四苯硼钠—季铵盐质量滴定法分析常量铷     

钟远  李海军  王涛  孙柏  李武  宋彭生 《盐湖研究》2014,(4):11-16

采用四苯硼钠—季铵盐质量滴定法分析溶液中的常量铷,考察了松节油用量和共存离子(Ca2+、Mg2+、Li+、CO2-3、SO2-4、B4O2-7)对氯化铷溶液中Rb+分析结果的影响。溶液中Rb+浓度为0.05%⁰.15%时,分析结果的相对误差<0.3%,加标回收率为99.20%0.15%时,分析结果的相对误差<0.3%,加标回收率为99.20%¹01.2%。溶液中的共存离子Ca2+、Li+和SO2-4对Rb+分析无影响。  相似文献   

SHORT COMMUNICATION DYNAMIC HEADSPACE ANALYSIS:OPTIMIZATION OF TITRATION BY EXPERIMENTAL DESIGN     

THIERRYTALOU  LUCRIGAL  ANTOINEGASET 《地理学报(英文版)》1988,(Z1)

The dynamic headspace titration of the volatile constituents of the black truffle(Tuber Melanosporum)isplanned to be carried out with the new gas chromatographic device DCI using Tenax trapping.In thispaper the necessary optimization of the experimental factors which influence the desorption of thevolatiles from the sample and the adsorption on the trap is carried out by experimental design.The studyof the isoresponse curves makes it possible to determine the optimum conditions for a rapid titration ofhighest sensitivity and reproducibility,avoiding water trapping.  相似文献   

Assessment of spill flow emissions on the basis of measured precipitation and waste water data   总被引：1，自引：0，他引：1  

Martin Hochedlinger  Günter Gruber  Harald Kainz 《Atmospheric Research》2005,77(1-4):74

Combined sewer overflows (CSOs) are substantial contributors to the total emissions into surface water bodies. The emitted pollution results from dry-weather waste water loads, surface runoff pollution and from the remobilisation of sewer deposits and sewer slime during storm events. One possibility to estimate overflow loads is a calculation with load quantification models. Input data for these models are pollution concentrations, e.g. Total Chemical Oxygen Demand (COD_tot), Total Suspended Solids (TSS) or Soluble Chemical Oxygen Demand (COD_sol), rainfall series and flow measurements for model calibration and validation. It is important for the result of overflow loads to model with reliable input data, otherwise this inevitably leads to bad results. In this paper the correction of precipitation measurements and the sewer online-measurements are presented to satisfy the load quantification model requirements already described. The main focus is on tipping bucket gauge measurements and their corrections. The results evidence the importance of their corrections due the effects on load quantification modelling and show the difference between corrected and not corrected data of storm events with high rain intensities.  相似文献   

EDTA-铅滴定法测定水中硫酸根条件试验     

彭雪娇 《华东地质学院学报》2003,26(3):281-283

测定水中硫酸根的方法有重量法、容量法、硫酸钡比浊法和间接极谱法等。常用硫酸钡比浊法和容量法来测定。EDTA 铅滴定法测定水中硫酸根的含量是一种经典的容量法,通过对该法滴定条件———溶液酸度、沉淀放置时间、缓冲溶液的加入量等进行较详细的试验。提出了测定时应控制的实验条件,验证了该法的可行性,且测定结果更精确。进一步氯离子的干扰试验表明:此方法适用于氯离子含量小于600mg·L-1的水样测定。  相似文献   

Complexation of Gold(III)-Chloride at the Surface of Hematite     

Olga N. Karasyova  Lyudmila I. Ivanova  Leonid Z. Lakshtanov  Lars Lövgren  Staffan Sjöberg 《Aquatic Geochemistry》1998,4(2):215-231

The acid/base properties of the hematite/water interface and surfacecomplexation with gold has been studied by potentiometric titrations in thefour component system H⁺ – FeOH –AuCl ₄ ^- – Cl^-. Equilibrium measurementswere performed in NaCl media at 298.2 K. In the evaluation of equilibriummodel from experimental data the constant capacitance model was applied. Theacid/base properties were investigated in 0.1 M NaCl in the range 2.6 pH 7.4. The resulting intrinsic constants for protonation anddeprotonation of hydroxyl groups at the surface were log _1,1,0,0(int) ^s = 7.10 ± 0.06 andlog _{-1,1,0,0(int)} ^s = - 7.80 ±0.06. The density of proton active surface sites was 2.85nm^-2 and the specific capacitance 2.5 C V^-1 m^-2. In the investigation of surface complexation of gold, thepotentiometric titrations were performed in the range 2.0 pH 10.2.Titration data was supplemented with analysis of Au in the aqueous phase byatomic absorbance spectrometry. The equilibrium model proposed consists ofthe following monodentate surface complexes: FeOHAuCl₃(log _0,1,1,-1 ^s = 1.45 ± 0.03),FeOHAuCl₂OH (log _-1,1,1,-2 ^s = -3.89 ± 0.02), FeOHAu(OH)₃ (log _-3,1,1,-4 ^s = -21.94 ± 0.05). Aslightly better fit could be obtained by assuming formation of a bidentatecomplex with the composition(FeO)₂Au(OH)H₂O. However, based onstructural arguments this complex was rejected.  相似文献   

Interactions of cadmium(II) and protons with dead biomass of marine algae Fucus sp.     

