Degradation of antipyrine in the Fenton-like process with a La-doped heterogeneous catalyst

A La-doped Co-Cu-Fe catalyst was synthesized for the antipyrine (ANT) removal. The La-doped catalyst had higher ANT removal than the control (95% vs. 54%). La reduced the particle size and increased the specific surface area of catalyst. The aim of this study was to synthesize a novel lanthanum (La) doped catalyst and to investigate antipyrine removal in wastewater using the Fenton-like process with the catalyst. The La-doped Co-Cu-Fe catalyst was synthesized using the modified hydrothermal method. Results showed that the La-doped catalyst had higher specific surface area and lower particle size than the catalyst without La doping (i.e., the control) (267 vs. 163 m²/g and 14 vs. 32 nm, respectively). Under the conditions of catalyst dosage 0.5 g/L, H₂O₂ concentration 1.70 g/L, and NaHCO₃ 0.1 g/L, the antipyrine removal within 60 min using the Fenton-like process with the La-doped catalyst was much higher than that with the control (95% vs. 54%). The hydroxyl radical concentration with the La-doped catalyst within 60 min was two times higher than that with the control (49.2 vs. 22.1 mg/L). The high catalytic activity of La-doped catalyst was mainly attributed to its high specific surface area based on the X-ray photoelectron spectroscopy result. Our La-doped catalyst should have great potential to remove antipyrine in wastewater using the heterogeneous Fenton-like process.     

The dynamics and drivers of environmental performance in Chinese cities: a decomposition analysis

Environmental Science and Pollution Research - This paper examines urban environmental performance using a unique database of 286 Chinese cities for the period 2002–2014. Both the dynamics of...     

System dynamic analysis of construction waste recycling industry chain in China

Environmental Science and Pollution Research - With the acceleration of China’s urbanization process, construction activities have led to a substantial increase in construction waste....     

Electrocatalytic oxidation of ciprofloxacin by Co-Ce-Zr/γ-Al2O3 three-dimensional particle electrode

Environmental Science and Pollution Research - In this work, Co-Ce-Zr/γ-Al2O33 particle electrodes were prepared for the efficient degradation of ciprofloxacin (CIP). Co-Ce-Zr/γ-Al2O3...     

基坑放坡开挖对下方既有地铁隧道影响计算及风险预测

为研究基坑放坡开挖对下方既有地铁隧道的影响以及预测隧道结构的风险,通过改进的计算方法得到放坡开挖基坑引起下方既有地铁隧道的竖向和横向附加荷载、位移、相对变形曲率共6个隧道结构安全的物理表现因子;将位移计算结果与前人理论计算结果、实测数据对比验证,并分析各土层物理力学参数对6个因子的敏感性;最后,基于正态分布概率模型对较敏感的土层物理力学参数随机取值,利用蒙特卡罗方法计算6个因子各级风险发生的概率和竖向、横向2类因子综合影响下隧道结构各级风险发生的总概率。研究结果表明:与原来仅限于矩形开挖基坑的计算方法相比,改进后的计算方法适用范围更广、实用性更强;在算例二分析中,隧道竖向位移和相对变形曲率超过控制值的概率分别为12%和68.7%,其余因子均为0,隧道竖向相对变形曲率是隧道结构处于不安全状态的最主要因子;若不采取预防措施,隧道结构将有高达73.27%的概率处于不安全状态,其中有68.7%的概率处于很不安全状态。     

配置SCR的柴油货车道路运行NOx排放分析

为了研究重型柴油货车在不同道路运行工况下的NO_x排放特性,以一辆配置选择催化还原(Selective CatalyticReduction,SCR)净化系统的国V排放标准的重型柴油货车为研究对象,开展实际道路运行车载排放测试,通过车载排放测试系统实时采集车辆行驶速度、NO_x排放体积分数与排气温度等数据,分析车速、排气温度、路况等对NO_x排放的影响。结果表明,车速低于40 km/h,NO_x排放随车速增大稍有增加; 40～70 km/h,随车速增大NO_x排放降低;高于70 km/h,随车速增大NO_x排放显著降低。车速与排气温度呈线性正相关,排气温度高于150℃,SCR才能显示出对NO_x的净化效果。市区工况车速低,排温低于150℃,SCR不能有效工作;市郊、高速工况下排温高于150℃,SCR催化效率提高,车速增大,排温升高,NO_x排放降低,因此NO_x排放市郊工况低于市区工况,高速工况低于市郊工况。配置SCR的重型柴油货车NO_x高排放区主要集中在中低车速、加速区间内。     

