硫化物 间接火焰原子吸收法

硫化物　间接火焰原子吸收法概述１．原理：水和废水中的硫化物，是指水体中可溶解的氢硫酸盐，硫化物及可溶性的金属硫化物，以及非离解的硫化氢。将水样酸化后转化成硫化氢，用氮气带出，被含有定量过量的铜离子吸收液吸收。分离沉淀后，通过测定上清液中剩余的铜离子，...     

碘量法测定水和废水中硫化物

设计制作了测定硫化物的酸化 -吹气 -吸收预处理装置 ,验证了装置对硫化物的回收效果 ,对分析条件进行了最佳选择 ,对干扰及消除情况进行了深入细致的研究 ,本方法的测量精密度和加标回收率均为良好 ,适用于含硫化物在0 .40 mg/L以上的水和废水的测定。     

直接显色光度法测定水中硫化物方法改进

用10mLφ（HEl）=0.5的溶液酸化水样，10mL锌氨络盐吸收液，于0．6L／min抽空气30min，溶液吸收硫化物后吸光值稳定，水和废水的测定加标回收率为94.4％～101％，精密度为2．87％～3.27％。改进后的直接显色分光光度法测定水中硫化物，酸化-抽气分离装置简单、操作方便。     

化学需氧量测定方法存在问题的讨论

1.无机还原物的干扰在《水和废水标准检验法》推荐的步骤中,氯离子和亚硝酸盐的干扰是分别通过加入硫酸汞和氨基磺酸来消除的,而亚铁盐、硫化物等的干扰则需首先测定其原始浓度,然后在假定其定量氧化的基础上,通过计算来加以消除.计算方法举例如下:     

电镀废水中硫氰酸根离子含量的自动电位滴定

研究了用自动电位滴定测定硫氰酸根离子的条件和方法。实验结果表明,选用银电极为指示电极,217型双液接电极为参比电极,在硝酸介质中滴定硫氰酸根离子,方法具有高选择性; 应用于电镀废水分析,方法简便快捷,在4min内能打印出分析结果。     

关于水和废水中硫化物测定的几个问题

1碘量法测定硫化物时 ,当采用低浓度 ( 0 .0 1mol/L )硫代硫酸钠标液 ,用 1 0 ml微量滴定管 ,在水样硫化物浓度在 0 .0 4～ 1 mg/L内可取得满意结果 :相对偏差 <4.0 % ,回收率 96%～ 98%。 2预处理时可将过滤好的硫化锌沉淀连同滤纸 (剪成几块 )放入碘量瓶 ,加 50 ml水浸泡几分钟 ,盖上瓶塞轻摇即可。 3用对氨基二甲基苯胺光度法测定时 ,用醋酸调节 p H值或不调吸收液 p H值均可取得较好准确度和精密度。关于水和废水中硫化物测定的几个问题@车轩$河北省环境监测中心站!河北石家庄050051…     

水和废水中挥发性悬浮物的测定

我国对水和废水中挥发性悬浮物的测定方法迄今还没有制订出统一方法,其他测定挥发性悬浮物的方法也不多见。美国《水和废水标准检验法》第15版中的测定方法是通过标准玻璃纤维滤片,将滤片放在滤膜滤器上或者放在     

紫外分光光度法测定水和废水中硫化物的适宜波长选择

对紫外分光光度法测定水和废水中硫化物的方法做了较为深入的研究和分析,并通过对实际样品的测定,对比和论述了在不同相关波长处空白值及方法灵敏度所受到的影响,进而选择出在紫外光区域测定水和废水中硫化物的适宜波长。     

几种COD测定方法的比较

化学需氧量 (ＣＯＤ)测定方法已有多种 ,从经典的重铬酸盐法 (ＧＢ 1 1 91 4- 89) ,到各种快速法和比色法 ,均得到较广泛的应用。现将各种测定方法作一比较列表 1。表 1　几种ＣＯＤ测定方法的比较方法 重铬酸盐法(经典法 ) 库仑法催化快速法密封催化消解法节能加热法比色法来源 ＧＢ 11914- 89《水和废水监测分析方法 (第 3版 )》中试行方法《水和废水监测分析方法 (第 3版 )》补充篇《水和废水监测分析方法 (第 3版 )》补充篇《水和废水监测分析方法(第 3版 )》补充篇美国Ｓｍａｒｔ、哈奇公司仪器消解时间及容器2ｈ2 5 0ｍＬ烧瓶15ｍｉｎ…     

测定水中亚硝酸盐氮絮凝方法的改进

测定水中亚硝酸盐氮絮凝方法的改进赵敏（深圳市宝安区环境保护局５１８１０１）根据《水和废水监测分析方法》，水中亚硝酸盐氮的测定采用Ｎ－（１－萘基）－乙二胺光度法，方法原理是：在磷酸介质中，ｐＨ＝１．８±０．３时，亚硝酸盐与对氨基苯磺酰胺反应，生成重氮盐...     

