首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到19条相似文献,搜索用时 218 毫秒
1.
北京大气气溶胶单个颗粒的化学表征   总被引:37,自引:1,他引:37  
汪安璞  沙因 《环境化学》1996,15(6):488-495
用安德逊分级采样器采集京都三个点(北辛安,冷泉村和生态环境研究中心)的大气气溶胶颗粒,用扫描电镜/X射线能谱观察和分析单个颗粒的形貌和元素成分,对粗细颗粒分别进行了X射线物相分析,通过对颗粒的形貌,组分和化合物形态等的综合分析结果表明,细粒样品中常含有较多的铁或铵的硫酸盐及氯化铵,粗粒样品中则主要为矿物物质如石英,方解石,石膏,白云石和一些粘土矿物,圆形颗粒可能是煤的燃烧产物,许多不规则形的颗粒大  相似文献   

2.
利用ICP-AES和AAS测得大熊猫、黑熊和小熊猫毛发中Mg、Al、P、K、Ca、Ti、V、Cr、Mn、Fe、Co、Ni、Cu、Zn、As、Se、Sr、Cd、Ba、Hg和Pb等21种无机元素。对几种与生理机能密切相关的元素的组分含量进行对比分析结果表明:大熊猫毛发中元素V、cu以及Cd的含量高于黑熊和小熊猫,而Zn和Se的含量低于黑熊和小熊猫;与黑熊和小熊猫相反,大熊猫雄兽毛发中元素K和Mn的含量高于雌兽含量。  相似文献   

3.
煤的化学脱硫研究   总被引:3,自引:1,他引:3  
高子群  胡旭东 《环境化学》1994,13(6):486-491
以我国的三种高硫煤-山东兖州、四川南楠、东林煤为试验煤样,考察了Fe2(SO4)3溶液和NaOH溶液加热处理的脱硫作用,以及热解时煤中有机硫的变化。试验发现,用2mol/lFe2(SO4)3在反应温度100℃,反应时间4h下,可脱除近80%的硫铁矿硫;经6%NaOH溶液处理后再用5%HCl浸煮,即可有效脱除煤中矿物质,也能明显脱硫;在煤热解时,煤中有机硫大部分滞留于煤焦中,被脱除的硫主要以H2S形  相似文献   

4.
贵州省原煤中微量元素的组成特征   总被引:10,自引:0,他引:10  
倪建宇  冯新斌 《环境化学》1998,17(4):339-344
研究了贵州省各主要煤田中主要采煤层的As,B,Ba,Be,Cd,Co,Cr,C,Hg,Li,Ni,Pb,Sb,Se,Sr,Tl,V,Zn等微量元素的组成特征,贵州省原煤中微量元素的含量总体上的世界范围内的一致,但Sb,As,Hg等有害元素则明显富集,由于煤炭成因上的特殊性,其微量元素的组成除受煤植物的影响外,后期在煤作用对其有决定性的影响。  相似文献   

5.
2℃低温下冬小麦幼苗质膜Ca^2+—ATPase的活性变化   总被引:1,自引:0,他引:1  
用氯化铈(CeCl3)沉淀的电镜细胞化学方法,对常温下及2℃低温自理后的冬小麦(Triticum aestivium L.)幼苗质膜Ca^2+_ATPase活性进行定位。结果显示:(1)常温下生长的冬小麦幼苗,质膜上有部分Ca^2_ATPase活性反应。(2)冬小麦幼苗经2℃低温处理1h,质膜上Ca^2_ATPase活性增加。处理3h,活性进一步加强。2℃下处理12h,有强的酶活性反应。处理24h  相似文献   

