离子色谱法检测无机阴离子用淋洗液改进

文章开展采用新型氢氧化钾淋洗液偏离HJ/T 84—2001《水质无机阴离子的测定离子色谱法》中规定的碳酸盐体系淋洗液的实验确认研究,对使用氢氧化钾淋洗液的离子色谱法测定阴离子的分离度、标准曲线、准确度、精密度和加标回收率进行一一评价,最终确认使用氢氧化钾淋洗液的离子色谱仪测定阴离子氟化物、氯化物、硫酸根、硝酸根能够满足实验要求,为使用此种淋洗液体系的离子色谱仪开展检测提供了质量保证依据。     

离子色谱法测定水中亚硫酸根和硫酸根

通过使用CIC-D120离子色谱仪对水中SO_3~(2-)、SO_4~(2-)测定,采用SH-AC-4亲水型阴离子色谱柱分离,优化淋洗液浓度配比和加入有机改进剂很好分离亚硫酸根和硫酸根离子。实验表明:采用3.3 mmol/LNa_2CO_3+7.4 mmol/LNaHCO_3+10%丙酮作淋洗液,SO_3~(2-)、SO_4~(2-)离子分离效果最好;对同一样品进行精密度试验,测定值的相对标准偏差(n=6)小于5.4%;按标准加入法进行回收率试验,回收率在91.8%~101%之间。分析表明本法能使测定的选择性、准确性、精密度和速度得到改善,且都可以得到很好的线性和较低的检出限。     

酸雨中的硫酸根在土壤中的吸附实验

1 前言降水中的硫酸根等阴离子在被土壤吸附的同时,土壤中可交换的氢氧根离子就会被置换出来。这一氢氧根离子将会消耗降水中的氢离子,通过对土壤中硫酸根离子的吸咐量的测定,就可以得知以交换性氢氧根为基     

我国西南湖塘溪流的水化学组成与离子平衡的研究

本文研究了我国重酸雨地区四川，贵州省湖塘溪流的水化学组成及离子平衡关系，结果表明：城郊之间水化学组成存在差异；同时，进行离子平衡衡算时，须对溶解态钙，镁进行校正，否则，会出现阴离子短缺现象，仅由钙，镁及硫酸根和弱酸根组成的简单离子平衡也是大致符合的，但其应用有一定的局限性。     

南通市大气降水中硫酸根的影响因素研究

随着环境空气污染的日益加重,研究硫酸根与降水中其他因子的相关关系对准确反映大气的质量状况具有重要意义.根据南通市2018年的降水监测数据,采用SPSS统计分析软件对降水中的硫酸根浓度与pH值、电导率以及常见阴、阳离子进行相关性分析,推断出离子的可能来源.通过多元线性回归模型可以对南通的硫酸根离子浓度进行预测.研究为南通...     

离子色谱法测定土壤有效硫

以磷酸二氢钾为浸提剂,采用离子色谱仪进行分离检测,根据硫酸根离子保留时间定性,峰高或峰面积定量计算土壤有效硫含量。采用离子色谱法测定某气田工区酸性和中性土壤有效硫,标准曲线的相关系数达到0.999以上;3个浓度的同一样品重复测定的相对标准偏差分别为3.01%,5.55%,5.25%;土壤样品的加标回收率分别为88%和90%;土壤标准样品的相对标准偏差为5.56%;精密度和准确度均优于NY/T 1121.14—2006《土壤检测第14部分土壤有效硫的测定》硫酸钡比浊法,解决了硫酸钡比浊法存在的标准曲线线性达不到要求、操作复杂、测定结果准确性差的问题。     

