碱金属和碱土金属的离子色谱法测定纲要

这里介绍的方法是用于测定锂、钠、钾、铷和铯等碱金属;镁、钙、锶的碱土金属;某些胺如铵、环已胺和吗啉。每种测定方法是通过阳离子交换分离和淋洗液化学抑制型电导检测实现的。 阳离子标准溶液的配制 为配制1.000ppm各阳离子的标准溶液,称量下列相应的纯盐溶于1升水中。为保证干燥,这些盐类在称量之前一直保存在     

铍的测定 原子吸收分光光度法

Ⅰ水中铍的测定简介采用仿制的CRA 63型微型石墨炉直接测定水中微量铍。以1％硫酸作为分析介质,一万倍于铍的铜、锌、铅、镉、钾、钠、铬、钼、镁、锰、钙、铁、铝、钡等对铍的吸光度无影响。当上述离子高于铍十万倍时,只有钙使铍的吸光度稍有增加。在无氘灯背景矫正设备的情况下,可用砷线2350埃或铜线2441埃扣除背景吸收,在所采用的条件下试样中的铜与砷均不会干扰。铍的灵敏度为9×10~(-13)克(1％吸收),检出限     

脱硫灰与钾矿石复合生产钾钙硅镁硫肥料研究

对脱硫灰与钾矿石复合生产钾钙硅镁硫肥的研究意义、反应原理、生产流程、环境安全性能以及施肥方法等进行了介绍和评估,并对其应用前景进行了展望。研究结果表明:利用脱硫灰与钾矿石复合生产钾钙硅镁硫肥在理论上可行;生产出的产品中硫酸钾的含量达10.34%～12.0%,枸溶氧化钙19.06%～32.28%,枸溶二氧化硅10.98%～14.46%,枸溶氧化镁1.46%～1.82%。产品的pH值从原脱硫灰的10.65下降到9.60。重金属含量低于农用粉煤灰国家标准,生产过程中不会产生SO2等有害气体污染。肥料的生产成本低于350元/t,该肥料不但可以增加土壤中钾、钙、硅、镁和硫等中微量元素的含量,而且可以提高或改善农作物的产量和品质。达到变废为宝,促进循环经济发展之目的。     

钼的测定 原子吸收分光光度法

Ⅰ土壤中有效态钼的测定(草酸铵—草酸溶液浸出) 简介:本法采用仿制的CRA—63微型石墨炉原子化器,不经分离富集直接测定土壤浸出液及植物消化液中的微量钼。灵敏度为3×10~(-11)克/1％吸收,检出限为2×10~(-11)克(取样量为10微升时相当于2微克/升)。试液中250倍于钼的镉、铅、铬、钙、镁、硅、铝和2500倍于钼的铜、锌、铁、锰、钠、钾不干扰测定。本法与钼的硫氰酸比色法对照,结果相近。     

糖类对正渗透膜的膜污染研究简

正渗透膜（FO）是一种低能耗的膜处理工艺,而膜生物反应器（MBR）是一种高效的污水处理工艺,其最大的瓶颈就是严重的膜污染问题,将FO应用到MBR中,即正渗透膜生物反应器。根据传统膜生物反应器的膜污染特点,研究SMP和EPS的主要组成成分中的糖类物质对膜的污染情况,利用海藻酸钠模拟糖类物质,并根据生活污水的特点,在海藻酸钠中加入钙、镁离子,研究其在含有不同金属离子时膜不同放置方式时的膜污染情况,将运行后的污染膜片剪下做SEM、AFM、FTIR-ATR分析。研究表明,海藻酸钠加不同金属离子的膜污染情况不一致,其膜污染大小顺序为藻酸钠+钙>藻酸钠+钙+镁>藻酸钠+镁,且不同膜放置方式的膜污染不同,活性层面向驱动液的通量较大。     

