高强循环磁场对低浓度铜离子溶液电沉积的强化机制

锂电池正极材料湿法回收过程中,因多金属浸出液的低浓度铜离子污染,造成有价金属回收工艺复杂以及二次废渣污染的共性问题。针对低浓度铜离子电沉积过程反应与传递受限造成的电沉积效率低问题,采用傅里叶显微红外光谱(FT-IR)、拉曼光谱(Raman)和紫外可见光谱(UV-VIS)等微结构检测方法研究了高强循环磁场对低浓度铜离子溶液电沉积的强化机制。结果表明,循环磁场可通过对水团簇与水合粒子结构形态的调控,提高扩散层离子传递速率与电沉积效率;在3 h预磁化时间内,电解液磁感应强度由0增加到3 T,DDAA(双质子双受体)型氢键结构破坏能力提高,0.01 mol/L CuSO4溶液与水黏度比(η/η0)由1.0197降低到0.9614,电沉积效率提升12.9%;在3 T高磁感应强度下,预磁化时间由0到24 h,0.01 mol/L CuSO4溶液与水黏度比(η/η0)由1.0197降低到0.9486,电沉积效率提升17.6%。电解质通过磁场磁化后,溶液中水分子与离子由于产生不同的感生磁场,溶液氢键数量减低,水合团簇减小,水合粒子半径降低,所以强化了扩散层传质过程,提高电沉积效率。

质量滴定法测定较高浓度金属离子溶液

通过减小滴定终点变量,适当增加乙二胺四乙酸二钠(EDTA·2Na)溶液滴定总质量以及混合缓冲液和指示剂于EDTA溶液的手段,运用质量滴定法测定较高浓度稀土离子和钙离子溶液的浓度.得到了重现性较高的实验数据,质量滴定结果的相对标准偏差(RSD)小于0.05%.

运用问题分析模型帮助学生克服认识障碍——以“水溶液中离子浓度关系的分析”复习教学为例

“水溶液中离子浓度关系的分析”属于程序性知识，学生在分析和解决这一类问题时往往存在思维障碍。基于知识特点分析，构建了“水溶液中离子浓度关系的分析模型”，在复习教学中引导学生经历形成分析模型，完善分析模型，并应用模型来解决问题的学习过程，帮助学生克服认识障碍，促进学生认识发展。

NaHSO3溶液中的离子浓度分析

从高中的教学层次分别以NaHSO3溶液中各种平衡变化关系及溶液的pH测定，得出该溶液中各离子浓度。利用溶液中三大守恒关系进行理论计算，求得NaHSO3溶液中离子浓度大小的关系为[Na^＋][HSO3^-]〉[H^＋]〉[SO3^2-]〉[OH^-],由此证明了该结论在一般情况下的正确性。

高炉粒化矿渣对混凝土孔溶液离子浓度的影响

通过离心和高压萃取法提取水泥-高炉粒化矿渣体系1 h和10～24 h液相,采用电感耦合等离子体发射光谱仪和pH计测试液相离子浓度和pH值,研究了高炉粒化矿渣掺量对体系液相离子浓度和pH值的影响。结果表明:随水化时间延长,水泥-高炉粒化矿渣体系早龄期液相中K^+、Na^+、SiO_4^(4-)浓度和pH值逐渐增大,Ca^(2+)和SO_4^(2-)浓度先增大后减小,10 h左右均达到峰值,AlO_2^-浓度呈类似变化;随高炉粒化矿渣掺量增加,液相中K^+、Na^+、Ca^(2+)、SO_4^(2-)和AlO_2^-浓度及pH值逐渐减小,SiO_4^(4-)浓度逐渐增大,40%高炉粒化矿渣掺量对Ca^(2+)浓度影响程度最显著。

溶液中离子浓度关系问题归类例析

以近几年高考题中溶液离子浓度关系问题部分选择题为例,进行分类解析小结,以使同学们加深理解,更好地掌握.

