铋电极差分脉冲伏安法测定水中痕量2,4-二硝基苯肼

以自制铋电极作为工作电极,建立了铋电极差分脉冲伏安法测定2,4-二硝基苯肼的分析方法。实验结果表明：以0.1 mol/L NaOH+0.1 mol/L KCl混合溶液（pH=13.0）配制测定底液,在扫描速率为100 mV/s的条件下,2,4-二硝基苯肼于-0.53 V处产生灵敏的氧化峰;在2,4-二硝基苯肼浓度为3.0×10-8~1.0×10-5 mol/L范围内,空白和试样的氧化峰电流强度差值与对应2,4-二硝基苯肼浓度的对数呈良好的线性关系,检出限达8.37×10-9 mol/L;将该方法应用于工业废水中痕量2,4-二硝基苯肼的检测,回收率为95.6%~103.1%,相对标准偏差小于3%。     

Statistical analysis of sudden chemical leakage accidents reported in China between 2006 and 2011

According to the data from authoritative sources, 1,400 sudden leakage accidents occurred in China during 2006 to 2011 were investigated, in which, 666 accidents were used for statistical characteristic abstracted with no or little damage. The research results were as follows: (1) Time fluctuation: the yearly number of sudden leakage accidents is shown to be decreasing from 2006 to 2010, and a slightly increase in 2011. Sudden leakage accidents occur mainly in summer, and more than half of the accidents occur from May to September. (2) Regional distribution: the accidents are highly concentrated in the coastal area, in which accidents result from small and medium-sized enterprises more easily than that of the larger ones. (3) Pollutants: hazardous chemicals are up to 95 % of sudden leakage accidents. (4) Steps: transportation represents almost half of the accidents, followed by production, usage, storage, and discard. (5) Pollution and casualties: it is easy to cause environmental pollution and casualties. (6) Causes: more than half of the cases were caused by human factor, followed by management reason, and equipment failure. However, sudden chemical leakage may also be caused by high temperature, rain, wet road, and terrain. (7) The results of principal component analysis: five factors are extracted by the principal component analysis, including pollution, casualties, regional distribution, steps, and month. According to the analysis of the accident, the characteristics, causes, and damages of the sudden leakage accident will be investigated. Therefore, advices for prevention and rescue should be acquired.     

Effects of bromide and iodide ions on the formation of disinfection by-products during ozonation and subsequent chlorination of water containing biological source matters

This study aims to investigate the influence of the coexistence of halogen ions (bromide/iodide) and biological source matters on the speciation and yield of trihalomethanes (THMs), haloacetic acids (HAAs), and N-nitrosodimethylamine (NDMA) during the ozonation and subsequent chlorination of water. The results show that the concentrations of brominated THMs and iodinated THMs increased with increasing bromide and iodide concentration. These results may be attributed to the higher reactivity of hypobromous acid and hypoiodous acid generated from the ozonation and subsequent chlorination in the presence of bromide or iodide ions. The presence of bromide increased the species of brominated HAAs. There was a shift from chlorinated HAAs to brominated HAAs after increasing the concentration of bromide. The effect of iodide on HAA formation was more complex than bromide. For most samples, the concentration of total HAAs (T-HAAs) increased to the maximum and then decreased with increasing iodide concentration. The components of the organic precursors also significantly influenced the formation of brominated and iodinated disinfection by-products (Br-DBPs and I-DBPs). Humic acids produced more CHBr₃ (596.60 μg/L) than other organic materials. Microcystis aeruginosa cells produced the most tribromoacetic acid (TBAA, 84.16 μg/L). Furthermore, the yield of NDMA decreased with increasing bromide concentration, indicating that the formation of NDMA was inhibited by the high concentration of bromide.     

催化铁与生物法耦合除磷工艺特性

为了研究催化铁与生物耦合后对生物除磷特性的影响,实验采用人工配水用厌氧／好氧间歇流式富集培养聚磷微生物。对比发现,催化铁与生物耦合组中厌氧末段ORP降低了约60mV,pH值小幅度的上升（≤0．3）,整个培养过程中铁离子的浓度开始快速增加,之后趋于稳定（约40mgFe／gMLSS）。对好氧末段污泥SVI值比较发现,耦合工艺污泥沉降性能得到改善。除磷曲线比较发现,耦合组中厌氧末段磷的释放量下降,而好氧阶段磷的吸收速率增加;胞内聚合物提取表明,耦合组厌氧末段聚磷菌细胞内PHA含量有提高,好氧末段糖原含量有下降。磷形态提取分析表明,耦合组好氧末段污泥中无机态PO3 4-- P含量更高。低浓度铁离子可以起到与生物耦合同步除磷的目的,本工艺长期运行未发现耦合体系中催化铁对除磷的抑制作用。     