改进钒基SCR脱硝催化剂的抗碱金属中毒性能

以锐钛矿型二氧化钛和钛钨粉(5%WO3-TiO2)为载体,制备了系列钒和钨负载量不同的钒钛催化剂,考察碱金属和碱土金属(钾、钠和钙)对催化剂在氨选择性催化还原(NH3-SCR)氮氧化物反应中催化活性的影响。钾、钠和钙对钒钛催化剂的中毒影响大小顺序为钾钠钙。提高钒钛催化剂中钒的含量可显著提高催化剂的SCR活性和抗碱金属中毒性能,但高钒负载量(4.5%V2O5)造成催化剂氮气选择性明显下降,氧化亚氮生成显著增加。钨的添加有利于提高钒钛催化剂的低温活性和抗碱金属中毒性能,对氮气选择性无明显影响。     

人体里有哪几种微量元素

人体中元素的种类及其在体IkJ的含量必需元素宏量元素含、…微量元索含量氧碳氢氮钙磷钾硫钠氯镁65.0%1 8 .0.0% 3 .0% 2 .0% 1 .0%0 .35%0 .25%0 .15%0 .15%0 .05%铁铜牛辛铬锰枯氟铂碘硒钒镍占体重的% (总和)99.95%占体重的% (总和)有毒元素含最 车里 砷 硅 稀土悄性气休 硼0 .IPllm锅铅汞锗锡锑披秘稼锢铂确pPm即百万分之一。人体里有哪几种微量元素~~     

土壤中氨氮的测定

简介土壤中氨氮,包括游离态和代换态,测定时以适当盐溶液提取,以代换胶体吸附的代换性氨氮,用苯酚-次氯酸盐法测定。用酸化的氯化钠溶液浸提土壤,测定代换氨氮和游离氨氮总量。用EDTA掩蔽钙、镁等干扰离子。以下同水中氨氮的测定。     

氨氮的测定 苯酚次氯酸盐法 水中氨氮的测定

简介:氨与苯酚及次氯酸钠在碱性介质中,加入亚硝酰铁氰化钠催化,可生成兰色的靛酚,颜色的强度与氨浓度成比例,可用分光光度法测定。钙、镁及其它金属离子的干扰可用EDTA掩蔽消除。测定范围为0.01—0.5毫克/升氨氮。仪器 (1)分光光度计 (2)酸度计 (3)恒温水浴     

山核桃加工废水的成分测定与分析

对山核桃加工废水和马铃薯培养基(PDA)进行了成分分析,为资源化利用山核桃加工废水提供理论依据。采用3,5-二硝基水杨酸法测定山核桃加工废水和PDA中还原糖的含量,总氮、总磷、悬浮物、浊度、pH及金属元素均采用国家标准中的测定方法进行测定与分析。废水中总糖、总氮和总磷的含量分别为1.79×103、149.00和27.00 mg/L;金属元素钠、钾、铜、铁、镁、锰和锌的含量分别为28.47、225.03、0.048、0.034、18.11、0.82和1.36 mg/L;悬浮物为5.43×102mg/L,COD高达1.06×104mg/L,pH为4.44,浊度为109.53 NTU。PDA中总糖、氮和磷含量为2.47×104、445.00和84.3 mg/L,COD为1.09×104mg/L,pH为7.2,金属元素钠、钾、锌、铜、铁和镁的含量为386.10、575.09、1.02、0.42和25.62 mg/L,几乎不含锰。山核桃加工废水中的总氮、总磷和COD等含量过高,对环境污染严重,不能直接排放;山核桃加工废水和PDA中的营养物质及金属元素种类基本一致,通过添加合适的成分,调整废水中C/N等微生物生长营养要素的比例,山核桃加工废水有望开发成用于实验室常见微生物培养的类似于PDA的半合成培养基。     

Levels of polychlorinated biphenyls, organochlorine pesticides, mercury, cadmium, copper, selenium, arsenic, and zinc in the harbour seal, Phoca vitulina, in Norwegian waters

