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1.
挥发酚的测定一般采用4一氨基安替比林光度法[1]。酚浓度小于0.1mg/L的采用4—氨基安替比林萃取光度法.大于0.1mg/L的采用4—氨基安替比林直接光度法。在例行监测中,我们事先并不知道水样中酚浓度的高低、仅根据以往的经验判断,这种判断时常有失误。由于直接法和萃取法所取馏出液的体积不同.加试剂的量也不同.当显色后发现浓度不在所用方法的范围之内时.只得重取水样.预蒸馏后用另一种方法显色测定,费时费力。为此.我们对直接法进行了改进,使其与萃取法所取馏出液体积相同,加试剂的量也相同.显色后若颜色较深.即用直接法…  相似文献   

2.
硫化物存在时直接测定工业废水中氰化物金芳澄(福建省环境监测中心站350003)一般来说废水中氰化物测定,先进行蒸馏,然后将馏出液用硝酸银标准溶液进行滴定。由于蒸馏操作耗时又麻烦,本文探讨革除蒸馏、直接滴定废水中氰化物,用硝酸铅沉淀样品中硫化物以排除干...  相似文献   

3.
有资料显示,不同总氰化物浓度的样品,同一时间内蒸馏出的氰化氢浓度和馏出速率存在较大差异,选择合适浓度和体积的氢氧化钠溶液是充分吸收氰化氢的关键。另外,蒸馏是耗时、耗水、耗电的过程,当氰化氢和可挥发性酸性气体的绝大部分已收集至蒸馏初期的若干毫升馏出液中时,蒸馏后期蒸馏出的只是水蒸气,故选择合适的馏出液体积,既可满足实验准确度要求,又可节能省时。  相似文献   

4.
偶氮比色法测定工业废水苯胺时预蒸馏操作的改进姜军(江苏盐城市环境监测站,盐城224002)苯胺测定的水样预蒸馏通常都是在蒸馏快结束前加入20ml蒸馏水继续蒸至所需体积。本文改为20ml水在蒸馏前先加入,一次蒸馏至馏出液为100ml止。经对照试验,结果...  相似文献   

5.
通常水中挥发酚的测定,均通过蒸馏预处理,并规定在蒸出原水样的90%体积后,加入原水样的10%体积的无酚水;—继续蒸馏至获得与原水样体积相同的馏出液,再以容量法或光度法测定。此一操作较为繁杂,且由于在第一次蒸馏后,需间隔稍长时间,方可打开磨砂瓶塞,然后加水并进行第二次蒸馏,致使操作周期延长,不利于大批样品的分析。  相似文献   

6.
异烟酸-巴比妥酸分光光度法测定水中总氰化物的探讨   总被引:1,自引:0,他引:1  
对异烟酸-巴比妥酸分光光度法测定水中总氰化物的试验条件进行了探讨,分析了蒸馏时馏出液体积对结果的影响,明确了显色剂的配制及保存时效等问题。提出样品预蒸馏时可适当减少馏出液的收集体积,测定结果无显著性差异;将氯胺T、异烟酸-巴比妥酸试剂在冰箱中于4℃保存,在正常情况下可稳定使用4周。  相似文献   

7.
采用城市绿地和降雨系统模拟装置,研究绿地系统对径流污染物的净化机理。研究表明,模拟绿地对径流污染物的削减和污染物总量的控制有较好作用。降雨0.5h内污染物质主要被0cm-15cm层土壤所吸附,2h后各层对有机质、氮磷的吸附能力基本相同。绿地系统对径流污染物中COD、NH4^+ -N、NO3^- -N及TP去除率为37.6%~49.9%;降雨期间污染物的去除主要靠土壤和植物根系的截留、吸附和吸收作用,因此对土壤NH4^+ -N、NO3^- -N及TP的吸附过程用Langmiur方程进行拟和,发现土壤对NH4^+ -N及TP的吸附反应在常温下自发进行程度较强,对NO3^- -N的吸附反应在常温下较难进行。且降雨后微生物开始降解吸附于土壤颗粒表面和植物根系的污染物,降雨后第5d~8d,土壤中微生物数量达到最大值,说明雨后土壤中污染物的降解主要发生在降雨后第2d-8d内,且t4d~17d土壤污染物含量基本降到降雨前水平,土壤得到再生.  相似文献   