Ascorbic acid reduction of active chlorine prior to determining Ames mutagenicity of chlorinated natural organic matter (NOM)

Many potable water disinfection byproducts (DBPs) that result from the reaction of natural organic matter (NOM) with oxidizing chlorine are known or suspected to be carcinogenic and mutagenic. The Ames assay is routinely used to assess an overall level of mutagenicity for all compounds in samples from potable water supplies or laboratory studies of DBP formation. Reduction of oxidizing disinfectants is required since these compounds can kill the bacteria or react with the agar, producing chlorinated byproducts. When mutagens are collected by passing potable water through adsorbing resins, active chlorine compounds react with the resin, producing undesirable mutagenic artifacts. The bioanalytical and chemoanalytical needs of drinking water DBP studies required a suitable reductant. Many of the candidate compounds failed to meet those needs, including 2,4-hexadienoic (sorbic) acid, 2,4-pentanedione (acetylacetone), 2-butenoic (crotonic) acid, 2-butenedioic (maleic and fumaric) acids and buten-2-ol (crotyl alcohol). Candidates were rejected if they (1) reacted too slowly with active chlorine, (2) formed mutagenic byproducts, or (3) interfered in the quantitation of known chlorination DBPs. L-Ascorbic acid reacts rapidly and stoichiometrically with active chlorine and has limited interactions with halogenated DBPs. In this work, we found no interference from L-ascorbic acid or its oxidation product (dehydroascorbic acid) in mutagenicity assays of chlorinated NOM using Salmonella typhimurium TA100, with or without metabolic activation (S9). This was demonstrated for both aqueous solutions of chlorinated NOM and concentrates derived from the involatile, ether-extractable chlorinated byproducts of those solutions.     

Nitrate and ammonium ions removal from groundwater by a hybrid system of zero-valent iron combined with adsorbents

Nitrate (NO(3)(-)) is a commonly found contaminant in groundwater and surface water. It has created a major water quality problem worldwide. The laboratory batch experiments were conducted to investigate the feasibility of HCl-treated zero-valent iron (Fe(0)) combined with different adsorbents as hybrid systems for simultaneous removal of nitrate (NO(3)(-)) and ammonium (NH(4)(+)) ions from aqueous solution. The maximum NO(3)(-) removal in combined Fe(0)-granular activated carbon (GAC), Fe(0)-filtralite and Fe(0)-sepiolite systems was 86, 96 and 99%, respectively, at 45 °C for 24 h reaction time. The NO(3)(-) removal rate increased with the increase in initial NO(3)(-) concentration. The NO(3)(-) removal efficiency by hybrid systems was in the order of sepiolite > filtralite > GAC. The NH(4)(+) produced during the denitrification process by Fe(0) was successfully removed by the adsorbents, with the removal efficiency in the order of GAC > sepiolite > filtralite. Results of the present study suggest that the use of a hybrid system could be a promising technology for achieving simultaneous removal of NO(3)(-) and NH(4)(+) ions from aqueous solution.     

Determination of cobalt,nickel and iron at trace level in natural water samples by in-column chelation-reversed phase high-performance liquid chromatography

This paper reports the utilization of 4-(2-pyridylazo) resorcinol (PAR) as a chelating reagent for in-column derivatization and the determination of trace Co, Fe, and Ni ions by reversed-phase high-performance liquid chromatography with photodiode array detector. A good separation of Co, Fe, and Ni chelates were achieved by using an Inertsil ODS-3 column and a mobile phase, consisted of methanol–THF–water mixture (50:5:45) containing ammonium acetate buffer (pH 5.0) and PAR. After full optimization, good repeatability of retention times (relative standard deviation (RSD) < 0.05%) and peak areas (RSD < 1.7%) was achieved as well as a good linearity (r ² > 0.9991). The detection limits (S/N = 3), expressed as micrograms per liter, were 0.50 (Co), 9.07 (Fe), and 2.00 (Ni). The applicability and the accuracy of the developed method were estimated by the analysis of spiked water samples and certified reference material BCR 715 wastewater-SRM.     

