滴定法快速测定多金属矿石中的铜铅锌铁

采用盐酸、硝酸、硫酸等试剂分解试样,铅形成硫酸铅沉淀,过滤洗涤使硫酸铅沉淀与铜、锌、铁等金属离子分离,沉淀加NaAc-HAc缓冲液溶解,用EDTA标准液滴定测铅.滤液以水定容至100mL,用移液管分别分取2份部分溶液,1份溶液用碘量法测定铜.另1份溶液加过量氨水使锌离子与铁离子等分离,过滤洗涤,滤液用EDTA标准液滴定...     

一种铅钙锌镁铝五元类塑料热稳定剂中金属含量测定的探索

介绍了铅-钙-锌-镁-铝五元类塑料热稳定剂中金属含量的测定方法:第一份试液,以三乙醇胺掩蔽铁等离子后,调pH为12,用EDTA滴定钙离子;第二份试液,调pH为3.5,加过量EDTA煮沸处理,再调节pH为4.2,促使铝和锌全部与EDTA络合,以锌盐标准溶液滴定剩余的EDTA,加氟化铵解蔽ED-TA-Al,再用锌盐标准溶液滴定释放出的EDTA,计算出铝的含量;第三份试液,用硫酸分离铅钙和锌镁铝,沉淀用醋酸-醋酸钠溶液溶解,用EDTA滴定铅离子含量,溶液用于锌镁的分析测试;第四份试液,取除掉钙铅的溶液一份调pH为5.5,加氟化铵掩蔽铝等离子后,用EDTA滴定锌离子;第五份试液,取除掉钙铅的溶液一份调pH为8.5趁热过滤以除去锌和铝。调pH为10,用EDTA滴定镁。该法准确度和精密度均较高,能满足工业分析要求。     

锆铬刚玉砖中Al203分析方法的探讨

叙述了通过717强碱阴离子交换树脂分离铬，采用控制酸度使锆与铝分离，然后用苦杏仁酸掩蔽钛，再加过量EDTA，在弱酸性溶液中铝与EDTA络合，以二甲酚橙为指示剂，用氟化铵置换—EDTA络合滴定法测得Al203量的过程，论证了这种测定方法的准确性和可行性。     

连续滴定法测定硅氟酸电解液中硅氟酸和铅

在电解液中加入饱和硫酸钾,使硅氟酸和铅生成沉淀与其他元素分离,用氢氧化钠滴定硅氟酸后,再用EDTA滴定溶液中的铅。硅氟酸回收率为97.9%~101.3%,铅回收率为97%~102.07%,方法简单,准确,快速,可满足生产的要求。     

EDTA滴定法测定铜冶炼烟灰中的铅

本文建立了铜冶炼烟灰中铅量的分析方法。样品经氟化氢铵—盐酸—硝酸—高氯酸—硫酸—氢溴酸溶解,在此条件下,砷和锑可以被挥发除去,过滤硫酸铅,沉淀连同滤纸一起在乙酸-乙酸钠缓冲体系溶解,加少许抗坏血酸,三滴二甲酚橙指示剂,2mL巯基乙酸（1+99）,EDTA络合滴定法测定铜冶炼烟灰中的主量铅,滤液中铅量用电感耦合等离子体发射光谱法来进行补正。本文从溶样方式、沉淀条件、乙酸-乙酸钠缓冲溶液的加入量实验、铋干扰消除实验、滤液中铅量的补正实验等多个方面进行研究,选择合理条件范围和消除干扰方法。本实验选取3个样品,将铅铋连续滴定测得铅量和本实验测定铅量进行比对,验证本实验的正确度,加标回收率在99.0～101.5之间,精密度良好,准确度高。     

燃烧法测定镀铬液中的硫酸根

一测定方法的提出及理论依据镀铬液中硫酸根的含量对于镀层质量和电流效率有着显著的影响。因此,快速测定镀铬液中的硫酸根,较好地控制镀铬液中硫酸根的含量具有重要的意义。硫酸根的测定通常用硫酸钡重量法,硫酸钡沉淀—EDTA滴定法,离心沉降法。前种方法速度太慢,后二种方法是对前法的改进。但分析精密度和准确度都较差。近年来,对硫酸根的测定作过不少的研究,提出了氢碘酸—次磷酸—盐酸混合试剂还原硫化铅光度法,苯甲酸银沉淀分离大量铬EDTA滴定法,磷换活性炭蒸馏碘量法,苯甲酸银分离铬—阳离子交酸钡电极法,小型Al_2O_3柱—铅电极法,四苯硼     