R. Herrero  B. Cordero  P. Lodeiro  C. Rey-Castro  M.E. Sastre de Vicente   《Marine Chemistry》2006,99(1-4):106

Samples of dead biomass from the marine brown algae Fucus ceranoides, Fucus vesiculosus and Fucus serratus were studied for their ability to remove cadmium from aqueous solutions. The metal sorption process is rapid, with 90% of the metal uptake completed within the first 25 min of contact. The kinetic data was described successfully by a pseudo second order chemical sorption process with rate constants of ca. 0.6 g mmol^− 1 min^− 1. At pH 4.5, the raw biomass of the three species exhibited equilibrium uptake capacities for Cd as high as 0.8 mmol g^− 1 (90 mg g^− 1), on a dry weight basis, without chemical pretreatment. These sorption capacities are much higher than those reported for activated carbon and chitin. The sorption of Cd was found to increase as pH increases, reaching a plateau at pH 5.Batch sorption experiments and continuous potentiometric titrations of acid-treated biomass samples in 0.05 M NaNO₃ were used to derive thermodynamic binding parameters according to the NICCA model. The total amount of acid sites was 2.4–2.9 mmol g^− 1, with median values of the affinity distribution for protons and cadmium ions, log K˜_H and log K˜_Cd, of 3.7 and 2.69, respectively (conditional values). The apparent heterogeneity of the sorbent was successfully taken into account by the empirical NICCA isotherm, which described very well the competition between protons and metal ions, in contrast with a simpler discrete competitive Langmuir model.The experimental results demonstrate that these seaweeds constitute a promising, efficient, cheap and biodegradable sorbent biomaterial for cadmium removal from wastewaters. This use would represent an example of exploitation of a renewable marine resource in water treatment technologies for the prevention of heavy metal pollution in the environment.  相似文献   

酸-碱滴定法测定海洋浮游植物细胞表面积     

王修林  马延军  李继亮  郁纬军  孙汉章 《海洋与湖沼》1997,28(4):356-362

1995年改进了浮游植物表面积的酸碱滴定测定法，其中应用改进BET方程对酸滴定曲线拟合求最大表面酸量，由此测定了18种海洋浮游植物（包括8种绿藻，7种硅藻，2种甲藻，1种红藻）的细胞表面积。结果表明，该方法精密度为15．2％，所测定的18种海洋浮游植物的表面积为2．78×10-8—6．9×10-6m2，变异系数为0．9％—31．3％，较传统的用光／电子显微镜粗略估算的方法，更为精确，并且设备简单，操作方便。  相似文献   

Ultraviolet absorbance titration for the determination of conditional stability constants of Hg（Ⅱ） and dissolved organic matter   总被引：1，自引：0，他引：1  

BAI Yingchen WU Fengchang WAN Guojing LIU Congqiang FU Pingqing LI Wen 《中国地球化学学报》2008,27(1):46-52

Strong interaction between natural dissolved organic matter （DOM） and Hg（Ⅱ） may influence the transport, conversion, toxicity and bio-validity of mercury in the environment. In this paper ultraviolet （UV） absorbance titration was employed for the first time for the determination of the conditional stability constants of Hg（Ⅱ） and （DOM）. With increasing Hg（Ⅱ） concentrations, the UV absorbance of fulvic acid, humic acid, and DOM in river increases progressively. By linear and non-linear model fitting, the conditional stability constants （lgK） of Hg（Ⅱ） and DOM were worked out to be 3.54-4.93 and 3.64-4.85, respectively. The results are consistent with those acquired by the typical fluorescence quenching titration method, with the maximum relative error of lgK being 2.6% and the average relative error being 0.2%. The UV absorbance titration method has the advantages of rapid determination, simple performance, and it will probably become a new approach to studying interactions between DOM and trace metallic ions.  相似文献   

液氮冷凝吸收热解-电感耦合等离子体质谱法测定岩石土壤沉积物中的溴碘   总被引：2，自引：1，他引：1  

宋萍  温宏利 《岩矿测试》2016,35(4):384-388

分析地质样品中的溴碘,目前常用的提取方法有半熔法、稀氨水密封溶样法和热解法,但由于元素含量低、易损失,样品分解和溴碘的提取过程是主要的误差来源。本文改进了传统热解法的吸收装置,用液氮冷凝吸收代替常规的碱溶液吸收,提取地质样品中的溴碘,用电感耦合等离子体质谱法测定其含量。以标准偏差的10倍计算,稀释倍数为50,溴碘的检出限分别为0.06μg/g、0.01μg/g,低于传统热解法和半熔法,略高于稀氨水密封溶样法;精密度(RSD)为6.4%~21.0%。本方法相对于传统的碱溶液吸收热解法,减少了碱试剂的引入,降低了基体空白和稀释倍数,提高了精密度,操作较半熔法简便,可作为稀氨水密封溶样法的一种补充方法。因此,对于土壤和水系沉积物,宜采用稀氨水密封溶样法;对于岩石以及采用稀氨水密封溶样法难以完全提取的样品,可采用本方法。  相似文献   

泥沙颗粒表面电荷特性及其对干容重影响试验研究          下载免费PDF全文

黄荣敏  陈立  卢炜娟 《水科学进展》2007,18(6):807-811

采用黄河及长江中的沙样在不同Ca2+浓度下分别进行电位滴定试验和干容重试验,得到以下结论:①随Ca2+浓度的增加,泥沙颗粒表面负电荷先不断减少然后趋于不变。②Ca2+对泥沙淤积干容重的影响可分为三个阶段:第一阶段干容重减小;第二阶段增加并达到最大值;第三阶段减小最后趋于不变。③在Ca2+浓度相同条件下,泥沙浓度对淤积干容重的影响根据所加Ca2+浓度不同也呈现不同的变化。④Ca2+浓度、泥沙浓度相同时,中值粒径越大干容重越大,且中值粒径大的泥沙干容重达到最大值所需Ca2+少。⑤在不同Ca2+浓度下泥沙颗粒由于表面电荷不同造成静电斥力不同,同时表面水膜作用力也不同,二者共同作用使得干容重体现不同的变化。  相似文献