天津市PM 2.5水溶性无机离子污染特征与来源分析

比较了天津市雾霾天和非雾霾天PM_(2.5)中水溶性无机离子(SO_4~(2-)、NO_3~-、Cl~-、NH_4~+、Ca~(2+)、Na~+、Mg~(2+)、K~+)的污染特征,并对其来源进行分析。结果表明:(1)非雾霾天PM_(2.5)日均质量浓度为35～60μg/m~3,均值为43μg/m~3,雾霾天PM_(2.5)日均质量浓度为120～332μg/m~3,均值为242μg/m~3;雾霾天水溶性无机离子浓度均高于非雾霾天。(2)非雾霾天SO_4~(2-)主要来自大气中燃煤源的SO_2二次转化,NO_3~-主要来自一次污染源,雾霾天SO_4~(2-)、NO_3~-主要来自大气中燃煤源的SO_2、NO_2二次转化;非雾霾天NH_4~+主要以(NH_4)_2SO_4和NH_4NO_3的形式存在,雾霾天NH_4~+主要以NH_4NO_3和NH_4HSO_4的形式存在;Na~+、K~+、Cl~-除了海盐来源外,煤和生物质的燃烧及其二次转化是主要贡献源;Ca~(2+)和Mg~(2+)主要来自建筑扬尘源和土壤扬尘源。(3)风速和相对湿度是雾霾天SO_4~(2-)、NO_3~-、NH_4~+浓度变化的重要原因。     

碱性硫酸铝吸收与解吸二氧化硫的机理及性能

采用实验的方法研究了碱性硫酸铝溶液吸收和解吸SO_2机理,同时探讨了碱度20%、铝量20 g·L~(-1)的碱性硫酸铝溶液温度变化对SO_2吸收率的影响效果。结果表明,SO_2进入碱性硫酸铝溶液中首先发生的是与活性Al~(3+)的结合反应,当活性Al~(3+)消耗殆尽后,则进行与H_2O的结合反应;而在解吸过程中,首先是与H_2O结合的SO_2发生解吸反应,其后是与活性Al~(3+)结合的SO_2发生解吸反应。当吸收液温度低于50℃,且每升溶液中SO_2通入量不高于5 L时,其吸收率均能维持在95%以上。     

天津冬季PM_(2.5)中水溶性无机离子污染特征研究

2015年12月3—21日对天津冬季 PM2.5进行了采样分析,重点分析了 Na~+、Mg~(2+)、NH_4~+ 、Ca~(2+)、K~+、Cl~-、SO_4~(2-) 、NO_3~-8种水溶性无机离子,结合风速、相对湿度、温度等气象资料,并利用主成分分析对水溶性无机离子来源进行了解析。结果表明,风速小、气温高和相对湿度大的天气条件以及冬季燃煤的人为原因是引起霾天的重要原因。采样期间PM_(2.5)平均质量浓度为104.22μg/m~3。霾天中,轻微霾天、轻度霾天、中度霾天、重度霾天的PM_(2.5)中总离子平均质量浓度分别为27.63、26.89、105.03、143.92μg/m~3,远高于非霾天的15.43μg/m~3。SO_4~(2-)是水溶性无机离子中含量最高的离子,约占总离子的1/3,SO_4~(2-)、NO_3~-、Cl~-和NH_4~+浓度之和占总离子的90%以上。随着霾程度加重,NH_4NO_3占比增加,(NH_4)_2SO_4占比减少。水溶性无机离子主要来源于海盐粒子、生物质燃烧、机动车尾气排放和燃煤等。     

西安市全年中PM_(2.5)水溶性无机离子变化特征

采用ICS-1100型离子色谱仪在2014年6月到2015年6月期间对西安市大气中PM_(2.5)水溶性离子(NO_3~-、NH_4~+、SO_4~(2-)、NO_2~-、Cl~-、Na~+、Ca~(2+)、Mg~(2+)、K+)进行的实时监测,分析了全年PM_(2.5)中水溶性无机离子变化特征。结果显示:采样期间,西安市PM_(2.5)中NO_3~-、NH_4~+、SO_4~(2-)和Cl~-年均值占总离子的89.49%,且有明显月变化趋势,峰值出现在11和12月份,月浓度均值较往年同期降低,最高达到30.26、15.19、11.43和16.60μg·m~(-3)。Na~+、Ca~(2+)、Mg~(2+)和K~+浓度变化趋势与主离子不完全一致。NO_3~-均值大于SO_4~(2-)均值,表明PM_(2.5)中水溶性离子的主要贡献者为移动源。NO_3~-小时均值高于SO_4~(2-)小时均值,且在10:00和20:00处形成2个峰值。PM_(2.5)中NO_3~-与NO_2~-在0.05水平上显著相关,SO_4~(2-)与Cl~-的在0.01水平上极显著相关。     

