Effects of temperature and concentration of sulfuric acid on the electrodeposition of grainy electrolytic manganese dioxide

The effects of temperature and the concentration of sulfuric acid on the cell voltage, the anode current efficiency of electrodeposition and the particle size of grainy electrolytic manganese dioxide （EMD） were investigated. The structure, particle size and appearance of grainy EMD were determined by powder X-ray diffraction, laser particle size analysis and scanning electron micrograph measurements. As the concentration of sulfuric acid increases, both the cell voltage and the average anode current efficiency decrease. With the increase of electrolysis temperature in the range of 30-60℃, the cell voltage, average anode current efficiency and particle size decrease. The optimum temperature of 30℃ and concentration of sulfuric acid of 2.5 mol/L for electrodeposition of the grainy EMD were obtained. XRD patterns show that the grainy EMD electrodeposited under the optimum conditions consists of γ-MnO2 and has an orthorhombic lattice structure. According to the results of SEM, the grainy EMD has a spherical or sphere-like appearance and a narrow particle size distribution with an average size of about 7μm. The grainy EMD is a promising cathode of rechargeable alkaline batteries for high energy density and a prospective precursor for production of the LiMn2O4 cathode of lithium ion batteries.     

电渗析法回收含Cu、Fe、Ni硫酸溶液中的硫酸

本文研究了用电渗析法从含铜、铁、镍离子的酸性溶液中回收硫酸的行为。测定了电流密度、给液的初始酸浓度、金属离子类别和浓度对硫酸回收效率的影响，实验结果表明：给液中初始硫酸浓度为１０～２００ｇ／ｌ，金属离子浓度４～５０ｇ／ｌ时，硫酸可以通过电渗析法有效地进行回收，有少量金属离子随同硫酸一起进入产物液．对产物液的污染程度为：铜＞＞铁＞镍．这一现象可由实验所测得的膜电阻：铜＜铁＜镍得到解释。电渗析过程中硫酸从给液到产物液的转移效率与给液中金属离子类型无关．而与给液的初始酸浓度和电流密度有关，能量消耗随电流密度的增加而增大，而与给液的初始酸浓度无关。     

Manufacturing microporous foam zinc materials with high porosity by electrodeposition

In order to get foam zinc materials of porous metal electrode, a novel method for preparing foam zinc was proposed, in which the polyurethane foam with diameter of 0.3 mm as substrate was processed by degreasing, roughening, activating, electroless plating and electrodeposition. The main factors affecting the process, such as ZnSO₄ content, temperature, pH value, current density, and electrodes distance, were investigated comprehensively. The optimal process conditions are 250 g/L ZnSO₄, 20 g/L Al₂(SO₄)₃, 40 g/L KAl(SO₄)₂, 30 g/L Na₂SO₄, pH=3.5, 4.0 cm of electrodes distance and 0.04 A/cm² current density at 30 °C. The result shows that adding ultrasonic on the process can elevate the deepening plating ability and current efficiency. Foam zinc material with a high porosity of 92.2% and a three-dimensional network structure can be fabricated by electrodeposition.     

反应气体加湿对PEM燃料电池温度分布的影响

采用流体计算软件Fluent模拟分析了一个包含10个直流道的单电池,探讨了电池工作电流密度及阴阳极气体加湿程度对电池内膜平面上温度分布的影响。工作电流密度比较高的情况下,膜上最高温度和温度分布的不均匀性都很大;阴阳极气体加湿程度对膜上温度分布的影响基本一致,加湿程度变小最高温度及温差都随之变小;膜上温度的位置随加湿程度的变化而变化,加湿程度高时最高温度靠近进口,加湿程度低时靠近出口。     