8.
对挥发酚测定时预蒸馏处理方法的改进陈国云(江都市环境监测站225200)测定水中挥发酚时,需进行预蒸馏处理,据《水和废水监测分析方法》(以下简称《方法》)规定:预蒸馏时,取250ml水样,在加热蒸馏出约225ml馏出液时,停止加热,放冷.向蒸馏瓶中加...  相似文献   

9.
1实验方法 :取 2 50 ml含酚水样的蒸馏液于50 0 ml分液漏斗中 ,加入 2 .0 ml缓冲溶液 ,混匀 ,此时 p H为 1 0 .0± 0 .2。加入 1 .5ml 4 - AAP溶液 ,混匀 ;再加入 1 .5ml铁氰化钾溶液 ,混匀。同时做一试剂空白实验 ,然后均以蒸馏水为参比 ,显色1 5min后 ,用 1 cm比色皿在 72 2型分光光度计上于波长 51 0 nm处测量吸光度 ,得出试剂空白值和含酚量溶液吸光度差值 ΔA。n=7时 ,相对标准偏差 2 .75% ;回收率 92 .5%~ 96.7%。2注意事项 :必须蒸馏 ,以消除色度、混浊和金属离子干扰 ;收集馏出液体积要与原蒸馏体积相当 ,否则影响测定结果。水中…  相似文献   

10.
示波极谱滴定法测定工业废水中的氰化物   总被引:1,自引:0,他引:1  
在pH为103的氯化铵氨水底液中,使氰化物与Ni2+离子形成稳定物〔Ni(CN)4〕2-络离子,过量的Ni2+离子用标准EDTA溶液返滴,以Ni2+离子在交流示波极谱图上的切口消失指示滴定终点,废水的色度、浊度等对测定不产生干扰,无须进行预蒸馏处理,操作简便,快速。方法的相对偏差小于10%,变异系数小于07%,水样的加标收率为96~107%。  相似文献   

11.
对火焰原子吸收分光光度法测定饮用水中银的方法作了改进。试验发现在酸性条件下,不利于银的测定,改加氨水氰化钾溶液则取得满意的结果,提高了测定灵敏度。银的特征质量浓度为0 016mg·L-1/1%吸收,检测限为0 001mg/L,相对标准差<2.5%,加标回收率在98%~103%之间。  相似文献   

12.
Water quality throughout south Florida has been a major concern for many years. Nutrient enrichment in the Indian River Lagoon (IRL) is a major surface water issue and is suggested as a possible cause of symptoms of ecological degradation. In 2005-06, water samples were collected weekly from seven sites along Ten Mile Creek (TMC), which drains into the Indian River Lagoon, to investigate and analyze spatial and temporal fluctuations of nutrients nitrogen (N) and phosphorus (P). The objective of this study was to understand the relationships among chlorophyll a concentration, nutrient enrichment and hydrological parameters in the surface water body.High median concentrations of total P (TP, 0.272 mg L(-1)), PO4-P (0.122 mg L(-1)), and dissolved total P (DTP, 0.179 mg L(-1)); and total N (TN, 0.988 mg L(-1)), NO3(-)-N (0.104 mg L(-1)), NH4+-N (0.103 mg L(-1)), and total Kjeldahl N (TKN, 0.829 mg L(-1)), were measured in TMC. The concentrations of TP, PO4-P, DTP, TN, NO3(-)-N, NH4+-N, and TKN were higher in summer and fall than in winter and spring. However, chlorophyll a and pheophytin concentrations during this period in TMC varied in the range of 0.000-60.7 and 0.000-17.4 microg L(-1), with their median values of 3.54 and 3.02 microg L(-1), respectively. The greatest mean chlorophyll a (10.3 microg L(-1)) and pheophytin (5.71 microg L(-1)) concentrations occurred in spring, while the lowest chlorophyll a (1.49 microg L(-1)) and pheophytin (1.97 mug L(-1)) in fall. High concentrations of PO4-P (>0.16 mg L(-1)), DTP (>0.24 mg L(-1)), NO3(-)-N (>0.15 mg L(-1)), NH4+-N (>0.12 mg L(-1)), and TKN (>0.96 mg L(-1)), occurred in the upstream of TMC, while high concentrations of chlorophyll a (>6.8 mug L(-l)) and pheophytin (>3.9 microg L(-l)) were detected in the downstream of TMC. The highest chlorophyll a (11.8 mug L(-l)) and pheophytin (6.06 microg L(-l)) concentrations, however, were associated with static and open water conditions. Hydrological parameters (total dissolved solid, electrical conductivity, salinity, pH, and water temperature) were positively correlated with chlorophyll a and pheophytin concentrations (P < 0.01) and these factors overshadowed the relationships between N and P concentrations and chlorophyll a under field conditions. Principal component analysis and the ratios of DIN/DP and TN/TP in the water suggest that N is the limiting nutrient factor for phytoplankton growth in the TMC and elevated N relative to P is beneficial to the growth of phytoplankton, which is supported by laboratory culture experiments under controlled conditions.  相似文献   