聚焦广东高考必考题之溶液中离子浓度关系问题

自2010年高考方案改革实施,纵观2010年~2014年广东高考卷,不难发现,溶液中的离子问题是高考的一大热点,它能有效地测试出学生对强弱电解质、电离平衡、水的电离、pH、离子反应、盐类水解等基本概念的掌握程度及对这些知识的综合运用能力。本文通过对广东省近五年的溶液中离子浓度考点的对比,从考点分析、命题预测、知识剖析、解题策略四方面对此题进行解读研究,进行思考总结,探究如何提高学生对溶液中离子浓度关系问题的解析能力。

低浓度钛离子水解的多项式描述

富钛材料是氯化法制备二氧化钛的主要原料,利用低浓度钛离子溶液制备高纯富钛材料是一种重要的方法.获得低浓度的钛离子溶液([TiO2+]<1.0 mol/L)不需要真空浓缩步骤,水解率可超过98%,足以制备高纯富钛材料.对硫酸钛溶液的水解率随时间的变化进行了研究,为了得到任意时刻的水解率,对所得到的时间-水解率曲线进行最小二乘法拟合,得到实验曲线的解析多项式,通过对多项式的推导,得到水解率与钛离子浓度、水解时间的关系.结果表明,在钛离子水解过程中,水解速率随钛离子浓度、水解时间的增加呈先增大后减小的趋势,并且水解速率存在一个峰值.

张家口柳川河河道治理膨润土防水毯防渗性能影响研究

随着我国工业技术的进步和社会经济的发展,工程实施过程中产生了大量的金属废水,对环境造成了较大的破坏。为了进一步掌握重金属离子对河道膨润土防水毯防渗效果影响规律,文章依托河北张家口柳川河河道清淤工程,对比分析了不同金属离子类型、离子浓度对传统针刺GCL和自制HDP GCL防渗效果的影响程度,研究结果表明:对于不同类型的离子溶液,渗透效果最强的为Cu 2+溶液,Zn 2+溶液略次之,最小的是Pb 2+溶液;4mm和7mm厚HDP GCL在离子溶液浓度大于1g/L时才会发生渗漏现象,且7mm HDP GCL防渗能力优于4mmHDP GCL和传统针刺GCL,表明影响HDP GCL防渗性能的关键因素是厚度。

高中化学“溶液中离子浓度大小比较”的教学反思

“溶液中离子浓度的大小比较”已成为高考化学的必考点，但学生分析这类问题的思路始终不清晰。本文阐述了赏题、观题、析题等活动，旨在提高课堂教学效率。

Separation of macro amounts of tungsten and molybdenum by ion exchange with D309 resin

Based on the difference in tendency to polymerize between tungsten and molybdenum, a new method using D309 resin was propounded. The batch tests indicate that the optimum pH value and contact time for the separation are 7.0 and 4 h respectively, the maxium separation factor of W and Mo is 9.29. And the experimental resules show that isothermal absorbing tungsten and molybdenum belongs to Langmuir model and Freundlich model respectively, and the absorbing kinetics for tungsten is controlled by intra-particle diffusion. With a solution containing 70 g/L WO3 and 28.97 g/L Mo, the effluent with a mass ratio of Mo to WO3 of 76 and the eluate with a mass ratio of WO3 to Mo of 53.33 are obtained after column test.

Equilibrium concentration of lithium ion in sodium aluminate solution

Excess lithium in alumina is significantly bad for aluminum reduction.In this study,the concentration variation of lithium ion in sodium aluminate solution with addition of synthetic lithium aluminate was investigated.Elevating temperature,increasing caustic soda concentration,reducing alumina concentration or raising molar ratioαk improved equilibrium concentration of lithium ion in sodium aluminate solution.Agitation speed had a minimal effect on lithium ion concentration.Over 0.65 g/L lithium ion equilibrium concentration was observed in digestion process,whereas 35 mg/L lithium ion concentration remained in solution after precipitation time of 9 h.Moreover,equilibrium concentration decreased sharply from digestion of boehmite or diaspore to seed precipitation,about 95%lithium was precipitated into red mud(bauxite residue)and aluminum hydroxide.This study provides a valuable perspective in removal or extraction of lithium from sodium aluminate solution in alumina refineries.

