Advanced Materials Research Vols. 518-523

Abstract: Gas-phase elemental mercury (Hg⁰) removal by an activated coke (AC) supported Fe₂O₃ catalyst (Fe₂O₃/AC) was studied under N₂+HCl atmosphere and compared with that by AC. The influences of Fe₂O₃ loading, temperature and inlet Hg⁰ concentration on Hg⁰ removal were investigated. The results indicate that the Hg⁰ removal capability of Fe₂O₃/AC was much higher than that of AC, indicating the important role of Fe₂O₃ oxidation activity. The capability of Fe₂O₃/AC increased with an increase of Fe₂O₃ loading (1-10 wt.%) and temperature (120-200 °C). Scanning electron microscope-energy dispersive X-ray (SEM-EDX) analysis confirmed the correlation between Fe₂O₃ and Hg adsorbed over Fe₂O₃/AC.

Abstract: This experiment aimed to explore the effect of high- concentration nitrogen removal by Anaerobic ammonium oxidation process. The mixed liquor suspended solid(MLSS)was 510 mg/L. In the beginning of the experiment, the inflow concentration rate of ammonia nitrogen and nitrite nitrogen was about 1:1.3 and the total nitrogen concentration was low. When the reactor reached the ideal treatment effect then gradually increased the total nitrogen concentration, until reaching the maximum nitrogen load rate(NLR) of the reactor. In the temperature of 34.4 °C, PH was 7.23, the inflow concentration of ammonia nitrogen was 223.3 mg. N/L, the inflow concentration nitrite nitrogen was 289.7 mg. N/L, the dissolved oxygen (DO) was 2.3 mg. N/L, the nitrogen load rate (NLR) was 6.08 kg. N / (m3. d), the nitrogen removal rate (NRR) was 5.60 kg. N / (m3. d), the total nitrogen (TN) removal rate was 92.2%, under this conditions, the reactor achieved the best effect.

Abstract: The study was to find low costs and superior performance immobilized carrier for microorganism cells using in industry. Ca-alginate , Agar , Gelatin-glutaraldehyde and polyvinyl alcohol (PVA) were investigated to immobilize Saccharomyces cerevisiae cells, and immobilized cells’ production capacity for ethanol, contents of ethanol and mechanical strength were also studied. Then, optical microscope picture and scanning electronic microscope pictures were given to research its microenvironment. Finally, Batch and Continuous fermentation with PVA immbiolized Saccharomyces cerevisiae were experimented. The PVA immobilized method is the best in the four methods with concentration of 8%, microscopic observation also offered a proof that PVA material was fit for immobilizing cells with the traits of polycellular and reticulate. At last, the production capacity for ethanol and reactivity were superior to free cells in batch and continuous fermentation. This research could provide important information on the commercial utilization immobilized-cells for biotransformation.

Abstract: A laboratory-scale study adopting mixture of manure and straw as substrate was carried out to elucidate the impact of inoculum to substrate ratio(ISR) on hydrolysis and acidification digestion with methanogenic effluent recycling. The chemical oxygen demand(COD), pH, and volatile fatty acids (VFAs) concentration were periodically analyzed in order to completely understand the digestion processing. In addition, ammonia-nitrogen was also monitored. The results showed that acetic acid was dominant in fermentation products of different ISRs and the percentage of acetic acid in total volatile fatty acids (TVFAs) increased with the increase of ISR, and acetic acid accounted to 68.74%, 72.02%, 75.89% and 86.65% of TVFAs when ISR were 15%, 25%, 35% and 50%. Propionic acid accounted for 6.68%, 5.92%, 5.54% and 2.67% of TVFAs produced, and the concentration was less than 0.60 g/L. The possible inhibition by free ammonia was null since the values were far below the threshold concentration reported in other literatures, but the potential inhibition maybe happen after long-term recycling of methanogenic effluent.

Abstract: A salt-tolerant PCBs degrading strain B2.6 which can use PCBs as the sole carbon source and energy was isolated from the deep sea sediments of southern Yellow Sea. It was identified as Vibrio splendidus, according to morphological, physiological and biochemical characteristics and 16SrDNA sequence analysis. The experimental results suggested that the optimum conditions for the degradation of PCBs are temperature 30°C, pH 7 to 8, the concentration of NaCl was 150g•L-1. Under the optimum conditions, the PCBs degradation could reach 98.27% in 72h which concentration was below 0.6mg•L-1. The genome was amplified with bacterium 16SrDNA primer. The amplified product was purified and sequenced forphylogenetic analyses with Genbank. The bacterium B2.6 was identified as Vibrio splendidus. RAPD analyses of B2.6 produced stable DNA fingerprint. These studies have provided parameter for the further dynamic resolution of bacterium clusters for the rehabilitation of PCBs contaminated underground water environment with B2.6 PRB method.

Abstract: Batch leaching experiments with different pH and temperature have taken to the pyrite samples from coal seams, state including the reaction system with bacteria of Acidiphilium sp. and aseptic control system. The migratory behavior of 2 hazardous elements of As and Pb was detected for a period of 15days. The analysis result displayed that the most releasing amount of As appeared in the bacteria reaction system with the condition of pH 1.5, 30°C and 1:100(g:mL) solid-liquid ratio, and the contents was 73 times higher than its aseptic control system. While as to Pb, the result was opposite, Acidiphilium sp. inhibit Pb releasing, it maybe this bacteria accumulation of Pb directly or indirect.

Abstract: We study a optimal control problem-optimal periodic harvesting strategy for the general autonomous system of single specie. Suppose the growth rate function f(x) is C^2, x* satisfies f'(x*)=0. We proved that if f"(x*)<0，then x* is the optimal trajectory, otherwise, x* is not the optimal trajectory.

Abstract: Atmospheric ions are produced by many natural and anthropogenic sources and their concentrations vary widely between different environments. In this study, we conducted in a southern coastal province of China, where we chose some typical sites to observe. The observations included negative air ion concentration, positive air icon concentration, wind speed, temperature and relative humidity, and negative air icon concentration in materials and plants. The results showed that negative air icon concentration changed more obviously in different water statuses, and showed a certain degree of mutual relations. In order to improve the urban ecological environment, the authors proposed the use of water and wind actively to increase the distribution of negative air anion concentration in urban planning and construction.

Abstract: After the straw fermentation and add in soil for pot experiment, analysis of the soil pH, salinity, respiration intensity, and the relationship between soil pH and respiration intensity, salinity and respiration intensity before and after pot, concluded: pot under experimental conditions help to reduce soil pH and salinity, increase soil respiration intensity, soil pH, salinity and soil respiration intensity trends reverse. Experimental results show that the conditions for the experimental group 19-27 are more conducive to low soil pH and salinity, increase soil respiration intensity, and to improve soil properties, making it suitable for crop growth.

Abstract: Synergistic inhibition effect of sodium oleate and sodium vanadate on the corrosion of pure aluminum in NaCl solution has been investigated by open circuit potential, potentiodynamic polarization curve, and electrochemical impedance spectroscopy(EIS). Experiment results show that the pure aluminum has the lowest corrosion current density under the optimum technological conditions at room temperature, which can be expressed as follows: the 3.5wt.% NaCl solution contains two inhibitors of sodium oleate and sodium vanadium, and their mole concentration ratio is 1:2, solution pH value is 8.0~8.5. In addition, these two inhibitors have played the major role of corrosion inhibition at different stage respectively, which can be attributed to the formation of continuous phase on the surface of pure aluminum.