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In the process of the double-layer gas-assisted extrusion of plastic micro-tubes, the external size and surface quality of the micro-tubes are greatly affected by the size of the assisting gas inlet slit inside the mold. Therefore, in this experiment, a two-phase flow model was established based on a compressible gas and a non-compressible melt. The Polyflow finite element solution software module was used to solve the velocity field, temperature field, pressure field, and section size of the melt under the condition of double-layer gas-assisted extrusion in a mold under different gas inlet slit widths. The results show that, with an increase in the width of the gas inlet slit, the melt outlet velocity increases, the surface temperature increases, wall thickness shrinkage increases, and interior diameter expansion increases. In the process of gas-assisted extrusion, the thickness of the air cushion is affected by adjusting the size of the gas inlet slit, and, hence, changes the shape and size of the plastic micro-tubes.

The chitosan-biochar composite is a clean and environmentally friendly immobilized microorganisms carrier. In this study, the chitosan-biochar composite as a carrier to immobilize a compound microbial agent contained Pseudomonas aeruginosa and Bacillus licheniformis, and investigated its role in the remediation of oil-contaminated soil. When using 1% (v/v) acetic acid, 3% (m/v) chitosan solution, 0.1% biochar, 4% (v/v) NaOH solution, freeze-drying 6 h, the optimal chitosan-biochar composite material could be obtained. The specific surfacearea of the material increased to 1.725 m

Microorganisms that can simultaneously remediate organic pollutants and heavy metal contamination are great significance in bioremediation. Nevertheless, reports of such microorganisms are still scarce. Here, Pseudomonas sp. YH-1 and Rhodococcus sp. YH-3 were isolated and identified, and they showed greater tolerance to hexavalent (VI) (750 and 800 mg·L

A series of ceramic monolith (cordierite, corundum and mullite-cordierite) supported La0.8Ce0.2MnO3 catalysts for toluene oxidation were prepared and characterized to study the structure-activity relationship. The effects of loading and support were investigated by discussing the specific surface area, reduction ability, oxygen vacancies, and toluene oxidation efficiency. Finally, the optimum catalyst was obtained; when loading of La0.8Ce0.2MnO3 was 15 wt% and the carrier was cordierite, the catalyst exhibited the largest specific surface area (21.4 m2·g−1) and best toluene conversion (T50 = 167 °C, T90 = 273 °C).

Along with the rapid development of industry, VOCs gradually move into the spotlight, and now become a kind of harmful environmental pollutants that cannot be overlooked. This paper introduces the hazards of VOCs and the common catalytic combustion catalysts, noble metal catalysts and non-noble metal catalysts, for the elimination of VOCs. Perovskite catalysts, as one of the non-noble catalysts, play an important role in the field of catalytic combustion in recent years. According to the classification of elements doping in perovskites, the research achievements in the past five years were analyzed and reviewed. In addition, this paper also analyzes and elaborates the reaction kinetics and QSAR/QSPR models for the introduction of structural properties and reaction mechanisms. Keywords: Perovskite, Volatile organic compounds (VOCs), Catalytic combustion, Metal oxide catalyst

Cordierite-supported three-dimensionally ordered macroporous (3DOM) and nanoparticle La0.8Ce0.2MnO3 catalysts were prepared by PMMA-templating and impregnation methods, respectively, to eliminate toluene in low temperature. The catalysts were characterized by BET, SEM, HRTEM, XRD, H2-TPR, NH3-TPD and XPS. The effects of calcination temperature and morphology on the specific surface area, pore volume and size, crystal phase, reduction ability, surface acid distribution and surface property were investigated, and then toluene removal efficiency and apparent active energy were also studied. The results show that the structure and morphology of the active component have a great influence on the specific surface area of the catalyst. At the same calcination temperature of 600 °C, the specific surface area of 3DOM La0.8Ce0.2MnO3/cordierite is 35.3 m2· g−1, which is much larger than that of the nanoparticle La0.8Ce0.2MnO3/cordierite (11.9 m2· g−1). Calcination temperature also can affect the properties of the catalyst and catalytic combustion performance. With different calcination temperatures of 600, 700 and 800 °C, the 3DOM sample calcinated at 600 °C (T50 = 147 °C, T90 = 217 °C, and Ea = 27.01 kJ·mol−1; SV = 6000 h−1) showed the best performances in reduction property, specific surface area, adsorption oxygen concentration, and catalytic combustion performance.

