Advanced Materials Research Vols. 726-731

Abstract: Yangtze estuary data, collected over three years, indicates that the temporal and spatial distributions of the environmental gradients reflect complicated seasonal changes and spatial differences in the exchange flux of the dissolved inorganic nitrogen (DIN= NH₄⁺+ NO₃^-+ NO₂^-) across the sediment-water interface. Overall in northern sites of Yangtze estuary, sediment was a source of ammonium (NH₄⁺) (-3.67~10.65 mmol·m^-2·d^-1) probably because of higher salinities. Sediment was a sink for NH₄⁺ in southern sites (-18.45~3.33 mmol·m^-2·d^-1) during most years. The exchange behavior of nitrate (NO₃^-) showed temporal and spatial variation from the upper to lower estuary and ranged from-32.8 mmol·m^-2·d^-1 to 35.8 mmol·m^-2·d^-1. The interface exchange direction of ammonium was affected by NH₄⁺ concentration, but the relationship between NO₃^- concentration and the direction of flux was not obvious. The concentration of nitrite (NO₂^-) was very low and its interface flux was not related to DIN concentration. Overall, the sediment of Yangtze Estuarine tidal flat was a source of DIN to overlying water in the spring, but a sink for DIN during the other three seasons of the year.

Abstract: The purpose of this paper is to study the speciation and contents of two types of heavy metals (Cd and Hg) in the sediments in Power Bridge (D1) and Nanshui Bridge (N2) in the middle part of the Ancient Canal in Zhenjiang. The relationship between the speciation of these heavy metals and their environmental factors were described. Morerover, the ecological hazard and trace to the source of these two types of heavy metals was also determined preliminarily. The results showed that (1) the main heavy metal contamination in the sediments of Power Bridge and Nanshui Bridge is Cd, and the average value is 20 mg/Kg, 17 mg/Kg, respectively, which were higher than environmental background value;(2) The peak value of Hg and Cd were near equilibrium in the 0.1-0.2m depth of Sediments; (3) Calculate the individual potential ecological risk index in the sediments of heavy metal element of two sample points both quantity of contents are Cd>Hg. And visible ecological threat of heavy metals were from Cd. After removing the Cd value, the RI value showed that ecological harm index basically below mild ecological harm degree.

Abstract: The influence on the growth and phenol biodegradation of Bacillus sp. CDQ by three different conventional carbon sources were investigated. The results indicated that conventional carbon sources certainly affected the growth of strain CDQ and the biodegradation of phenol. Under the concentration of 1.5 to 3 g L^-1, contrasting to the comparison, glucose improved the growth of the Bacillus sp. CDQ but inhibited the phenol biodegradation by Bacillus sp. CDQ. And the effect of inhibition increased with increasing glucose concentration. Below 1.5 g L^-1, the rate of phenol removal increased with the amount of glucose added. Phenol biodegradation rate obviously decreased in the presence of sodium acetate. Lactose can significantly improve the rate of phenol biodegradation. However, no noticeable improvement on the removal rate of phenol was observed under different concentrations of lactose.

Abstract: Deyeuxia angustifolia were grown under three different levels of CO₂ concentration conditions, 370μmol mol^-1(ambient CO₂), 550μmol mol^-1(elevated CO₂) and 700μmol mol^-1(elevated CO₂) respectively. We investigated the responses of photosynthesis and growth of D.angustifolia under different CO₂ concentration conditions. Leaf photosynthesis and chlorophyll content were checked. The results showed that the values of net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO₂ concentration (Ci), transpiration (E), chlorophyll content were influenced by the elevated CO₂ concentrations. The photosynthetic parameters changed in parallel with CO₂ enrichment. CO₂ enrichment in short term improved the photosynthetic ability of leaves, whereas the capacity was weakened under long-term elevated CO₂ concentration condition. The leaves of D.angustifolia grown under elevated CO₂ concentrations at the end of growth, had lower Pn, Gs, Ci, E and chlorophyll content than those grown and measuered under ambient CO₂ concentration. The results indicated that D.angustifolia appeared photosynthetic acclimation.

