Advanced Materials Research Vols. 807-809

Abstract: A pyroprocessing technology has been developed to process spent nuclear fuels with decreased waste and increased proliferation resistance. A main process of the pyroprocessing is an electrorefining which requires a post-treatment for recovered uranium. A distillation approach is adopted to remove an electrolyte salt residue on the uranium. In this work, the vapor composition of the distillation process and the total pressure were estimated to obtain basic data for process design and integration. Six chlorides including KCl, LiCl, UCl₃, PuCl₃, CeCl₃, and YCl₃ were considered to understand the behavior of the representative components of actinides and lanthanides. It was found that small amount of the actinides and lanthanides would be accompanied by the electrolyte salts (KCl and LiCl) during the distillation under high vacuum.

Abstract: Ultraviolet light emitting diodes(UV-LEDs)presenting the advantages of high efficiency,small size,energy saving and without mercury,are gradually replacing mercury lamps in disinfection systems.This study focused 280nm wavelength of UV-LEDs,the Escherichia coli was served as objective in wastewater,the inactivation efficiency and photoreactivation percentage were examined compared with traditional mercury lamps.A series of UV-LEDs dose caused different inactivationefficiency and photoreactivation percentage of E.coli.When UV dose was 1.8 mJ/cm2, inactivation efficiency reached 2.7-lg,then under a 40w sunlight lamp irradiation,the photoreactivation percentage was up to 2.7%;at 3.6 mJ/cm2, inactivation efficiency reached 3-lg,photoreactivation percentage was up to 0.98%.In advanced wastewater treatment,a threshold dose 3.6 mJ/cm2 is suggested of 280nm UV-LEDS.UV dose higher than 3.6 mJ/cm2 can achieve the depth of sterilization effect,that reaches the effect of mercury lamp 40mJ/cm2.The results indicate great advantages of UV-LEDs compared with mercury lamps.

Abstract: In anaerobic digestion system, the functional niche of hydrogen-producing acetogens (HPAs) is between acidogenic fermentation bacteria and methanogens. HPAs are quite difficult to be isolated by pure and ampliative cultures due to the obligate anaerobic metabolism property in syntrophic association with methanogenic. In order to enhance the HPAs activities in anaerobic disgestion, the physioecologic and metabolic properties of HPAs under different medium conditions, such as carbon and nitrogen type, influent temperature and pH was investigated in batch cultivation experiments. The result illustrated that under the cultivation temperature of 45°C and pH of 8.0, the butyrate, propionate and benzoate could be utilized by the syntrophic acetogenesis coculture, of which the uptake rate of butyrate was highest. The glucose and sucrose were repulsed however. The metabolic activity of HPAs could be enormously simulated as the mixture of tryptone and yeast was taken as the nitrogen source.

Abstract: Active species injection generated by a surface discharge plasma reactor (SDPR) was studied to oxidize elemental mercury (Hg⁰) in the flue gas. The reactor was inserted in the simulated flue duct. The effects of several operational parameters, such as applied voltage, inlet Hg⁰ concentration, applied frequency and air injection flow rate, were well investigated. Experimental results showed that Hg⁰ oxidation efficiency of 83.8% was achieved at specific energy density of 4.0 J L^-1 and the flow rate of 1.6 L min^-1. Increasing applied voltage and air injection flow rate was beneficial for Hg⁰ oxidation due to higher production of active species. Lower Hg⁰ oxidation efficiency was observed with an increase of initial concentration. With an increase of applied frequency, Hg⁰ oxidation efficiency significantly increased, but the energy yield dropped.

Abstract: The degradation of PAEs (DMP, DEP and DBP) at low concentration (μg·L-1 range) by the O3 oxidation and H2O2/O3 oxidation process were investigated in this study. The experiment results showed that the H2O2/O3 ratio was 2.0, the pH value was 10, the PAEs removal rates were 90%~95% in model wastewater, and were over 70% in the tail water from municipal sewage plant with the H2O2/O3 oxidation process.

