葡萄糖电化学还原研究

本研究测定了阴极材料，电流密度，溶液ｐＨ以及温度等电解参数对葡萄糖电化学还原的电流效率的影响，为选择合适的电解条件提供依据。通过极化曲线的测定，进一步从理论上分析了电极材料对电流效率影响的原因。     

固定床电化学反应器研究(Ⅱ)硝基苯电化学还原制备对氨基苯酚

研究了在固定床电化学反应器内硝基苯电化学还原制备对氨基苯酚的过程.采用文献[7,8]建立的固定床电化学反应器模型对该反应过程进行了反应器设计.实验测得该反应的摩尔选择性β≥80%,电流效率η_i≥75%,反应器表观电流密度i≥1500A/m~2.本研究为固定床电化学反应器内硝基苯电化学还原制备对氨基苯酚过程工业化奠定了重要的理论基础.     

固定床电化学反应器研究(Ⅱ)硝基苯电化学还原制备对氨基苯酚

研究了在固定床电化学反应器内硝基苯电化学还原制备对氨基苯酚的过程.采用文献[7,8]建立的固定床电化学反应器模型对该反应过程进行了反应器设计.实验测得该反应的摩尔选择性β≥80%,电流效率η_i≥75%,反应器表观电流密度i≥1500A/m~2.本研究为固定床电化学反应器内硝基苯电化学还原制备对氨基苯酚过程工业化奠定了重要的理论基础.     

L－半胱氨酸的电化学还原制备（Ⅰ）

研究了包括电极材料、电解方式和电流密度在内的几个因素对Ｌ－胱氨酸电化学还原为Ｌ－半胱氨酸的影响。结果表明，经处理后的Ｓｎ能明显地提高反应速度；恒电位电解可使Ｌ－半胱氨酸的产率和电流效率分别达到９８％和１００％；恒电流电解的适宜电流密度为１２～１６Ａ·ｄｍ－３，产率和电流效率各为９７．６～９８；５％和７０～７８％；分段控制电流法的产率为９６．４％，电流效率为９２％。     

靛蓝的媒质间接电化学还原及其动力学

研究了以Fe2（SO4）3／三乙醇胺（TEA）／NaOH为媒质体系间接电化学还原靛蓝的工艺条件及动力学。采用循环伏安法（cV）确定络合体系的还原电位为-0．9V（相对氧化汞电极）。采用恒流法还原靛蓝,以在线光谱仪监测反应过程中靛蓝转化率随时间的变化来考察反应条件对还原的影响。结果表明,当还原靛蓝浓度为0．02g／L时,合适的反应条件为电流密度3mA／cm^2,Fe2（SO4）3浓度0．0040mol／L,50℃,pH值14．0,TEA浓度0．150mol／L。当满足一定的电流密度和媒质浓度时,靛蓝还原由其颗粒表面溶解速率决定,其活化能为26．1kJ／mol。     

L—半胱氨酸的电化学还原制备（Ⅰ）

研究了包括电极材料，电解方式和电流在内的几个因素对Ｌ－胱氨酸电化学还原为Ｌ－半胱氨酸的影响。结果表明，经处理后的Ｓｎ能明显地提高反应速率；恒电位电解可使Ｌ－半胱氨酸的产率和电流效率分别达到９８％和１００％；恒电流电解的适宜电流密度为１２－１６Ａ；ｄｍ＾２，产率和电流效率各为９７．６－９８．５％和７０－７８％；分段控制电流法的产率为９６．４％，电流效率为９２％。     

制浆造纸厂富铁污泥中Fe3+的电化学还原研究

采用电化学法将制浆造纸厂废水Fe^nton氧化产生的难处理富铁污泥中的Fe^3+还原为Fe^2+,以便于其再利用。研究表明,以不锈钢为阴极材料可较大幅度降低Fe^3+还原的过电位;当Fe^3+质量浓度为2000 mg/L时无需辅助电解质,在极水比为0.48 cm^2/mL,电流密度为0.65 mA/cm^2的条件下反应2 h,Fe^2+再生率可达60.1%,电流效率为92.1%。将酸处理后的富铁污泥溶液在上述条件下还原3 h,Fe^2+再生率达68.8%,电流效率近100%。电化学法是富铁污泥中Fe^3+再利用的可行方法。     

