Advanced Materials Research Vols. 610-613

Abstract: Use NH₄F as the electrolyte, prepared TiO₂ nanotubes which orderly arranged by anodic oxidation. CdS was load to the TiO₂-nanotubes by using chemical deposition method, then controlled size of CdS particles and uniformly load had been found when the EDTA-2NA was mixed in. The structure and morphology of TiO₂ nanotubes and modified TiO₂ nanotubes were observed by SEM. Use humic acid as simulate pollutant, investigate the efficiency of the CdS / TiO₂nanotubes photocatalytic oxidation of organic compounds .The results show that CdS modified TiO₂nanotubes arrays after added EDTA-2NA, the degradation rate of humic acid increased from 57.1 % to 85.4 % after illumination.

Abstract: With sunflower straw as low-cost biosorbent, the biosorption of methylene blue (MB) from aqueous solution was studied by batch biosorption technique. The biosorption experiments were carried out under different conditions of solution pH, sunflower straw dose, and temperature. The results showed that biosorption of MB on to sunflower straw affected remarkably by the pH value, and the maximum biosorption amount was achieved at an optimum pH of 12.0; the equilibrium biosorption amount decreased as temperature was increasing, and the biosorption process might be depicted primly by Langmuir function; It was shown that the biosorption of methylene blue could be described by the pseudo-second-order equation.

Abstract: Application of sludge-to-energy is an important direction for disposal of sludge, and it is necessary to provide the contents change of heavy metals in sludge. Through sampling in situ and analysis in laboratory, distributions of seven heavy metals in five kinds of sludge, which were come from wastewater treatment plant of Jilin Petrochemical Company of Petro China, were studied, and contents change of heavy metals in the course of sludge-to-energy were analyzed. The results were compared with the other sludge in the factory and municipal wastewater treatment plants and the national standard. The results showed that the heavy metal contents are different in the different sludge, and the mean is Fe>Cu>Zn>Mn>Pb >Cr>Cd, the total content distributions from high to low is incinerated sludge, chemical sludge, activated sludge, neutralization sludge, digested sludge. Contents of Cu and Zn exceeded the the mean of 44 municipal wastewater treatment plants and GB18918-2002. After biogas of digested sludge and energy of incinerated sludge were recovered, heavy metal contents exceeded in varying degrees, which were paid more attention for treatment and utilization.

Abstract: OpdA is one of organic phosphorus degradation enzyme gene from Agrobacterium radiobacter that may be the most promising targets for the digestion of digestion. In this study, we describe for the cloning and expression in Escherichia coli (E. coli) of plasmid pET28b-opdA, followed by purification by NTA-Ni2+ agarose affinity chromatography. Protein expression and purification were evaluated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE).The Results showed that the optimal value of inoculum OD600 before induction, inducing time, final IPTG concentration and inducing temperature respectively were 0.5,5h,1 mmol/L,37°C. We obtained the concentration of renatured protein was 18.312mg / L. The Km was 4.26μmol/L at 37 °C, and the maximum reaction velocity (Vmax) was 3.2669μmol/L • min.

Abstract: The mercury removal performance of the 150 mesh coal fly ash was evaluated through multiphase flow reactor designed by Shanghai University of Electric Power and different types of fly ash and absorption liquid were analyzed with HYDRA AA. The results showed that UV light almost had no oxidation capacity for gaseous mercury without fly ash, but the removal efficiency was significantly improved from 38.5% to 66.1% in the UV light by adding fly ash into the simulated flue gas. The fly ash after exposure to UV irradiation can improve the removal efficiency of Hg and the capture capacity of oxidized Hg had been greatly enhanced. Most of mercury adsorbed on the surface of fly ash in light conditions was Hg0 (g) and most Hg2+(g) stayed in the simulated flue gas and then was absorbed by absorption liquid.

Abstract: The stability factors for Cr⁶⁺ and Cr³⁺ in microbiological media, including temperature, preservation conditions and medium components were studied in this research project, through potassium permanganate oxidation and DPC (Diphenylcarbazide) spectrophotometry. It shows that the protein component mainly influences Cr⁶⁺ content changes at pre- and post- heat sterilization to the chromium ionic liquid medium, other than being impacted basically by inorganic salt ions. It also indicates that the method can be introduced into experiment researches for microbe dechromisation i.e. Chromium ion aqueous solution and fluid medium are sterilized separately, and then are made into the chrome ions liquid as per a certain concentration. The concentration of hexavalent chromium ions is affected by preservation time and temperature also. For this reason, chromium ionic liquid medium is kept at low temperature, and as quickly as possible for the test.

Abstract: Two bacteria strains (Azotobacter strain N1, Bacillus strains B1) were isolated from the soil and purified. Then they were inoculated onto the root of Ophiopogon plant.After that the oxide dismutase (SOD) and peroxidase activities of the plant were determined as well as chlorophyll content. Through comparative analysis, the result showed that after inoculation of exogenous microorganisms both the two enzyme activities and the chlorophyll content of Ophiopogon increased significantly. And these changes are enhanced with the addition of the microbial biomass. Meanwhile the mixed cultures of two bacteria strains showed a greater impact in the increase of two enzyme activities and the chlorophyll content than each single strain culture. In conclusion the inoculation of exogenous microorganisms can improve the physiological metabolism of Ophiopogon and its enzyme activity.

Abstract: 5 highly efficient hydrocarbon-degrading mixed bacteria were obtained from the petroleum-contaminated soil samples by the traditional method of enrichment and acclimation. The KL9-1 consortium had a wide temperature tolerance range and higher hydrocarbon degrading ability. The degradation rate of thin oil and heavy oil was up to 43.27% and 20.09% respectively through 7 d at 45^oC. After several times of isolation and purification, three dominant strains with the capability of hydrocarbon-degrading were obtained, and their petroleum degradation rates were all over 30%. According to its morphological and 16S rDNA sequence characteristics, KL9-1-1 and KL9-1-2 were identified as Pseudomonas sp., and the KL9-1-3 was identified as Rhodococcus sp..

Abstract: Eutrophication in water bodies affects the growth of aquatic plants. In this study, we conducted static experiments to better understand the metabolic responses of Elodea nattalii under eutrophication conditions. The nitrogen (N) and phosphorous (P) levels in tissue, malondiadehyde (MDA), and activities of three antioxidases (peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT)) of Elodea nattalii cultured at different nutrient levels (oligotropher, mesotropher, eutropher, and hypertrophics) were investigated. The results showed that with nutrient concentration increase, N and P contents of Elodea nattalii increased. The MDA content improved with nutrient increase. the POD activity initially increased and later decreased. CAT and SOD activities decreased during the experimental time period. These finding suggested that changes in stem the increase of antioxidant enzyme activity can be served as the indicators of the response of Elodea nattalii to eutrophication conditions.

Abstract: Cadmium contamination of soil has become a major environmental problem in the whole world. Soil washing is a possible remediation method for extracting contaminants from the contaminated soil. Natural organic acids seem to be promising environmentally friendly for removing toxic metals from soils. Batch soil-washing experiments were conducted to investigate the behavior of cadmium desorption from soils by citric acid. Results showed that cadmium removal by citric acid was highly dependent on the initial pH and the concentration of citric acid. The removal of cadmium declined sharply with the rise of pH. Contrarily, cadmium desorption increased with increasing citric acid concentration. More than 90% cadmium was extracted from soil by 80 mmol L-1 citric acid.