13.
Total suspended particulate (TSP) samples were collected during wintertime from November 24, 1998 to February 12, 1999 in Beijing. Ionic species including Cl-, NO3(-), SO4(2-), Na+, NH4(+), K+, Mg2+ and Ca2+ were determined by Ion Chromatography (IC). The sum average concentration of all the determined ions accounted for 18.9% of the TSP concentration, and SO4(2-) appeared the dominant ion with an average concentration of 30.84 microg m(-3); the sum mass concentration of SO4(2-), NO3(-), Ca2+ and NH4(+) accounted for about 83.2% of all the eight ions measured. The study indicated that the chemical form of sulfate and ammonium varies with TSP concentration levels. During heavy pollution periods, the average TSP concentration was 0.66 mg m(-3), and the NH4(+)/SO4(2-) molar ratio was low (0.58). It indicated that sulfate may present as CaSO4 and (NH4)2SO4 x CaSO4 x 2H2O. When TSP concentration (average 0.186 mg m(-3)) was relatively low, the NH4(+)/SO4(2-) molar ratio was 1.94, close to the theoretical ratio of 2 of (NH4)2SO4. Under this condition (NH4)2SO4 is expected to exist as the major form of sulfate. When the TSP concentration level was medium (average 0.35 mg m(-3)), the NH4+/SO4(2-) molar ratio appeared an average value (1.27), (NH4)2SO4, (NH4)2SO4 x CaSO4 x 2H2O and CaSO4 are expected to be present in those aerosol particles. Meteorological conditions including wind speed and wind direction were related to the TSP concentration level.  相似文献   

14.
Nitrogen (N) contamination in the Yellow River mainstream and its tributaries was studied using data from 1960 to 2000 from 312 monitoring sites in the Yellow River system. Data showed that N concentrations in the Yellow River have increased since 1960, especially after 1990. N concentrations in the Yellow River mainstream increased from the upper reaches (less than 1.0 mg L(-1) for TN and less than 0.10 mg L(-1) for NH4(+)-N) to lower reaches (higher than 4-5 mg L(-1) for TN and higher than 1.0 mg L(-1) for NH4(+)-N). However, the highest N contaminations (50-250 mg L(-1) for TN and 10-20 mg L(-1) for NH4(+)-N) was found in some tributaries, which was attributed as an effect of industrial wastewater and municipal sewage. Nitrogen concentrations from several monitoring sites were positively correlated with several regional socio-economic indices, such as population density, fertilization rates, livestock, industrial input and GDP. Depending on location, seasonal N concentrations contrasted among watersheds. Monitoring stations located in rural and agricultural areas showed higher N concentrations during the flood season while those located in areas with urban and industrial centers showed higher N concentration during the dry season. Mainstream flow and N concentrations showed a strong inverse relationship; with higher N concentrations as the river flow declined. Intensive water extraction for agricultural irrigation and increasing N input to the river from fertilized agricultural fields could explain the increasing N concentrations during extensive droughts.  相似文献   

15.
广州市白云山降水的化学特征及源解析   总被引:3,自引:0,他引:3       下载免费PDF全文
以2006年广州市白云山降水监测资料为基础,对其降水样品的化学特征进行了分析。结果表明,白云山降水样品pH值分布为3.04—6.41,雨量加权pH平均值为4.26,酸雨频率为70.2%,降水中的主要阳离子是Ca^2+和NH^+4分别占阳离子总量的46.4%和17.5%;主要阴离子为SO^2-4和NO^-3,分别占阴离子总量的59.0%和19.9%。相对酸度(FA)和中和因子(NF)计算结果表明,约有84.7%的降水酸度被碱性成分Ca^2+和NH^+4中和。利用富集系数方法,计算结果表明SO^2-4和NO^-3主要来源于人类活动,而Ca^2+和K^+主要来源于岩石/土壤风化。  相似文献   

