Electrochemical oxidation of humic acid at the antimony- and nickel-doped tin oxide electrode

This work investigated the degradation of humic acid （HA） in aqueous solution by electrochemical oxidation with Antimony- and Nickel-doped Tin oxide electrode （Ni-Sb-SnO2/Ti electrode） as the anode. Initial concentrations of HA ranged from 3 to 9 mg-L 1. Under such a concentration scope, the degradation of HA was a mass transfer controlled process. Degradation rate increased with the increase of HA initial concentration. Test on the effect of tert-butanol revealed that · OH played an important role in the oxidation of HA. The absence of cation Ca2＋ was beneficial to HA degradation, which suggested that both indirect and direct electrolyze happened during the whole electrochemical oxidation process. Alkaly （pH = 12） and neutral （pH = 7） conditions were benefical to HA degradation.     

Simultaneous quantification of several classes of antibiotics in water,sediments, and fish muscles by liquid chromatography-tandem mass spectrometry

Precise and sensitive methods for the simultaneous determination of different classes of antibiotics, including sulphonamides, fluoroquinolones, macrolides, tetracyclines, and trimethoprim in surface water, sediments, and fish muscles were developed. In water samples, drugs were extracted with solid-phase extraction （SPE） by passing 1000 mL of water through hydrophilic lipophilic balanced （HLB） SPE cartridges. Sediment samples were solvent-extracted, followed by tandem SPE （strong anion exchange （SAX） ＋ HLB） clean-ups. Fish muscles were extracted by a mixture of acetonitrile and citric buffer （80：20, v/v） solution, and cleaned by SPE. Liquid chromatography-tandem mass spectrometry （LC-MS/ MS） with multiple reaction monitoring （MRM） detection was employed to quantify all compounds. The recoveries for the antibiotics in the spiked water, sediment, and fish samples were 60.2%-95.8%, 48.1%-105.3%, and 59.8%- 103.4%, respectively. The methods were applied to samples taken from Dianchi Lake, China. It showed that concentrations of the detected antibiotics ranged from limits of quantification （LOQ） to 713.6 ng- L1 （ofloxacin） in surface water and from less than LOQ to 344.8 μg·kg-1 （sulphamethoxazole） in sediments. The number of detected antibiotics and the overall antibiotic concentrations were higher in the urban area than the rural area, indicating the probable role of livestock and human activities as important sources of antibiotic contamination. In fish muscles, the concentration of norfioxacin was the highest （up to 38.5 μg·kg-1）, but tetracyclines and macrolides were relatively low. Results showed that the methods were rapid and sensitive, and capable of determining several classes of antibiotics from each of the water, sediment, and fish matrices in a single run.     

Combined biologic aerated filter and sulfur/ceramisite autotrophic denitrification for advanced wastewater nitrogen removal at low temperatures

An innovative advanced wastewater treatment process combining biologic aerated filter （BAF） and sulfur/ ceramisite-based autotrophic denitrification （SCAD） for reliable removal of nitrogen was proposed in this paper. In SCAD reactor, ceramisite was used as filter and Ca （HCO3）2 was used for supplying alkalinity and carbon source. The BAF-SCAD was used to treat the secondary treatment effluent. The performance of this process was investigated, and the impact of temperature on nitrogen removal was studied. Results showed that the combined system was effective in nitrogen removal even at low temperatures （8℃）. Removal of total nitrogen （TN）, NH4＋ -N, NO3-N reached above 90% at room temperature. Nitrification was affected by the temperature and nitrification at low temperature （8℃） was a limiting factor for TN removal. However, denitrification was not impacted by the temperature and the removal of NO3 -N maintained 98% during the experimental period. The reason of effective denitrification at low temperature might be the use of easily dissolved Ca（HCO3）2 and high-flux ceramisite, which solved the problem of low mass transfer efficiency at low temperatures. Besides, vast surface area of sulfur with diameter of 2-6 mm enhanced the rate of microbial utilization. The removal of nitrate companied with the production of SO42-, and the average concentration of SO27 was about 240mg.L^-1. These findings would be beneficial for the application of this process to nitrogen removal especially in the winter and cold regions.     

Laboratory study on high-temperature adsorption of HCI by dry-injection of Ca（OH）2 in a dual-layer granular bed filter

Combustion-generated hydrogen chloride （HCl） is considered to be a very hazardous acid gaseous pollutant. This paper presents a laboratory study on the dry adsorption of HCl. The experiments were conducted in a dual-layer granular bed filter, at gas temperatures of 500℃-700℃ and n（Ca）/n（Cl）molar ratios of 1.0-5.0 using the silver nitrate titration method by dry adsorbent powders Ca（OH）2. Mainly, the adsorption efficiency of HCI and utilization efficiency of Calcium were studied, by varying relevant factors including n（Ca）/n（Cl）, tempera- ture, feeding method, water vapor and CO2. With a relatively higher HCl concentration of 1000ppm, the experimental results revealed that 600℃ may be the optimum temperature for HCl adsorption when optimum n （Ca）/n（Cl） was 2.5 in our tests. The results also demonstrated that the feeding at a constant pressure was more effective, and the HCl adsorption efficiency could rapidly reach over 90% with n（Ca）/n（Cl） = 2.5 at 600℃. Furthermore, the HCl adsorption efficiency was found to be slightly promoted by water vapor, while could be impeded by CO2, and the utilization efficiency of calcium could be up to 74.4% without CO2, while was only 36.8% with CO2 when n（Ca）/n（Cl） was 2.5 at 600℃.     