Using multivariate statistical methods to assess the groundwater quality in an arsenic-contaminated area of Southwestern Taiwan

Groundwater is a major water resource in Southwestern Taiwan; hence, long-term monitoring of water quality is essential. The study aims to assess the hydrochemical characteristics of water in the arsenic-contaminated aquifers of Choushui River alluvial fan and Chianan Plain, Taiwan using multivariate statistical methods, namely, factor analysis (FA), cluster analysis (CA), and discriminant analysis (DA). Factor analysis is applied to reveal the processes controlling the hydrochemistry of groundwater. Cluster analysis is applied to spatially categorize the collected water samples based on the water quality. Discriminant analysis is then applied to elucidate key parameters associated with the occurrence of elevated As concentration (>10 μg L(-1)) in groundwater. Major water types are characterized as Na-Ca-Cl and Na-Mg-Cl in the Choushui River alluvial fan and Chianan Plain, respectively. Inorganic species of arsenic (As), particularly As(III), prevail in these two groundwater catchments, and their levels are higher in the Chianan Plain than in the Choushui River alluvial fan. Through FA, three factors, namely, the degree of salination, As reduction, and iron (Fe) reduction, are determined and denoted irrespective of some differences between the factorial compositions. Spatial distribution patterns of factors As reduction and Fe reduction imply that the redox zonation is delineated by As- and Fe-dominance zones separately. The results of CA demonstrate that three main groups can be properly explained by the factors extracted via FA. Three- (Fe(2+), Fe(3+), and NH (4) (+) ) and four-parameters (Fe(2+), Fe(3+), NH (4) (+) , and Ca(2+)) derived from discriminant analysis for Choushui River alluvial fan and Chianan Plain are elucidated as key parameters affecting the distribution of As-contained groundwater. The analytical results indicate that the reductive dissolution of Fe minerals is prerequisite for the mobilization of As, whereas the shift of redox condition from Fe- to As-reducing leads to the accumulation of dissolved As in this area.     

高效液相色谱-串联质谱法测定废水中5种喹诺酮类抗生素

建立高浓度有机废水中5种喹诺酮类抗生素的高效液相色谱-串联质谱测定方法。水样经HLB固相萃取小柱富集净化,12 ml甲醇洗脱、浓缩并加入内标溶液后,定容至1 mL待测。以C18柱为分离柱,含0.01%甲酸的甲醇-含0.01%甲酸的水溶液为流动相,目标物质在10 min内分离。在0.25~1 250 ng/mL范围内,目标物质线性关系良好(R20.99)。基质加标试验结果表明,纯水中的回收率为61.40%~91.92%,废水中的回收率为54.92%~101.87%,检出限为0.25~2.5 ng/L,方法定量限为0.36~3.99 ng/L。应用该方法对21家猪场的64份废水样品进行分析,5种喹诺酮类抗生素的检出频率为47%~95%,平均检出浓度为980~5 734 ng/L。该方法快速、准确,适用于高浓度有机废水中喹诺酮类抗生素的同时测定。     

邻菲啰啉直接光度法测定水中总铁

为了准确快速测定印染企业生产用水中的铁，探讨了Fe3＋在水浴和室温25℃时的还原反应试验，发现在这2个条件下Fe3＋均能被盐酸烃胺快速还原为Fe3＋，进而提出了测定水中总铁的新方法——邻菲哕啉直接光度法。并对该方法的检出限、显色络合物的稳定性、干扰及消除、盐酸用量、校准曲线、精密度和准确度进行了试验。检出限为0．03mg／L，显色络合物显色15min可稳定6个月，精密度RSD〈4．32％，加标回收率为95．3％～103％。通过地下水、地表水、工业废水和铁标准样品的比对实验表明，邻菲哕啉直接光度法与邻菲啰啉光度法（标准法）的测定结果无显著差异。     

The role of GC-MS and LC-MS in the discovery of drinking water disinfection by-products

Gas chromatography-mass spectrometry (GC-MS) has played a pivotal role in the discovery of disinfection by-products (DBPs) in drinking water. DBPs are formed when disinfectants, such as chlorine, ozone, chlorine dioxide or chloramine, react with natural organic matter in the water. The first DBP known--chloroform--was identified by Rook in 1974 using GC-MS. Soon thereafter, chloroform and other trihalomethanes were found to be ubiquitous in chlorinated drinking water. In 1976, the National Cancer Institute published results linking chloroform to cancer in laboratory animals, and an important public health issue was born. Mass spectrometry and, specifically, GC-MS became the key tool used for measuring these DBPs in water and for discovering other DBPs that were formed. Over the last 25 years, hundreds of DBPs have been identified, mostly through the use of GC-MS, which has spawned additional health effects studies and regulations. Early on, GC with low resolution electron ionization (EI)-MS was used, together with confirmation with chemical standards, for identification work. Later, researchers utilized chemical ionization (CI)-MS to provide molecular weight information and high resolution El-MS to aid in the determination of empirical formulae for the molecular ions and fragments. More recently, liquid chromatography-mass spectrometry (LC-MS) with either electrospray ionization (ESI) or atmospheric pressure chemical ionization (APCI) has been used to try to uncover highly polar DBPs that most experts believe have been missed by earlier GC-MS studies. Despite 25 years of research in the identification of new DBPs, new ones are being discovered every year, even for chlorine which has been the most extensively studied.     