Abstract: In order to study the remedation technology of eutrophic artificial lake, an integrated restoration technique consisted of aquatic vegetation near lakesides, Effective Microorganisms (EM) , fingerlings and intermittent aeration system was constructed in Guilin City, Guangxi of China. The results indicated that the removal rates of Chemical Oxygen Demand (COD),total nitrogen (TN),total phosphorus (TP),suspended substance (SS) and turbidity achieved by this kind of technique were 63.14%~77.10%,54.18%~60.54%,85.76%~87.98%,82.36%,79.28% respectively, and the coverage ratio of duckweed decreases from 90% to 10%. Compared with conventional wastewater treatment systems, the integrated restoration technique do not cause secondary pollution, and has an obvious effect, especially it can maintain good water quality for a long time.

Abstract: In order to reduce the damage of deicing salt to green belt soil in highway, the research used organic multi-fertilizer SFO featured with water conservation and anti-deicing salt to test the effect on plant growth and soil moisture and ion composition in Jingcheng high way, Beijing, It set 12 t/hm²7.5 t/hm²4.5 t/hm² dosage processing in test Experimental index include plant growth, soil moisture, ion composition and the improvement effect of saline-alkali soil. In treatment of 4.5 t/hm² and 7.5 t/hm² SFO dosage, the fresh treetop growth of Juniper were increased 25.9% and 85.7% higher than that of CK, but less than that in treatment of 12 t/hm² dosage. The soil moisture in all treatments was improved 0.8% -2.1% high than that in CK. The analysis showed that SFO can regulate the ion balance of soil, Ca²⁺Mg²⁺K⁺ content of soil in all treatments were raised as the increasing of SFO dosage, but the Na+Cl-ion contens decreased 38% and 48% on average than that of CK,and the Sodium Adsorption Ratio (SAR) significantly was reduced markedly. In which the 7.5 t/hm² dosage treatment of SFO is the best effect. The results certificated that SFO has the comprehensive effect on reducing soil salinization and can improve soil structure and the soil moisture, and can be applied in controlling soil salinization of green belt caused by using deicing salt in high way widely.

Abstract: A century ago, Songnen Plain was a prairie which was suitable for grazing and farming with adequate water and vegetation resources and fertile land. Since the mid-20th century, due to anthropogenic and natural factors, salinization and desertification have rapidly expanded, which restricted the development of agriculture and animal husbandry in the area. Russian melilotus offcinalia was used for saline-alkaline grassland improvement, obtaining significant environmental, ecological and economic benefits, playing an important role in the protection of land resources and the promotion of food security. The article suggests the bio-engineering technology for soil improvement to repair and rehabilitate degraded ecological environment of agriculture and animal husbandry.

Abstract: Electrochemical reduction of carbon dioxide (CO₂) to useful organic compounds is of great significance to decrease CO₂ emission. The electrochemical reduction of CO₂ is carried out in acetonitrile with tetrabutylammonium perchlorate as the electrolyte on a stainless steel cathode in a single cell; by using a sacrificial zinc anode, the product is zinc oxalate when the cathode potential is between 2.5 V and 3.5 V vs. Ag rod electrode. When the potential is less than 3.5 V, acetonitrile is decomposed, and the product is mainly zinc cyanide; when it is higher than 2.5 V, the main product is a basic zinc carbonate. Therefore, only when the cathode potential is in a proper range can CO₂ molecule obtain an electron and dimerize to form C₂O₄², which combines Zn²⁺ from the anode to form zinc oxalate.

Abstract: As the widely used collector, environmental pollution and toxicity of xanthates have got more and more concerns. In the present work, the flocculation process had been used to treat xanthate wastewater. The results showed that Al₂(SO₄)₃ was the optimal flocculant. At the conditions of dosage of 0.1mol·L^-1Al₂(SO₄)₃ 0.5 mL, the initial pH 6.5, vibrating time 90 min and settling time 120 min, sodium isobutyl xanthate was removed nearly up to 100%.