基于超级站观测的乌鲁木齐市PM2.5组分特征分析

为了解乌鲁木齐市PM_2.5各组分浓度及其变化特征，利用2022年乌鲁木齐市大气环境超级站PM_2.5及其组分连续监测数据进行特征分析，结果表明：PM_2.5组分中有机碳、元素碳、水溶性阴、阳离子等组分浓度与PM_2.5浓度呈现“采暖季高、非采暖季低”的季节性变化；PM_2.5各组分中硫酸根、硝酸根、铵根和有机碳占比较大；无机元素浓度高低顺序为：钙>铁>氯>钾；有机碳与元素碳比值为6.08；硝酸根离子与硫酸根的比值小于1；典型污染过程中PM_2.5组分浓度中硫酸盐、硝酸盐、铵盐和有机物等二次气溶胶占比明显增加。说明2022年乌鲁木齐市冬季PM_2.5浓度受SO₂、NO₂和NH₃等污染物二次转化影响，而夏季则受有机物二次转化和一次扬尘源的共同影响，应重点控制相关行业污染排放，减少重污染天气。     

工业盐酸中硫酸根分析方法的改进和研究

为了能够快速准确地分析工业盐酸中硫酸根的含量,现行国标方法对操作人员技术要求比较高,因而较难操作。通过使用离子色谱法和等离子光谱法对样品进行一系列的数据分析和比对,选择适合的方法,从而改进了硫酸根的分析方法。     

淄博市“十二五”期间大气降水化学组分变化趋势分析

为研究"十二五"期间淄博市大气降水化学组分变化趋势,采用离子当量浓度百分比变化和秩相关系数法对9个监测点5年的监测数据进行了分析。分析结果表明:淄博市降水中总阴阳离子在0.8~1.2允许变动范围内,总体保持平衡,但硫酸根离子对酸性降水的贡献值减弱,硝酸根离子的贡献值加大;钙离子对降水的中和能力减弱,铵离子的中和能力增强。     

实验用水对总氮检测结果的影响

用RO纯水与超纯水分别作为实验用水,通过标准曲线及空白、标准样品、水样等总氮测定对比实验,发现两种实验用水的标准曲线及空白值、标准样品的检测均受控,但两种纯水对比实验显示相对于超纯水而言,RO纯水中有一定浓度的总氮,同时在水样检测中用RO纯水作实验用水测定值明显低于用超纯水作实验用水的测定值,其差值与RO纯水中总氮值相符。实验结果表明总氮检测中不能只以标准曲线、空白值和标准样品测定值作为受控标准,要考虑实验用水中硝酸根离子的影响。     

成都市2002年1月2日至4日浓雾天气雾的化学组成

为了查明雾天雾的化学学组成，2002年1月2日至1月4日，利用人为结露的方法采集了雾天的雾，并洲定了阴离子组成。与室内采集的凝结露水的研究进行比较，大雾天的雾中含有极高的硝酸粮，这是因为雾的形成过程中亚硝酸根进一步氧化为硝酸根的原因。     

FOG AND ACIDIFICATION IMPACTS ON ION BUDGETS OF BASINS IN NOVA SCOTIA,CANADA1

ABSTRACT: We examined hydrogeochemical records for a dozen watersheds in and near Kejimkujik National Park in southwestern Nova Scotia by relating stream ion concentrations and fluxes to atmospheric deposition, stream type (lake inlet versus outlet; brown versus clear water), and watershed type (catchment area, topography, soils, and dominant forest cover type). We found that fog and dry deposition make important contributions to S, N, Cl, H, Ca, Mg, K, and Na inputs into these watersheds. Seasalt chloride deposition from rain, snow, fog, and dry deposition equal total stream outputs on a region‐wide basis. Chloride outputs, however, differ among watersheds by a factor of about two, likely due to local differences in air flow and vegetational fog interception. We found that most of the incoming N is absorbed by the vegetation, as stream water NO3^‐ and NH4⁺ are very low. Our results also show that the vegetation and the soils absorb about half of the incoming SO4². In comparison with other North American watersheds with similar forest vegetation, Ca outputs are low, while Mg and K outputs are similar to other regions. Soil exchangeable Ca and soil cation exchange capacity are also very low. We found that first‐order forest streams with no upstream lakes have a distinct seasonal pattern that neither corresponds with the seasonal pattern of atmospheric deposition, nor with the seasonal pattern of downstream lake outlets.     

