Advanced Materials Research Vols. 726-731

Abstract: The combined catalysts Mn/Ba/Al₂O₃-Pt/Ba/Al₂O₃ and Mn/Ba/Al₂O₃+Pt/Ba/Al₂O₃ for NO_x storage-reduction were investigated. Mn/Ba/Al₂O₃ indicated high activity of NO oxidation and NO_x storage in the oxidation-storage reaction and certain reduction activity in the storage-reduction reaction. The combination of Pt/Ba/Al₂O₃ with Mn/Ba/Al₂O₃ could enhance the activity of NO_x storage-reduction under dynamic lean-rich burn conditions. Compared to Pt/Ba/Al₂O₃ catalyst, although the Pt content decreased half over Mn/Ba/Al₂O₃-Pt/Ba/Al₂O₃ and Mn/Ba/Al₂O₃+Pt/Ba/Al₂O₃ , the NO_x conversion increased 9.4% and 6.3% at 350 °C. The pollutions such as NO_x and CO could be eliminated effectively over two combined catalysts with low Pt content under dynamic lean-rich burn conditions.

Abstract: The numerical simulation model was established using FLUENT code to analysis the flow field of pulse cleaning process of filtration system. The pressure variation with pulse cleaning time was studied. The effect of nozzle shape and diffuser shape on flow field was investigated. The diffuser construct can affect the flow field distribution, but the effect is little. The converged nozzle can bring better pulse cleaning effect by bring higher velocity and lower pressure at outlet.

Abstract: Studying and screening nuclide hyper-accumulator plants and their planting methods for rapid and effective radioactive decontamination in the environment is the vital study content of the environmental radioactive contamination rehabilitation and control. This study measures and analyzes the accumulating amount and characteristics of Cs in Chenopodium album Linn by taking Chenopodium album Linn as the experimental material and CsCl solutions at different concentrations as the treatment factors, and applying the technology of pot culture to simulate the natural contaminate environment with radioactive nuclide Cs. The results indicate that the accumulating amount of Cs in Chenopodium album Linn increases as the CsCl concentration rises. The accumulating amount in the above-ground plant parts reaches the highest level of 0.964mg/g DW as the CsCl concentration reaches its highest one of 100mg/Kg; and that in the underground counterparts is 0.306mg/g DW. The accumulating amount of S (of the above-ground plant parts) /R (of the underground counterparts) > 1, having the basic characteristics of Cs hyper-accumulator plants.

Abstract: Studying and screening nuclide hyper-accumulator plants and their planting methods for rapid and effective radioactive decontamination in the environment is the vital study content of the environmental radioactive pollution rehabilitation and control. Taking Comnyzacanadensis (L.) Cronq as experimental material, this study measures and analyzes the accumulating characteristics of nuclide Sr in Comnyzacanadensis (L.) Cronq by treating them with SrCl₂ of various concentrations and applying the technology of pot culture to imitate the natural environment polluted by radioactive nuclide Sr. The results show that as the concentration of SrCl2 increases, the accumulation of Sr in Comnyzacanadensis (L.) Cronq also increases; when the concentration of SrCl2 content reaches a maximum level of 200mg/Kg, the SrCl2 content of the above-ground part shows its highest level of 0.709mg/g DW, while the SrCl₂ content of foot end 0.201mg/g DW. The experiment results indicate that Comnyzacanadensis (L.) Cronq has the basic characteristics of Sr Hyper-accumulator, due to the fact that the accumulated amount of S in its above-ground part is larger than that of R in its foot end, i.e. S/R >1.

Abstract: In this paper, an experimental investigation was conducted using Vehicle Emission Testing System to study on-road gaseous emissions (CO, THC, NO_X, CO₂) characteristics based on diesel oxidation catalyst (DOC) and catalyzed diesel particulate filter (CDPF) technology. The results show that after the implementation of DOC + CDPF device, CO, THC emissions are significantly reduced, while the NO_X, CO₂ emissions remain almost the same. Under steady conditions, the reduction percentages of CO, THC, NO_X, CO₂ emission factors are 56.0%, 66.0%, 18.3%, 17.5%, respectively. Under transient operation conditions, the reduction percentages of CO, THC, NO_X, CO₂ emission factors are found to be 43.2%, 65.9%, 13.7%, 10.9%, respectively. Addition to the THC emission factor, the emission factors of CO, NO_X and CO₂ in transient operation conditions are higher than steady conditions.