16.
Atmospheric inputs of reactive nitrogen (N) to ecosystems are a particular concern in the northeastern USA, including New York State, where rates of atmospheric N deposition are among the highest in the nation. We calculate the seasonal and annual spatial variations of contemporary inorganic atmospheric N deposition loading to multi-scale watersheds across New York State using numerous monitoring datasets of precipitation and ambient atmospheric N concentrations. Our models build upon and refine previous efforts estimating the spatial distribution of N deposition. Estimates of total inorganic wet deposition (NH4-N + NO3-N) across New York ranged from 4.7 to 10.5 kg ha(-1) yr(-1) under contemporary conditions (averaged 2002-2004), and both seasonal and annual predicted rates of inorganic N deposition (NH4-N, NO3-N, and total) fit relatively well with that of observed measurements. Our results suggest that "hot spots" of N deposition are, for the most part, spatially distributed according to geographic positions (i.e., relative location from sources and the Great Lakes system) and elevation. We also detect seasonal variations in deposition, showing that total wet atmospheric inorganic N deposition inputs to watersheds (extracted from the four-digit HUC calculations) are highest during the spring (mean = 2.4 kg ha(-1), stddev = 0.29) and lowest during the winter months (mean = 1.4 kg ha(-1), stddev = 0.23). Results also suggest that wet NO3(-) consistently comprises a slightly higher proportion of wet N deposition than wet NH4+ throughout watersheds of New York, ranging from 2.5 to 6.1 kg NO3-N ha(-1) yr(-1) compared to NH4+, which ranges from 2.2 to 4.4 kg NH4-N ha(-1) yr(-1).  相似文献   

17.
吹脱-电导法测定水中氨氮及其自动分析仪   总被引:5,自引:0,他引:5       下载免费PDF全文
建立了吹脱-电导法测定水和污水中的氨氮的方法。该方法是在90℃温度下,以气体将水样中氨氮吹出,用5mmol/L硫酸吸收,吸收液电导率的方法,在一定浓度范围内与氨氮吹出量成正比。测定标准样品的相对标准差和相对误差均为2.7%,方法的精密度和准确度均较好。根据该方法原理研制的氨氮在线自动分析仪测定自行配制的氨氮标准溶液,相对误差在2.8%以内,测定值准确可靠,最低检出限为0.1mg/L,两台样机分别用于黄河边国家水质自动站测定地表水和济南水质净化一厂测定污水,经过约5个月的运转,情况良好。  相似文献   

18.
海河下游水体中DO与NH_3-N、COD_(Mn)相关关系探讨   总被引:2,自引:0,他引:2  
本文应用近年来海河下游监测数据对DO与NH3N和CODMn进行一元线性回归,得到两回归方程:NH3N=-128DO+1054;CODMn=-113DO+1692。并经相关系数和回归系数显著性检验,表明在999%的置信水平下DO与NH3N和CODMn线性相关均极其显著  相似文献   

19.
A Neubauer plantlet experiment was carried out using Inceptisol (Typic Haplustept) and Vertisol (Typic Chromustert) soils contaminated with 134Cs at 74 kBq kg(-1) soil to study the transfer factor to wheat crop (Triticum aestivum) as influenced by four levels of humic acid (100, 200, 300, 400 mg HA kg(-1) soil), potassium and NH4-N (36.4, 54.5, 72.7 and 90.9 mg K or NH4 kg(-1) soil) under tropical climate. The biomass yield and K uptake by wheat were significantly improved in Vertisol with NH4-N and K application. The potassium application significantly increased the potassium concentration in wheat plants. The increase in the levels of each of the treatments dramatically improved the yield, K content and K uptake parameters, irrespective of the soils. The 134Cs transfer factors, irrespective of the treatments were observed to be higher in Vertisols as compared to Inceptisols. Among the treatments, the effect of HA was significantly greater than that of K and NH4-N application in Inceptisol, however, in Vertisols both HA and NH4-N were observed to be superior as compared to K application. With each increment in the levels of the treatments, a significantly lowered TF value was found, higher in Inceptisols (56.3%) than Vertisols (48.5%). Comparison of treatments indicates that in general higher potassium concentration in plant drastically lowered radiocesium transfer to wheat. Neubauer plant culture study, a rapid laboratory experimental model based on simple soil-plant system was quite clearly brought out the potential effectiveness of N, K and HA on soil-to-wheat transfer of radiocesium. Such screening technique needs to be extended to cover wider crop species, different climatic conditions and factors governing/modifying the mobility of radiocesium in soil and its absorption by crop plants.  相似文献   

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