电解液条件对苯酚降解及羟自由基生成的影响

以钛基Pb O2电极为活性阳极,通过电化学氧化法降解处理苯酚模拟废水,系统考察了羟自由基(·OH)抑制剂、支持电解质、酸碱性等电解液条件对苯酚水溶液COD去除率的影响。同时,以水杨酸(SA)为·OH捕捉剂,通过高效液相色谱分析技术对不同电解液条件下·OH的生成量进行间接检测。结果发现,Pb O2电极上苯酚水溶液的COD去除符合一级反应动力学规律,其表观反应速率常数在分别加入·OH抑制剂Na HCO3、Na2CO3和叔丁醇时显著下降,表明苯酚的电化学氧化降解遵循·OH反应机理;支持电解质对电解液体系中·OH生成量的影响不明显,主要通过在阳极氧化生成的氧化剂参与苯酚的降解,以Na Cl为支持电解质时降解效率最高,其次是Na2SO4,最后为Na NO3;随电解液p H值的增加,苯酚水溶液的COD去除速率不断提高,而·OH的生成量在碱性条件下亦显著增加。     

沉淀剂对稀土Gd掺杂SnO2/Ti涂层阳极性能的影响

实验采用共沉淀法,以无机盐SnC14·5H2O、Sb2O3、Gd(NO3)3为前驱体,制备稀土Gd掺杂SnO2/Ti多组分涂层阳极.研究了用不同沉淀剂制备的电极以苯酚为目标有机物的电化学降解特性,以考察沉淀剂对稀土Gd掺杂SnO2/Ti阳极性能的影响;并对所制备的涂层阳极进行了SEM、XRD、XPS等表征及阳极极化曲线、循环伏安曲线测试,分析并讨论了沉淀剂对稀土Gd掺杂SnO2/Ti阳极性能的影响机理.结果表明,沉淀剂对稀土Gd掺杂SnO2/Ti电极性能有较大的影响,在本实验条件,以氨水为沉淀剂所制备的电极电催化性能较好,稳定性能较高.     

Sb、Ce共掺杂SnO2/C/Ti电极对含酚废水的电催化性能研究

采用溶胶-凝胶法合成Sb、Ce共掺杂SnO2/C/Ti电极,经XC-72R炭黑吸附后得到钛基炭载金属氧化物SnO2-Sb(2.5%(质量分数,下同))-Ce(2.5%)/C/Ti电极,利用电化学交流阻抗法(EIS)测试电极的交流阻抗值随电位和不同浓度苯酚的变化情况。结果表明,在不同电位(0.10、0.95、1.01V)时,SnO2-Sb(2.5%)-Ce(2.5%)/C/Ti电极的膜电阻、电化学电阻、总电阻和苯酚氧化阻力随着电位的增加而减小;此外,在恒电位(0.95V)、不同质量浓度(100、200、300mg/L)苯酚溶液的条件下,电极的膜电阻、电化学电阻、总电阻和苯酚氧化阻力随着苯酚浓度的增加而增大。电极在反应过程中表现良好的活性,对苯酚的催化氧化较彻底。     

溶胶-凝胶法制备稀土Gd掺杂SnO2电催化电极的实验研究

本实验采用溶胶-凝胶法,以无机盐SnCl4·5H2O、Sb2O3、Gd(NO3)3为前驱体,制备稀土(Gd)掺杂Sn、Sb溶胶,以钛电极为基材利用该溶胶制备稀土(Gd)掺杂SnO2涂层电极.优化了溶胶-凝胶法制备稀土Gd掺杂SnO2涂层电极的实验条件,研究了在不同加水量、柠檬酸量、pH值等条件下所制备的电极以苯酚为目标有机物的电化学降解特性,对所获得的电极进行了TOC测试及SEM、XRD和XPS等表征,分析并讨论了稀土掺杂对SnO2电极性能的影响机理.结果表明,溶胶-凝胶法制备稀土掺杂SnO2涂层电极是可行的,稀土Gd的掺杂有利于SnO2电极电催化性能的提高,而且不同的加水量、柠檬酸量、pH值对电极性能有一定的影响.本实验条件下,加水量(水与前驱体总量摩尔比)R为36、柠檬酸加入量(柠檬酸与前驱体总量之摩尔比)N为1.0、溶胶pH值为2时所制备的电极降解效果最好,电极最稳定.所获得的电极为纳米涂层电极,其表面涂层中SnO2、Gd2O3等催化活性物质的含量均较高,对苯酚的降解有较好的效果.     