Residue levels of the chlorinated hydrocarbons polychlorinated biphenyls (PCBs), total DDT, alpha-, beta- and gamma-hexachlorocyclohexane (HCH), hexachlorobenzene (HCB), and oxychlordane in blubber, and the elements mercury, cadmium, copper, selenium, arsenic, and zinc in liver, of 82 harbour seals, Phoca vitulina, were determined. The seals were found dead or dying in Norwegian waters during the disease outbreak caused by a morbilli virus in 1988. Of the chlorinated hydrocarbons, the highest concentrations were found of PCBs, which were 2-4 times higher than the total DDT concentrations. P,p'-DDE was the main contributor to the total DDT, and constituted about 80%. The PCB and total DDT concentrations ranged from 0.4-38 and 0.1-8.8 mg kg(-1), respectively. The mercury concentrations ranged from 0.1-89 mg kg(-1). Significantly higher mean levels of PCBs (13 mg kg(-1) and mercury (16 mg kg(-1)) were found in blubber and liver, respectively, of seals from the Southern coast of Norway, as compared to the corresponding mean levels in seals from the Oslofjord (8.8 and 4.1 mg kg(-1)), and at the Northwestern coast (5.8 and 7.9 mg kg(-1)), respectively. A significant positive correlation was found between the concentrations of selenium and mercury. When the seals were grouped according to sex and age, females of ageclass > 1 and pups of both sexes had significantly lower PCB and total DDT levels than males ageclass > 1. Significantly higher hepatic mercury levels were found in seals ageclass > 1 as compared to pups. Only low levels of the other organochlorines, cadmium and arsenic, were found. Copper and zinc were considered to be present at normal physiological levels. The present organochlorine and heavy metal concentrations gave no support to suggestions that organochlorines and heavy metal pollution may be directly involved in the observed seal deaths.     

Lead,mercury, cadmium,chromium, nickel,copper, zinc,calcium, iron,manganese and chromium (VI) levels in Nigeria and United States of America cement dust

This study was aimed at investigating the relative abundance of heavy metals in cement dust from different cement dust factories in order to predict their possible roles in the severity of cement dust toxicity. The concentrations of total mercury (Hg), copper (Cu), chromium (Cr), cadmium (Cd), nickel (Ni), manganese (Mn), lead (Pb), iron (Fe) and chromium (VI) (Cr (VI)) levels in cement dust and clinker samples from Nigeria and cement dust sample from the United States of America (USA) were determined using graphite furnace atomic absorption (GFAAS), while Zn and Ca were measured by flame atomic absorption spectrophotometry (FAAS), and Cr (VI) by colorimetric method. Total Cu, Ni and Mn were significantly higher in cement dust sample from USA (p < 0.05), also, both total Cr and Cr (VI) were 5.4–26 folds higher in USA cement dust compared with Nigeria cement dust or clinker (p < 0.001). Total Cd was higher in both Nigeria cement dust and clinker (p < 0.05 and p < 0.001), respectively. Mercury was more in both Nigeria cement dust and clinker (p < 0.05), while Pb was only significantly higher in clinker from Nigeria (p < 0.001). These results show that cement dust contain mixture of metals that are known human carcinogens and also have been implicated in other debilitating health conditions. Additionally, it revealed that metal content concentrations are factory dependent. This study appears to indicate the need for additional human studies relating the toxicity of these metals and their health impacts on cement factory workers.     

Emission inventory of eight elements,Fe, Al,K, Mg,Mn, Na,Ca and Ti,in dust source region of East Asia

Based on calculation of the emission rate of the atmospheric mineral dust and the data of elemental contents in surface soils, this paper calculates the emission inventory of eight main elements of the atmospheric dust, Fe, Al, K, Mg, Mn, Na, Ca and Ti, in the dust source region of East Asia. As the dust sources in both Northern China and the Southern Mongolia are of three types and, in each of the six source type areas, surface soils are relatively uniform in soil types and soil texture, a simple method to calculate the emission of an element in one source type area is proposed by multiplying the total emission of the dust PM₁₀ and PM₅₀ in the source type area with the mean percentage content of the element in surface soils of the area. Comparison of our calculation of the total Fe emission in the source region of East Asia with the total Fe deposition to the North Pacific Ocean, measured and calculated by previous authors, shows very good agreement. This general method can also be used for the emission calculation of any other element.     

