Comparison of lignin peroxidase and horseradish peroxidase for catalyzing the removal of nonylphenol from water

Concentrations of aqueous-phase nonylphenol (NP), a well-known endocrine-disrupting chemical, are shown to be reduced effectively via reaction with lignin peroxidase (LiP) or horseradish peroxidase (HRP) and hydrogen peroxide. We systematically assessed their reaction efficiencies at varying conditions, and the results have confirmed that the catalytic performance of LiP toward NP was more efficient than that of HRP under experimental conditions. Mass spectrum analysis demonstrated that polymerization through radical–radical coupling mechanism was the pathway leading to NP transformation. Our molecular modeling with the assistance of ab initio suggested the coupling of NP likely proceeded via covalent bonding between two NP radicals at their unsubstituted carbons in phenolic rings. Data from acute immobilization tests with Daphnia confirm that NP toxicity is effectively eliminated by LiP/HRP-catalyzed NP removal. The findings in this study provide useful information for understanding LiP/HRP-mediated NP reactions, and comparison of enzymatic performance can present their advantages for up-scale applications in water/wastewater treatment.     

膜电解法退镀废ABS电镀件及回收铜和镍

采用膜电解法对废丙烯腈-丁二烯-苯乙烯（ABS）电镀件进行退镀处理。以退镀废液作为阴极液和阳极液,在阳极室退镀ABS电镀件,在阴极室电解退镀废液,进行铜镍分离,回收铜粉和NiCl₂。实验结果表明：在阴极电流密度为500 A/m²、初始铜离子质量浓度为24.00 g/L的条件下电解160 min,阴极铜回收率可达97.65%,电流效率达86.60%,得到的铜粉纯度为97%~99%,处理1 L退镀废液可回收铜粉20.0 g,2 mol/L盐酸0.87 L,NiCl₂晶体43.8 g;在阳极电流密度为500 A/m²、液固比为6的条件下电解60 min, ABS电镀件的退镀率为77.22%。     

Volatile organic compounds in the unsaturated zone from radioactive wastes

Volatile organic compounds (VOCs) are often comingled with low-level radioactive wastes (LLRW), but little is known about subsurface VOC emanations from LLRW landfills. The current study systematically quantified VOCs associated with LLRW over an 11-yr period at the USGS Amargosa Desert Research Site (ADRS) in southwestern Nevada. Unsaturated-zone gas samples of VOCs were collected by adsorption on resin cartridges and analyzed by thermal desorption and GC/MS. Sixty of 87 VOC method analytes were detected in the 110-m-thick unsaturated zone surrounding a LLRW disposal facility. Chlorofluorocarbons (CFCs) were detected in 100% of samples collected. Chlorofluorocarbons are powerful greenhouse gases, deplete stratospheric ozone, and are likely released from LLRW facilities worldwide. Soil-gas samples collected from a depth of 24 m and a horizontal distance 100 m south of the nearest waste-disposal trench contained >60,000 ppbv total VOCs, including >37,000 ppbv CFCs. Extensive sampling in the shallow unsaturated zone (0-2 m deep) identified areas where total VOC concentrations exceeded 5000 ppbv at the 1.5-m depth. Volatile organic compound concentrations exceeded background levels up to 300 m from the facility. Maximum vertical diffusive fluxes of total VOCs were estimated to be 1 g m yr. Volatile organic compound distributions were similar but not identical to those previously determined for tritium and elemental mercury. To our knowledge, this study is the first to characterize the unsaturated zone distribution of VOCs emanating from a LLRW landfill. Our results may help explain anomalous transport of radionuclides at the ADRS and elsewhere.     

回收与降解聚驱采出水的工艺探讨

含聚污水的处理是困扰石油行业的难题之一。基于聚驱采出水的特点,围绕聚合物的回收利用和降解理论及技术,探讨国内外含聚污水处理技术的研究与应用现状,对比分析现有处理技术存在的问题及适应性,提出采用化学混凝、气浮和水质改性等技术来回收利用PAM(聚丙烯酰胺)的新思路,打破了降解PAM的传统思维,同时分析含聚污水处理与利用技术的可行性与应用前景,有望实现含聚污水的循环利用。     

文思湖底泥COD释放规律模拟研究

采用室内模拟实验方法,研究环境因子（温度、pH、扰动强度、供气量）对底泥释放COD的影响。结果表明,水温升高能加速底泥中有机质的释放;上覆水在弱酸至中性条件下底泥释放有机质最低;扰动上覆水体会加快有机质的释放。     