电化学氧化法处理模拟黄连素制药废水的研究

以RuO2/Ti为阳极,研究了电化学氧化法对黄连素制药废水的处理效果.通过比较在KCI与K2SO42种支持电解质体系中的处理效果,同时考察了电流强度、初始pH、电解质浓度和电极间距等因素对废水中黄连素及COD去除率的影响,明确了电化学原位生成活性氯是黄连素降解的主要原因;确定了电流强度、pH、电解质浓度和电极间距等最优...     

电化学方法用于酸性红B模拟废水脱色试验研究

本文研究了两种电极材料 (SnO2 Ti和RuO2 Ti)对酸性红B模拟废水的脱色效果 ,考察了不同 pH、电流密度(j)及外加电解质 (Na2 SO4/NaCl)对处理过程的影响。结果表明 ,两种电极材料都能对酸性红B染料废水进行有效脱色 ,主要是Cl-在电解过程中的间接氧化作用 ,同时也包括电极表面的直接氧化作用。     

La掺杂SnO2/Ti电极电催化降解邻硝基苯酚

采用凝胶一溶胶法制备了La掺杂SnO2/Ti电极并用于邻硝基苯酚废水的电解研究.分析了电流密度、电极距离、溶液初始pH对邻硝基苯酚电解效果的影响,确定了最佳电解条件.结果表明,La/Sn(摩尔比)为0.03,热处理温度为450℃下制备的La掺杂SnO2/Ti电极对邻硝基苯酚的降解效果最好.当电流密度为20 mA/cm2,电极距离为2 cm,溶液初始pH为6～7时,电解180 min后的邻硝基苯酚的降解率可达95.1%.利用液相色谱和离子色谱检测了邻硝基苯酚电解产物,并初步分析了邻硝基苯酚的降解途径.     

直接电解法处理染料废水的研究

实验以Ti为基体，分别采用热分解法和阳极电沉积法制备了SnO2和PbO2电极。用XRD、SEM、XPS和稳态极化、循环伏安法分别对上述电极进行结构特性表征和电化学特性检测。实验结果表明，在相同工作条件下，SnO2电极的析氧电势比PbO2电极高300～500mV，且其作为阳极降解的直接染料(直接橙S和直接耐晒黑G)模拟废水COD值下降速度快。在模拟染料废水处理体系中，提高反应温度有利于染料的降解。SnO2电极阳极氧化染料溶液过程中，能定性检测到降解产物——CO2。     

组合阳极联合气体扩散阴极电催化降解苯胺

采用气体扩散电极为阴极，钛基氧化物（Ti／SnO2-Sb2O5-IrO2）和金属铁构成组合阳极，构建了新型电化学氧化体系用于降解有机污染物。利用该氧化体系，在不同实验条件下考察了苯胺降解的效果与降解过程的相关规律。结果表明，阴极电位、铁阳极通电时间以及苯胺初始浓度均显著影响苯胺的降解效果。当阴极电位为-0．7V，pH3．0，铁阳极通电时间20min时，电化学处理200mg／L苯胺480min，TOC的去除效率达到80．4％，矿化电流效率（MCE）为8．6％，显示了该氧化体系具有良好的有机物降解能力。此外，苯胺降解过程中氨氮和硝态氮浓度的变化表明，苯胺分子中的氮主要转化为NH4和NO3^-。     

Ti/SnO2-Sb2O3/β-PbO2阳极消毒处理医院污水

采用热分解+电沉积法制备Ti/SnO2-Sb2O3/β-PbO2作为阳极消毒处理医院污水,初步探讨其杀菌基本原理,并研究了阳极材料、电流密度、电极间距、NaCl电解质浓度对消毒效果的影响。结果表明,以Ti/SnO2-Sb2O3/β-PbO2作为阳极,碳纤维作为阴极,在电流密度为80 A/m2,消毒时间为12 min,电极间距为5 mm,不添加电解质的实验条件下,处理后出水的粪大群肠菌数小于500 cfu/L,符合污水综合排放一级标准(GB8978-1996)。     

