomposition of dimethyl sulfide was investigated experimentally by a wire-cylinder pulse corona reactor at room temperature. A new type of high voltage pulse generator with a thyratron switch and a Blumlein pulse-forming network was used in the experiments. The experiments were conducted at a fixed pulse frequency of 100 pps. The DMS decomposition efficiency as well as energy yield was investigated using varying oxygen concentration (0.6–21.0%), humidity (0–1.0%) and different balance gas (air, N 2, Ar). Breakdown voltage of DMS in Ar is lower than that of DMS in N 2, both of which are proportional to the gas pressures. The conversion of DMS in Ar is more efficient than that in N 2 and air at a fixed peak voltage. In addition, it is found that 5% oxygen is the optimum concentration in decomposition of DMS, due to higher conversion of DMS and relatively fewer yields of by products, such as O 3, NO x and SO 2. The highest DMS removal efficiency where the energy yield was 1.24 mg kJ −1 was achieved with the gas stream containing 0.3% H 2O in air.

Decomposition of dimethyl sulfide in a wire-cylinder pulse corona reactor

Decomposition of dimethyl sulfide (DMS) in air was investigated experimentally by using a wire-cylinder dielectric barrier discharge (DBD) reactor at room temperature and atmospheric pressure. A new type of high pulse voltage source with a thyratron switch and a Blumlein pulse-forming network (BPFN) was adopted in our experiments. The maximum power output of the pulse voltage source and the maximum peak voltage were 1 kW and 100 kV, respectively. The important parameters affecting odor decomposition, including peak voltage, pulse frequency, gas flow rate, initial concentration, and humidity, which influenced the removal efficiency, were investigated. The results showed that DMS could be treated effectively and almost a 100% removal efficiency was achieved at the conditions with an initial concentration of 832 mg/m3 and a gas flow rate of 1000 ml/min. Humidity boosts the removal efficiency and improves the energy yield (EY) greatly. The EY of 832 mg/m3 DMS was 2.87 mg/kJ when the relative humidity was above 30%. In the case of DMS removal, the ozone and nitrogen oxides were observed in the exhaust gas. The carbon and sulfur elements of DMS were mainly converted to carbon dioxide, carbon monoxide and sulfur dioxide. Moreover, sulfur was discovered in the reactor. According to the results, the optimization design for the reactor and the matching of high pulse voltage source can be reckoned.

Photocatalytic behavior of layered aluminum dihydrogen triphosphate under UV irradiation

The photocatalytic behavior of layered aluminum dihydrogen triphosphate (ALP) under UV (254 nm) irradiation was investigated. In a one-path reaction vessel, dimethyl sulfide (DMS), a typical odor compound, decomposed effectively on a layered ALP under UV (254 nm) irradiation. It was shown that DMS decomposed oxidatively from DMS conversion and CO 2 generation. The signal of OH radical was observed on layered ALP after UV irradiation from the ESR studies. This radical would promote the decomposition of DMS.

A high active type of hydroxyapatite for photocatalytic decomposition of dimethyl sulfide under UV irradiation

Abstract A very active type of hydroxyapatite (HAp-2) for photocatalytic decomposition of dimethyl sulfide (DMS) under UV irradiation and its structural characteristics were studied. The conversion of DMS using HAp-2 was 98–100% at the space velocity of 340 h−1 under UV irradiation, and the activity of HAp-2 was higher than that of another type of HAp (HAp-1). The photocatalytic decomposition of DMS proceeded oxidatively and effectively on HAp-2 under UV irradiation. It was recognized that DMS converted stoichiometrically to CO2 on HAp-2. From the X-ray diffraction (XRD) studies, the HAp-1 crystals had a lower crystallinity than crystals of HAp-2 toward the apatite a-axis, but a similar crystallinity toward the c-axis. Then, it was concluded that the photocatalytic activity of HAp must be due to the crystallinity toward the a-axis of HAp crystal.

Adsorption and photocatalytic decomposition of odor compounds containing sulfur using TiO 2/SiO 2 bead

Adsorption and photocatalytic decomposition of dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) using an improved type of silica bead inner-supported with TiO 2 (TiO 2/SiO 2) were investigated. The specific surface area of the TiO 2/SiO 2 bead was 321 m 2 g −1 and the adsorption capacity of the bead for DMS or DMDS was 49.9, 116 μg g −1, respectively. Photocatalytic decomposition of DMS using the bead was about 100% at the space velocities of 33.5–134 h −1 after the equilibrium between adsorption and desorption of the compound, whereas, that of DMS using surface-supported TiO 2/SiO 2 was below 65% at the same conditions as described in previous paper. Though photocatalytic decomposition of DMDS using the inner-supported bead was below 53% for the same condition as DMS, the removal of DMDS in the lighting up condition from the start using the bead was about 100% for 50 h at a space velocity of 67 h −1. It was suggested that DMDS was treated completely by the composite effects of adsorption and photocatalytic decomposition.

Decomposition of dimethyl sulfide in the presence of Al2O3, and catalyst deactivation

The catalytic decomposition of dimethyl sulfide has been studied over the temperature range of 400–500 °C. The main reaction products are methylmercaptane, H2S and methane. Catalyst deactivation is due to its coking during the reaction. The possibility of oxidative catalyst regeneration at 550 °C has been shown.

ChemInform Abstract: Adsorption and Catalytic Decomposition of Dimethyl Sulfide and Dimethyl Disulfide on Metal Films of Iron, Palladium, Nickel, Aluminum and Copper

ChemInform Abstract: Adsorption and Catalytic Decomposition of Dimethyl Sulfide and Dimethyl Disulfide on Metal Films of Iron, Palladium, Nickel, Aluminum and Copper