STUDIES ON TBP-NO_x——A NEW OXIDIZING AGENT PREPARED FROM NITROGEN OXIDES

Nitrogen oxides(NO_2 and NO)are absorbed by tributyl phosphorate(TBP)to fom a new complex mixture of TBP-NO_x. which is used as a selective oddizing agent to oxidize benzylalcohols to corresponding sldehydes or ketones In high yield. In the reaction process, nitrogen oxides are llberated mildly and mainly reduced to nitrogen, while tributyl phosphorate is recovered end recycled.

Different oxidation routes for lattice oxygen recovery of double-perovskite type oxides LaSrFeCoO6 as oxygen carriers for chemical looping steam methane reforming

Double-perovskite type oxide LaSrFeCoO（LSFCO） was used as oxygen carrier for chemical looping steam methane reforming（CL-SMR） due to its unique structure and reactivity. Two different oxidation routes,steam-oxidation and steam-air-stepwise-oxidation, were applied to investigate the recovery behaviors of the lattice oxygen in the oxygen carrier. The characterizations of the oxide were determined by X-ray diffraction（XRD）, X-ray photoelectron spectroscopy（XPS）, hydrogen temperature-programmed reduction（H-TPR） and scanning electron microscopy（SEM）. The fresh sample LSFCO exhibits a monocrystalline perovskite structure with cubic symmetry and high crystallinity, except for a little impurity phase due to the antisite defect of Fe/Co disorder. The deconvolution distribution of XPS patterns indicated that Co,and Fe are predominantly in an oxidized state(Feand Fe) and(Coand Co), while O 1s exists at three species of lattice oxygen, chemisorbed oxygen and physical adsorbed oxygen. The double perovskite structure and chemical composition recover to the original state after the steam and air oxidation, while the Co ion cannot incorporate into the double perovskite structure and thus form the CoO just via individual steam oxidation. In comparison to the two different oxidation routes, the sample obtained by steam-oxidation exhibits even higher CHconversion, CO and Hselectivity and stronger hydrogen generation capacity.

The effect of sunblock against oxidative stress in farmers：a pilot study

Farmers are frequently exposed to ultraviolet（UV） radiation which causes various diseases by inducing oxidative stress.This study aimed to assess the effects of sunblock on oxidative stress in the body.Eighty-seven farmers were divided into two groups：those who wore sunblock for five days and those who did not.The total antioxidant capacity（TAC） in urine,which is an antioxidant indicator,and 8-hydroxy-2-deoxyguanosine（8-OHdG） levels in urine,an oxidative stress indicator,were measured.The urinary TAC of sunblock users was significantly higher than that of non-users,but urinary 8-OHdG levels were not significantly different.Even after adjustment for potential confounders,urinary TAC was found to be markedly increased with sunblock usage.These results suggest that sunblock is effective in preventing oxidative stress among farmers.In addition,they show that urinary TAC can be used as a good effect marker of oxidative stress caused by UV exposure.

CeO_2/CuO catalysts using different template agent for preferential CO oxidation in H_2-rich stream

The CeO2/CuO catalysts using different template agent（F68 L64, F127 and P123） were synthesized by the simple template and impregnation method. They were characterized by FESEM, XRD, N2 physisorption and H2-TPR techniques. It is found that the CeO2/CuO catalysts are double pore distribution, and CeO2 can enter into the gap of CuO supports and form the contact interface of copper and cerium. Among the asprepared catalysts, the CeO2/CuO-F127 catalyst displays better activity at lower temperature and the CeO2/CuO-P123 catalyst presents higher activity at higher temperature. The CeO2/CuO-P123 catalyst has the smallest crystallite sizes of CuO and CeO2 as well as the largest size of cubes, which may improve the interaction of copper and cerium and enhance the performance of CO oxidation.

Oxidation of diesel soot on binary oxide Cu Cr(Co)-based monoliths

Binary oxide systems（Cu Cr2O4, Cu Co2O4）, deposited onto cordierite monoliths of honeycomb structure with a second support（finely dispersed Al2O3）, were prepared as filters for catalytic combustion of diesel soot using internal combustion engine’s gas exhausts（O2, NOx, H2 O, CO2） and O3 as oxidizing agents. It is shown that the second support increases soot capacity of aforementioned filters, and causes dispersion of the particles of spinel phases as active components enhancing thereby catalyst activity and selectivity of soot combustion to CO2. Oxidants used can be arranged with reference to decreasing their activity in a following series： O3 NO2〉 H2 O 〉 NO 〉 O2〉 CO2. Ozone proved to be the most efficient oxidizing agent： the diesel soot combustion by O3 occurs intensively（in the presence of copper chromite based catalyst） even at closing to ambient temperatures.Results obtained give a basis for the conclusion that using a catalytic coating on soot filters in the form of aforementioned binary oxide systems and ozone as the initiator of the oxidation processes is a promising approach in solving the problem of comprehensive purification of automotive exhaust gases at relatively low temperatures, known as the ＂cold start＂ problem.