煤制甲醇循环水系统中块状污垢的分析和控制

煤制甲醇厂的循环冷却水系统中因轻微泄漏出现泡沫和微小块状污垢,取样后通过光学显微观察、扫描电镜和化学显色分析表明,该污垢主要为细菌纤维素,并采用微生物学分离手段获得1株优势菌。经16S rDNA基因序列及BIOLOG碳源利用分析表明,该菌为木葡糖酸醋杆菌(Gluconacetobacter xylinus)。甲醇浓度和pH值对该菌产纤维素能力影响较大,甲醇浓度为15~25 mL/L时产纤维素最强,pH值为8~9时纤维素产量仅为pH值5.0时的50%。当与其他甲醇降解菌共同生长时,由于竞争性排除、生态位争夺等作用,该菌产纤维素能力下降超过37.9%。该发现为生物法控制煤制甲醇循环冷却水系统中的纤维素污垢提供科学依据。     

Preparation of metal-doped Cu–Mn/HTS-1 catalysts and their mechanisms in efficient degradation of toluene

In order to study their synergistic catalytic effects in toluene degradation, CuMn_2O_4/HTS-1(HTS-1 was a titanium silicon molecular sieve), Cu_(0.7)Mn_2Y_(0.3)O_x/HTS-1 and Cu_(0.7)Mn_2Ce_(0.3)O_x/HTS-1 catalysts were prepared by the impregnation method.The textural properties, redox properties and acidity of the catalysts were characterized by X-ray diffractometer(XRD),transmission electron microscopy(TEM), scanning electron microscopy(SEM), H_2 temperature-programmed reduction(H_2-TPR), X-ray photoelectron spectroscopy(XPS),frustrated total internal reflection(FT-IR), ammonium temperature-programmed desorption(NH_3-TPD) and pyridine adsorption internal reflection(Py-IR) measurements.The potential roles of Lewis acid sites(activating dioxygen) were discussed, and the experimental results indicated that the most efficient route for toluene degradation over Cu_(0.7)Mn_2Ce_(0.3)O_x/HTS-1(toluene conversion rate of 90%(T99) = 295℃) was ascribed to regulation of the synergistic effects of redox properties(activating molecular toluene) and Lewis acid sites(activating dioxygen).The Mars–Van–Krevelen(MVK) model was adopted to describe the reaction process of toluene oxidation, which gave an in-depth view into the toluene degradation over CuMn_2O_4/HTS-1, Cu_(0.7)Mn_2Y_(0.3)O_x/HTS-1 and Cu_(0.7)Mn_2Ce_(0.3)O_x/HTS-1.In addition, the synergistic effects between redox properties and Lewis acid sites were studied in detail.     

TOF–SIMS surface analysis of chemical components of size–fractioned urban aerosols in a typical heavy air pollution event in Beijing

Size–fractioned atmospheric aerosol particles were collected during a typical heavy air pollution event in Beijing. The organic and inorganic components on the surfaces of the samples were analyzed using time–of–flight secondary ion mass spectrometry(TOF–SIMS).The variation characteristics of the surface chemical composition and influencing factors were studied, and the possible sources of these chemical compositions were identified through principal component analysis. The results showed that inorganic components such as crustal elements and sulfate, and organic components such as aliphatic hydrocarbons and oxygen–containing organic groups were present. Some surface components, such as polycyclic aromatic hydrocarbons, heavy metals and fluorides may exert adverse effects on human health. The species and relative percentages of the chemical components varied with particle size, diurnal and pollution progress. During a heavy pollution event, the species and relative percentages of secondary components such as oxygen–containing organic groups and sulfurous compounds increased, indicating that particles aged during this event. The surface chemical composition of the aerosol particles was affected mainly by emissions from coal combustion and motor vehicles. In addition, air pollution, meteorological factors, and air mass transport also exerted a significant effect on the surface chemical composition of aerosol particles.     

A conductive polypyrrole based ammonium ion selective electrode

In view of the development of miniaturized sensor arrays, a solid-contact ammonium ion selective electrode has been investigated. A conductive polypyrrole film was electrochemicallydeposited on a glassy carbon surface and used as an internal solid contact layer between the sensing membrane and solid electrode surface. A systematic evaluation of the importantparameters affecting the electromotive force (emf) response ispresented. The performances of this solid-contact sensor were verified using a batch-mode measurement setup and a wall-jet flow cell system. The designed sensor exhibited excellent selectivity for the primary ion and a linear response over the pNH₄ ⁺ range 1–5 with a slope of 56.3 mV decade^-1. The sensor has a fast response and is relativelyrobustness, and was also used to determine ammonium concentrations in natural waters, with promising results.     

室内甲醛污染及对人体健康的影响

通过对三种不同类型居室内甲醛监测表明,甲醛浓度与室内装饰、吸烟和燃料的不完全燃烧有关.兰州地区夏季室内甲醛超标率高,为41.0％～51.3％.室内主要污染物除TSP以外,甲醛居第2位,且一天中浓度最高值在中午.新建居室比普通居室甲醛浓度高,在所有情况下,室内浓度高于室外.     

高压纸上电泳研究汞的络合水解状态 ⅠHgCl2-NaCl体系

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Rapid infiltration wastewater treatment for small communities in Beijing

This rapid infiltration (RI) system is proposed as the first one in China. The RI system treated 500 m3/d of municipal and industrial wastewater. About 0.36 ha of field was used. It has been evaluated that the RI system has an excellent ability to treat the wastewater. The infiltration rate was 50.3 m/a.     

大气中汞的分布及其污染预报的研究

本实验用疏基棉定量吸附无机汞和有机汞的方法。测定某地区大气中汞含量。以局部地理变化函数研究该地大气中汞的化学状态,得到汞的分布等值线图,并建立了汞污染预报的季节变化数学模式。     

人工湿地控制滇池面源水污染适用性研究

由于滇池面源污染主要发生在农村地区 ,而这些地区在水污染控制方面的资金投入和管理水平有限 ,所以应用于面源污染的水污染控制技术要求是低投入、易管理的工艺方法。而人工湿地是一种基建费用低 ,运行成本低 ,维护技术低的“三低”技术 ,氮磷去除效果显著 ,是一种适合应用于发生在农村地区的面源污染控制的工艺方法     

莲花电站库区水污染防治对策研究

莲花电站位于牡丹江干流下游,是一座以发电为主,兼顾防洪、养鱼等综合利用的大型水利枢纽工程.近年来,随着地区经济的快速发展,莲花电站下游用水量逐年增加,需要莲花电站补充一定的水量,并对水库水质提出了更高的要求.同时,上游牡丹江市经济的快速发展和人民生活水平的不断提高,导致进入莲花电站库区的污染物量增加,加剧了库区水体的污染程度.通过对水质现状分析,找出污染来源,提出莲花电站库区水污染防治对策.