Gas dynamics in eutrophic lake sediments affected by oxygen, nitrate, and sulfate

In many freshwater ecosystems, the contents of NO3- and SO4(2-) have increased, whereas O2 has been depleted due to the increased acid and nutrient loads. These changes may affect carbon turnover and the dynamics of the major greenhouse gases CO2, CH4, and N2O. We studied the effects of O2, NO3-, and SO4(2-) availability on carbon mineralization, and fluxes of CO2, CH4, and N2O in the sediments of hyper-eutrophic Lake Kev?t?n, Finland. Undisturbed sediment cores from the deep (9 m) and shallow (4 m) profundal were incubated in a laboratory microcosm with oxic and anoxic water flows with NO3- or SO4(2-) concentrations of 0, 30, 100, 300, and 2000 microM. The carbon mineralization rate (i.e., the sum of released CO2-C and CH4-C) was not affected by the oxidants. However, the oxidants did change the pathways of carbon degradation and the release of CH4. All of the oxidants depressed CH4 fluxes in the shallow profundal sediments, which had low organic matter content. In the deep profundal sediments rich in organic matter, the CH4 release was reduced by O2 but was not affected by SO4(2-) (the effect of NO3- was not studied). There was an increase in N2O release as the overlying water NO3- concentration increased. Anoxia and highly elevated NO3- concentrations, associated with eutrophication, increased drastically the global warming potential (GWP) of the sedimentary gases in contrast to the SO4(2-) load, which had only minor effects on the GWP.     

Cottongrass effects on trace elements in submersed mine tailings

Phytostabilization may limit the leakage of metals and As from submersed mine tailings, thus treatment of acid mine drainage with lime could be reduced. Tall cottongrass (Eriophorum angustifolium Honckeny) and white cottongrass (E. scheuchzeri Hoppe) were planted in pots with unlimed (pH 5.0) and limed (pH 10.9) tailings (containing sulfides) amended with sewage sludge (SS) or a bioashsewage sludge mixture (ASM). Effects of the amendments on plant growth and plant element uptake were studied. Also, effects of plant growth on elements (Cd, Cu, Pb, Zn, and As), pH, electrical conductivity (EC), and concentrations of SO4(2-), in the drainage water as well as dissolved oxygen in tailings, were measured. Both plant species grew better and the shoot element concentrations of white cottongrass were lower in SS than in ASM. Metal concentrations were lowest in drainage water from limed tailings, and plant establishment had little effect on metal release, except for an increase in Zn levels, even though SO4(2-) levels were increased. In unlimed tailings, plant growth increased SO4(2-) levels slightly; however, pH was increased and metal concentrations were low. Thus, metals were stabilized by plant uptake and high pH. Amendments or plants did not affect As levels in the drainage water from unlimed tailings. Thus, to reduce the use of lime for stabilizing metals, phytostabilization with tall cottongrass and white cottongrass on tailings is a sound possibility.     

Leachability and phytoavailability of nitrogen, phosphorus, and potassium from different bio-composts under chloride- and sulfate-dominated irrigation water

Concerns over increased phosphorus (P) application with nitrogen (N)-based compost application have shifted the trend to P-based composed application, but focusing on one or two nutritional elements does not serve the goals of sustainable agriculture. The need to understand the nutrient release and uptake from different composts has been further aggravated by the use of saline irrigation water in the recent scenario of fresh water shortage. Therefore, we evaluated the leachability and phytoavailability of P, N, and K from a sandy loam soil amended with animal, poultry, and sludge composts when applied on a total P-equivalent basis (200 kg ha(-1)) under Cl(-) (NaCl)- and SO4(2-) (Na2SO4)-dominated irrigation water. Our results showed that the concentration of dissolved reactive P (DRP) was higher in leachates under SO(4)(2-) than Cl(-) treatments. Compost amendments differed for DRP leaching in the following pattern: sludge > animal > poultry > control. Maize (Zea mays L.) growth and P uptake were severely suppressed under Cl(-) irrigation compared with SO4(2-) and non-saline treatments. All composts were applied on a total P-equivalent basis, but maximum plant (shoot + root) P uptake was observed under sludge compost amendment (73.4 mg DW(-1)), followed by poultry (39.3 mg DW(-1)), animal (15.0 mg DW(-1)), and control (1.2 mg DW(-1)) treatment. Results of this study reveal that irrigation water dominated by SO4(2-) has greater ability to replace/leach P, other anions (NO3(-)), and cations (K+). Variability in P release from different bio-composts applied on a total P-equivalent basis suggested that P availability is highly dependent on compost source.     

