环境样品中有机氯化合物的监测分析

有机物对环境的污染日益受到各国的关注,尤其是多氯代二苯并－ｐ－二类（ＰＣＤＤｓ）、多氯代二苯呋喃（ＰＣＤＦｓ）和ＰＣＢｓ等。在我国新修订的“污水综合排放标准”中,也增加了许多有机氯化物项目;本文就二类等有机氯化物的环境监测分析方法作以概括介绍。     

固废焚烧氯化物的测试分光光度法

研究以丙酮作为增容剂,硝酸银为沉淀剂,氯化银浊度法测试固废焚烧吸收液中氯离子的试验条件。测定波长为360nm,氯化物含量在0mg/L~40mg/L呈线性关系。     

硝酸银滴定法测量水中氯化物含量的不确定度评定

采用硝酸银滴定法测量水中氯化物含量,根据化学分析项目建立数学模型,对测定水样中氯化物的不确定度来源-配制NaCI标准溶液、标定AgNO3标准溶液浓度、测水样消耗AgNO3溶液体积、取水样体积、样品重复性测定等参数引入的不确定度分量进行识别和分析,进而对所有不确定度分量进行量化,得出测量不确定度结果,提出了该方法的合成不确定度及监测过程中的注意环节。     

氯化物排放标准的制定

河北省是工业大省,一些企业生产过程排放的污水中含大量的氧化物,由于目前国家没有制定相应的排放标准,造成企业在排污过程中无限制地排放,直接影响了水环境质量。河北省为加强地方流域的水环境管理,依法限制污染物的排放,提出了河北省特征污染物氯化物地方排放标准的制定原则、方法和基本思路。     

离子色谱法测定黄河鄂尔多斯段水体中F-、Cl-、NO3-、SO4 2-浓度

随这鄂尔多斯经济的迅猛发展,城市规模的不断壮大。鄂尔多斯市制定了引用黄河水的战略措施。使黄河水成为鄂尔多斯城市居民的日常生活水源,所以黄河鄂尔多斯段的水质问题成为当地居民的热议话题。而其中F-、Cl-、NO3 -、SO4 2- 几种离子是作为水源地的必测项目。其水体的基本特点是泥沙含量高,浑浊,有机物含量丰富,因此Cl-、SO4 2-含量比较高,F-、NO3-含量比较小。笔者通过对实际样品有效的预处理,并选择恰当的稀释倍数,用ICS-1500离子色谱一次进样同时测定了F-、Cl-、NO3-、SO4 2-取得了满意的结果。     

Investigation of heavy metal partitioning influenced by flue gas moisture and chlorine content during waste incineration

The impact of moisture on the partitioning of the heavy metals including Pb,Zn,Cu and Cd in municipal solid waste (MSW) was studied in a laboratory tubular furnace.A thermodynamic investigation using CHEMKIN software was performed to compare the experimental results.Simulated waste,representative of typical MSW with and without chlorine compounds,was burned at the background temperature of 700 and 950°C,respectively.In the absence of chlorine,the moisture content has no evident effect on the volatility of Pb,Zn and Cu at either 700 or 950°C,however,as flue gas moisture increasing the Cd distribution in the bottom ash increased at 700°C and reduced at 950°C,respectively.In the presence of chlorine,the flue gas moisture reduced the volatility of Pb,Zn and Cu due to the transformation of the more volatile metal chlorides into less volatile metal oxides,and the reduction became significant as chlorine content increase.For Cd,the chlorine promotes its volatility through the formation of more volatile CdCl 2.As a result,the increased moisture content increases the Pb,Zn,Cu and Cd concentrations in the bottom ash,which limits the utilization of the bottom ash as a construction material.Therefore,in order to accumulate heavy metals into the fly ash,MSW should be dried before incineration.     

纳米双金属体系催化降解有机氯化物研究进展

综述了国内外在双金属体系催化降解氯代芳香烃及衍生物、氯代脂肪烃、有机氯农药等有机氯化物领域的研究情况,简要分析了纳米双金属体系的还原脱氯反应机理和优缺点,并讨论了该研究领域的发展前景。     

Speciation evolutions of target metals （Cd,Pb） influenced by chlorine and sulfur during sewage sludge incineration

In sludge incineration, the thermal behavior of heavy metal is a growing concern. In this work, the combined analysis of metal partitioning behavior between vapor phase and condensed phase, speciation redistribu- tion in condensed phase and the difference of metal species in binding energy was carried out to investigate the possible volatilization-condensation mechanism of heavy metals in high-temperature sludge incineration. It was found that there were two steps in metal volatilization. The initial volatilization of heavy metal originated from their exchangeable （EXC）, carbonate bound （CAR） and iron- manganese bound （FM） fractions, which is primarily composed of simple substance, chlorides, oxides and sulfides. With the increase of chlorine and sulfur in sludge, the inner speciation redistribution of heavy metals occurred in condensed phase, which was an important factor affecting the potential volatility of heavy metals. A partial of metal species with complexed （COM） and residual （RES） fractions gradually decomposed into simple substance or ions, oxides and carbonates, which signifi- cantly strengthened the second volatility. In presence of chlorine, about 46% of Cd with the RES fraction disappeared when the volatility rate of Cd increased by 44.89%. Moreover, about 9% of Pb with COM fraction disappeared when there was an increase of nearly 10% in the volatilization rate. Thus, the second volatilization was mainly controlled by the decomposition of metal species with COM and RES fractions. By virtue of XRD analysis and the binding energy calculation, it was found that metal complex and silicates were inclined to decompose under high temperature due to poor thermo stability as compared with sulfates.     

南通长江口北支咸潮上溯对水环境的影响

针对长江口北支近20多年来咸潮超常上溯的状况,通过现场调查监测及与文献资料对比,分析了咸潮上溯对水源地供水水质、河口区河道水质和地下水水质的影响。结果表明,长江口北支咸潮上溯对北支水环境影响主要在于入侵时水体中电导率和氯化物浓度急剧升高,一定程度上影响了北支沿线水源地的供水功能。咸潮对现有水质评价体系下的水质类别影响尚不明显,但高氯离子对化学需氧量的测定有明显的干扰。由于受堤围和水闸控制,咸潮期间入江闸门普遍关闭,导致间接水环境影响,主要集中在入海主河道。部分区域咸潮上溯严重时氯化物浓度升高,水质已不能满足农田灌溉需求。北支沿线启东市24%的地下水采样点氯化物浓度已属轻度入侵水,采样区域已属于海水轻度入侵范围。     

应用蚕豆微核技术对煤矿塌陷塘水质的监测

用蚕豆微核技术对淮南大通和谢二煤矿塌陷塘的水体水质进行监测,同时测定了水体的氯化物、电导率、CODCr、BOD5、DO和总磷、总氮。结果表明:大通和谢二煤矿塌陷塘水质已经受到中度污染;蚕豆微核技术与氯化物、电导率、CODCr、BOD5、DO和总磷、总氮具有一定的相关性。