污水同步脱氮除磷技术及运行控制要点

以污水脱氮除磷机理为基础,从反应动力学和过程动力学角度对同步脱氮除磷的主要影响因素:溶解氧DO浓度、有机负荷、亚硝酸盐和硝酸盐浓度、污泥龄θC、流态和回流比进行了分析,指出通过模拟试验来确定运行控制参数并对其进行智能控制(IC),可保证系统稳定、高效、节能运行。     

铊在黄铁矿中的相态分布及碳酸盐在其释放过程中的作用

采用分级提取-电感耦合等离子体质谱法,对黄铁矿中铊的相态分布进行了考察.结果表明,黄铁矿中的铊主要以存在于硅酸盐相中和以酸可交换的形式存在于矿物结构中的铊为主,这部分铊分别占到58.3%和25.1%;以可氧化态形式结合在黄铁矿(FeS2)中的铊次之,占11.2%;以易还原态形式存在于铁氧化物相中的铊最少,为5.4%.自然条件下铊的释放主要是酸可交换态铊和可氧化态铊的释放迁移过程.漫反射红外光谱表征发现,黄铁矿在表面氧化过程中其表面羟基增多,表明存在表面溶解及表面酸化现象.进一步的释放机理探讨认为,铊在黄铁矿表面存在一种"溶解-吸附沉淀"平衡,这一平衡由碳酸盐中和作用和黄铁矿表面氧化共同控制,并决定了铊的释放迁移.     

大气模拟烟雾箱系统的研究进展

烟雾箱是研究大气光化学反应的主要工具.30年来国内外有多个研究机构建立了烟雾箱,并对各种光化学反应进行了研究,以收集数据来发展和检验大气光化学反应机理.从系统构造、配置仪器及所进行的光化学实验几个方面,综述了国内外烟雾箱系统的研究进展,其中背景影响较小的烟雾箱能为评价化学反应机理提供精度较高的数据,二次有机气溶胶(secondary organic aerosol,SOA)的形成机理成为目前的研究热点.     

A位掺杂LaSrCoO4对CO和C3H8氧化性能研究

采用聚丙烯酰胺溶胶-凝胶法制备了A位掺杂(Cu、Ce)LaSrCoO4复合氧化物催化剂,考察了它们对CO和C3H8的催化氧化活性,并运用XRD,TPR和TPD等手段对催化剂进行了表征。结果表明,不同稀土掺杂对LaSrCoO4复合氧化物的CO和C3H8氧化活性的影响不同,Cu掺杂能增加Co3+、化学吸附氧和晶格氧的数量,提高复合氧化物的活性,而Ce则相反。     

阴离子膜矿浆电解回收干电池正极材料中的锰

研究了硫酸介质中阴离子膜矿浆电解回收废旧干电池正极材料中锰的工艺条件。实验结果表明,阴极室浸出锰离子的较佳条件为:电流密度150A/m2,酸度1.0mol/L,液固比8∶1,温度20℃。在此条件下恒电流电解90min,锰的回收率为25.77%,阴极表观电流效率为101.1%。经反应机理分析得出,在浸出前1h,反应的控制步骤为混合控制,1h后为化学反应控制,活化能为52.85kJ/mol。采用该法可实现资源的循环利用,具有环境和经济效益。     

PCR技术在水生毒理学研究中的应用

介绍了聚合酶链式反应(PCR)技术的基本原理,并在此基础上综述了PCR技术在水生毒理学研究中的应用及国内外最新研究进展,其中涉及的模式生物包括原生动物、浮游植物、浮游动物和鱼类等。PCR技术不仅为污染物对水生生物的毒性检测带来了便利,还有助于从分子水平上阐述污染物的毒性作用机制。最后指出了目前PCR技术应用的局限性及未来的发展前景。     

One-step ball milling-prepared nano Fe2O3 and nitrogen-doped graphene with high oxygen reduction activity and its application in microbial fuel cells

