Mesoporous cobalt monoxide-supported platinum nanoparticles: Superior catalysts for the oxidative removal of benzene

Mesoporous Co_3 O_4(meso-Co_3 O_4)-supported Pt(0.53 wt.% Pt/meso-Co304) was synthesized via the KIT-6-templating and polyvinyl alcohol(PVA)-assisted reduction routes.Mesoporous CoO(meso-CoO) was fabricated through in situ reduction of meso-Co304 with glycerol,and the 0.18-0.69 wt.% Pt/meso-CoO samples were generated by the PVA-assisted reduction method.Meso-Co_3 O_4 and meso-CoO were of cubic crystal structure and the Pt nanoparticles(NPs) with a uniform size of ca.2 nm were well distributed on the mesoCo_3 O_4 or meso-CoO surface.The 0.56 wt% Pt/meso-CoO(0.56 Pt/meso-CoO) sample performed the best in benzene combustion(T_(50%)=156℃and T_(90%)=186℃at a space velocity of 80,000 mL/(g h)).Introducing water vapor or C02 with a certain concentration led to partial deactivation of 0.56 Pt/meso-CoO and such a deactivation was reversible.We think that the superior catalytic activity of 0.56 Pt/meso-CoO was intimately related to its good oxygen activation and benzene adsorption ability.     

河流水质灾害的Thomas修正式的稳态分析和临界氧亏计算

水质数学模型是水中污染灾害演化特征的高度概括,也是制定水资源保护规划的基本工具．本文根据对恒定流动的Thomas模型方程组的分析,确定水质灾害的判别标准,预测氧亏的最大值．     

一起氧气瓶爆炸事故的技术分析

针对一起氧气瓶爆炸事故,进行了详细的实际调查,并以科学理论和数据为依据,进行了多角度的技术分析。     

浮头式换热器的腐蚀及对策

针对浮头式换热器的腐蚀现象,分析了造成腐蚀的多种原因,指出冷凝水的氧腐蚀应是主要因素。并给出了控制和解决氧腐蚀的几种方法。     

Experimental study on oxygen consumption rate of residual coal in goaf

In order to research the actual oxygen consumption rate of residual coal in goaf, the heating and oxidizing experiment was conducted respectively on five types of single particle size of coal samples and one hybrid particle size of coal samples by using self-developed CSC-B2 test system. This study measured inlet and outlet oxygen concentration of the oxidation tank, and calculated the oxygen consumption rate of each coal sample at different temperatures. For the residual coal in the same goaf, which is regarded as a hybrid particle size of coal consisting of a variety of single granularity of coal, its oxygen consumption rate is the mass weighted average of the rate of each particle size of coal. Accordingly, this paper established the equation of oxygen consumption rate of hybrid particle size of coal samples, taking into account temperature, granularity and oxygen concentration. Then comparison between the calculated value and the actually measured value of oxygen consumption rate of hybrid particle size of coal samples at different temperatures was conducted. And the results reveal that the calculated value basically coincide with the actually measured one. Moreover, the results prove that the established calculation formula for oxygen consumption rate can be used to accurately calculate the actual oxygen consumption rate of residual coal samples. The achievement of this research is of theoretical and practical significance for learning about the characteristics of coal spontaneous combustion and forecasting the self-ignition of residual coal in goaf.     

Reduction of wastewater toxicity and change of microbial community in a hydrolysis acidification reactor pre-treating trimethylolpropane wastewater

