Iron improving bio-char derived from microalgae on removal of tetracycline from aqueous system

Novel magnetic carbonaceous bio-char was hydrothermal prepared from microalgae under different loadings of iron and its structures and surface chemistry were characterized with Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and nitrogen adsorption-desorption isotherm (BET). The morphology of bio-char changed from sheet to particle as iron loading increased and its surface area also increased. When 3.0 g of dried microalgae and 6.0 mmol iron salt ((NH₄)₂SO₄·FeSO₄·6H₂O) were mixed and treated, the obtained bio-char possessing the highest amount of oxygen-containing functional groups resulted in the best adsorption performance on tetracycline (TC). This adsorption process was fitted to Langmuir adsorption isotherm and the maximum adsorption capacity was 95.86 mg/g, which is higher than other bio-char reported. The iron loading contributed to the higher adsorption capacity of bio-char, which may be due to three factors, the high surface area, more hydrogen bonding, and bridging effects of the structural Fe for TC. Our data suggest that bio-char may have more important role in stabilization of pollutants in the environment.     

Simultaneous separation of apigenin,luteolin and rosmarinic acid from the aerial parts of the copper-tolerant plant Elsholtzia splendens

Elsholtzia splendens is a copper-tolerant plant species which grows on copper deposits in China. The generation of a valuable E. splendens biomass on specific contaminated sites has become one of the promising phytotechnologies. The simultaneous separations of apigenin, luteolin, and rosmarinic acid yielded in the ethyl acetate extracts of the flowering aerial parts was achieved by the use of a macroporous resin, polyamide, and silicagel columns during chromatography. Chemical identification confirmed the structures based on the spectra of FTIR, NMR, and HPLC/ESI-MS. The isolated compounds of purity above 98.3 % were evaluated for their in vitro cytotoxic activities against human cancer cell lines including A549 (non-small lung), A431 (skin), and Bcap37 (breast). Among these compounds, luteolin and apigenin presented the best cytotoxic activities against A549, A431, and Bcap37 cells and, therefore, both could be the valuable products for the post-harvest processing of E. splendens biomass.     

Oxidation of polycyclic aromatic hydrocarbons by horseradish peroxidase in water containing an organic cosolvent

Polycyclic aromatic hydrocarbons (PAHs) are environmental contaminants that are toxic, mutagenic, and carcinogenic. We investigated the horseradish peroxidase (HRP)-catalyzed oxidation of PAHs in water containing N,N-dimethylformamide. Four PAHs (anthracene, phenanthrene, pyrene, and fluoranthene) were investigated using single-PAH and mixed-PAH systems. The results provide useful information regarding the preferential oxidation of anthracene over other PAHs regardless of the reaction time, enzyme dosage, and hydrogen peroxide concentration. The removal of PAHs was found to be very strongly correlated with the ionization potential (IP), and much greater PAH oxidation was observed at a lower IP. The oxidation of anthracene was specifically pH- and temperature-dependent, with the optimal pH and temperature being 8.0 and 40 °C, respectively. The redox mediators 1-hydroxybenzotriazole and veratryl alcohol promoted the transformation of anthracene by HRP; 9,10-anthraquinone was the main product detected from the anthracene oxidation system. The results of this study not only provide a better understanding of the oxidation of PAHs by utilizing a plant biocatalyst, but also provide a theoretical basis for establishing the HRP-catalyzed treatment of PAH-contaminated wastewater.     

污泥淤砂分离器再分离底流污泥

研究了污泥淤砂分离器对分离原污泥所得的底流污泥进行再分离时,分离分流污泥的性质。实验结果表明,原污泥MLVSS/MLSS为0.372,1次分离后得到的底流污泥MLVSS/MLSS为0.222,2次分离后得到的底流污泥MLVSS/MLSS为0.126,表明通过底流污泥再分离,能够进一步降低底流污泥中生物有机质的含量,提高底流污泥中无机淤砂的含量。同时,原污泥CST为2.85(s·L)/g SS,1次分离后得到的底流污泥CST为0.98(s·L)/g SS,2次分离后得到的底流污泥CST为0.12(s·L)/g SS,表明底流污泥再分离进一步提高了底流污泥的脱水性能,最终得到的底流污泥脱水性能良好。     