Abstract: The adsorption of methyl orange dye from aqueous solution was investigated with active carbon powder as sorbents. Effects of selected factors were studied through the use of L₁₆ (4⁴) orthogonal experiment for the optimal parameter. The results demonstrated that the orders of their influences were contact time > initial dye concentration > the dosage of active carbon powder > pH. It was then concluded that contact time must be given priority in removing methyl orange dye from wastewater. Under the optimum conditions (the dosage 10g, time70min, initial dye concentration 35mg/L, pH7), The active carbon powder possessed good adsorption capacity to methyl orange which the removal efficiency could reached 95.96%.

Abstract: A system termed hydrolysis acidification-improved upflow anaerobic sludge blanket (HA-IUASB) was developed for alcohol wastewater treatment. The improvements of the UASB were that: a reflux pipe was set below the three-phase separator, and the mud mixture treated by the granular sludge bed returned into the water inlet.The improved UASB starts up completely after 61 days operation and the COD removal rate is between 70~96% during startup stage. The mature granule size reachs 3 mm and the methanogenic bacteria inside are mainly bacillus and cocci through Scanning Electron Microscope (SEM) observation. The treatment efficiency of the improved UASB is high and COD removal rate is 55%~80%. COD removal rate reachs 70%~87% by HA-UASB system under the condition of high concentration alcohol wastewater. CH₄ is the main constituent and the percentage is 81.61% according to the gas composition analysis. This study proves that HA-IUASB is a feasible and practical means to treat alcohol wastewater.

Abstract: The B-F codoped nano-TiO₂ particles powders were prepared by the sol-gel method. The PS/B-F co-doped nano-TiO₂ composite was synthesized with in situ polymerization. The films of PS/SBS/B-F co-doped nano-TiO₂ composites were prepared by the hot-pressing machine, and the accelerated photodegradation of films were investigated with a 1000W xenon lamp. The surface morphology and Tg of the films in the process of degradation were detected by SEM and DSC. Results showed that the Tg of PS/SBS/B-F codoped nano-TiO₂ composite is the lowest of all samples. More and large holes were observed in the surface of PS/SBS/B-F codoped nano-TiO₂ composite film.

Abstract: The main aim of this study was to evaluate the ability of the activated sludge from sewage treatment plant to degrade a part of the 12 randomly selected metalworking fluids (MWFs) according to OECD 302B (with different addition of activated sludge AS 0.25 g/l, 0.50 g/l and 1.00 g/l of suspended solids - SS). The degradability test showed that, after the first 3 hours of cultivating, adsorption grew with the increasing amount of inoculums. In the case of AS addition 1.00 g/l of SS were the adsorption rate lower than 20 % in four samples, in the case of AS addition 0.50 g/l of SS in 9 samples and in the case of AS addition 0.25 g/l of SS in all 12 tested samples. In four samples were also observed the lag phase (adaptation of the bacterias to the presented carbon source). If occur adsorption rate more than 20% it is probably impossible to distinguish biological degradation of organic matter from abiotic elimination from the suspension.

Abstract: The modified corncobs was prepared by using citric acid. Conditions of preparation, the effects of pH, initial concentrations of Cr (VI) and adsorption time to adsorption of Cr (VI) was studied. Results show that when citric acid concentration at 3molL^-1, heating treatment temperature at 160°C, the treatment time at 2h, the modified corncobs had a high adsorption of Cr (VI). At room temperature, Cr (VI) initial concentration at 10 mgL^-1, medium aqueous solution pH at 2.5, adsorption time at 150min, the absorption rate of modified corncobs for Cr (VI) was 96.13%, higher than absorption rate of ordinary corncobs for 22.83%.