北京西山典型游憩林内PM_(2.5)质量浓度及水溶性离子特征分析

以北京西山森林公园为观测点,运用双通道颗粒物在线监测设备监测PM_(2.5)质量浓度,使用离子色谱仪测定样品中水溶性离子浓度,对北京西山油松林PM_(2.5)质量浓度及水溶性离子特征进行分析。结果表明:PM_(2.5)质量浓度为冬季(121.29±16.78)μg·m~(-3)春季(106.06±12.68)μg·m~(-3)秋季(88.01±17.44)μg·m~(-3)夏季(72.67±12.18)pg·m~(-3);SO-4~(2-)、Na~+、N0_3~-、HC0O~-是PM_(2.5)中最主要的水溶性离子成分,占所测水溶性离子浓度在四季分别为94.99%、72.66%,72.66%、89.52%,PM_(2.5)受SO_4~(2-)、Na~+、N0_3~_、NH_4~+影响较大基本呈正相关关系,SO_4~(2-)、Na~+、N0_3~-、NH_4~+、PM_(2.5)浓度季节变化一致,即在冬季最高,夏季最低春秋次之,且水溶性离子季节差异显著。SO_4~(2-)和N0_3~-、Na~+、NH_4~+的相关性极显著(r=0.85、0.80、0.92),NO_3~-和Na~+、NH_4~+之间关系也较大(r=0.87,0.66),Ca~(2+)和Mg~(2+)相关性极明显(r=0.98),其他水溶性离子间无明显的相关性,固定源和海洋源对水溶性离子贡献程度呈现出季节差异,秋季机动车尾气排放对空气硫和氮污染贡献达最高,春季最低,夏秋季海洋源对Cl~-影响明显。通过对森林植被区PM_(2.5)、水溶性离子特征及关系进行分析,更好地发挥植被的生态效益,提高空气质量。     

济南市PM2.5化学组分及污染特征分析

为探讨济南市大气PM_(2.5)主要化学组分和污染特征,2017年在济南市开展了PM_(2.5)样品采集工作,分析了PM_(2.5)中有机碳(OC)、元素碳(EC)和水溶性离子浓度水平。结果表明:采样期间济南市PM_(2.5)中OC、EC年均质量浓度分别为9.10、2.68μg/m~3,全年OC与EC质量浓度的比值为3.4,二次有机碳污染严重;OC、EC季节分布特征明显,均为冬季浓度最高,且秋、冬季两者相关系数较高,表明秋季和冬季OC、EC来源较为一致。NO_3~-、SO_4~(2-)、NH_4~+年均质量浓度之和为34.29μg/m~3,占水溶性离子总量的88.9%,是济南市PM_(2.5)中最重要的组分;各水溶性离子浓度具有明显的季节变化特征,NO_3~-、SO_4~(2-)、NH_4~+、Cl~-和K~+均冬季浓度最高,而Ca~(2+)春季浓度最高;PM_(2.5)中NO_3~-与SO_4~(2-)质量浓度的比值为1.10,说明相比于固定污染源,移动污染源对济南市PM_(2.5)影响更大。     

NaClO_2/H_2O_2复合吸收剂同时脱硫脱硝实验研究

在喷淋塔中,对NaClO_2/H_2O_2复合吸收剂(简称复合吸收剂)同时去除烟气中的SO_2和NO进行了研究。考察了复合吸收剂摩尔浓度(H_2O_2与NaClO_2摩尔浓度之和)、H_2O_2和NaClO_2的摩尔比、pH、温度和液气比对SO_2和NO去除率的影响。结果表明:保持H_2O_2和NaClO_2的摩尔比为6,当复合吸收剂摩尔浓度小于7mmol/L时,SO_2和NO去除率随着复合吸收剂浓度的升高而增加,当复合吸收剂摩尔浓度大于7 mmol/L时,SO_2和NO去除率基本不再变化;保持复合吸收剂摩尔浓度为7 mmol/L,当H_2O_2和NaClO_2的摩尔比在6以下时,摩尔比越大,SO_2和NO的去除率越高,超过6以后,去除率不再增加;复合吸收剂的氧化性能在pH为5.5时最大;当温度在60℃以下时,随着温度的升高,NO的去除率增加,但当温度超过60℃后,NO的去除率反而降低。综合考虑成本和处理效果,最优化条件为H_2O_2和NaClO_2的摩尔比为6,复合吸收剂摩尔浓度为7 mmol/L,pH为6.0,温度为60℃,液气比为20.0L/m3。在最佳条件下,SO_2和NO去除率分别达到99.5%、84.3%。     