铬天青S用作有机磷快速微量分析中的指示剂

有机化合物中磷含量的分析,已有许多方法,1969年等提出用铬天青S作指示剂测定有机化合物中磷的容量分析法。后来,Lalancette等人提出以镧盐(为LaPO_4)沉淀磷,再用NaOH滴定释放的H~+。Grob用特殊铅电极作指示加过量铅标准溶液以沉淀磷酸根,再以EDTA回滴过量铅。Ionescu提出用电位滴定法,用Hg(NO_3)_2标准溶液沉淀磷酸根,因所用Hg(NO_3)_2有毒,须作浓度校正曲线,均不简便。我们曾进行过铬天青S作指示剂测定有机磷的微量法研究,提出了     

复混肥料中钾含量测定的不确定度评定（偏导数法）

1测定方法 按照GB／T8573—2002《四苯硼酸钾重量法》测定，称取适量试样，经预处理、定容，制备为测定用试液。吸取一定量试液，加入EDTA溶液等步骤操作后，滴加四苯硼酸钠溶液沉淀钾。沉淀经过滤、洗涤后，干燥，称量。     

硫酸锶晶体生长动力学研究

为了从控制晶体生长角度，说明制备纳米硫酸锶沉淀体系中存在的EDTA对产品粒径的影响作用，根据过程机理，用恒组成法研究硫酸锶晶体生长动力学。根据叠加模型和弱化模型，建立体系中有EDTA存在时，硫酸锶沉淀过程的晶体生长动力学模型。结果表明，硫酸锶沉淀过程中晶体生长属于表面反应控制机理。EDTA存在能降低晶体生长速率，有利于减小粉体粒径。     

氨水沉淀法由含钛滤液提取二氧化钛

以含钛高炉渣为原料,经硫酸铵熔融法得到含钛滤液,然后以氨水为沉淀剂,控制pH值使钛水解,水解产物经600℃煅烧2 h得到二氧化钛。考察了螯合剂的加入量、溶液pH值和反应时间对钛沉淀率的影响,实验结果表明:反应过程中铁与钛发生共沉淀,造成二氧化钛产物中的铁含量过高。EDTA几乎完全抑制了铁的沉淀,明显降低了二氧化钛产物的全铁含量;2-羟基丙烷-1,2,3-三羧酸的加入降低了产物中二氧化硅的含量,提高了产物中二氧化钛的含量。当2-羟基丙烷-1,2,3-三羧酸与硅的摩尔比为1,EDTA与铁的摩尔比为3,pH值为2.0,反应时间为90 min时产物中二氧化钛的含量为96.35%。     

乙二胺四乙酸和聚环氧琥珀酸对污泥中铅的萃取研究

以某公司废水处理池中的污泥为研究材料,分别以乙二胺四乙酸二钠盐(EDTA)和聚环氧琥珀酸(PE-SA)作为萃取剂,研究了它们在不同pH、萃取剂浓度、搅拌时间下Pb的萃取率。实验结果表明,在最佳的实验条件下,EDTA对Pb萃取率为83.32%;而PESA对Pb萃取率达到92.36%。PESA不含有氮、磷,不会引起水体富营养化,是环境友好的水溶性聚合物。     

Leaching of Pb Contaminated Soil using Ozone/UV Treatment of EDTA Extractants

Abstract

One of the main problems of EDTA based soil‐washing technologies for remediation of heavy metals contaminated soils is the separation of EDTA‐heavy metals complexes from the waste extractant. In our study an advanced oxidation process using ozone and UV was used for the decomposition of EDTA‐Pb complexes in soil extractants obtained during leaching of Pb contaminated soil. Released Pb was removed by absorption. Twenty consecutive soil treatments with 2.5 mmol kg^?1 EDTA removed 58.4% of Pb and greatly reduced the Pb mobility and oral‐availability. The waste extractant was colorless, with slightly basic pH and with low Pb and EDTA concentrations.     

