Zhang Xinya

Total oxidation of isopropanol over manganese oxide modified ZSM-5 zeolite membrane catalysts

Manganese oxide modified ZSM-5 membrane catalysts were prepared for the catalytic combustion of a volatile organic compound (isopropanol) over a zeolite membrane reactor. Characterization of all samples was carried out by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), N2 adsorption/desorption, X-ray photoelectron spectroscopy (XPS) and H2-temperature programmed reduction (H2-TPR). The performance of the catalytic oxidation of a single VOC (isopropanol) was investigated over the zeolite membrane reactor based on Mn/ZSM-5/PSSF catalysts, the experimental results showed that the 0.5 M Mn/ZSM-5/PSSF-350 °C catalyst exhibited the best catalytic activity for isopropanol oxidation with 90% conversion of isopropanol at 222 °C with a feed concentration of 4.5 mg L−1 and GHSV of 7643 h−1, which was much lower than that of granular Mn/ZSM-5 catalyst (297 °C). The results of a reaction stability test revealed that the Mn/ZSM-5/PSSF catalysts possess excellent reaction stability for isopropanol oxidation for 50 h, and the conversion of isopropanol remained above 97% at 280 °C with a feed concentration of 4.5 mg L−1 and GHSV of 7643 h−1.

The growth of latex particles during the Vac/BA copolymerization

The semi-continuous seeded emulsion copolymerization of vinyl acetate and butyl acrylate was carried out with hydroxyethyl cellulose as a colloid stabilizer. The morphology of the latex particle and the relationship between the reaction time and the average particle diameter and/or the conversion ratio during the polymerization were investigated. The experimental results show that the morphology of the latex particle possesses the stable steric construction. In the seeded polymerization, the average particle diameter of latex decreased while the conversion ratio increased. At the second term of the emulsion copolymerization (the growth stage of particle size), the latex particle average diameter increased with copolymerization continuously, but the instantaneous conversation ratio was not large, so it was very necessary to properly prolong the time during the holding temperature stage.