Sun De-zhi

Demulsification of water-in-oil emulsion by wetting coalescence materials in stirred- and packed-columns

Abstract Demulsification of emulsified water-in-oil droplets was developed using wetting coalescence materials. Demulsification tests were carried out using conventional stirred- and packed-columns. Of the four kinds of natural fibers and two kinds of inorganic materials tested, natural fiber A, selected from shaves of a wood showed the best performance in demulsification. The demulsification efficiency can exceed 97% when demulsification conditions are optimized. The packed-column showed much better performance both in terms of demulsification efficiency and repeated use of the recovered oil phase for extracting cadmium in a simulated wastewater. Operating variables that govern the demulsification efficiency were investigated.

Kinetics of Acetamiprid Photolysis in Solution

Photolysis of acetamiprid was investigated in detail under different reaction conditions. The photolysis of acetamiprid in solution followed pseudo-first-order kinetics under the experimental conditions. Acetamiprid kept stable under irradiation of high-pressure xenon lamp but degraded relatively fast when exposure to medium-pressure mercury lamp irradiation. The experimental results indicated that the degradation rate of acetamiprid in acetone was the largest among the used media and acetamiprid was more stable in basic media. The addition of oxygen, increase of light intensity and temperature will enhance the photolysis.

Photocatalytic Degradation of Toluene Using a Novel Flow Reactor with Fe-doped TiO2 Catalyst on Porous Nickel Sheets¶

Abstract A novel continuous-flow photocatalytic reactor was designed to decompose toluene by using porous nickel sheets that were coated with a Fe-doped TiO2 catalyst. While locating the UV lamp at the central axis, the catalyst sheets were located along the inner wall and positioned vertically with an equal space of 50 mm along the reactor. This geometry ensures better use of UV light, and a zigzag flow pattern of gas between the vertically located sheets provides for better mass transfer. The X-ray diffraction, scanning electron microscope and electric field–induced surface photovoltage spectra characterizations showed that Fe3+ ions were embedded effectively and distributed evenly throughout the TiO2 crystal lattice and an optimum molar ratio of Fe:Ti was 0.007. The reactor was used to investigate the factors that affect toluene degradation. The results showed that inlet toluene concentration, relative humidity and gas flow rate significantly affect toluene decomposition. The conversion decreases as inlet concentration increases. Degradation efficiencies of more than 95% can be achieved provided that the toluene concentration is kept below 3200 mg/m3. The conversion is affected little when oxygen content exceeds 21%. The optimal relative humidity is 25%. From the experimental data, a rate constant k of 131 mg/(m3·min) and Langmuir adsorption coefficient K of 0.0175 m3/mg were obtained.