Study on the denitrification performance of FexLayOz/activated coke for NH3-SCR and the effect of CO escaped from activated coke at mid-high temperature on catalytic activity

Currently, activated coke is widely used in the removal of multiple pollutants from industrial flue gas. In this paper, a series of novel Fe_xLa_yO_z/AC catalysts was prepared by the incipient wetness impregnation for NH₃-SCR denitrification reaction. The introduction of Fe-La bimetal oxides significantly improved the denitrification performance of activated coke at mid-high temperature, and 4% Fe_0.3La_0.7O_1.5/AC exhibited a superior NO_x conversion efficiency of 90.1% at 400 °C. The catalysts were further characterized by BET, SEM, XRD, Raman, EPR, XPS, FTIR, NH₃-TPD, H₂-TPR, et al., whose results showed that the perovskite-type oxide of LaFeO₃ and oxygen vacancies were produced on the catalysts’ surfaces during roasting. Fe-La doping enhanced the amount of acid sites (mainly Lewis and other stronger acid sites) and the content of multifarious oxygen species, which were beneficial for NO_x removal at mid-high temperature. Moreover, it was investigated that the effect of released CO from activated coke at mid-high temperature on the NO_x removal through the lifetime test, in which it was found that a large amount of CO produced by pyrolysis of activated coke could promote the NO_x removal, and long-term escaping of CO on the activated coke carrier did not have a significant negative impact on catalytic performance. The results of the TG-IR test showed that volatile matter is released from the activated coke while TG results showed that the weight loss rate of 4% Fe_0.3La_0.7O_1.5/AC only was 0.0015~0.007%/min at 300–400 °C. Hence, 4% Fe_0.3La_0.7O_1.5/AC had excellent thermal stability and denitrification performance to be continuously used at mid-high temperature. Finally, the mechanisms were proposed on the basis of experiments and characterization results.

     

屏蔽服冷却系统对人体表面温度影响的研究*

为科学有效地论证多种方式组合的冷却屏蔽服在不同环境条件下对人体表面温度控制的效果，需要对冷却系统及人体敏感部位发热量进行客观评估。通过对5名健康男性的高温测试，探究人体在不同环境温度下体表温度的变化，得出胸部、背部及额头为热量最高部位，并构建以“人体-降温屏蔽服-外界环境”为主体的冷却系统数值模型，对不同环境中的屏蔽服冷却效果展开研究，分析穿戴冷却屏蔽服时人体躯干部分的温度分布及影响。结果表明:在屏蔽服中靠近胸部、背部部位引入相变材料和风扇，均可帮助人体降低体温，提高舒适度。     

MCM-41分子筛负载铁铈催化降解甲基橙

采用等体积浸渍法制备了负载型有序介孔Fe-Ce/MCM-41催化剂。研究了该催化剂降解甲基橙的适宜工艺条件,并采用XPS,XRD,TEM技术对该催化剂进行了表征。实验结果表明,该催化剂Fenton氧化降解甲基橙的较适宜工艺条件为:溶液pH 5.0、甲基橙溶液初始质量浓度100 mg/L、催化剂加入量2.0 g/L、H_2O_2浓度20 mmol/L,在此适宜条件下反应120 min时,甲基橙去除率接近100%。表征结果显示:Fe-Ce/MCM-41催化剂主要由铁、铈、氧、碳4种元素组成;铁与铈的摩尔比接近3∶1;铁和铈主要以Fe_3O_4和CeO_2的形态存在于催化剂表面。     

Mechanism of the intermittent motion of two-phase debris flows

A typical two-phase debris flow exhibits a high and steep flow head consisting of rolling boulders and cobbles with intermittent or fluctuating velocity. The relative motion between the solid phase and the liquid phase is obvious. The motion of a two-phase debris flow depends not only on the rheological properties of the flow, but also on the energy transmission between the solid and liquid phases. Several models have been developed to study two-phase debris flows. An essential shortcoming of most of these models is the omission of the interaction between the two phases and identification of the different roles of the different materials in two-phase debris flows. The tracer particles were used for the velocity of solid phase and the velocity of liquid phase was calculated by the water velocity on the surface of the debris flow in the experiments. This paper analyzed the intermittent feature of two-phase debris flows based on videos of debris flows in the field and flume experiments. The experiments showed that the height of the head of the two-phase debris flow increased gradually in the initiation stage and reached equilibrium at a certain distance from the start of the debris flow. The height growth and the velocity of the flow head showed fluctuating characteristics. Model equations were established and the analyses proved that the average velocity of the two-phase debris flow head was proportional to the flood discharge and inversely proportional to the volume of the debris flow head.     