聚苯胺电致变色薄膜的制备及性能

以苯胺单体为原料,采用电化学沉积法在玻璃衬底FTO导电薄膜上合成聚苯胺电致变色薄膜．采用恒电流法,研究苯胺单体浓度、酸的种类、电沉积时间、电流密度等对薄膜制备及电致变色性能的影响,确定合成聚苯胺薄膜的最佳条件．结果表明,聚苯胺电致变化薄膜的最佳制备条件是0．15mol／L苯胺单体的1mol／L硫酸溶液,以10．A／cm^2的电流密度电沉积40min．该条件下制备的薄膜的着色效率较无机电致变色薄膜高,但仅能循环105次．     

大气中SO_2对铜的腐蚀行为研究

利用三电极电化学电池和Cu/Fe双电极原电池对铜在含SO2大气中的腐蚀行为进行研究.通过电化学阻抗谱、极化曲线和电偶电流测定分析了金属铜在不同厚度液膜、不同SO2气体浓度条件下的初期腐蚀行为.结果显示:电极表面液膜越薄,金属铜的腐蚀电流密度越大;随着SO2浓度的增加,铜电极反应电阻减小,电极的去极化作用增强,Cu/Fe双电极原电池的电偶电流明显增大.     

单室空气阴极微生物燃料电池性能

以石墨毡为阳极、Pt/C为阴极、葡萄糖模拟废水为基质构建了一个单室空气阴极微生物燃料电池(air-cathode microbial fuel cell,ACMFC),研究了电池内流体、不同葡萄糖底物质量浓度等条件对电池产电性能及污水处理效果的影响.研究结果表明:水流流量为15 mL/min、葡萄糖底物的质量浓度为1.0 g/L时,电池的最大功率为85.9 mW/m2,ACMFC运行48 h,对模拟废水的COD去除率可达81.6%.     

电解法合成高铁酸钠的实验研究

通过改变传统电极设置位置,评定影响电解效率的各因素以实现电流效率的最大化.在简化电解装置的同时,不影响电流效率的提高.实验结果表明,将传统左右式设置电极改为上下式设置电极,阴极距液面2cm,阳极距底面4cm,电流密度2mA/cm2,NaOH浓度14mol/L,温度60℃,电解1.5h,并加入搅拌的情况下电流效率最大达到58%.     

Reclaim nickel and remove organics from the spent electroless nickel-plating bath by electrolysis

Electroless plating is a growing segment of metalfinishing, especially in the electronics industry. Inelectroless plating, metals are deposited onto the sur-face of a part without the use of electricity as a sourceof electrons. Instead, the bath solution supplies the e-lectrons for the deposition reaction. These baths are ex-tremely complex using a variety of chelating and/orcomplexing agents that hold the metals in the solution.Common chelating agents include ethylenediaminetet-raacetic acid …     

固体氧化物燃料电池阳极材料La0.8Mg0.2Cr0.8M0.2O3-δ（M=Zn,Al,Zr）的研究

采用Sm0.2Ce0.8O1.9(SDC)作为电解质材料,La0.6Sr0.4Co0.2Fe0.8O3-δ(LSCF)作为阴极材料,以溶胶—凝胶法制备的La0.8Mg0.2Cr0.8Zn0.2O3-δ,La0.8Mg0.2Cr0.8Al0.2O3-δ,La0.8Mg0.2Cr0.8Zr0.2O3-δ粉体作为阳极材料,组装硫氧固体氧化物燃料电池。分别以硫蒸汽和二氧化硫气体为燃料气,测试电池阳极材料性能。结果表明:以硫蒸汽为燃料,La0.8Mg0.2Cr0.8Zn0.2O3-δ在750℃达到最大开路电压420 mV,此时最大功率密度为23 mW/cm2;以二氧化硫为燃料,La0.8Mg0.2Cr0.8Zn0.2O3-δ在650℃获得最大开路电压162 mV,最大功率密度为2 mW/cm2。催化效果顺序为La0.8Mg0.2Cr0.8Zn0.2O3-δ>La0.8Mg0.2Cr0.8Al0.2O3-δ>La0.8Mg0.2Cr0.8Zr0.2O3-δ。     