Cornmeal-induced resistance to ciprofloxacin and erythromycin in enterococci

Triclosan is used as an antibacterial agent in household items and personal care products. Since this compound is found in maternal milk of humans and bodies of wild animals, there is growing concern among some consumer groups and scientific community that triclosan is adverse for humans and wild animals. In order to estimate adverse actions of triclosan, the effects of triclosan on intracellular Zn²⁺ concentration and cellular thiol content were studied in rat thymocytes by the use of flow cytometer with appropriate fluorescent probes. Triclosan at 1-3 μM (sublethal concentrations) increased the intensity of FluoZin-3 fluorescence (intracellular Zn²⁺ concentration) and decreased the intensity of 5-chloromethylfluorescein (5-CMF) fluorescence (cellular thiol content). Negative correlation (r = −0.985) between triclosan-induced changes in FluoZin-3 and 5-CMF fluorescences was found. Removal of external Zn²⁺ did not significantly affect the triclosan-induced augmentation of FluoZin-3 fluorescence, suggesting an intracellular Zn²⁺ release by triclosan. These actions of triclosan were similar to those of H₂O₂ and triclosan significantly potentiated the cytotoxicity of H₂O₂. Therefore, the results may suggest that triclosan at sublethal concentrations induces oxidative stress that decreases cellular thiol content, resulting in an increase in intracellular Zn²⁺ concentration by Zn²⁺ release from intracellular store(s). Since recent studies show many physiological roles of intracellular Zn²⁺ in cellular functions, the triclosan-induced disturbance of cellular Zn²⁺ homeostasis may induce adverse actions on the cells.     

Historical change of mercury pollution in remote Yongle archipelago, South China Sea

We collected three ornithogenic coral sand sedimentary profiles from Jinyin Island, Jinqing Island and Guangjin Island of Yongle archipelago, South China Sea and reconstructed the deposition flux of anthropogenic Hg over the past 700 years in the study area. On the whole, the anthropogenic Hg flux is relatively low; it remained at a low level before the Industrial Revolution with a small peak at about 1450-1550 AD, which may record the enhanced metallurgy activity in Ming Dynasty of China. During the 20th century, the deposition flux of anthropogenic Hg increased rapidly, but two troughs occurred during the periods around 1940s and 1970s, corresponding to the economic depression caused by World War II, Civil War in China (1945-1949), and the Culture Revolution (1966-1976) in China. Since the 1970s the deposition flux of anthropogenic Hg has been persistently increasing, apparently the result of fast economic development in East and Southeast Asia countries around South China Sea.     

Effect of factors on decolorization of azo dye methyl orange by oxone/natural sunlight in aqueous solution

Purpose  

The oxone process for azo dye decolorization has drawbacks such as difficulties with reuse, risks of secondary pollution, and high costs associated with UV irradiation. This study aims to explore the use of oxone for decolorization in the absence of catalyst and under natural sunlight conditions (i.e., oxone/natural sunlight system) and evaluate the impacts of operating parameters (reagent dosage, initial methyl orange (MO) concentration, and initial pH) and coexisting substances (humic acid, NO₃⁻, metal ions) on the system’s decolorization efficiency.     

Arsenic accumulation and speciation in the submerged macrophyte Ceratophyllum demersum L.

Introduction

Ceratophyllum demersum L. is a widespread submerged macrophyte in aquatic environments.

Methods

Simulation experiments were conducted in the laboratory to investigate arsenic (As) accumulation, speciation, and efflux of C. demersum exposed to arsenate and arsenite solutions.

Results

Plant shoots showed a significant accumulation of As with a maximum of 862 and 963???g?As?g^?1 dry weight after 4?days of exposure to 10???M arsenate and arsenite, respectively. Regardless of whether arsenate or arsenite was supplied to the plants, arsenite was the predominant species in plant shoots. Furthermore, a dramatically higher influx rate of arsenate compared with arsenite was observed in C. demersum exposed to As solutions without the addition of phosphate (P). Arsenate uptake was considerably inhibited by P in this study, suggesting that arsenate is taken up by C. demersum via the phosphate transporters. However, arsenite uptake was unaffected by P and markedly reduced in the presence of glycerol and antimonite (Sb), indicating arsenite shares the aquaporin transport pathway. In addition, C. demersum rapidly reduces arsenate to arsenite in the shoot of the plant and extrudes most of them (>60?%) to the external solutions. The efflux of arsenite was much higher than that of arsenate; the former is supposed to be both active and passive processes, and the latter through passive leakage.

Conclusion

C. demersum is a strong As accumulator and an interesting model plant to study As uptake and metabolism due to the lack of a root-to-shoot translocation barrier.     

铁炭微电解工艺处理采油废水的研究

随着采油废水产生量的逐渐增大以及排放标准的日益严格,寻找一种经济、高效的处理方法显得十分必要。采用铁炭微电解技术对冀东油田采油废水进行了处理。考察了铁屑粒径、pH值、Fe/C质量比和反应时间对COD去除率的影响并设计了正交实验,结果表明,影响微电解工艺的因素主次关系为:pH>Fe/C质量比>反应时间,在最佳条件pH=5,Fe/C质量比为7∶1,反应时间50 min下,原水COD由170 mg/L降至95.6 mg/L,去除率达43.85%,出水满足国家二级排放标准。