水中抗生素药物的迁移分布特征研究进展

环境水体中存在的痕量抗生素药物及其潜在危害影响已引起环境研究人员的广泛关注,已成为继传统持久性环境污染物,如多环芳烃、多氯联苯、农药等之后的又一个研究焦点。尽管抗生素药物在环境中的暴露浓度相对很低,但由于其本身具有较强的持久性、生物反应活性和难生物降解性等特点,特别是对细菌微生物抗药性的选择性效应,可以导致这类抗药性菌群在环境中的快速演变和散播,这将会对人类和其它生物的健康和安全造成长期性的潜在威胁。基于目前的研究现状和发展动态,文章综合分析了环境地表水体、地下水和饮用水中不同抗生素药物的主要来源、浓度分布和迁移特征,在此基础上,提出开发水中快速、准确、价廉的检测分析方法,以及痕量抗生素药物的生态风险评估将是今后的研究发展方向。     

Efficient purification of Al30 by organic complexation method

A method was developed for preparing high purity Al₃₀O₈(OH)₅₆(H₂O)₂₄^18 + (Al₃₀) through elimination of impurities by complexation. Polyaluminum chloride II (PAC₃₀) with Al_c content of 75% was adopted as the source of Al₃₀. The PAC₃₀ was prepared under conditions of total aluminum concentration 0.1?mol/L and OH^?/Al ratio 2.2 to obtain the highest content of Al₃₀. A precipitation/metathesis method, organic solvent precipitation method and organic complexation method were examined to separate and purify Al₃₀. It was found that only by the organic complexation method could high purity Al₃₀ products be obtained in large yield economically. In the experiments, benzoic acid was used as the coordinating reagent to decompose the main impurity AlO₄Al₁₂(OH)₂₄(H₂O)₁₂^7 + (Al₁₃), and the Al₃₀ product could be obtained by precipitation and metathesis operations. It was noteworthy that the decomposition of impurities by benzoic acid could be completed in 2?hr. The Al₃₀ product was characterized by Ferron assay, ²⁷Al-NMR, SEM, XRD and TGA. The results showed that the purity of the Al₃₀ product could exceed 92%.     

Co-present Pb(II) accelerates the oxidation of organic contaminants by permanganate: Role of Pb(III)

• Simultaneous removal of organic contaminants and Pb(II) was achieved by Mn(VII). • Pb(II) enhanced Mn(VII) oxidation performance over a wide pH range. • Pb(II) did not alter the pH-rate profile for contaminants oxidation by Mn(VII). • Mn(VII) alone cannot oxidize Pb(II) effectively at pH below 5.0. • Pb(III) plays important roles on enhancing Mn(VII) decontamination process. The permanganate (Mn(VII)) oxidation has emerged as a promising technology for the remediation and treatment of the groundwater and surface water contaminated with the organic compounds. Nonetheless, only a few studies have been conducted to explore the role of the heavy metals (especially the redox-active ones) during the Mn(VII) oxidation process. In this study, taking Pb(II) as an example, its influence on the Mn(VII) decontamination performance has been extensively investigated. It was found that, with the presence of Pb(II), Mn(VII) could degrade diclofenac (DCF), 2,4-dichlorophenol, and aniline more effectively than without. For instance, over a wide pH range of 4.5–8.0, the dosing of 10 μmol/L Pb(II) accelerated the DCF removal rate from 0.006–0.25 min⁻¹ to 0.05–0.46 min⁻¹ with a promotion factor of 1.9–9.4. Although the UV-vis spectroscopic and high resolution transmission electron microscopy analyses suggested that Mn(VII) could react with Pb(II) to produce Mn(IV) and Pb(IV) at pH 6.0–8.0, further experiments revealed that Pb(II) did not exert its enhancing effect through promoting the generation of MnO₂, as the reactivity of MnO₂ was poor under the employed pH range. At pH below 5.0, it was interesting to find that, a negligible amount of MnO₂ was formed in the Mn(VII)/Pb(II) system in the absence of contaminants, while once MnO₂ was generated in the presence of contaminants, it could catalyze the Pb(II) oxidation to Pb(IV) by Mn(VII). Collectively, by highlighting the conversion process of Pb(II) to Pb(IV) by either Mn(VII) or MnO₂, the reactive Pb(III) intermediates were proposed to account for the Pb(II) enhancement effect.     

Occurrence of pharmaceuticals in a municipal wastewater treatment plant: mass balance and removal processes

Occurrence and removal efficiencies of fifteen pharmaceuticals were investigated in a conventional municipal wastewater treatment plant in Michigan. Concentrations of these pharmaceuticals were determined in both wastewater and sludge phases by a high-performance liquid chromatograph coupled to a tandem mass spectrometer. Detailed mass balance analysis was conducted during the whole treatment process to evaluate the contributing processes for pharmaceutical removal. Among the pharmaceuticals studied, demeclocycline, sulfamerazine, erythromycin and tylosin were not detected in the wastewater treatment plant influent. Other target pharmaceuticals detected in wastewater were also found in the corresponding sludge phase. The removal efficiencies of chlortetracycline, tetracycline, sulfamerazine, acetaminophen and caffeine were >99%, while doxycycline, oxytetracycline, sulfadiazine and lincomycin exhibited relatively lower removal efficiencies (e.g., <50%). For sulfamethoxazole, the removal efficiency was approximately 90%. Carbamazepine manifested a net increase of mass, i.e. 41% more than the input from the influent. Based on the mass balance analysis, biotransformation is believed to be the predominant process responsible for the removal of pharmaceuticals (22% to 99%), whereas contribution of sorption to sludge was relatively insignificant (7%) for the investigated pharmaceuticals.     