Preparation and characterization of the Zr/CuO pyrotechnical battery

A pyrotechnical battery is successfully prepared, including an anode and cathode having pyrotechnic charges with Zr, CuO and asbestos. The anode and cathode are separated by a separator formed from LiF, ZrO2, and a fibrous sponge. A digital phosphor oscilloscope (DPO) is used to analyze discharge characterization of the pyrotechnical battery. Then the properties of the electrode materials are characterized by EDS, SEM and a temperature recorder, respectively. The discharge mechanism and safety characteristic are also discussed. The results indicate that the combustion temperature of electrode materials is determined as 1 500.6 ℃ according to thermometry analysis (the case temperature of the battery is lower). The combustion product is identified as ZrO2, Cu2O and Cu by X-ray diffraction (XRD). When the diaphragm is completely melted, Li+ migration and an embedded-based conductive process are formed. Then an electromotive force will immediately reach to the maximum. The discharge performance of the pyrotechnical battery then takes on stability. The electromotive force is up to 2.29 V, and that discharge time continues for more than 18 s. The current density in the small area (less than 2.88 Acm-2) is most effective. The conversion efficiency of electric energy is 96%. The pyrotechnical battery is very safe for the production and use processes.     

电化学氧化法处理氨氮废水的影响因素

为了考查电化学氧化对低浓度废水中氨氮的处理效果,研究阴极材料、阳极材料、电流密度、氯离子质量浓度、极板间距、沸石的添加和氨氮的初始质量浓度等影响因素对氨氮和总氮降解的影响,同时比较研究二维和三维电极对氨氮的去除效果.结果表明,电化学氧化法是一种适宜于废水脱氮的技术,较佳的工艺条件为：极板间距1 cm、电流密度5 mA/cm2、阳极RuO2-IrO2-SnO2/Ti、阴极钛网、氯离子质量浓度200 mg/L、改性沸石为粒子电极,在该条件下反应20 min后氨氮的去除率可达95%.与二维电极对比,三维电极是在多种物理化学过程协同作用下完成对氨氮的去除,可以达到更高的氨氮降解效果和电流效率.     

Removal of nickel from spent electroless nickel-plating bath with nickel foam cathode

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膜电解硫酸钠再生酸的研究

用膜电解的方法分解硫酸钠,试验进行了电解硫酸钠的阴极、阳极材料选择,研究了硫酸钠浓度和氢氧化钠浓度对电解的影响,测定了电解硫酸钠的槽电压组成,找到较好的电解条件.在[Na2SO4]=1.5 mol/L,[NaOH]=0.5 mol/L,铅合金阳极、镍阴极的条件下,膜电解硫酸钠的分解电压为3.4 V.     

Performance of a thermally regenerative ammonia-based battery using gradient-porous copper foam electrodes

Gradient-porous copper foam electrodes were applied to alleviate the adverse effects of the uneven current distribution of electrodes along the electrolyte flow direction in thermally regenerative ammonia-based batteries(TRABs). The results indicated that gradient-porous copper foam with a decreasing pore size(TRAB-LMS) provided the most uniform current distribution and generated the highest power density(15.5 W/m~2), total charge(1800 C) and energy density(1224 W h/m~3). With the increase in flow rate, the power density of the TRAB-LMS increased considerably within a certain range and then decreased slightly, with the optimal flowrate at 15 mL/min. Under the optimal flow rate, the performance of TRAB-LMS increased when the ammonia concentration rose from 0.5 to 2 M(1 M=1 mol L~(-1)); however, it decreased slightly when the ammonia concentration further increased to 3 M. The slight decrease in the cathode potential suggested that the flow and ammonia concentration beyond the optional values facilitated not only the transfer of ammonia into the porous anode, but also the crossover of ammonia from the anode to the cathode.     