Fe~(3+)催化过氧化钙体系降解水中三氯乙烯

采用Fe~(3+)催化过氧化钙(CP)处理水溶液中三氯乙烯(TCE),考察了CP和Fe~(3+)投加量、地下水中常见阴离子和腐殖酸对TCE降解效果的影响。结果表明,Fe~(3+)催化CP体系可以有效降解TCE,但相同药剂投加量下效率低于Fe~(3+)催化H_2O_2体系。在TCE初始摩尔浓度为0.15mmol/L,CP和Fe~(3+)投加量分别为3.00、6.00mmol/L时,180min时TCE去除率达到了96.1%。常见阴离子Cl~-、HCO_3~-和SO_4~(2-)对TCE的降解有抑制作用,NO_3~-对TCE降解几乎无影响,而腐殖酸对TCE降解有促进作用。自由基清除实验表明TCE降解的主导自由基为HO·,Cl~-的释放效果显示HO·的氧化作用可使降解的TCE完全矿化。因此,Fe~(3+)催化CP技术适用于污染场地地下水中TCE的修复治理。     

Fenton法降解废弃聚乙烯醇面料的实验研究

采用Fenton法降解废弃聚乙烯醇(PVA)面料,以反应温度、初始pH、Fe~(2+)/COD质量比和H_2O_2/Fe~(2+)摩尔比为考察因素,得到最佳降解条件。结果表明,Fenton法的最佳降解条件为:反应温度60℃,pH=4,Fe~(2+)/COD质量比0.3,H_2O_2/Fe~(2+)摩尔比11。此时,降解质量浓度为50g/L的PVA面料废水,降解率超过90%,降解后黏均分子量下降了99.63%,COD去除率为61.57%,BOD/COD为0.46,吨水处理的经济成本为13 069.71元。     

秸秆基Li/Al层状双金属氢氧化物纳米复合吸附剂的制备及其除磷性能研究

将纳米Li/Al层状双金属氢氧化物(LDH)负载到改性小麦秸秆上制得秸秆基Li/Al LDH纳米复合吸附剂(简称复合吸附剂),并通过一系列单因素吸附试验对其除磷性能进行评价。结果表明:升高温度有利于该吸附剂的吸附;最佳吸附pH约为4;动力学实验表明,100min时吸附过程即可达到平衡;以NO_3~-、Cl-、SO_4~(2-)作为共存离子,3者对于复合吸附剂除磷的影响程度为SO_4~(2-)Cl-NO_3~-,且共存离子浓度较高时复合吸附剂对磷仍有较好的吸附选择性;脱附再生实验表明,使用5mol/L NaOH和0.01mol/L NaCl的混合溶液可达到较好的脱附效果。     

Optimization of Height of Release of Air Pollutants

A number of key projects in the Environmental Protection Agency (EPA) particulate R&;D program having applicability to industry are presented. For electrostatic precipitators (ESP) there is presented the result of work on large diameter discharge electrodes which provide a decrease in penetration of up to a factor of 4 when compared to conventional small diameter electrodes. Also discussed is the multistage ESP which provides a collection efficiency that would require a collecting plate area 4 or 5 times larger with conventional ESP technology. The E-SOX technology makes use of the multistage concept to free up space in the ESP for SO₂ removals of up to 90%. Electrostatically augmented fabric filtration provides a reduction in pressure drop of about 5 0% as compared to conventional fabric filtration. Wind tunnel modeling of windbreaks for material storage piles indicates a potential for providing engineering design data that would allow significant emission reduction caused by wind erosion     

Investigation of the characteristics of the reflectivity of clouds

This paper investigates some of the reflectivity characteristics that clouds (when modelled as solid bodies) must exhibit to be compatible with observations that the reflecting surface of a cloud (i) appears almost equally bright across its face, (ii) is brightest when the cloud is opposite to the Sun but decreases in brightness as the cloud moves to other positions and (iii) increases in brightness with increasing optical thickness of the cloud in the observer's line of sight. These observations, respectively, are shown to imply that the peak value of the bidirectional total reflectivity from a cloud surface (i) increases in inverse proportion to the cosine of the angle between the Sun and the normal to the cloud surface, as the incident angle increases, (ii) appears to be directed back in the direction of the incident radiation, and (iii) increases as optical thickness of the cloud in the observer's line of sight increases. The results could have application in many fields (e.g. modelling diffuse radiance distributions for cloudy skies).     