Field-scale remediation of a metolachlor-contaminated spill site using zerovalent iron

Pesticide spills are common occurrences at agricultural cooperatives and farmsteads. When inadvertent spills occur, chemicals normally beneficial can become point sources of ground and surface water contamination. We report results from a field trial where approximately 765 m3 of soil from a metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide] spill site was treated with zerovalent iron (Fe0). Preliminary laboratory experiments confirmed metolachlor dechlorination by Fe0 in aqueous solution and that this process could be accelerated by adding appropriate proportions of Al2(SO4)3 or acetic acid (CH3COOH). The field project was initiated by moving the stockpiled, contaminated soil into windrows using common earth-moving equipment. The soil was then mixed with water (0.35-0.40 kg H2O kg(-1)) and various combinations of 5% Fe0 (w/w),2% Al2(SO4)3 (w/w), and 0.5% acetic acid (v/w). Windrows were covered with clear plastic and incubated without additional mixing for 90 d. Approximately every 14 d, the plastic sheeting was removed for soil sampling and the surface of the windrows rewetted. Metolachlor concentrations were significantly reduced and varied among treatments. The addition of Fe0 alone decreased metolachlor concentration from 1789 to 504 mg kg(-1) within 90 d, whereas adding Fe0 with Al2(SO4)3 and CH3COOH decreased the concentration from 1402 to 13 mg kg(-1). These results provide evidence that zerovalent iron can be used for on-site, field-scale treatment of pesticide-contaminated soil.     

Anaerobic treatment of sulfate-rich wastewater in an anaerobic sequential batch reactor (AnSBR) using butanol as the carbon source

Biological sulfate reduction was studied in a laboratory-scale anaerobic sequential batch reactor (14 L) containing mineral coal for biomass attachment. The reactor was fed industrial wastewater with increasingly high sulfate concentrations to establish its application limits. Special attention was paid to the use of butanol in the sulfate reduction that originated from melamine resin production. This product was used as the main organic amendment to support the biological process. The reactor was operated for 65 cycles (48 h each) at sulfate loading rates ranging from 2.2 to 23.8 g SO(4)(2-)/cycle, which corresponds to sulfate concentrations of 0.25, 0.5, 1.0, 2.0 and 3.0 g SO(4)(2-) L(-1). The sulfate removal efficiency reached 99% at concentrations of 0.25, 0.5 and 1.0 g SO(4)(2-) L(-1). At higher sulfate concentrations (2.0 and 3.0 g SO(4)(2-) L(-1)), the sulfate conversion remained in the range of 71-95%. The results demonstrate the potential applicability of butanol as the carbon source for the biological treatment of sulfate in an anaerobic batch reactor.     

Transport and fate of nitrate in a glacial outwash aquifer in relation to ground water age,land use practices,and redox processes

