恒电位下活性艳蓝KN-R在活性炭纤维电极上的脱色行为

在恒电位模式下,采用隔膜电解槽,分别以活性炭纤维（ACF）为阳极或阴极,研究了蒽醌染料活性艳蓝KN-R的脱色行为.测量了ACF的线性扫描极化曲线,进行了控电位下活性艳蓝KN-R在ACF电极上的整体电解,考察了脱色率、TOC、COD_Cr去除率同电极电位之间的关系.结果表明：该染料在ACF电极上的起始氧化电位和起始还原电位分别为0.5 V和-0.7 V,氧化峰电位为1.1 V;当电位为-0.6～0.4 V时,脱色源于染料在ACF上的吸附,极化对吸附行为影响不大;当电位为-1.5～-0.7 V时,脱色以染料的电还原为主,反应遵循准一级动力学;当电位为0.5～1.6 V时,脱色以染料的电氧化为主,反应同样遵循准一级动力学.     

ACF电极上苋菜红的恒电流电化学脱色

在恒电流模式下,研究了活性炭纤维(ACF)分别作阳极或阴极时对偶氮染料苋菜红的电氧化和电还原脱色.确定了ACF上苋菜红发生氧化和还原反应的电极电位分别是0.6V和-0.4V.ACF对苋菜红的脱色机制因电流密度的不同,明显地分为电氧化、电还原和吸附脱色三种过程.电氧化和电还原过程均遵循准一级反应动力学方程,并且电氧化的脱色速率常数与电流密度线性相关.电氧化脱色率在电流密度为0.5 mA·cm-2时可以达到99.1%,TOC和COD去除率最大可分别达到32.8%和52.1%;电还原脱色率在电流密度为-1.0 mA·cm-2时达到100%,TOC和COD去除率最大可分别达到58.0%和61.4%.     

成对ACF电极电解脱色偶氮染料苋菜红

研究了偶氮染料苋菜红在成对ACF(活性炭纤维)电极上的电解脱色和发生成对电解脱色的电流密度.在恒电流模式下,采用无隔膜电解槽,同时以活性炭纤维(ACF)为阳极和阴极,考察了不同电流密度下的脱色效果和脱色机制.结果表明:(1) 0～0.2 mA·cm-2时,脱色是由于染料在ACF上的吸附,极化对吸附行为影响不大,脱色率在15%以下;(2) 0.3～0.4 mA·cm-2时,阴极电位达到该染料在ACF上的还原电位(-0.4 V),阳极电位未达到其氧化电位(0.6 V),脱色是由于阴极电还原和阳极吸附,脱色率最高可达44%;(3) 0.5～1.0 mA·cm-2时,发生成对电解,即阳极电氧化和阴极电还原同时使染料脱色,当染料初始浓度为250 mg·L-1,电解6 h,脱色率最高可达84%.     

蒽醌染料活性艳蓝KN-R的ACF电极成对电解脱色

在恒电流模式下,采用无隔膜电解槽,同时以活性炭纤维（ACF）为阳极和阴极,研究了不同电流密度下蒽醌染料活性艳蓝KN-R的脱色效果和脱色机制.结果表明：0～0.1 mA·cm^-2时,脱色是由于染料在ACF上的吸附,极化对吸附行为影响不大,脱色率在15%左右;0.2～0.6 mA·cm^-2时,阳极电位达到该染料在ACF上的氧化电位（0.5 V）,阴极电位未达到其还原电位（-0.7 V）,脱色是由于阳极电氧化和阴极吸附,脱色率最高可达52%;0.7～1.0 mA·cm^-2时,发生成对电解,即阳极电氧化和阴极电还原同时使染料脱色,脱色率最高可达83%.     

活性炭纤维阴极电Fenton法降解甲基橙的研究

以石墨为阳极、活性炭纤维(ACF)为阴极,电Fenton法氧化降解甲基橙溶液。结果表明,在甲基橙溶液浓度为4 mmol/L、pH值为3、电压为8 V、硫酸亚铁的浓度为0.2 mmol/L、反应时间为60 min时脱色率可达到98.12%,并且甲基橙氧化降解遵循一级反应动力学。     

电化学氧化降解蒽醌染料动力学研究

利用形稳阳极原位电生成活性氯对蒽醌型染料活性艳蓝KN-R进行氧化脱色.以该染料的2个特征波长处吸光度为主要指标,对染料脱色及其芳环结构氧化降解的过程进行同步分析.在电流密度15A/m2、0.1mol/L Na2SO4、0.2 mol/LNaCl、0.1 mmol/L活性艳蓝KN-R、初始pH值6.4、温度30℃的实验条件下,经4h的电解,可使染料100%脱色,45%左右的染料芳环结构被破坏,处理每千克染料的能耗为0.28 kWh.实验结果表明,电流密度、氯化钠浓度、染料浓度、温度对染料的脱色及其母体结构氧化降解有较强的影响;染料脱色及其芳环结构氧化降解过程遵循准一级动力学;在整个的电氧化过程中,电解液未发生矿化.     