铋/纳米洋葱碳电极的制备及其电化学还原CO2性能研究

采用水热法制备Bi/MCNOs电极催化剂,通过XRD、SEM对Bi/MCNOs催化剂进行表征,考察了Bi/MCNOs电极电化学还原CO₂制甲酸的性能。结果表明,在水热过程中,MCNOs成功负载到Bi上,Bi/MCNOs具有更小的球状结构。Bi/MCNOs电极电化学活性表面积为Bi电极的3.4倍。Bi/MCNOs电极的电流密度是Bi电极的4倍,且具有更正的起峰电位。通过对KHCO₃电解液浓度、还原电位对电化学还原CO₂制甲酸的分析可知,KHCO₃电解液浓度为0.5 mol/L、电势为-1.6 V vs.Ag/AgCl时,电化学还原CO₂效果最好,具有较高的电流效率。由此可见,Bi/MCNOs电极具有更高的活性,可有效提高电化学还原CO₂的催化效果。     

间接电化学合成香草醛

应用Mn~(3+)/Mn~(2+)作为氧化还原中介体体系,间接电化学氧化异丁子香酚合成香草醛。研究了电流密度、反应物浓度、中介体浓度、介质条件、流速、电极材料、温度和反应时间等因素对产率的影响。应用优化设计方法得到了较高的产率。     

老龄垃圾渗滤液高氨氮的电化学氧化及其能耗分析

针对垃圾渗滤液高氨氮、难生物降解的特点,采用电化学氧化法对含高浓度氨氮的垃圾渗滤液进行预处理,考察了不同电极材料、电流密度、Cl-质量浓度、pH、极水比等因素对渗滤液中高NH3-N去除的影响,分析了电化学氧化法处理垃圾渗滤液的能耗和电流效率。结果表明,在电流密度30 mA.cm-2、Cl-质量浓度5 000 mg.L-1、pH为8、极水比17.8 m2.m-3的条件下,以Ti/RuO2-IrO2-TiO2电极为阳极电解6 h后,NH3-N的去除率、电流效率和比能耗分别为99.9%、35%和91.9 kWh.kg-1。     

阴丹士林艳绿FFB的间接电化学还原

The indirect electrochemical reduction of Indanthrene Brilliant Green FFB (IBG) was investigated in detail by cyclic voltammetry and electrolytic experiments. Triethanolamine (TEA) was used as ligand to form elec-trochemically active Fe(III)-complexes in alkaline solution. The effects of operating parameters including reaction temperature, current density, concentration of NaOH and Fe(III)-TEA mediator had been studied by orthogonal ex-periments and the mechanism of radicals on electrochemical reduction was discussed. The cyclic voltammetry ex-perimental results show that Fe(III)-TEA complexes are well suited for the indirect electrochemical reduction of IBG. The electrolytic experiments show that high current efficiency (49.9%) can be successfully achieved under op-timized conditions and the current density is found to be the main influence factor.     

还原染料电化学还原染色方法研究进展

还原染料的电化学还原染色方法是环境友好的新型染色方法,具有还原剂使用量少或不使用还原剂、排放的废水少,染色过程易于控制等特点。介绍了还原染料的间接电化学还原、直接电还原和电催化氢化方法的原理、特点和工艺过程,探讨了三种方法各自的优点和需要解决的问题。     

Multi-cathode cell with flow-through electrodes for the production of iron(ii)-triethanolamine complexes

Nonregenerable reducing agents used in dye houses for the application of indigo, vat dyes and sulfur dyes can be substituted by indirect cathodic reduction techniques. An electrochemical cell for the indirect cathodic reduction of dispersed indigo dyestuff using an alkaline solution of the Fe(iii/ii)-triethanolamine complex as redox mediator was constructed and tested. The cell is built up as divided cell (cathode area 5–10m2, catholyte volume 12L, anolyte volume 1.5L) with several three dimensional cathode units (up to 10) in the same cathode compartment. The cathodes were connected to a common anode and to separately adjustable power supplies. The catholyte was circulated through the porous cathode units parallel to the current direction. Two different electrode materials (copper and stainless steel) and cathode constructions were tested, resulting in an optimized cell construction. The electrochemical cell was characterized by a series of batch electrolysis experiments. Results are given dealing with the cell voltage drop in the cathode, the product yield and the current efficiency at different current densities and cell current. After an optimization step the current efficiency reaches 70–80% at 2 A m–2 current density and 7.8×10–3moldm–3 Fe(ii)-complex. The cell current is 10A.     