Solvent extraction of zinc from zinc sulfate solution

The extraction of zinc from zinc sulfate solution was investigated, using 20% saponified D2EHPA as an extractam and 260^# sulfonate kerosene as a diluent. The solution was stirred for 8 min at phase ratio （Vσ/Va） of 1.0：1.0, initial pH of 2.0 and stirring speed of 200 r/min. The results show that 75% zinc can be extracted from the zinc sulfate solution when the concentration of zinc is 18.7 g/L after being settled for 10 min. 88.60% zinc can be stripped by 196 g/L sulfuric acid, and zinc ion can be separated from ferric ion.

Effect of solution conditions on depression of chlorite using CMC as depressant

The effect of solution conditions on the depression of chlorite using CMC (carboxymethyl cellulose) as depressant was studied through flotation tests and adsorption measurements. Flotation and adsorption tests were first studied as a function of initial solution conditions. The results show that electrostatic repulsion between CMC molecules and chlorite surface hinders the approach of the CMC molecules to the chlorite surface and CMC adsorbs to a great extent at high ionic concentration (10-4 mol/L ions as opposed to 0 mol/L ions) or low pH (3 as opposed to 9). The enhanced adsorption density is attributed to the decreased electrostatic repulsion between CMC and mineral surface. The solution condition that yielded the lowest initial adsorbed amount (0 mol/L ions, pH 9) was used as a reference to investigate the response of the adsorbed CMC layer to a switch in solution conditions after adsorption. The two kinds of solution switches (reducing the solution pH or increasing ionic concentration) result in an increased depression effect of CMC on chlorite flotation, as a result of conformational change of CMC pre-adsorbed layer. The change in the flotation recovery of the CMC-coated chlorite following the solution switches is reversible.

Phosphate removal from aqueous solution by Donnan dialysis with anion-exchange membrane

The removal of phosphate from aqueous solution by Donnan dialysis with anion-exchange membrane was investigated.The results show that phosphate could be removed from aqueous solution without supplying external high pressure or electrical potential.Under the conditions of influent phosphate of 2.0 mg/L,counterion(Cl-)concentration of 0.1 mol/L,stirring speed of 500 r/min and phase temperature of 298 K,the removal of phosphate achieves 70.0%.Decreasing counterion concentration has little influence on the removal of phosphate,but phosphate amount in anion-exchange membrane increases significantly.With the increase of stirring speed and phase temperature,the removal efficiency of phosphate greatly is improved.Existing forms of phosphate in aqueous solution affected transport of phosphate and only strong acidic pH of feed solution(pH=3.0)decreases the removal of phosphate.Transport of phosphate is also accompanied by change of pH value of feed solution.In consequence,it might be a promise potential process for phosphate advanced wastewater treatment,especially in the area where high salted nature water can be utilized.

Corrosion behavior of AZ31 magnesium alloy in simulated acid rain solution

The corrosion mechanism of AZ31 magnesium alloy used as automobile components and the influence of the concentration of Cl- ion in simulated acid rain(SAR)were studied by electrochemical tests and SEM.The results show that pitting corrosion happens around the AlMn phases locating at the grain boundary.The corrosion of AZ31 magnesium alloy in SAR is controlled by the rate of anodic dissolution and hydrogen evolution,and the corrosion rate of AZ31 increases with increasing concentration of Cl- ion.However,the Cl- ion in SAR is not the main influencing factor inducing the pitting corrosion.