用于磷吸附的载铁（β-FeOOH）沸石制备及特性

以天然沸石为载体,采用FeCl3水解法制备用于磷吸附的载铁沸石（β-FeOOH-Z）,优化β-FeOOH-Z的制备条件,包括FeCl,溶液浓度、负载pH值、负载时间、负载温度和烘干温度,并利用x射线衍射（XRD）和傅里叶变换红外光谱（FTIR）对β-FeOOH-Z及其磷吸附特性进行分析。结果表明,β-FeOOH-Z的优化制备条件为：FeCl3溶液浓度1mol／L、负载pH值6、负载时间24h、负载温度25℃和烘干温度60℃。优化制备条件下,100-120目沸石的载铁量为100．2mg／g,铁的负载率为18％,其磷吸附量为7．68mg／g,比天然沸石提高79．6％。XRD分析结果表明,β-FeOOH-Z中的杂质元素较天然沸石减少,并有效负载β-FeOOH;制备条件对β-FeOOH-Z的成分有较大影响,FeCl,溶液浓度较低、负载温度和烘干温度过高均使β-FeOOH-Z中含有α-Fe2O3,并导致其磷吸附效率降低。FTIR分析结果表明,β-FeOOH-Z的表面羟基在其吸附磷过程中起重要作用,羟基与磷酸根离子的配位交换是β-FeOOH-Z吸附磷的主要作用机制。     

La1-x Cex Cuy Mn1-yO3／HZSM-5催化剂低温去除柴油机碳烟和NOx

为实现对柴油机碳烟和NOx的低温同步去除,采用柠檬酸络合法制备分子筛负载钙钛矿型金属复合氧化物催化剂,应用x衍射分析仪（XRD）和电镜扫描仪（SEM）对催化剂性能进行表征,并在微型固定床反应器中对催化剂低温去除碳烟和NOx进行活性评价。利用程序升温反应（TPR）技术,进行催化剂活性评价、柴油机负荷和排放等特性实验。结果表明,A位用适量Ce部分取代La,B位用适量cu部分取代Mn,可使碳颗粒燃烧温度降低,CO2选择性好,NOx转化率升高。La0.4 Ce0.6 Cu0.2 Mn0.8O3／HZSM-5催化剂的最大NOx转化率为81．0％,Ti、Tm和Tf分别为250、350和475℃,表明该催化剂具有较好的催化活性,能在低温条件下去除碳烟和NOx。     

催化铁与生物法耦合除磷工艺特性简

为了研究催化铁与生物耦合后对生物除磷特性的影响,实验采用人工配水用厌氧/好氧间歇流式富集培养聚磷微生物。对比发现,催化铁与生物耦合组中厌氧末段ORP降低了约60 mV,pH值小幅度的上升（≤0.3）,整个培养过程中铁离子的浓度开始快速增加,之后趋于稳定（约40 mg Fe/g MLSS）。对好氧末段污泥SVI值比较发现,耦合工艺污泥沉降性能得到改善。除磷曲线比较发现,耦合组中厌氧末段磷的释放量下降,而好氧阶段磷的吸收速率增加;胞内聚合物提取表明,耦合组厌氧末段聚磷菌细胞内PHA含量有提高,好氧末段糖原含量有下降。磷形态提取分析表明,耦合组好氧末段污泥中无机态PO^3-₄-P含量更高。低浓度铁离子可以起到与生物耦合同步除磷的目的,本工艺长期运行未发现耦合体系中催化铁对除磷的抑制作用。     

电渗透脱水污泥干燥特性曲线及干燥模型简

通过电渗透脱水技术及自然风干技术两种预处理方式降低污泥含水率,当污泥初始含水率相近时,研究经两种方式处理后污泥的干燥特性曲线,并对电渗透脱水污泥干燥特性曲线的优势情况进行探讨。在40~120℃的低温条件下,研究电渗透脱水污泥（泥饼厚度为3.5 mm）的干燥特性曲线并分析其干燥特性。通过所得电渗透脱水污泥的干燥特性曲线,引入薄层污泥干燥模型进行数值分析。结果表明,在实验条件下,电渗透脱水污泥的干燥速率要优于自然风干污泥的干燥速率。随着温度的升高,电渗透脱水污泥的干燥速率随之升高,干燥到所需含水率的时间则随之减少。Logarithmic模型比其他模型更适合描述薄层电渗透脱水污泥在低温条件下的干燥特性。     

蒙自矿冶重金属冶炼废水处理工程改造与实践简

蒙自矿冶重金属冶炼废水深度处理工程主要对含重金属污酸和酸性污水处理系统进行改造。针对原有中和处理法存在的诸多问题,本工程在石灰中和处理的基础上新增电絮凝处理系统、化学沉淀微滤处理系统和深度处理系统。工程实践表明,该深度处理工程运行稳定,自动化程度高,处理效果好,废水达到《地表水环境质量标准（GB3838-2002）》Ⅲ类标准,经过处理后的水可全部用于生产系统,实现零排放,同时为冶炼行业重金属废水治理和污染控制提供实践经验。     

制革废水中丙烯酸类鞣剂的膜分离特征

针对3种丙烯酸类鞣剂超滤(UF)、反渗透(RO)分离参数进行了实验研究,探索其在废水深度处理中膜去除的可行性,研究结果表明,3种鞣剂在分离参数:浓度为200 mg/L,超滤的操作压力(P UF)为0.11 MPa,反渗透的操作压力(P RO)为0.4 MPa的条件下UF-RO分离,效果最好。其次,丙烯酸类鞣剂对膜通量影响较大,导致产生的清液较少,所以用UF、RO处理含有这类物质的制革废水时,应尽可能对废水进行预处理。最后,丙烯酸类鞣剂分子中含有极性较强的基团时,粒径分离效果不同。