6.
天津市土壤风沙尘元素的分布特征和来源研究   总被引:8,自引:0,他引:8  
通过与土壤标准和背景值的比较分析了天津市土壤风沙尘元素的质量分数分布特征,通过富集因子法分析了天津市风沙尘元素的富集特征,进而说明天津市风沙尘元素的来源及其变化。结果表明,(1)Cr、Ni、Cu、Zn和As质量分数均有超过土壤标准的现象。(2)Ni、Cu、Pb、Zn和Ag超过背景值10倍以上,受到了人为污染。(3)粗颗粒中西青区的Pb元素,津南区的Ni元素和Pb元素以及细颗粒中东丽区的Ca元素和Zn元素,西青区的Cu、Pb,津南区的Cr、Ni、Pb等元素达到显著污染级别;各区粗细颗粒中的Ag元素污染级别最高,有的为极强烈污染;这些元素是典型的人为污染元素。(4)粗颗粒中只有Ca和Ni污染级别有所增加,细颗粒中只有Na、Ni、As等3种元素的富集因子略有增加。所以,天津市土壤风沙尘的治理重在控制人为来源的Ni、Cu、Pb、Zn、Ag、Cr和Ca等高污染元素。  相似文献   

7.
煤中痕量元素分布的多变量分析及实验研究   总被引:10,自引:1,他引:10  
陆晓华 Ali  A 《环境化学》1995,14(6):494-499
本文用多变量分析法研究了煤中痕量元素的分布,并用实验研究了有机溶剂提取前后青山烟煤中痕量元素的变化。多变量分析结果表明:As,Cr,Co,Ni,Cu,Cd,V,Pb等元素与Be,Ge在煤中具有不同的分布特征,对青山烟煤的实验研究结果则表明:Cr,Co,Ni,Cu,Cd,Pb等元素趋向于与煤中的矿物质相结合,而Be,Ge两元素有较强的有机亲和性。实验研究结果与多变量分析结果相符。  相似文献   

8.
型煤燃烧固硫的钠离子效应   总被引:15,自引:0,他引:15  
傅勇  林国珍 《环境化学》1994,13(6):492-497
本文用脉冲二氧化硫荧光分析仪连续测试了煤样中二氧化硫的浓度,并用X荧光、X衍射和电子扫描电镜等方法,分析了添加钠离子样品的含硫率、物相及表面形貌。实验结果表明,钠离子添加剂改变了二氧化硫释放过程,抑制了硫酸钙的分解。灰样成分中既有稳定的三元化合物3CaO.3Al2O3.CaSO4,也有不稳定的化合物硫酸钙存在,说明钠离子添加剂对提高固硫率有促进作用。  相似文献   

9.
型煤燃烧过程中CaS的形成及其固硫作用   总被引:6,自引:0,他引:6  
吕欣  周广柱 《环境化学》1998,17(6):528-531
本文研究了不同温度和燃烧条件下Fe-Si体系钙基固硫剂的作用效果,实验表明,煤粒子子直接进入已达一定的温度的炉内时,其固硫效果较在程序升温条件下明显提高,在1300℃高温仍肌77%的固硫率,含硫物相以CaS为主,该条件下造成了煤粒子的缺陷氧燃烧,由此造成的局部还原气氛促了CaS为主。从而提高固硫率,Ca可能是高温条件的理想固硫产物。  相似文献   

10.
含磷酸盐的三氯化铁水解溶液的化学特征   总被引:30,自引:0,他引:30  
田宝珍  汤鸿霄 《环境化学》1995,14(4):329-337
通过对含磷酸盐三氯化铁水解溶液的pH驰豫,电导率,可见光光谱和不同化学反应活性组分的分布等一系列化学物理性质的表征,说明在FeCl3-NaH2PO4-NaHCO3溶液体系中,PO4^3参与了Fe(Ⅲ)的水解-聚合反应,形成了Fe-OH-Fe-PO4-Fe结构共同控制溶液性质。使溶液性质发生了从量变到质变的过程,证明PO4^3对Fe(Ⅲ)溶液的水解形态有重要影响。  相似文献   

11.
The bulk magnetic susceptibility of sediments from artificial and natural lakes around a large coal-fired power station in NE Spain has been measured. Higher magnetic susceptibility values are found in lake sediments located SE of the power station. This distribution of susceptibility values is compatible with environmental and meterological studies of emissions from the power station, which indicate a dominant SE plume direction. Mineralogical studies, by means of X-ray diffraction and scanning electron microscopy, show that the highest susceptibility values found in the sediments are caused by magnetic iron spinels in the fly ash that is transferred to the environment by the power station particulate emissions. After the quantitative mineralogical studies of fly ash, two different methods of fly ash content determination in the sediments have been devised, showing very similar results. The low background magnetic susceptibility of the sediments in the study area and the high susceptibility resulting from the input of magnetic fly ash particles allows both delimitation of the polluted area around the power station, and quantification of the fly ash input into the natural sediments.  相似文献   