Reactivation of severely aged commercial three-way catalysts by washing with weak EDTA and oxalic acid solutions

Ethylene diamine tetraacetic acid (EDTA) which is a well-known reagent for its metal extraction efficiency was studied for the first time towards the improvement of the catalytic activity and oxygen storage and release properties (OSC) of severely aged commercial three-way catalysts (TWC) on a laboratory scale. Optimization of the experimental parameters of EDTA-washing procedure of TWC was carried out by varying the washing time, volumetric flow rate, and temperature of EDTA solution. The EDTA-washing procedure of TWC was compared with that of oxalic acid-washing regarding their efficiency in removing P, Pb, S, Ca, Zn, Fe, Cu, Cr, Ni, and Mn, all known TWC contaminants that many of them cause severe deterioration of TWC's activity and oxygen storage and release properties. EDTA appears to be significantly efficient in removing Pb, Zn, Ca, Mn, Fe, Cu and Ni metal contaminants and sulfur but not of phosphorus (P). Phosphorus-containing species were found to be efficiently removed from the aged TWCs after oxalic acid washing. All regeneration procedures applied led to a significant partial recovery of catalytic activity of TWC (CO, C_xH_y and NO_x conversions) under real exhaust gas conditions (dynamometer tests) due to the removal of large amounts of contaminants accumulated on the aged TWC. The washing procedures using oxalic acid alone or in combination with EDTA led to more significant improvements of both catalytic and OSC performance compared with those of EDTA washing alone. This was due to the ability of oxalic acid to remove P-containing compounds which appear to be one of the main causes of commercial three-way catalyst deactivation.     

柠檬酸-EDTA电镀光亮Sn-Pb合金的研究(Ⅰ)工艺研究

研究了以柠檬酸和EDTA为络合剂,QB-1为添加剂的电镀光亮Sn-Pb合金工艺。探讨了络合剂含量、[Sn~(2+)]/[Pb~(2+)]、阴极电流密度及温度对镀层中Pb含量的影响。综合考虑合金镀层组成、镀层的光泽度及镀液的稳定性,确定了电镀光亮sn-Pb合金的最佳镀液组成及工艺条件。     

Lead(II)‐ion removal by ethylenediaminetetraacetic acid ligand functionalized magnetic chitosan–aluminum oxide–iron oxide nanoadsorbents and microadsorbents: Equilibrium,kinetics, and thermodynamics

Novel nanosized and microsized chitosan–Al₂O₃–Fe₃O₄ (CANF and CAMF, respectively) adsorbents were functionalized with ethylenediaminetetraacetic acid (EDTA) ligands and applied to the removal of Pb(II) ions. The prepared adsorbents were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and Brunauer–Emmett–Teller analysis, and their adsorption potentials were investigated with Pb(II) as a target metal under various experimental conditions. Our results show that the EDTA functionalization of CANF and CAMF increased their adsorption capacities about 31.5 and 38 times, respectively. The optimum dosage obtained was 1.0 g/L for both EDTA‐functionalized adsorbents, and the maximum adsorption took place at pH = 5.3. The kinetic results revealed that the adsorption obeyed the pseudo‐second‐order model and that the pore diffusion process played a key role in the adsorption kinetics. Also, the results of equilibrium isotherms indicate the good fit of the experimental data by the Langmuir isotherm model under the studied concentration and temperature ranges, and the adsorptions of Pb(II) ions from aqueous solution followed the monolayer coverage of the adsorbents. The maximum Pb(II)‐ion adsorption capacities of EDTA–CANF and EDTA–CAMF were 160 and 157 mg/g, respectively. These metal‐loaded adsorbents could be readily recovered from aqueous solution by magnetic separation and reused. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44360.     

Preparation of Uniform Submicrometer Particles of Calcium Titanate and Lead Niobate by Replacement Reactions

Uniform submicrometer particles of calcium titanium peroxo-hydroxide were prepared by adding calcium salts to the solution of peroxotitaniun. species chelated with nitrilotriacetic acid (NTA). Similarly, corresponding leadniobium compodnd of [Pb]/[Nb] = 0.75 was obtained by introducing lead salts into the solution of chelated niobium complex with ethylenediaminetetraacetic acid (EDTA) at pH 3. Calcium ions in solutions containing a mixture of NTA-chelated Pb and NTA-chelated Nb complexes also caused the precipitation of lead niobium oxo-hydroxide of [Pb]/[Nb] = 1.5 at pH 9. The so-obtained precursor powders were converted on calcination to the corresponding composite oxides. The mechanisms of these reactions were suggested, based on the chemical, thermal, and X-ray diffraction analyses.     