Free alkali recovery from NaOH leaching liquor of tungsten ore by electrolysis with ion-exchange membrane

Ｔｈｅｃａｕｓｔｉｃｓｏｄａｌｅａｃｈｉｎｇｌｉｑｕｏｒｏｆｔｕｎｇｓｔｅｎｏｒｅ（ｗｏｌｆｒａｍｉｔｅｏｒｓｃｈｅｅｌｉｔｅ）ａｌｗａｙｓｃｏｎｔａｉｎｓａｇｒｅａｔｄｅａｌｏｆｆｒｅｅａｌｋａｌｉｆｏｒｔｈｅｒｍｏｄｙｎａｍｉｃａｎｄｋｉ－ｎｅｔ...     

不锈钢表面电镀Cu—Mn3O4复合涂层

铁素体不锈钢的热膨胀系数与固体氧化物燃料电池（SOFC）的组元相近,成本低廉,具有良好的抗氧化性,已被广泛用作SOFC电池堆的金属连接体材料．但是表面Cr2O3膜的挥发会导致SOFC阴极Cr中毒,缩短SOFC的服役寿命．为解决这一问题,本文利用电镀的方法在铁素体不锈钢（SUS430）连接体表面沉积cu—MnsO。复合涂层,研究了复合电镀Cu—Mn3O4涂层的电镀工艺,结果表明：复合电镀的适宜工艺参数为：溶液pH值为3,阴极电流密度为2．12A／dm^2,镀液温度为35℃,溶液中Mn3O4粉末添加量为20g／L,并研究了涂覆不锈钢在800℃空气中的氧化行为及氧化膜的导电性能．涂覆Cu—Mn3O4不锈钢氧化后表面生成CuO、（Mn,Ca）3O4和（Fe,Cu）3O4尖晶石氧化物,表面氧化物的导电性良好,并能有效阻止Cr向外迁移和扩散．     

Effects of current density on preparation of grainy electrolytic manganese dioxide

Grainy electrolytic manganese dioxide was prepared by electrodeposition in a 0.9 mol/L MnSO4 and 2.5 mol/L H2SO4 solution. The structure, particle size and appearance of the grainy electrolytic manganese dioxide were determined by powder X-ray diffraction, laser particle size analysis and scanning electron micrographs measurements. Current density has important effects on cell voltage, anodic current efficiency and particle size of the grainy electrolytic manganese dioxide, and the optimum current density is 30 A/dm^2. The grainy electrolytic manganese dioxide electrodeposited under the optimum conditions consists of γ-MnO2 with an orthorhombic lattice structure; the grainy electrolytic manganese dioxide has a spherical or sphere-like appearance and a narrow particle size distribution with an average particle diameter of 7. 237μm.     

Cathode erosion of graphite and Cu/C materials in airarcs

Cathode erosion of graphite and Cu/C was studied in direct current arcs, which were ignited between two electrodes comprised of two kinds of carbon materials and a tungsten anode in air. The arced zones on the cathode surface were investigated by a scanning electron microscope. Also, the cathode erosion rates of the investigated materials were measured. The results show that two distinct zone can be seen on both cathodes. The eroded area was located at the zone just opposite to the anode and surrounded by a white zone. The arced surface on the Cu/C containing 9.3 % Cu is rougher than that of the pure graphite. Many particles with various sizes distributed on the Cu/C. The vaporization of Cu can lower the surface temperature and reduce the cathode erosion. Therefore, the cathode erosion rate of the Cu/C is lower than that of the pure graphite.     

氯化浸出铅阳极泥回收金的研究

试验对湿法处理铅阳极泥回收金进行了研疣．实验结果表明：铜的浸出是酸浸除杂的主要影响因素,在温度为65℃,盐酸浓度为2．9moL／L,氯化钠浓度为1．3mol／L,硫酸浓度为0．3mol／L时,铜的浸出率达到92．03％,杂质能有效去除．在氯化浸金的过程中,温度与氯酸钠的用量对金的浸出率影响最大．随着两者的增加,金的浸出率将明显地增加．当温度大于80℃,氯酸钠用量大于料重的12．5％,硫酸浓度为1．5mol／L时,金的浸出率大于98％．