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A kind of novel catalyst Co-Fe@GAC was prepared by the method of impregnation-calcination with cobalt and iron oxides attached onto granular activated carbon (GAC), and microscopic morphology and structure of the catalyst were analyzed by scanning electron microscopy and X-ray diffraction. Then the laboratory experiment was conducted focusing on examining the effects of degrading Rhodamine B (RhB), a representative organic pollutant, by peroxymonosulfate (PMS) that was activated by Co-Fe@GAC in different circumstances including co-existing ions and humic acids contained in the system. The experiment revealed that by increasing the dosage of Co-Fe@GAC catalysts and PMS concentration it could significantly improve the removal efficiency of RhB, and the system also showed a good degradation performance in a wide-range of pH, in addition, with interference resistance; and the oxidative species quenching test indicated that both hydroxyl radicals and sulphate radicals (SO4•-) existed in the Co-Fe@GAC/PMS system, and SO4•- was the dominant radical in RhB degradation. Besides, Co-Fe@GAC, being re-usable, was considerable stable in terms of catalytic performance. [ABSTRACT FROM AUTHOR]

Few studies on the low-temperature combustion behavior of MIPK, being a promising fuel additive, have been conducted. In this work, ignition delay times (IDTs) of MIPK were measured in the temperatures ranging between 780–910 K and pressures of 20 and 25 bar using a rapid compression machine (RCM). Oxy-fuel combustion combined with biofuel could remove CO 2 from the atmosphere. The IDTs of MIPK were measured in the temperatures ranging between 1125–1600 K under the O 2 /CO 2 atmosphere at the pressures of 1 and 10 bar using a shock tube. A low to high-temperature MIPK kinetic model (HUST-MIPK model) was proposed, in which the low-temperature sub-model consists of 19 low-temperature reaction classes and was constructed by analogy-based method, the high-temperature sub-model was adapted from the works of Cheng et al.. The predictions of HUST-MIPK model are in good agreement with the present low-temperature IDTs, high-temperature O 2 /CO 2 atmosphere IDTs, and the literature experimental data. The negative temperature coefficient (NTC) behavior was not observed in the temperature range from 790 to 910 K in the present RCM experiments, but was observed for methyl propyl ketone (MPK) and diethyl ketone (DEK) under similar conditions. The low-temperature chemistry of three pentanone isomers (MIPK, MPK, and DEK) was compared using the flux and sensitivity analysis. The comparison of the experimental high-temperature IDTs between O 2 /CO 2 and O 2 /Ar atmospheres indicates the IDTs of MIPK under O 2 /CO 2 atmosphere are longer than those under O 2 /Ar atmosphere at 1 bar, and the effects of CO 2 are almost independent of the pressure. The physical and chemical effects of CO 2 on the ignition were studied in detail. [ABSTRACT FROM AUTHOR]

Pressurized oxy-fuel combustion has been attracting increasing attentions due to its improved efficiency and low cost. The present study reports ignition delay times (IDTs) of pyridine under O 2 /CO 2 atmospheres within a temperature range from 1202 to 1498 K at pressures from 2.2 to 10 bar for equivalence ratios of 0.5, 1.0, and 2.0. The experimental results were compared with the IDTs of pyridine under O 2 /Ar atmospheres from MacNamara et al.. The comparison results indicate that the IDTs of pyridine under O 2 /CO 2 atmospheres are evident longer than those under O 2 /Ar atmospheres even at low pressure. A modified kinetic model (HUST pyridine Model) was proposed based on our previous mechanism. HUST pyridine Model predicted well the IDTs under both O 2 /CO 2 and O 2 /Ar atmospheres obtained in shock tubes and the species profiles under both O 2 /CO 2 and O 2 /N 2 atmospheres obtained in plug flow reactors. HUST pyridine Model, Alzueta Model, and Pyridine LTO Model were evaluated. The results show that the performance of HUST pyridine Model is much better than Alzueta Model, and Pyridine LTO Model. The main reason is that the net reaction rate of C 5 H 5 N + O = C 5 H 4 N + OH in HUST pyridine Model is much faster than that in Aluzeta Model. The effect of CO 2 on the ignition of pyridine at elevated pressures has been analyzed in detail. The oxidation pathways of pyridine are also analyzed at different pressures. [ABSTRACT FROM AUTHOR]