碳毡电极用于电芬顿脱色性能及机理研究

为了探究CF电极在电芬顿脱色中的应用性能及机理，通过对阴极材料的对比，建立了以碳毡为阴极的电芬顿降解体系，探讨了不同操作参数如废液pH、O₂流量、电压、Fe²⁺浓度等因素对活性红195染料废水的脱色率、COD去除率的影响。根据实验结果，采用碳毡做阴极，Fe²⁺浓度为20 mg/L,pH为3、O₂流量60 mL/min、电压3 V条件下，反应3 h染料几乎完全脱色，COD去除率可达73.31%；利用猝灭实验初步探讨了染料降解的主要机制，·OH的生成及其强氧化作用是染料降解的主要因素；利用UV-Vis及GC-MS对染料降解机理进行了分析，发现反应前30 min降解速度最快；电极稳定性实验及扫描电子显微镜(SEM)形貌分析证明了碳毡阴极具有良好的电化学稳定性。     

污泥活性炭处理亚甲基蓝染料废水的研究

采用污泥活性炭处理亚甲基蓝模拟染料废水,研究了模拟废水初始浓度、污泥活性炭投加量、pH值、水浴吸附时间等因素对染料废水的脱色率和COD去除率的影响,探讨污泥活性炭处理染料废水的适宜工艺条件。实验结果表明:随着染料废水初始浓度的增大,脱色率和COD去除率均表现出下降趋势;随着污泥活性炭投加量的增加,脱色率和COD去除率效果均十分明显;随着模拟废水pH值的增大,其脱色率基本呈现增大趋势,而COD去除率则先增大后减小,当pH在7.6～7.8时,脱色率与COD去除率均出现最大值;在延长水浴时间的同时,脱色率和COD去除率均表现出较好的效果。本实验处理染料废水的适宜条件为:染料废水的初始浓度为2.5mg/L,调节染料废水的pH值7~8,加入0.8g污泥活性炭,30℃条件下2h。     

军光放电降解酸性红染料废水

利用辉光放电这一高级氧化技术处理酸性红染料废水。辉光放电降解酸性红的动力学过程显示,符合一级反应动力学方程;研究了不同条件下（如电压、电极间距和pH）辉光放电降解酸性红的降解效率,得出实验室内辉光放电降解酸性红的最佳试验条件：酸性条件pH3、电压600V和电极间距10mm。在此条件下,辉光放电降解酸性红染料废水具有降解率高、时间短和效果好等优点。     

双氰胺-甲醛脱色剂的制备及性能研究

以双氰胺-甲醛等为原料,与聚合氯化铝和氯化铵混合使用,通过"二步法缩合"工艺,合成脱色絮凝剂。通过高锰酸钾法测定COD,模拟废水和染料来考察COD去除效果和脱色效果。结果表明,在COD去除中,p H对COD去除率无明显影响,脱色剂用量在0.062 5 m L/m L时效果最好,最佳条件下能将其去除至600 mg/L左右,去除率在40%~45%。在脱色率去除中,脱色最佳p H值为9,脱色剂用量在0.05 m L/m L时效果最好;脱色剂对于靛蓝甲基红染料脱色率能达到85%以上,对于模拟废水的脱色率达到了92%以上。本方法制得的脱色剂对COD及脱色率具有良好的效果。     

脲基乙酸内酰胺的废水处理研究

采用浓缩-氧化-碱洗-活性炭纤维吸附工艺处理生产脲基乙酸内酰胺的废水。着重研究了活性炭纤维吸附规律及再生方法。研究表明：该工艺处理后的废水COD去除率为95．0％,乙醇氰去除率为97．6％,脲基乙酸内酰胺去除率达92．0％,废水的气味和颜色全部除去,废水达到排放标准。     

Electrosorption and inhibition properties of p-norborn2-yl phenolate ions at the mercury/solution interface

The electrosorption properties of p-norborn-2-yl phenolate ions in alkaline solutions were investigated by ac polarographic and electrocapillary measurements.

Two adsorption regions were found. At low bulk surfactant concentrations the adsorption at the positively charged electrode (−0.2 E −0.6 V) is predominant while at higher surfactant concentrations the adsorption at the negatively charged electrode (−0.6 E −1.0 V) is more pronounced. At E = −0.40 V the adsorption parameters were determined (a ≈ 2; ΔG°_A = −32.5 ± 1 kJ mol⁻¹. Between −0.6 E −1.0 V one potential of maximum adsorption for all concentrations does not exist and therefore the adsorption parameters could not be calculated.

At E = −0.40 V progressive two-dimensional nucleation with a nucleation order of 3 was observed which corresponds well with the high attraction constant.