A study of the Fe(III)/Fe(II)-triethanolamine complex redox couple for redox flow battery application

The electrochemical behavior of the Fe(III)/Fe(II)-triethanolamine(TEA) complex redox couple in alkaline medium and influence of the concentration of TEA were investigated. A change of the concentration of TEA mainly produces the following two results. (1) With an increase of the concentration of TEA, the solubility of the Fe(III)-TEA can be increased to 0.6 M, and the solubility of the Fe(II)-TEA is up to 0.4 M. (2) In high concentration of TEA with the ratio of TEA to NaOH ranging from 1 to 6, side reaction peaks on the cathodic main reaction of the Fe(III)-TEA complex at low scan rate can be minimized. The electrode process of Fe(III)-TEA/Fe(II)-TEA is electrochemically reversible with higher reaction rate constant than the uncomplexed species. Constant current charge-discharge shows that applying anodic active materials of relatively high concentrations facilitates the improvement of cell performance. The open-circuit voltage of the Fe-TEA/Br₂ cell with the Fe(III)-TEA of 0.4 M, after full charging, is nearly 2.0 V and is about 32% higher than that of the all-vanadium batteries, together with the energy efficiency of approximately 70%. The preliminary exploration shows that the Fe(III)-TEA/Fe(II)-TEA couple is electrochemically promising as negative redox couple for redox flow battery (RFB) application.     

Direct electrochemical reduction of indigo: process optimization and scale-up in a flow cell

Reducing agents required in the dyeing process for vat and sulfur dyes cannot be recycled, and lead to problematic waste products. Therefore, modern economical and ecological requirements are not fulfilled. The industrial feasibility of the direct electrochemical reduction of indigo as a novel method has been determined and a preliminary optimization of electrolytic conditions was performed using a laboratory-scale flow-cell system. The role of current density, pH, temperature and the rate of mass transport are discussed. The influence of particle size reduction by the application of ultrasound is critically considered.     

Direct cathodic reduction of Leuco Sulfur Black 1 and Sulfur Black 1

The electrochemical activity of Leuco Sulfur Black 1 in alkaline solution is shown by the means of voltammograms of the dyestuff recorded in a flow cell. The voltammograms indicate the possibility for further dyestuff reduction by cathodic electron transfer. In batch electrolysis experiments successful reduction of Leuco Sulfur Black 1 was achieved using a multi cathode cell. Applying similar experimental conditions cathodic reduction of the insoluble oxidized dyestuff Sulfur Black 1 was achieved. In a first step the dispersed Sulfur Black 1 is reduced to give an alkaline soluble form of the dyestuff that can be reduced further to yield Leuco Sulfur Black 1. Analogous to the electrochemical behaviour of technically produced Leuco Sulfur Black 1, which contains reducing agents, the solution of Leuco Sulfur Black 1 formed by electrolysis is able to undergo further cathodic electron transfer. The cathodic dyestuff reduction is of importance for the development of sulfur dyeing processes which do not require addition of reducing chemicals.     

Electrochemical reduction of indigo in fixed and fluidized beds of graphite granules

Reducing agents required in the dyeing process for vat and sulfur dyes cannot be recycled and lead to problematic waste products. The electrochemical reduction of indigo on a fixed bed cathode consisting of graphite granules has been investigated by spectrophotometric experiments in laboratory cells. Experiments yield information about the kinetics and show the possibility of this process for production of water soluble leuco indigo, which offers environmental benefits. The influence of noble metals deposited on the granules and of different pretreatment methods of the graphite is demonstrated. In addition, the immobilization of quinoid molecules on the graphite surface has been investigated.     

还原染料还原方法的研究进展

目前工业上主要采用化学法来还原染料,该方法存在废水处理成本高、还原剂不可再生、环境污染严重等问题。而电化学法利用电子为清洁能源,只需很少的化学还原剂就能得到满意的还原效率,大大减少了废水的排放。文章主要讨论了各种还原方法的优缺点,并结合其还原机理分析了还原染色技术的未来发展动向。     

Direct electrochemical reduction of indigo

Reducing agents required in the dyeing process for vat and sulfur dyes cannot be recycled, and lead to problematic waste products. Therefore, modern economical and ecological requirements are not fulfilled. The application of direct electrochemical reduction of indigo as a novel route has been investigated by spectrophotometric and voltammetric experiments in laboratory cells. Experiments yield information about the reaction mechanism and the kinetics, and they show the possibility of this new route for production of water-soluble indigo, which offers tremendous environmental benefits.     

Electrochemical reduction of nitrates and nitrites in alkaline media in the presence of hexavalent chromium

Electrochemical reduction of nitrates and nitrites in alkaline media at constant current is rendered inoperable in the presence of hexavalent chromate. Even at chromate concentrations as low as 9mgdm–3, the chromium hydroxide film, formed by the reduction of chromate, interferes with the reduction of nitrate and nitrite. We show that reversing the polarity of the electrodes at constant time intervals minimizes the adverse effects of the chromium hydroxide film, enabling the electrochemical reduction of nitrates and nitrites to proceed efficiently. The optimum current and reversal time are coupled through an optimum charge density of 625Ccm–2 per cycle. We also demonstrate through long-term studies that the reversal technique can be operated on a continuous basis.