Effect of different treatments on electrokinetic remediation of Zn,Pb and Cd from a contaminated calcareous soil

Electrokinetic remediation is a promising method to decontamination of the heavy metals from soils.In this paper,the remediation of a contaminated calcareous soil with Zn,Cd and Pb sampled from around Zanjan province of Iran,was investigated using electrokinetic method.In this paper,the soil contain a high concentration of Zn (1400 mg·kg-1),Cd (15 mg·kg-1) and Pb (250 mg·kg-1).Electrokinetic decon-tamination consists of two series of experiments as follows:(1) the effect of five treatments including the use of distilled water,acetic acid and EDTA electrolyte solutions,and approaching anodes systems,and the circulation flow of electrolyte at two different voltage gradient (i.e.1.33 and 2.66 V·cm-1),and(2) the effect of moisture content (saturated,FC and 0.7FC,FC indicated soil moisture at "Field Capacity") with a voltage gradient of 1.33 V·cm-1.After applying electric current for 5 days,the results of experiments indicated that the removal efficiency of heavy metals can be increased by raising the volt-age gradient.In this matter,the highest remediation can be observed among different treatments in EDTA(Ethylene diamine tetra acetic acid) treatment (40.11％,43.10％ and 24.7％ for Zn,Cd and Pb,respectively).Moreover,the heavy metals removal at the saturated moisture was at the highest level so that 32.62％cadmium,31.33％ zinc and 18.82％ lead being removed after 120 h of electric current application.By decreasing moisture to 0.7FC,the removal percentage for the three heavy metals obtained 20.97％,18.44％ and 12.25％,respectively.Furthermore,Cd had the highest removal,and Zn and Pb were next among the three heavy metals in question.     

Facile preparation of EDTA‐functionalized chitosan magnetic adsorbent for removal of Pb(II)

A novel magnetic adsorbent (EDTA /chitosan/ PMMS) was facilely prepared by reacting chitosan with EDTA anhydride in presence of PEI ‐ coated magnetic microspheres. The as‐synthesized EDTA/ chitosan /PMMS was characterized by XRD, SEM, TGA, FT‐IR , and VSM, and then employed in removal of heavy metals of Pb(II) from aqueous solution. The results of the batch adsorption experiments revealed that the adsorbents had extremely high uptake capacities for Pb(II) in the pH range of 2 to 5.5, and the adsorption kinetics for EDTA/ chitosan /PMMS was consistent with the pseudo – second ‐ order kinetic model. Moreover, its equilibrium data were fitted with the Langmuir isothermal model well, which indicated that the adsorption mechanism was a homogeneous monolayer chemisorptions process. The maximum adsorption capacity of EDTA/ chitosan /PMMS for Pb(II) was found to be 210 mg g ^{? 1} at pH 4 (30 ° C), and further reuse experiments results suggested that EDTA /chitosan/ PMMS could be a potential recyclable magnetic adsorbent in the practical wastewater treatment. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42384.     

PSSMA修饰磁性氧化石墨烯对Pb2+、Cu2+ 的吸附性能

以氧化石墨烯(GO)、FeCl_3·6H_2O及聚(4-苯乙烯磺酸-共聚-马来酸)钠盐(PSSMA)为主要原料,通过简便一步溶剂热法制备了阴离子聚电解质修饰磁性氧化石墨烯(MGO@PSSMA),并将其用于水溶液中重金属Pb~(2+)、Cu~(2+)的吸附去除。采用FTIR、SEM、TEM、VSM和DLS对制备的MGO@PSSMA进行了表征。考察了溶液pH、吸附时间、溶液初始质量浓度对Pb~(2+)、Cu~(2+)在MGO@PSSMA及未经PSSMA修饰磁性氧化石墨烯(MGO)上吸附的影响。探讨了吸附等温过程、吸附动力学及吸附作用机理。结果表明:MGO表面引入PSSMA可有效增加其对Pb~(2+)、Cu~(2+)的吸附量。在pH=5,溶液初始质量浓度为300 mg/L时,MGO@PSSMA对Pb~(2+)和Cu~(2+)的实际吸附量达141.1和104.8 mg/g。当溶液初始质量浓度为150 mg/L时,MGO@PSSMA对Pb~(2+)和Cu~(2+)的吸附平衡时间分别为2和1.5 min。MGO@PSSMA对Pb~(2+)、Cu~(2+)的吸附动力学及吸附等温数据分别符合准二级吸附动力学模型和Langmuir吸附等温模型。使用乙二胺四乙酸(EDTA)和HCl可实现MGO@PSSMA的有效再生;通过外加磁场作用可实现MGO@PSSMA的回收再利用。     

EDTA荧光探针测定微量铅

pH=4.00,c=0.3M的EDTA溶液在激发波长λex=267.5 nm,发射波长λem=380.8 nm时,有较强的荧光发射峰,随着Pb2＋的定量加入,其荧光猝灭与Pb2＋加入量成线形关系,相关系数r=0.9983,检测限为c=0.1 μg·L-1,测量范围为c=0～120 μg·L-1.从而可以利用EDTA荧光探针来测量未知样中Pb2＋的浓度.