Ignition temperatures of dust layers and bulk storages in hot environments

In many industrial installations, particulate solids (cereals, agri-food products, coal, plants, etc.) are stored or processed. Self-heating of these products, which can lead to fires and explosions, can occur in a variety of situations. Examples include large storage at room temperature, formation of a layer on a hot surface, layer deposited on a surface – insulating or conductive – in a hot environment or even storage of product exposed to heating on one side.The main parameters that determine the occurrence of self-heating are the size of the container, the temperature, the residence time and the characteristics of the product. Depending on the type of situation encountered and these implementation conditions, the analysis of self-heating risks must be based on specific models and/or parameters.This paper presents the different variants and combinations of the theoretical model from the theory of thermal runaway to represent self-heating, taking into account in particular the symmetry or asymmetry of heating, reagent consumption and boundary conditions. It also discusses their adaptation to the previous identified industrial situations.Nine products were chosen to be representative of those used in the different considered industrial situations. They were subjected to self-heating basket tests in isothermal ovens in order to determine the parameters for applying the described theoretical models. These results were compared with the results of self-heating tests in layers of different thicknesses in a hot environment, on an insulating or conductive plate, using a specially developed test protocol, as well as with the results of standardized tests of minimum ignition temperature in 5 mm layers.This led to the proposal of the most appropriate theoretical model to represent the self-heating phenomenon for each of the four identified industrial situations.This analysis can promote better design of industrial equipment and production conditions (temperatures, volumes or product flows …) in order to prevent fires and explosions.     

国家濒危植物永瓣藤分布的土壤环境特征

永瓣藤(Monimopetalum chinense)是卫矛科(Celastraceae)的一个中国特有单型属植物,被列为国家二级稀有濒危保护物种。本文对永瓣藤分布区14个样地土壤样品的pH值、有机质、全氮、水解氮、硝态氮、全磷、速效磷和全钾进行了检测分析,以期弄清该物种分布与土壤环境因子的关系。结果表明,其pH值的变化幅度为4.55～5.57,主要处于强酸性范围,适应幅度较窄。有机质与氮素非常丰富,相互间具有明显的相关性,有利于永瓣藤的生长与繁衍,但土壤中磷、钾素较为缺乏。土壤酸碱度和有机质的质量分数在某种程度上对永瓣藤的分布范围具有制约作用。     

Zr/TiO2纳米颗粒的制备及其光催化活性

以钛酸丁酯,乙醇为原料,用固相合成法制备了Zr/TiO2纳米颗粒,用XRD、TEM对其组成、颗粒大小、形貌进行了表征.通过对罗丹明B的降解反应,考察了Zr/TiO2的光催化活性.结果表明,Zr/TiO2为纳米颗粒,平均粒径为12.7 nm左右,且颗粒均匀;掺杂金属离子Zr提高了TiO2光催化效率,掺杂2.0%Zr的催化剂活性最高.Zr/TiO2的光催化反应,首先是反应物在Zr/TiO2表面发生吸附作用,然后进一步发生光催化降解.     

火山岩填料曝气生物滤池的SNAD工艺启动特性及功能菌丰度演替

为研究同步亚硝化、厌氧氨氧化耦合反硝化(SNAD)工艺在浸没式生物滤池反应器(SBAF)内的运行特性,同时接种亚硝化污泥和富集ANAMMOX的填料启动SNAD反应器.结果表明在60 mg·L~(-1)有机物浓度下,自养脱氮和反硝化实现较好的耦合,并在该浓度下稳定运行了67 d,其总氮去除率最高可达92.0%,COD去除率最高达82.9%,最高总氮去除负荷为2.3 kg·(m~3·d)~(-1).与全程自养脱氮(CANON)工艺相比,SNAD工艺的平均总氮去除率提高了12.6%.荧光定量PCR结果显示,系统启动后AOB菌的丰度有所增长,ANAMMOX菌的丰度增长了1个数量级,而NOB菌和反硝化菌的数量维持在较低水平(小于10~7 copies·g~(-1)),表明以火山岩为填料的浸没式生物滤池反应器有利于ANAMMOX和AOB的协同生长,可快速实现SAND工艺的启动.