Trimethylolpropane (TMP) wastewater is one of the most toxic petrochemical wastewater. Toxicants with high concentrations in TMP wastewater often inhibit the activity of microorganisms associated with biological treatment processes. The hydrolysis acidification process (HAP) is widely used to pretreat petrochemical wastewater. However, the effects of HAP on the reduction of wastewater toxicity and the relevant underlying mechanisms have rarely been reported. In this study, an HAP reactor was operated for 240 days, fed with actual TMP wastewater diluted by tap water in varying ratios. The toxicity of TMP wastewater was assessed with the inhibition ratio of oxygen uptake rate. When the organic loading rates were lower than 7.5 kg COD/m³/d, the toxicity of TMP wastewater was completely eliminated. When the actual TMP wastewater was directly fed into the reactor, the toxicity of TMP wastewater decreased from 100% to 34.9%. According to the results of gas chromatographymass spectrometry analysis, four main toxicants contained in TMP wastewater, namely, formaldehyde, 2-ethylacrolein, TMP and 2-ethylhexanol, were all significantly removed, with removal efficiencies of 93.42%, 95.42%, 72.85% and 98.94%, respectively. Compared with the removal efficiency of CODCr, the reduction rate of toxicity is markedly higher by HAP. In addition, the change of microbial community in the HAP reactor, along the operation period, was studied. The results revealed that, compared with the seed sludge, Firmicutes became the dominant phylum (abundance increased from 0.51% to 57.08%), followed by Proteobacteria and Bacteroidetes (abundance increased from 59.75% to 25.99% and from 4.70% to 8.39%, respectively).

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差压法测试生化需氧量的校验方法及过程

介绍了在用差压法测试生化需氧量的校验过程中所需的技术要求、校验条件、校验项目,并通过测试数据阐述了效验过程,计算结果显示：比对结果通过校验方法要求。     

N-doped CoAl oxides from hydrotalcites with enhanced oxygen vacancies for excellent low-temperature propane oxidation

A series of nitrogen-doped CoAlO (N-CoAlO) were constructed by a hydrothermal route combined with a controllable NH₃ treatment strategy. The effects of NH₃ treatment on the physico-chemical properties and oxidation activities of N-CoAlO catalysts were investigated. In comparison to CoAlO, a smallest content decrease in surface Co³⁺ (serving as active sites) while a largest increased amount of surface Co²⁺ (contributing to oxygen species) are obtained over N-CoAlO/4h among the N-CoAlO catalysts. Meanwhile, a maximum N doping is found over N-CoAlO/4h. As a result, N-CoAlO/4h (under NH₃ treatment at 400°C for 4 hr) with rich oxygen vacancies shows optimal catalytic activity, with a T₉₀ (the temperature required to reach a 90% conversion of propane) at 266°C. The more oxygen vacancies are caused by the co-operative effects of N doping and suitable reduction of Co³⁺ for N-CoAlO/4h, leading to an enhanced oxygen mobility, which in turn promotes C₃H₈ total oxidation activity dominated by Langmuir-Hinshelwood mechanism. Moreover, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs) analysis shows that N doping facilities the decomposition of intermediate species (propylene and formate) into CO₂ over the catalyst surface of N-CoAlO/4h more easily. Our reported design in this work will provide a promising way to develop abundant oxygen vacancies of Co-based catalysts derived from hydrotalcites by a simple NH₃ treatment.     

水中生化需氧量能力验证的经验探讨

介绍了应用电化学探头法测定BOD₅能力验证样品的分析过程、注意事项及稀释倍数的确定。指出准确确定水样稀释倍数,严格控制测定和培养温度,减少操作过程中的误差,才能确保能力考核样品的准确度与精密度。     

污染河流的纯氧曝气复氧

纯氧曝气复氧是治理污染河流、消除黑臭的有效工程措施之一。由于纯氧的压力高于空气中的氧分压，纯氧曝气可显著提高氧的转移速率。该文介绍了德国梅塞尔（Ｍｅｓｓｅｒ）集团开发的ＢＩＯＸ工艺，应用微孔软管曝气垫，可使水深５ｍ时氧利用率高达８０％。通过上海苏州河新泾港下游的应用实例和中试，结果表明，该工艺具有设备简单、运行安全可靠、维修极少、不生产任何噪声、对河水流态不生产扰动等突出优点，尤其适用于航运繁忙的