Biosorption of Cr（VI） by carbonized Eupatorium adenophorum and Buckwheat straw： thermodynamics and mechanism

High quality and low cost carbon can be prepared from Eupatorium adenophorum （E. adenophorum） and Buckwheat straw. The biosorbent was used for Cr（VI） removal. The effect of experimental parameters, such as pH, sorbent dosage and temperature were examined and the optimal experimental condition was determned. Solution pH is found influencing the adsorp- tion. Cr（VI） removal efficiency is found to be maximum （98%） at pH= 1. Langmuir and Freundlich adsorption isotherms were applicable to the adsorption process and their constants were evaluated. The adsorption data obtained agreed well with the Langmuir sorption isotherm model. The maximum adsorption capacities for Cr（VI） ranged from 46.23 to 55.19mg.g^-1 for temperature between 298 K and 308 K under the condition of pH = 1.0. Thermodynamic parameters such as free energy change （AG）, enthalpy （AH） and entropy （AS） indicate a spontaneous, endothermic and increased randomness nature of Cr（VI） adsorption. Studies found that the raw E. adenophorum and buckwheat straw mixed materials with simple treatment had a high efficiency for the removal of Cr（VI） and would be a promising adsorbent.     

Microalgae Scenedesmus obliquus as renewable biomass feedstock for electricity generation in microbial fuel cells （MFCs）

Renewable algae biomass, Scenedesmus obliquus, was used as substrate for generating electricity in two chamber microbial fuel cells （MFCs）. From polarization test, maximum power density with pretreated algal biomass was 102mW·m^2 （951mW·m^3） at current generation of 276mA·m^-2. The individual electrode potential as a function of current generation suggested that anodic oxidation process of algae substrate had limitation for high current generation in MFC. Total chemical oxygen demand （TCOD） reduction of 74% was obtained when initial TCOD concentration was 534mg · L^-1 for 150 h of operation. The main organic compounds of algae oriented biomass were lactate and acetate, which were mainly used for electricity generation. Other byproducts such as propionate and butyrate were formed at a negligible amount. Electrochemical Impedance Spectroscopy （EIS） analysis pinpointed the charge transfer resistance （112Ω ） of anode electrode, and the exchange current density of anode electrode was 1214 nA·cm^-2.     

海外石油钻探项目HSE管理能力评价指标体系研究 ——基于大庆油田海外项目的案例

石油是保障国民经济安全的重要战略资源。当今,国际石油企业间的竞争已由过去单纯依靠资本和技术的竞争,转化成包含健康、安全和环境（HSE）在内的多元要素的竞争。采用问卷调查方法,基于对大庆油田海外石油钻探项目团队349份有效问卷的数据,运用探索性因子分析和验证性因子分析方法,对海外石油钻探项目HSE管理能力评价指标体系和模型进行了实证研究,研究发现:（1）对员工进行适度的健康教育培训可以显著提高项目HSE管理水平;（2）健全的物料安全管理制度对于提高项目HSE管理水平至关重要;（3）预防及应对环境污染能力直接影响项目的HSE管理水平。最后,基于上述研究结论,提出了相应的对策建议。     

管座焊缝内侧的相控阵超声自动检测

本文介绍应用相控阵技术结合配有编码动作的机械装置,对插入式管座焊缝从接管内侧用线阵探头进行超声检测的方法。建立实验模型,可为声柬全覆盖所必须考虑的物理参数,提供验证数据。建模和实测结果表明：利用声线跟踪法,扫查布置图（Scanplan）能提供所需覆盖范围的适当显示。当从接管内表面进行扫查时,用于引导探头扫查动作的机械装置往往可设计得减少复杂性。本文所述方法可望为承压设备结构较复杂的管座焊缝,实施超声相控阵检测（PAUT）符合ASME最新版要求提供有用借鉴。     

厌氧发酵污泥燃料电池处理含铬废水的效能及机理

以厌氧发酵污泥为阳极底物、Cr(VI)为阴极电子受体构建双室微生物燃料电池(MFC),考察厌氧发酵污泥MFC系统处理含铬废水的性能及机理,并与原污泥MFC系统进行比较.发酵污泥MFC系统的开路电压为1.05V,最大功率密度为5722mW/m3,比原污泥MFC系统提高了57.8%.发酵污泥MFC系统的表观内阻为119.1Ω,比原污泥MFC系统降低了8.5%.发酵污泥MFC系统对Cr(VI)的去除符合一级动力学模型,速率常数为0.0514h-1,比原污泥MFC系统提高了36.7%.污泥经厌氧发酵后可溶性有机物浓度增加,产生了大量短链脂肪酸,它们是产电微生物易于摄取的阳极底物,因而提高了MFC系统的产电性能及Cr(VI)去除效果.     

零价纳米铁吸附去除水中六价铬的研究

利用液相还原法制备的零价纳米铁(nZVI)进行了去除水中Cr(Ⅵ)的实验研究.结果表明,nZVI对Cr的去除效果明显优于还原铁粉和粉末活性碳;pH值越小、初始Cr浓度越低、nZVI放置时间越短及投加量越大均有利于水中Cr(Ⅵ)的去除,最佳去除率近100%;反应动力学拟合结果表明,nZVI去除六价铬符合准二级动力学模型;反应后nZVI颗粒的扫描电镜及电子能谱结果显示Cr占12.02%(wt),结合对反应溶液中Cr(Ⅵ)和Cr(Ⅲ)分析,说明吸附、还原与共沉淀可能是nZVI去除水中六价铬的主要机理.