12.
孙敏  唐莹  郝亚婷  季宏兵 《环境化学》2021,40(3):678-686
酸雨对露天粉煤灰堆积场的淋滤作用导致周围环境产生重金属污染是一种广泛现象.为研究酸雨对贵阳市水源地红枫湖周边一大型粉煤灰堆积场的重金属迁移影响,本文以这一粉煤灰堆积场为研究对象,通过静态淋溶实验探讨了粉煤灰中Cr、Ni、CU、Zn、AS、Cd、Pb等7种重金属元素的含量、存在形态、淋溶时间、堆积时间、粒度对重金属溶出规律的影响.结果表明,粉煤灰中Ni、Cu、Zn、Pb、As和Cd等6种重金属的含量随堆积时间增加而增大,Cr含量变化与上述反之;在淋溶实验中,堆积时间的增加使Cr、Ni、Cu和Zn重金属元素的可溶态减小;在淋溶第28—48天期间,Cr、Ni和Cu元素溶出浓度降低的粒度顺序为细粒度>中粒度和粗粒度、Cd元素溶出浓度降低的粒度顺序为中粒度>粗粒度>细粒度.本研究对红枫湖水源地和周边地下水的重金属防控提供一定的参考依据.  相似文献   

13.
Fly ash is a hazardous byproduct of municipal solid wastes incineration (MSWI). An alkali activated blast furnace slag-based cementitious material was used to stabilize/solidify the fly ash at experimental level. The characteristics of the stabilized/solidified fly ash, including metal leachability, mineralogical characteristics and the distributions of metals in matrices, were tested by toxic characteristic leaching procedure (TCLP), X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectrometer (SEM-EDS) respectively. Continuous acid extraction was utilized to extract metal ions and characterize their leaching behavior. The stabilization/solidification procedure for MSWI fly ash demonstrates a strong fixing capacity for the metals by the formation of C-S-H phase, hydrated calcium aluminosilicate and ettringite. The stabilized/solidified fly ash shows a dense and homogeneous microstructure. Cr is mainly solidified in hydrated calcium aluminosilicate, C-S-H and ettringite phase through physical encapsulation, precipitation, adsorption or substitution mechanisms, and Pb is mainly solidified in C-S-H phase and absorbed in the Si-O structure.  相似文献   

14.
焚烧炉飞灰熔融处理组成特性分析   总被引:2,自引:0,他引:2  
将焚烧飞灰在不同温度下进行熔融实验,用扫描电镜对熔融前后试样的微观结构和形貌变化进行比较,结果显示:熔融体表观结构平整光滑,有较高的硬度,其断面有光泽产生且无明显气孔,试样已达到完全熔融;用X射线衍射分析仪对试样熔融前后成分的变化进行分析,未经熔融处理的试样主要晶相为:NaCl,KCl,SiO2,CaCO3,CaSO4,Ca2SiO4以及Ca12Al14O33,CaS和钙黄长石为熔融后试样的主要晶相.其次还有CaO和透灰石;浸出实验结果显示熔融处理后飞灰的毒性得到降解.  相似文献   

15.
The technical feasibility of utilization of fly ash as a low-cost adsorbent for the removal of metals from water has been studied. For two types of fly ashes, the retention capacities of copper, lead, and zinc metal ions have been studied. Contact time, initial concentration, and pH have been varied and their effect on retention mechanism has been studied. The dominant mechanisms responsible for retention are found to be precipitation due to the presence of calcium hydroxide, and adsorption due to the presence of silica and alumina oxide surfaces in the fly ash. First-order kinetic plots have revealed that the rate constant increases with increase in the initial concentration and pH. Langmuir adsorption isotherms have been plotted to study the maximum adsorption capacities for metal ions considered under different conditions. X-ray diffraction studies revealed the formation of new peaks corresponding to respective metal ions precipitates under alkaline conditions.  相似文献   