Enhancing sensitivity of microbial fuel cell sensors for low concentration biodegradable organic matter detection: Regulation of substrate concentration, anode area and external resistance

The relatively low sensitivity is an important reason for restricting the microbial fuel cell (MFC) sensors’ application in low concentration biodegradable organic matter (BOM) detection. The startup parameters, including substrate concentration, anode area and external resistance, were regulated to enhance the sensitivity of MFC sensors. The results demonstrated that both the substrate concentration and anode area were positively correlated with the sensitivity of MFC sensors, and an external resistance of 210 Ω was found to be optimal in terms of sensitivity of MFC sensors. Optimized MFC sensors had lower detection limit (1 mg/L) and higher sensitivity (Slope value of the linear regression curve was 1.02), which effectively overcome the limitation of low concentration BOM detection. The essential reason is that optimized MFC sensors had higher coulombic efficiency, which was beneficial to improve the sensitivity of MFC sensors. The main impact of the substrate concentration and anode area was to regulate the proportion between electrogens and nonelectrogens, biomass and living cells of the anode biofilm. The external resistance mainly affected the morphology structure and the proportion of living cells of the anode. This study demonstrated an effective way to improve the sensitivity of MFC sensors for low concentration BOM detection.     

抗大气复合污染的城市森林植物初步筛选

大气复合污染成为我国最主要的城市病之一.城市森林建设的植物选择除了达到景观要求和色彩效果外,根据各城市需求选择对污染物综合抗性阈值大的树种,成为当今环境污染背景下维持城市森林生态功能可持续发展的保障.综合分析我国常见城市森林537种植物对二氧化硫、二氧化氮、氟化氢、氯气、臭氧和颗粒物这6种大气污染物的吸附吸收能力,并对植物进行抗性赋值和综合因子分析,得出对大气复合污染综合抗性能力较强的树种主要为桑树、侧柏和臭椿等;对大气复合污染综合抗性中等的树种主要为毛白杨、五角枫、圆柏、山桃、垂柳、泡桐和油松等;对大气复合污染综合抗性相对较弱的树种主要为刺槐、加杨、银杏、核桃、悬铃木、栾树、紫薇和连翘等.根据中国南北方各城市气候背景、经济结构和空气污染特点,因地制宜选择对当地主要空气污染物吸收量较大的植物种类,充分发挥城市森林群落对复合空气污染物的最大净化效果.     

我国会展业发展的若干思考

本文从会展业的概念,会展业的效用分析和国际国内会展业发展的状况入手,对我国会展发展对策作初步研究.     

Enhanced adsorptive removal of naphthalene intermediates from aqueous solution by introducing reed straw into sewage sludge-based activated carbon

The disposal of sewage sludge (SS) and reed straw (RS) has becoming a critical issue due to their rapid production. In this study, the SS-based activated carbon (SSC) was produced by introducing the RS as a component material. Properties including BET surface area, pore volume, surface chemical groups, and morphologies were characterized. The adsorption of 1-diazo-2-naphthol-4-sulfonic acid (1,2,4-Acid) and 2-Naphthol (2-Nap), which differs in their physicochemical properties, on as-prepared carbons were investigated. The overall adsorption was found to be jointly controlled by external mass transfer and intraparticle diffusion, and the optimal pH was found to be 5 due to their electrostatic attraction. Further study revealed that the SS- and RS-based carbons (SC and RSC, respectively) exhibited different adsorption behavior toward 1,2,4-Acid and 2-Nap. The calculated adsorption capacity from Langmuir–Freundlich model of SC and RSC for the two intermediates was 141.0, 84.6 mg g^-1 and 48.2, 110.2 mg g^-1, respectively, whereas their hybrid product (SSC) showed comparable capacity for 1,2,4-Acid (117.8 mg g^-1), as well as higher capacity for 2-Nap (157.5 mg g^-1). It was found that the presence of meso- or macropores facilitates the precipitation of mineral phases of inorganic substances during carbonization, attracting the molecules with polar functional groups, while the introduction of C-rich RS to SS enhances the adsorption of hydrophobic molecules.     

反馈控制理论在安全隐患管理中的应用

事故防制是安全管理的核心,而事故隐患是导致事故发生的根源.因此,有效的隐患管理成为安全管理工作的重中之重.将反馈闭环控制机制应用在安全隐患管理的全过程中,收到了良好的效果,提高了隐患管理水平,保证现场安全生产的正常展开.