• Nano Fe₂O₃ and N-doped graphene was prepared via a one-step ball milling method. • The maximum power density of Fe-N-G in MFC was 390% of that of pristine graphite. • Active sites like nano Fe₂O₃, pyridinic N and Fe-N groups were formed in Fe-N-G. • The improvement of Fe-N-G was due to full exposure of active sites on graphene. Developing high activity, low-cost and long durability catalysts for oxygen reduction reaction is of great significance for the practical application of microbial fuel cells. The full exposure of active sites in catalysts can enhance catalytic activity dramatically. Here, novel Fe-N-doped graphene is successfully synthesized via a one-step in situ ball milling method. Pristine graphite, ball milling graphene, N-doped graphene and Fe-N-doped graphene are applied in air cathodes, and enhanced performance is observed in microbial fuel cells with graphene-based catalysts. Particularly, Fe-N-doped graphene achieves the highest oxygen reduction reaction activity, with a maximum power density of 1380±20 mW/m² in microbial fuel cells and a current density of 23.8 A/m² at –0.16 V in electrochemical tests, which are comparable to commercial Pt and 390% and 640% of those of pristine graphite. An investigation of the material characteristics reveals that the superior performance of Fe-N-doped graphene results from the full exposure of Fe₂O₃ nanoparticles, pyrrolic N, pyridinic N and excellent Fe-N-G active sites on the graphene matrix. This work not only suggests the strategy of maximally exposing active sites to optimize the potential of catalysts but also provides promising catalysts for the use of microbial fuel cells in sustainable energy generation.     

Redox reactions of iron and manganese oxides in complex systems

• Mechanisms of redox reactions of Fe- and Mn-oxides were discussed. • Oxidative reactions of Mn- and Fe-oxides in complex systems were reviewed. • Reductive reaction of Fe(II)/iron oxides in complex systems was examined. • Future research on examining the redox reactivity in complex systems was suggested. Conspectus Redox reactions of Fe- and Mn-oxides play important roles in the fate and transformation of many contaminants in natural environments. Due to experimental and analytical challenges associated with complex environments, there has been a limited understanding of the reaction kinetics and mechanisms in actual environmental systems, and most of the studies so far have only focused on simple model systems. To bridge the gap between simple model systems and complex environmental systems, it is necessary to increase the complexity of model systems and examine both the involved interaction mechanisms and how the interactions affected contaminant transformation. In this Account, we primarily focused on (1) the oxidative reactivity of Mn- and Fe-oxides and (2) the reductive reactivity of Fe(II)/iron oxides in complex model systems toward contaminant degradation. The effects of common metal ions such as Mn²⁺ , Ca²⁺, Ni²⁺, Cr³⁺ and Cu²⁺, ligands such as small anionic ligands and natural organic matter (NOM), and second metal oxides such as Al, Si and Ti oxides on the redox reactivity of the systems are briefly summarized.     

ORS-ICP-MS测定工业污泥中的重金属元素

建立了八极杆碰撞/反应池电感耦合等离子体质谱(ORS-ICP-MS)法测定工业污泥中Cr、Ni、As、Cd、Sb、Sn、Hg和Pb等8种重金属元素的分析方法。应用ORS技术消除了多原子离子对待测元素产生的质谱干扰,通过研究He碰撞气流速的变化对Cr、Ni、As和Sb预估检测限(EDL)的影响情况确定了最佳碰撞气流速,采用Rh为内标元素校正了质谱分析中基体效应并补偿了信号漂移。方法对工业污泥样品的检出限为13.5~34.3 ng/L,加标回收率在93.0%~107.6%之间,相对标准偏差(RSD)为1.5%~2.8%。     

Comparison of homologous and heterologous formats in nanocolloidal gold-based immunoassays for parathion residue determination

The effectiveness of homologous and heterologous formats in a nanocolloidal gold-based immunoassay for pesticide residue determination was investigated. Parathion, one of the most toxic organophosphorus pesticides, was used as the target analyte. One-step homologous and heterologous test strips based on a nanocolloidal gold-labeled monoclonal antibody were developed for the rapid detection of parathion residues. The results showed that the heterologous format was more effective than the homologous format, being more sensitive, more specific to parathion and more tolerant of matrix interferences. The best competitive hapten was found to have a moderate heterology and the opposite electronic distribution to the immunizing hapten. The detection limits for parathion using the preferred heterologous strip were 1 μg/L in water samples and 5 μg/kg in soil and food samples.