Estimation of uncertainty of sampling for analysis of pesticide residues

Abstract

A computer model was used to take random samples from primary sample populations obtained from field trials to simulate the uncertainty of sampling for residue analysis of plant commodities and soil. The results indicate about 40%, 30% and 20% relative uncertainty when random samples of size 5, 10 and 25 are taken respectively, from a single lot. Therefore the sample size should be the same for establishing and enforcing legal limits.     

扬中生态环境建设的思考与实践

结合扬中生态环境的基本情况和存在的不足，进行了具体分析，对扬中未来生态建设的发展方向提出了建议及实施措施。     

An application of the theory of kinematics of mixing to the study of tropospheric dispersion

The most common technique used for numerical simulations of tracer mixing is that of the numerical solution of the advection–diffusion equation with the unresolved fluxes parameterized using the similarity theory. Despite correct predictions of the overall directions of transport, models based on a numerical solution of the advection–diffusion equation lack sufficient accuracy to correctly reproduce the coupling of mixing with small scale processes which are sensitive to the microstructure of the tracer distribution. The objective of this paper is to revisit the basic formalism employed in numerical models used to investigate atmospheric tracers. The main mathematical method proposed here is the theory of kinematics of mixing which could be applied effectively for simulations of atmospheric transport processes. At the beginning of the paper, we introduce simple mathematical transformations in order to demonstrate how complex topological structures are created by mixing processes. These idealistic flow systems are essential to explain transport properties of much more complex three-dimensional geophysical flows. An example of the application of the kinematics of mixing to the analysis of tracer transport on a planetary scale is presented in the following sections. The complex filamentary structures simulated in the numerical experiment are evaluated using some commonly applied statistical measures in order to compare the results with the data published in the literature. The results of the experiment are also analysed with the help of simple conceptual models of fluid filaments. The microstructure of the tracer distribution introduced in the paper is essential to increase our understanding of atmospheric transport and to develop more realistic parameterizations of small-scale mixing. The presented results could also be used to improve calculations of the coupling between microphysical processes and tracer mixing.     

次氯酸钠发生器的研制

介绍了电解法生产次氯酸钠的原理 ,并在原有生产工艺的基础上进行了重新设计和对设备的重新选择、改造 ,得出了各个工艺参数的最佳值 ,生产出高品质的次氯酸钠     

实验室质量管理体系内部审核的实施

在实施ISO／IEC17025：1999标准《检测和校准实验室能力的通用要求》过程中，通过实验室质量管理体系内部审核的实践与系统分析，识别出内部审核实施阶段的关键环节，提出召开首次会议、收集审核证据、确定审核发现和召开末次会议的技术方法，对提高内部审核的质量和有效性、获得可靠的审核结论具有重要意义。     

实验室质量管理体系内部审核的策划

在实施ISO／IEC 17025：1999标准《检测和校准实验室能力的通用要求》过程中，通过实验室质量管理体系内部审核的实践与系统分析，识别出内部审核策划阶段的关键环节，提出审核范围确定、审核计划和抽样方案制订的质量控制要求，为有序高效地实施内部审核提供了技术方法。     

Characterization of products of ozonolysis of acrylonitrile in liquid phase

In order to elucidate the reaction mechanism of the ozonolysis of acrylonitrile in the liquid phase, characterization of reaction products has been attempted. One of the products, which was volatile, has been found to be formaldehyde by derivatizing with dimedone. The infrared and mass spectra of the derivative corresponded with that of alkylidene dimedone. Three other reaction products were isolated by TLC using silica gel, CHCl₃:MeOH (80:20). These have been tentatively identified as glyoxal, epoxide of acrylonitrile and acetamide from their mass spectra. Based on these findings a reaction pathway for the formation of formaldehyde is proposed to be that described by Criegee.