Different sulfur contents of diesel oils were used for biodesulfurization to study the desulfurization capacity of Gordonia sp. SC-10 in oil–water two-phase reaction system. Gordonia sp. SC-10 showed great properties in desulfurizing diesel oil with different sulfur contents. This bacterium could decrease sulfur contents in different diesel oils from 194.7 ± 3.7 to 30.4 ± 0.5 mg/l and from 3035.3 ± 23.8 to 1792.8 ± 48.9 mg/l, respectively. Furthermore, this bacterium could desulfurize broad range of organosulfur compounds and had strong desulfurization activity against alkylated DBTs. For low-sulfur diesel oil, sulfur could be removed from 10.2 ± 0.1 to 5.0 ± 0.1 mg/l. The newly isolated bacteria Gordonia sp. SC-10 showed a good performance in desulfurizing diesel oils, and it might be a useful desulfurizing biocatalyst to enable the industrialized application of biodesulfurization process.

The biodesulfurization capacity of Gordonia sp. SC-10 in a biphasic reaction system was investigated in this study. Model oil containing dibenzothiophene was used as the sole sulfur source of bacte...

In this research, the response surface method designed by Box-Behnken was used to study the effect of temperature, pH value and TPH concentration on the biodegradation of Enterobacter sp. S-1contam...

This paper uses response surface methodology based on the Box-Behnken design to investigate the influence of substrate concentration, inoculation quantity and temperature on the biodegradation of p...

To reduce the harm caused to the environment by fuel combustion and meet the increasingly stringent emission standards, the sulfur content of fuels should be reduced. Dibenzothiophene, benzothiophene, and their derivatives are sulfur-containing components of fuels that are difficult to desulfurize and can therefore cause great environmental damage. Biodesulfurization is a desulfurization method that has the advantage of being able to remove dibenzothiophene and its derivatives removed easily under conditions that are relatively mild when compared with hydrodesulfurization. This paper introduces the advantages of thermophilic biodesulfurization compared with mesophilic biodesulfurization; analyzes the desulfurization mechanism, including the desulfurization pathways and enzymic systems of desulfurization bacteria; and discusses the application of biodesulfurization in oil desulfurization. The main problems existing in biodesulfurization and possible solutions are also analyzed in this paper. Biological desulfurization is a promising method for desulfurization; accordingly, more studies investigating biodesulfurization of actual oil are needed to enable the industrialized application of biodesulfurization.

Biodesulfurization is a promising, environmentally friendly method to desulfurize the organosulfur compounds in crude oils through the highly selective cleavage of carbon-sulfur bonds under mild reaction conditions. In this study, the behavior of a hydrophobic bacterium, Gordonia sp. SC-10, was evaluated in the presence of diesel oils. The biodesulfurization pathways, bacterium hydrophobicity, and cell ultrastructure were investigated, and the capability of strain SC-10 to desulfurize diesel oil was also studied. The results showed that strain SC-10 can desulfurize organosulfur compounds through sulfur-specific desulfurization pathways by producing corresponding hydroxylated products in oil-water polyphasic systems. Mycolic acids consisting of 47 and 58 carbon atoms chains were produced on the cell surface, and inclusion bodies were produced in the cells, both of which may improve the bioavailability of the substrates, thereby enhancing its adaptability to oil-water polyphasic systems. To our knowledge, this is the first report of intracellular inclusion body formation during biodesulfurization. Strain SC-10 also exhibited broad substrate specificity towards organosulfur compounds and effectively desulfurized diesel oils. The sulfur content in real-life diesel oil was reduced from 167.7 mg/L to 19.7 mg/L, with 88.3% of sulfur removed after five days of biodesulfurization. This study showed that Gordonia sp. SC-10 can be effectively used for the biodesulfurization of diesel oils.