三氯卡班对小鼠血浆内源性物质影响的代谢组学研究

三氯卡班被认定为一种新型的环境污染物,可能对动植物和人体产生危害,为探究三氯卡班的有害作用机制,选择C57BL6小鼠作为载体,利用分子生物学和报告基因方法考察了三氯卡班对肝脏的作用,同时利用代谢组学技术考察三氯卡班对血浆内源性代谢物变化的影响。结果表明,三氯卡班是核受体CAR的激活剂,可以提高肝脏CYP2b10的m RNA表达。同时血浆主要的内源性代谢物也产生了显著性变化,血浆中的脂肪酸比例都呈下降趋势,肉毒碱与乙酰肉碱的比例都呈上升趋势,花生四烯酸与肌酸的比例都呈上升趋势,这都与核受体CAR被激活密切相关,由此说明利用代谢组学技术能够全面地反映三氯卡班所造成的对机体的影响。     

PVA降解混合菌系生长和产酶的营养条件分析

研究碳源、氮源以及不同金属离子对PVA降解混合菌系生长和产酶的影响。结果表明,混合菌系生长过程中无机氮源优于有机氮源;补充碳源可促进混合菌系的生长,但酶活比不添加时稍有降低。金属离子对酶活影响的正交实验表明Mg2＋浓度影响最大,其次是Fe2＋和K＋浓度,Ca2＋、Mn2＋、Zn2＋和Cu2＋浓度影响较小;最佳浓度分别为Mg2＋0.05 g/L、Fe2＋0.04 g/L、K＋2 g/L和Ca2＋0.05 g/L。     

国内外可持续发展评价方法对比分析

国际、国内很多组织都对可持续性评价方法进行过研究分析,但大多是特定的案例研究.目前国内外对可持续发展评价方法没有一个全面系统的分析比较,使得不同地区比较起来很困难.本文对各种评价方法如环境可持续性指数法、生态足迹法、能值分析法和指标综合评价法的来源、理论和应用作了介绍.得出各方法适用范围:可持续性指数法适合于国家间的综合评价;生态足迹和能值分析法适合于各种范围,包括国家、区域、地区和小系统;指标体系综合评价法对于小范围更合适.同时对各种方法的优势和缺陷进行了分析讨论,得出:可持续性指数法信息量大,但是计算复杂;生态足迹法计算过程简单,但是缺失一些可持续性信息;能值分析法考虑问题全面,但是其原理涉及热力学知识,很难被一些学者认同;指标体系评价法变通性较大,可随着评价系统的变化而进行调整,但是主观性较强.通过分析指出不同方法适用范围并指出每种分析方法的优势和不足,为以后选择合适的分析方法评价对象的可持续性提供依据.     

MicroRNA: a novel implication for damage and protection against ionizing radiation

Environmental Science and Pollution Research - Ionizing radiation (IR) is a form of high energy. It poses a serious threat to organisms, but radiotherapy is a key therapeutic strategy for various...     

Revealing the impact of water conservancy projects and urbanization on hydrological cycle based on the distribution of hydrogen and oxygen isotopes in water

Environmental Science and Pollution Research - In recent years, the development and utilization of water resources have imposed great impacts on hydrological characteristics and ecological...     

Development of highly efficient and reusable magnetic nitrogen-doped carbon nanotubes for chlorophenol removal

Environmental Science and Pollution Research - Nitrogen-doped carbon nanotubes (N-CNTs) were synthesized via a hydrothermal method and further modified with magnetic Co0.5Cu0.5Fe2O4 nanoparticles...