Monitoring of the three organophosphate esters TBP,TCEP and TBEP in river water and ground water (Oder,Germany)

The behaviour of the three organophosphate esters tributyl phosphate (TBP), tris(2-chloroethyl)phosphate (TCEP) and tris(2-butoxyethyl)phosphate (TBEP) during infiltration of river water to ground water has been investigated. The monitoring site is the Oder River and the adjacent Oderbruch aquifer. From March 2000 to July 2001, 76 ground water samples from monitoring wells located close to the Oder River and nine river water samples were collected. Additionally, influent and effluent samples from local waste water treatment plants, one sample of rain water and samples of roof runoff were collected. All samples were analysed by solid-phase-extraction followed by gas chromatography/mass spectrometry. TBP, TCEP and TBEP were detected at mean values of 622 ng l(-1), 352 ng l(-1), and 2955 ng l(-1), respectively in municipal waste water effluents. This points to a major input of these compounds into the Oder River by municipal waste water discharge. The concentrations of TBP and TBEP decreased downstream the Oder River possibly due to aerobic degradation. TBP, TCEP and TBEP were detected in ground water influenced predominantly by bank-filtered water. This demonstrates a transport of organic compounds by river water infiltration to ground water. TBP, TCEP and TBEP were also detected in rain water precipitation, roof runoff and ground water predominantly influenced by rain water infiltration. This hints to an input of these compounds to ground water by dry and wet deposition after atmospheric transport. Organophosphate esters were also detected in parts of the aquifer at 21 m depth. This demonstrates low anaerobic degradation rates of TBP, TCEP and TBEP.     

荧光分光光度法测定废水中的微量硫化物

建立了一种基于荧光素汞在碱性条件下与S^2-作用生成荧光性的物质，从而使荧光素汞的荧光强度下降，根据荧光强度的下降值来测定水样中S^2-含量的方法，测定范围为0.007-0.8mg/L，线性相关系数r为0.9987。大部分共存物质不干扰测定，加入甲醛溶液可消除CN^-的干扰，加入酒石酸可消除Fe^3 的干扰，测定结果令人满意。     

Occurrence and behaviour of dissolved, nano-particulate and micro-particulate iron in waste waters and treatment systems: new insights from electrochemical analysis

Cyclic-, Differential Pulse- and Steady-state Microdisc Voltammetry (CV, DPV, SMV) techniques have been used to quantify the occurrence and fate of dissolved Fe(ii)/Fe(iii), nano-particulate and micro-particulate iron over a 12 month period in a series of net-acidic and net-alkaline coal mine drainages and passive treatment systems. Total iron in the mine waters is typically 10-100 mg L(-1), with values up to 2100 mg L(-1). Between 30 and 80% of the total iron occurs as solid phase, of which 20 to 80% is nano-particulate. Nano-particulate iron comprises 20 to 70% of the nominally "dissolved" (i.e. <0.45 μm) iron. Since coagulation and sedimentation are the only processes required to remove solid phase iron, these data have important implications for the generation or consumption of acidity during water treatment. In most waters, the majority of truly dissolved iron occurs as Fe(ii) (average 64 ± 22%). Activities of Fe(ii) do not correlate with pH and geochemical modelling shows that no Fe(ii) mineral is supersaturated. Removal of Fe(ii) must proceed via oxidation and hydrolysis. Except in waters with pH < 4.4, activities of Fe(iii) are strongly and negatively correlated with pH. Geochemical modelling suggests that the activity of Fe(iii) is controlled by the solubility of hydrous ferric oxides and oxyhydroxysulfates, supported by scanning and transmission electron microscopic analysis of solids. Nevertheless, the waters are generally supersaturated with respect to ferrihydrite and schwertmannite, and are not at redox equilibrium, indicating the key role of oxidation and hydrolysis kinetics on water treatment. Typically 70-100% of iron is retained in the treatment systems. Oxidation, hydrolysis, precipitation, coagulation and sedimentation occur in all treatment systems and - independent of water chemistry and the type of treatment system - hydroxides and oxyhydroxysulfates are the main iron sinks. The electrochemical data thus reveal the rationale for incomplete iron retention in individual systems and can thus inform future design criteria. The successful application of this low cost and rapid electrochemical method demonstrates its significant potential for real-time, on-site monitoring of iron-enriched waters and may in future substitute traditional analytical methods.