A combination of ground water modeling, chemical and dissolved gas analyses, and chlorofluorocarbon age dating of water was used to determine the relation between changes in agricultural practices, and NO3- concentrations in ground water of a glacial outwash aquifer in west-central Minnesota. The results revealed a redox zonation throughout the saturated zone with oxygen reduction occurring near the water table, NO3- reduction immediately below it, and then a large zone of ferric iron reduction, with a small area of sulfate (SO4(2-)) reduction and methanogenesis (CH4) near the end of the transsect. Analytical and NETPATH modeling results supported the hypothesis that organic carbon served as the electron donor for the redox reactions. Denitrification rates were quite small, 0.005 to 0.047 mmol NO3- yr(-1), and were limited by the small amounts of organic carbon, 0.01 to 1.45%. In spite of the organic carbon limitation, denitrification was virtually complete because residence time is sufficient to allow even slow processes to reach completion. Ground water sample ages showed that maximum residence times were on the order of 50 to 70 yr. Reconstructed NO3- concentrations, estimated from measured NO3- and dissolved N gas showed that NO3- concentrations have been increasing in the aquifer since the 1940s, and have been above the 714 micromol L(-1) maximum contaminant level at most sites since the mid- to late-1960s. This increase in NO3- has been accompanied by a corresponding increase in agricultural use of fertilizer, identified as the major source of NO3- to the aquifer.     

苯和菲在含水层的典型介质中迁移转化研究

石油烃污染会对人类生存的环境造成严重危害,地下水系统中石油烃污染物的研究已受到国内外的高度重视。本文针对某石油烃污染场地的污染状况及水文地质条件,利用模拟柱实验研究石油烃中常见组分苯和菲在典型含水层中的迁移转化,实验结果表明,苯和菲在4种含水层介质中(粉砂、中砂、粗砂、砾砂)受到的迁移阻滞作用都是随着粒径的减小而增大。菲在4种介质中的迁移速率要小于苯,说明4种介质对菲的阻滞作用要大于苯。通过检测各模拟柱出水中Fe2+、Fe3+、NH4+-N和NO3--N浓度的变化可知,在苯和菲的砾砂模拟柱中,由于水流速度快,试验周期短,模拟柱内各项指标变化较小,生物作用较弱;而在苯和菲的粗砂、中砂和粉砂模拟柱中,NO3--N浓度减少,NH4+-N和Fe3+含量增加,说明微生物开始利用NO3--N和Fe3+降解苯和菲,微生物对苯和菲在粗砂、中砂和粉砂中的迁移转化过程有显著的作用。     

Removal of selenate from water by zerovalent iron

Zerovalent iron (ZVI) has been widely used in the removal of environmental contaminants from water. In this study, ZVI was used to remove selenate [Se(VI)] at a level of 1000 microg L(-1) in the presence of varying concentrations of Cl-, SO(2-)4, NO(-)3, HCO(-)3, and PO(3-)4. Results showed that Se(VI) was rapidly removed during the corrosion of ZVI to iron oxyhydroxides (Fe(OH)). During the 16 h of the experiments, 100 and 56% of the added Se(VI) was removed in 10 mM Cl- and SO(2-)4 solutions under a closed contained system, respectively. Under an open condition, 100 and 93% of the added Se(VI) were removed in the Cl- and SO(2-)4 solutions, respectively. Analysis of Se species in ZVI-Fe(OH) revealed that selenite [Se(IV)] and nonextractable Se increased during the first 2 to 4 h of reaction, with a decrease of Se(VI) in the Cl- experiment and no detection of Se(VI) in the SO(2-)4 experiment. Two mechanisms can be attributed to the rapid removal of Se(VI) from the solutions. One is the reduction of Se(VI) to Se(IV), followed by rapid adsorption of Se(IV) to Fe(OH). The other is the adsorption of Se(VI) directly to Fe(OH), followed by its reduction to Se(IV). The results also show that there was little effect on Se(VI) removal in the presence of Cl- (5, 50, and 100 mM), NO(-)3 (1, 5, and 10 mM), SO(2-)4 (5 mM), HCO(-)3 (1 and 5 mM), or PO(3-)4 (1 mM) and only a slight effect in the presence of SO(2-)4 (50 and 100 mM), HCO(-)3 (10 mM), and PO(3-)4 (5 mM) during a 2-d experiment, whereas 10 mM PO(3-)4 significantly inhibited Se(VI) removal. This work suggests that ZVI may be an effective agent to remove Se from Se-contaminated agricultural drainage water.