Abstract: Nickel is a kind of rare metal which is widely distributed in the earth's crust, and is mainly used in manufacturing alloy. Nickel is a trace element essential to animals and plants growth and development, but high concentration of nickel will hamper the growth of plants and animals, and even produce toxic effects. This paper summarizes the physical and chemical properties of nickel, the sources of organisms exposed to nickel and the influence of different concentrations of nickel on animal and plant, and summarizes the relevant research progress.

Abstract: Non-ionic surfactant and oxygen-vectors may influence the growth of Blakeslea trispora and its primary product β-carotene. Compared with other non-ionic surfactants, Triton X-100 at 0.1% yielded the highest biomass production at 52.5 g/L and increased the production of β-carotene from 793.5 mg/L in the control to 923.5 mg/L. The β-carotene production and the yield of biomass were increased when oxygen-vectors were added to the medium. With 1% n-dodecane added on the 0 day, the biomass and β-carotene production was 17.2% and 10.0% higher than that of the control. The highest β-carotene and biomass production were obtained when 0.1% Triton X-100 and 1% n-dodecane were added together on the 0 day of fermentation.

Abstract: Studying the relationship of oil-water IFT and the stability of oil emulsion will further explain oil displacement mechanism in crude oil flooding. In this article, for nonylphenol polyoxyethylene ether can resist multivalence cations, the performance of associative surfactant containing HABS and nonylphenol polyoxyethylene ether (NP), the influence of the improvement of emulsion stability on the interfacial tension were studied by evaluating the interfacial tension and emulsion stability. Results show that nonionic surfactant NP-x (x=4, 6, 10) can improve the tolerance of HABS to NaOH with low concentration, and NP-6 appears the best synergistic effect, when C_NaOH is not more than 1.2wt%, the IFT_eq is lower than 9.9×10^-3mN/m, within the concentration range of the investigation. At the same time, NP-x can improve oil emulsion stability, when C_NaOH is 0.6wt%, C_HPAM is 0.18wt%, total concentration of the surfactant (ω_HABS:ω_NP=8:2) are 0.05wt% and 0.1wt%, decreasing the balance interfacial tension between oil and water can be regarded as the guarantee of the emulsion stability.

Abstract: Iron oxides play an important role in controlling P activity and availability in environmental systems. Two iron oxides (goethite and ferrihydrite) were synthesized characterized by X-ray diffraction, transmission electron microscopy and N₂ adsorption method. To investigate the effect of silicon on phosphorus adsorption of them, batch equilibration method was used. Attempts were made to explore the mechanisms involved by eliminating effects of pH and accompany ions. Results reveal that the ability of two kinds of iron oxides adsorbed phosphorus were as follows: ferrihydrite > goethite. Compared with the control, silicon inhibited the adsorption of phosphorus on two iron oxides, and this effect increased with the increasing of silicon content. Langmuir, Freundlich and Temkin equations could be used to describe the adsorption characteristics of phosphorus on iron oxides well, but the Langmuir model was optimal. With silicon addition, the adsorption equilibrium constants (K) decreased of the phosphorus absorbed on iron oxide, the free energy(ΔG)dropping degree increased, the maximum adsorption capacity(X_m)and maximum buffering capacity (MBC) reduced.

Abstract: The effect of the reaction time and the amount of additives on the decomposition rate and temperature of phosphogypsum were studied in the weak reducing atmosphere of 3%Vol CO by using the mixture of phosphogyp-sum and a certain percentage of CaCl₂, Fe₂O₃ and MgO additives. The result shows that the decomposition rate of phosphogypsum reached 85% by adding CaCl₂ and Fe₂O₃, and the decomposition temperature of phosphogypsum was only 950°C which was 100 °C lower than the one of decomposition reaction of phosphogypsum without any adductives. And the addition of MgO had no significant effects on the decomposition of phosphogypsum under the same condition.

Abstract: Copper (Cu), a redox active metal, is an essential nutrient for all species studied to date. But excessive amounts of copper in the body or plant can also pose a risk. To better understand the toxicity of Cu to organisms it is necessary to understand the mechanism by which Cu influences biological and chemical processes in the environment. This paper summarizes the properties of physical and chemical of copper, the sources of organisms exposed to copper and the influence of different concentrations of copper on animal and plant, and also summarizes the relevant research progress.