Electrokinetic phenomena of poly(vinyl butyral) hollow fiber membranes in different electrolyte solutions

The streaming potential of poly（vinyl butyral） （PVB） hollow fiber membrane was studied in different electrolyte solutions （including NaCl, KCl, CaCl2 and MgCl2）, the effects of ionic strength, ion valence and pH value on the streaming potential （SP） of the membrane were investigated. The zeta potentials and surface charge densities of the membrane were estimated on the basis of Helmholtz-Smoluchowski equation and Gouy-Chapmann theory. The results show that the PVB membrane has a weak negative charge due to the specific adsorption of ions. Moreover, the streaming potential, the zeta potential and the surface charge density of the membrane depend strongly on the salt concentration and the type and valence of ions. The iso-electric point （IEP） of the PVB membrane is arotmd 3.0 in the monovalent media （NaC1 and KC1） and 3.5 in divalent electrolytes （CaCl2 and MgCl2）. A few retentions were obtained for PVB membrane in low concentration solutions. This result verifies that the negative charged membrane surface can reject inorganic solutes by means of electrostatic repulsion effect even though the size of membrane pores is much larger than the size of salts.

Study on a Novel Disphase Supplying Supported Liquid Membrane for Transport Behavior of Divalent Nickel Ions

A novel d!sphase supplying supported liquid membrane （DSSLM）, containing supplying feed phase andsupplying stripping phase tor transport behavior ot NI（Ⅱ）, have been studied. The supplying supported feed phase included feed solution and di（2-ethyhexyl） phosphoric acid （HDEHP） as the carrier in kerosene, and supplying stripping phase included HDEHP as the cartier in kerosene and HC1 as the stripping agent. The effects of volume ratio of membrane solution to feed solution （O/F）, pH, initial concentration of Ni（Ⅱ） and ionic strength in the feedsolution, volume ratio of membrane solution to stripping solution （O/S）, concentration of H2SO4 solution, HDEHP concentration in the supplying stripping phase on transport of Ni（/I）, the advantages of DSSLM compared to the traditional supported liquid membrane （SLM）, the system stability, the reuse of membrane solution and the reten- tion of membrane phase were studied. Experimental results indicated that the optimum transpgrt of Ni（Ⅱ） was oh-tained when H2SO4 concentration was 2.00 mol＇L-＇, HDEHP concentration was 0.120 mol·L-1, and O/S was 4· 1 in the supplying stripping phase, O/F was 1 ： 10 and pH was 5.20 in the supplying feed phase. The ionic strength in supplying feed phase had no obvious effect on transport of Ni（Ⅱ）. When initial Ni（Ⅱ） concentration was 2.00x 10-4 mol/L, the transport percentage of Ni（Ⅱ） was up to 93.1% in 250 min. The kinetic equation was deduced in terms of the law of mass diffusion and the interface chemistry.

水泥基材料极早期水化机理及微观结构分析

测试了水泥浆体中孔溶液离子浓度在水化极早期的演变规律;运用原子力显微镜(AFM),采用碱性模拟溶液腐蚀粉煤灰的方法来研究了水化过程中孔溶液碱度对粉煤灰化学反应活性以及水化反应和水化产物生成的影响。研究结果表明:粉煤灰掺量分别为0、10%、20%的三种水泥水化孔溶液各离子浓度随水化时间的推移,其变化趋势基本是相同的。水化最开始的阶段孔溶液离子浓度主要是由碱性物溶解控制,其变化呈现差异性。AFM观察结果表明,碱性溶液可以侵蚀粉煤灰颗粒表面,改变其微观结构,改变的程度与侵蚀溶液碱离子浓度密切相关。经侵蚀的粉煤灰颗粒表面有纤维状水化产物形成。

Formation of Polyethersulfone Film with Regular Microporous Structure by Water Vapor Induced Phase Separation

Polyethersulfone(PES)film with regular microporous structure was formed using dichloromethane as the solvent via water vapor induced phase separation(VIPS).The effects of solution concentration,atmospheric humidity and temperature,as well as molecular weight of PES on the surface morphology of the polymer film were investigated.The surface morphology characterized by SEM showed that the pore size reduced as the solution concentration increased.There was an optimum range of relative humidity for the formation of regular pore structure, which was from 60%to 90%at concentration of 20 g·L-1 and 20°C.With the atmospheric temperature varied from 20 to 30°C,the pore became larger and the space between pores increased.The pore size in the PES film with low molecular weight was smaller than that with high molecular weight.