16.
The purpose of this study was to determine heavy metal concentrations in ash samples taken from the filter of the gas cleaning system of biomass incinerators in Austria. Knowing the concentrations of heavy metals is important for the decision of further treatment or utilization of the ashes. The heavy metals contained in the ashes remain in the bottom ash of the incinerator or leave the incinerator with the off-gas and are collected in the off-gas filter. The amount of the metals in the collected fly ash depends on the composition of the input material. The aim of this study was to examine this influence and compare the results with literature data. For measurement, the fly ash samples were at first dissolved in a microwave digestion unit using nitric acid and hydrochloric acid. Afterwards, 20 metals were analyzed by inductively coupled plasma optical emission spectrometry. Al, Fe, Mg, Mn, and Zn were found in higher concentrations in the fly ash samples. The enrichment factor between the concentrations in the fly ash and the concentrations in the input material was on average in the range of 18.  相似文献   

17.
• Washed MSWI fly ash was used as partial cement or sand substitute. • Sand replacing is beneficial for strength, while cement replacement reduces strength. • Cementing efficiency factor and mortar pore structure explain the strength results. • Health risk assessment was conducted for MSWI fly ash blended cement mortar. • CR and HI contributed by different exposures and heavy metals were analyzed. The strength of cement substituted mortar decreases with the increase in fly ash amount, whereas the strength increases when the fly ash is blended as sand substitute. A mortar with highest strength (compressive strength= 30.2 Mpa; flexural strength= 7.0 Mpa) was obtained when the sand replacement ratio was 0.75%. The k value (cementing efficiency) of fly ash varied between 0.36 and 0.15 for the fly ash fraction in binder between 5% and 25%. The k values of fly ash used for sand replacement were all significantly above that used for cement substitution. The macropores assigned to the gaps between particles decreased when the fly ash was used as sand replacement, providing an explanation for the strength enhancement. The waste-extraction procedure (toxicity-sulphuric acid and nitric acid method (HJ/T 299-2007)) was used to evaluate metal leaching, indicating the reuse possibility of fly ash blended mortar. For the mortar with the mass ratio of fly ash to binder of 0.5%, the carcinogenic risks (CR) and non-carcinogenic hazard quotient (HQ) in sensitive scenario for blended mortar utilization were 9.66 × 10-7 and 0.06, respectively; these results were both lower than the threshold values, showing an acceptable health risk. The CR (9.89 × 10-5) and HQ (3.89) of the non-sensitive scenario for fly ash treatment exceeded the acceptable threshold values, indicating health risks to onsite workers. The main contributor to the carcinogenic and non-carcinogenic risk is Cr and Cd, respectively. The CR and HQ from inhalation was the main route of heavy metal exposure.  相似文献   

18.
城市垃圾焚烧飞灰中重金属的形态及酸浸出性研究   总被引:3,自引:1,他引:3  
王涛  刘廷凤  高占啟  孙成 《环境化学》2007,26(5):658-661
研究了城市垃圾焚烧飞灰中重金属形态在不同粒径上的分布,以及HNO3对飞灰中重金属的浸出性.结果表明:飞灰中重金属主要以残渣态存在,可交换离子态含量很少;易挥发性的重金属在较大粒径上有较高分布,亲石性重金属Cr和Ni的分布与粒径的相关性不大,在各粒径上的分布较均匀;飞灰中以碳酸盐结合态存在的重金属对酸不稳定,易被HNO3浸出,而残渣态部分对酸较稳定,不易被HNO3浸出.  相似文献   

19.
本文研究了湖北省武当山风景区石英云母片岩发育的7个土样的粘土矿物组成、粘粒氧化物含量。土壤电荷量及电荷零点.结果表明:(1)供试土壤粘土矿物均以2∶1型矿物占优势,在海拔440m以下的土壤中主要是水云母和蛭石,在海拔670m以上的土壤中主要是1.4nm过渡矿物、绿泥石和水云母;(2)土液粘粘中氧化铁和氧化铝的含量、粘粒硅铝率及氧化铁的游离度随海拔的变化而变化的趋势不甚明显,但非晶形铝铁氧化物的含量及氧化铝和铁的活化度随海拔升高而趋于增加;(3)土壤可变负电荷量、阴离子吸附量和电荷零点随海拔升高而趋于增加。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号