Effects of elevated CO2, nitrogen supply and tropospheric ozone on spring wheat-II. Nutrients (N, P, K, S, Ca, Mg, Fe, Mn, Zn)

CO(2) enrichment is expected to alter leaf demand for nitrogen and phosphorus in plant species with C(3) carbon dioxide fixation pathway, thus possibly causing nutrient imbalances in the tissues and disturbance of distribution and redistribution patterns within the plants. To test the influence of CO(2) enrichment and elevated tropospheric ozone in combination with different nitrogen supply, spring wheat (Tritium aestivum L. cv. Minaret) was exposed to three levels of CO(2) (361, 523, and 639 microl litre(-1), 24 h mean from sowing to final harvest), two levels of ozone (28.4 and 51.3 nl litre(-1)) and two levels of nitrogen supply (150 and 270 kg ha(-1)) in a full-factorial design in open-top field chambers. Additional fertilization experiments (120, 210, and 330 kg N ha(-1)) were carried out at low and high CO(2) levels. Macronutrients (N, P, K, S, Ca, Mg) and three micronutrients (Mn, Fe, Zn) were analysed in samples obtained at three different developmental stages: beginning of shoot elongation, anthesis, and ripening. At each harvest, plant samples were separated into different organs (green and senescent leaves, stem sections, ears, grains). According to analyses of tissue concentrations at the beginning of shoot elongation, the plants were sufficiently equipped with nutrients. Elevated ozone levels neither affected tissue concentrations nor shoot uptake of the nutrients. CO(2) and nitrogen treatments affected nutrient uptake, distribution and redistribution in a complex manner. CO(2) enrichment increased nitrogen-use efficiency and caused a lower demand for nitrogen in green tissues which was reflected in a decrease of critical nitrogen concentrations, lower leaf nitrogen concentrations and lower nitrogen pools in the leaves. Since grain nitrogen uptake during grain filling depended completely on redistribution from vegetative pools in green tissues, grain nitrogen concentrations fell considerably with severe implications for grain quality. Ca, S, Mg and Zn in green tissues were influenced by CO(2) enrichment in a similar manner to nitrogen. Phosphorus concentrations in green tissues, on the other hand, were not, or only slightly, affected by elevated CO(2). In stems, 'dilution' of all nutrients except manganese was observed, caused by the huge accumulation of water soluble carbohydrates, mainly fructans, in these tissues under CO(2) enrichment. Whole shoot uptake was either remarkably increased (K, Mn, P, Mg), nearly unaffected (N, S, Fe, Zn) or decreased (Ca) under CO(2) enrichment. Thus, nutrient cycling in plant-soil systems is expected to be altered under CO(2) enrichment.     

Half-lives of tetra-, penta-, hexa-, hepta-, and octachlorodibenzo-p-dioxin in rats,monkeys, and humans--a critical review

The elimination half-lives (t1/2) in Sprague-Dawley rats for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 1,2, 3,7,8-pentachlorodibenzo-p-dioxin (PeCDD), 1,2,3,4,7,8-hexachlorodibenzo-p-dioxin (HxCDD), 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (HpCDD) and 1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin (OCDD) were estimated in long-term studies by Schlatter, Poiger and others. Furthermore, there are some published half-lives of TCDD in adult humans. The average half-life of TCDD in adult humans is approximately 2840 days, while in Sprague-Dawley rats the average t1/2 of TCDD is 19 days. The t1/2 of TCDD in humans is about 150 times that of rats. This factor was used to calculate the t1/2 values of the other polychlorinated dibenzo-p-dioxins (PCDDs) in humans from the rat data. Furthermore, the terminal t1/2 values of PCDDs in adult humans were calculated from the regression equation: logt1/2H = 1.34 logt1/2R + 1.25 which was recently established for 50 xenobiotics (t1/2H = terminal half-lives in days for humans, t1/2R = terminal half-lives in days for rats). The following terminal half-lives in adult humans were obtained: 12.6 years for 1,2,3,7,8-PeCDD, 26-45 years for 1,2,3,4,7,8-HxCDD, 80-102 years for 1,2,3,4,6,7,8-HpCDD and ca. 112-132 years for OCDD. These half-lives of PCDDs are critically compared with measured t1/2 values of PCDDs and other persistent organic pollutants in rats, monkeys and humans.     

Phthalic acid esters in grains,vegetables, and fruits: concentration,distribution, composition,bio-accessibility,and dietary exposure

Environmental Science and Pollution Research - Grain, vegetable, and fruit samples were collected from Xi’an City in Northwest China and analyzed for the characteristics, bio-accessibility,...