Controlled Exposures of Volunteers to Respirable Carbon and Sulf uric Acid Aerosols

Respirable carbon or fly ash particles are suspected to increase the respiratory toxicity of coexisting acidic air pollutants, by concentrating acid on their surfaces and so delivering it efficiently to the lower respiratory tract. To investigate this issue, we exposed 15 healthy and 15 asthmatic volunteers in a controlled- environment chamber (21°C, 50 percent relative humidity) to four test atmospheres: (i) clean air; (ii) 0.5-μm H2SO4 aerosol at =100 μg/m³, generated from water solution; (iii) 0,5-μm carbon aerosol at =250 μg/m³, generated from highly pure carbon black with specific surface area comparable to ambient pollution particles; and (iv) carbon as in (iii) plus =100 μg/m³ of ultrafine H2SO4 aerosol generated from fuming sulfuric acid. Electron microscopy showed that nearly all acid in (iv) became attached to carbon particle surfaces, and that most particles remained in the sub-μm size range. Exposures were performed double-blind, 1 week apart. They lasted 1 hr each, with alternate 10-min periods of heavy exercise (ventilation =50 L/min) and rest. Subjects gargled citrus juice before exposure to suppress airway ammonia. Lung function and symptoms were measured pre-exposure, after initial exercise, and at endexposure. Bronchial reactivity to methacholine was measured after exposure. Statistical analyses tested for effects of H₂SO₄ or carbon, separate or interactive, on health measures. Group data showed no more than small equivocal effects of any exposure on any health measure. One individual's responses were consistent with a clinically significant excess airway constriction from H₂SO₄ plus carbon, and 2-3 others showed slight excess responses to the combined pollutants, but all these observations might have reflected chance variations. We conclude that coexisting carbon aerosol did not increase respiratory irritancy of H₂SO₄, in most healthy and asthmatic subjects exposed for 1 hr under simulated "worst-case" ambient conditions.     

江苏省地理标志概况与价值评估体系构建研究

以江苏省43个地理标志为研究对象,根据国家地理标志的分类方法对其进行分类,构建价值评估体系,探讨地理标志产品的内在价值及发展重点。研究表明,江苏省地理标志类型较为单一,分布均匀;开发程度不同,可分为开发匮乏型、有待开发型和开发成熟型。通过价值体系评价可见,江苏省应重点挖掘产品的自身特色,发展价值意义突出的地理标志。     

绿色油田建设中存在的问题及对策探讨

文章分析了石油开发对环境的影响,提出了绿色油田建设的必要性与重要性。通过对国内外绿色油田建设现状的调研与对比,总结出目前我国建设绿色油田的瓶颈,提出了建议与对策,并展望了建设绿色油田的前景。     

Molecular and physiological characterization of fluoroquinolone resistance in relation to uropathogenicity among Escherichia coli isolates isolated from Wenyu River, China

Increasing antibacterial resistance and pathogenicity in the environment is of growing concern due to its potential human risk. In the present study, 236 Escherichia coli isolates were collected from Wenyu River in China on drugless (48 isolates) and quinolone-containing plates (189 isolates). Their minimum inhibitory concentrations (MICs) were determined ranging from 0.125 μg mL⁻¹ to 128 μg mL⁻¹. Mutation points related to fluoroquinolone resistance were observed at S83 to L and D87 to N or Y in the GyrA subunit and S80 to R or I and E84 to G in the ParC subunit. Generally, MICs of LEV and GAT are dependent on the patterns of these mutation points. The profile with three mutation points was related to LEV-resistant E. coli isolates, and the (S83L, D87N + S80I) mutation profile was most prevalent (65.7%) in LEV-resistant isolates, while a large proportion of isolates, even those with three mutation points, were susceptive to GAT. The incidence of virulence factors in LEV-resistant isolates (44.7%, 59/132) was much higher than in nonresistant isolates (23.1%, 24/104) (χ² = 11.925, 1° of freedom, p < 0.001) indicating that fluoroquinolone-resistant E. coli would pose a potential risk. A similar distribution was also found in isolates resistant to GAT (χ² = 7.843, 1° of freedom, p = 0.0079).