The electrode reaction S₂O²⁻₈ + 2e⁻ → 2 SO²⁻₄ is inhibited by norborn-2-yl phenolate ions in the potential range −0.2 E −0.6 V. In the second potential range of capacity decrease the electrode process is much less retarded. At E = −0.40 V, in a similar manner as described for neutral molecules, a linear dependence of the log k_s (k_s apparent rate constant) on ln c_A and π (π = surface film pressure), respectively, has been found.     

Study on the treatment of waste metal cutting fluids using electrocoagulation

Electrocoagulation (EC) technique is applied for the treatment of waste metal cutting fluids (WMCFs) characterized by high COD and TOC concentration, discharged from metal manufacturing facilities including automotive engine, transmission, and stamping plants. The effects of initial pH, current density and operating time on the performance of EC are investigated by using sacrificial Al and Fe electrodes. Upon treatment by EC, the COD of WMCF is reduced by 93% and the TOC is reduced by 78% for Al electrode at pH 5.0, current density of 60 A/m² and operating time of 25 min. For Fe electrode, the reduction in COD is 92% and reduction in TOC is 82% at pH 7.0, current density of 60 A/m² and operating time of 25 min. Under optimal operating conditions, the operating costs are calculated as 0.497 $/m³ (0.023 $/kg removed COD or 0.144 $/kg removed TOC) for Fe electrode, and 0.768 $/m³ (0.036 $/kg removed COD or 0.228 $/kg removed TOC) for Al electrode. Fe electrode is found to be more efficient than Al electrode in terms of parameters such as COD and TOC removal efficiencies and operating costs.     

Use of a PbO2 electrode of a lead-acid battery for the electrochemical degradation of methylene blue

In this work, the electrochemical degradation efficiency of synthetic azo dye, methylene blue, at positive electrode PbO₂ of lead-acid battery was investigated. The structure and morphology of the electrode was investigated by X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectrometry. The influence of several operating parameters on electro-oxidation of 100 mL of methylene blue solution 100 mg/L was studied. Results indicated that lead-acid battery electrode is effective for removing color and chemical oxygen demand (COD). It is found that current density, the stirring speed, and the supporting electrolyte concentration have a positive effect on decolorization and mineralization, and no significant effect of the distance between the electrodes on methylene blue degradation and COD removal was observed. By contrast, the percentage of color and COD removal decreases with increasing of pH. Kinetic analysis of the results revealed that the COD removal follows a pseudo-first-order kinetics.     

玻碳电极上碘仿电解合成的机理

本文采用循环伏安法研究了在Na2CO3溶液介质中KI在金电极和玻碳电极上的电化学行为.在0.2V～1.2V电位范围内玻碳电极上仅发生I-被氧化为I2的反应,而在金电极上除了I-被氧化为I2外,还发生生成IO3-的氧化反应.同时通过不同电位扫描速度下的循环伏安行为分析发现电极过程为传质控制步骤.     

斜板液膜反应器光电催化降解罗丹明B

采用溶胶-凝胶法制备了TiO2/Ti电极,进行光电催化降解罗丹明B(RhB)试验。确定了最佳降解条件:外加偏压+0.8 V、废水流量7.7 L/h、初始pH=2.5和电解质质量浓度2.0 g/L。在最佳条件下,处理20 mg/L的RhB溶液1.5 h,脱色率和TOC去除率分别达到97.3%和76.2%。结果表明,由于同时强化了激发光源的利用率和溶液的传质效率,斜板液膜反应器可高效降解RhB。     

General scheme of adsorption,electroreduction and catalytic hydrogenation of nitro-compounds of platinum—I. Kinetics and mechanism of adsorption

The kinetics and mechanism of adsorption of nitro-compounds (nitro-methane, nitro-ethane and nitro-benzene) on platinum and platinum group metals have been investigated by complex potentiodynamic pulses' and charging curves' techniques. The adsorption of nitro-compounds on platinum in the potential range from 0 to 1 V has been shown to proceed mainly with the formation of two types of chemisorbed particles. For potentials more positive than 0.35 V nitro-compounds are adsorbed due to a nitro-group with the formation of NPt and OPt bonds. In this region of potentials the adsorption of nitro-compounds is not accompanied with the flow of considerable amounts of electricity through the electrode—solution interface. These adsorbed particles react very rapidly with adsorbed hydrogen with the formation of semi-reduced chemisorbed particles, whose formation can be observed at 0 < E_r < 0.35 V, that is in the range of hydrogen desorption on platinum. Two hydrogen atoms are spent on the formation of a semi-reduced chemisorbed particle from a nitro-compound molecule, and the particle formed occupies 4 adsorption centres on the surface.The dependence of steady-state coverage of the platinum electrode surface with chemisorbed particles in nitro-compounds solutions is described by the Temkin isotherm and the adsorption kinetics by the Roginsky—Zel'dovich equation.