基于Ti/SnO_2阳极氧化法的典型染料废水电化学氧化规律

采用Ti/SnO2电极间接阳极氧化法处理直接深棕M和活性艳蓝KNR模拟染料废水,研究电解质种类、pH、电压、NaCl投加量及电解时间对其降解效果的影响;在最佳组合条件下,通过分析UV-Vis光谱以及降解过程中氮元素的存在形式,研究上述2种染料的降解规律。结果表明,在pH为3,电压20 V,NaCl投加量为2.5 g/L的条件下,电解30 min后,直接深棕M和活性艳蓝KNR的脱色率分别达到80%和95%,60 min后直接深棕M的COD去除率可达75%,活性艳蓝KNR的COD去除率达到90%;电解60 min后,直接深棕M的偶氮双键完全破坏,萘环和苯环结构被逐步降解,活性艳蓝KNR溶液电解2 min,其分子结构中的蒽醌共轭体系被破坏,随反应的进行,蒽醌结构逐渐被破坏,染料逐步降解。     

电催化氧化处理除草剂异草酮废水的效能简

为有效处理含异草酮除草剂废水，以Sb掺杂Ti/SnO₂电极为阳极，不锈钢板为阴极，采用电催化氧化技术对异草酮废水进行降解，研究了不同影响因素对异草酮去除率的影响，并分析了异草酮的降解效果。结果表明，当异草酮初始浓度为100 mg/L、电流密度为20 mA/cm²、电解质投加量为0.10 mol/L，反应120 min后，异草酮去除率达到94%，此时TOC去除率为57.9%，能耗为25 kWh/m³，且废水的可生化性能显著提高。     

非均相Fenton体系中无机助剂对亚甲基蓝脱色的影响

直接使用有机过渡金属化合物二茂铁作为催化剂，研究了非均相Fenton反应中亚甲基蓝的降解，并考虑了实际排放的印染废水中存在的无机助剂，进一步分析了典型无机助剂CuSO4、NaCl、Na2CO3、Na2SO4、Na2S的存在对该非均相Fenton体系的影响，结果表明：直接使用二茂铁做催化剂反应120min后，亚甲基蓝的剩余率为0．6％，羟基自由基的表观生成率为83．4％。NaCl、Na2CO3、Na2SO4、Na2S的加入会阻碍反应的进行，而CuSO4的加入会促进反应的进行。     

Sequential electrochemical treatment of dairy wastewater using aluminum and DSA-type anodes

Dairy wastewater is characterized by a high content of hardly biodegradable dissolved, colloidal, and suspended organic matter. This work firstly investigates the performance of two individual electrochemical treatments, namely electrocoagulation (EC) and electro-oxidation (EO), in order to finally assess the mineralization ability of a sequential EC/EO process. EC with an Al anode was employed as a primary pretreatment for the conditioning of 800 mL of wastewater. A complete reduction of turbidity, as well as 90 and 81 % of chemical oxygen demand (COD) and total organic carbon (TOC) removal, respectively, were achieved after 120 min of EC at 9.09 mA cm^?2. For EO, two kinds of dimensionally stable anodes (DSA) electrodes (Ti/IrO₂-Ta₂O₅ and Ti/IrO₂-SnO₂–Sb₂O₅) were prepared by the Pechini method, obtaining homogeneous coatings with uniform composition and high roughness. The ^·OH formed at the DSA surface from H₂O oxidation were not detected by electron spin resonance. However, their indirect determination by means of H₂O₂ measurements revealed that Ti/IrO₂-SnO₂–Sb₂O₅ is able to produce partially physisorbed radicals. Since the characterization of the wastewater revealed the presence of indole derivatives, preliminary bulk electrolyses were done in ultrapure water containing 1 mM indole in sulfate and/or chloride media. The performance of EO with the Ti/IrO₂-Ta₂O₅ anode was evaluated from the TOC removal and the UV/Vis absorbance decay. The mineralization was very poor in 0.05 M Na₂SO₄, whereas it increased considerably at a greater Cl^? content, meaning that the oxidation mediated by electrogenerated species such as Cl₂, HClO, and/or ClO^? competes and even predominates over the ^·OH-mediated oxidation. The EO treatment of EC-pretreated dairy wastewater allowed obtaining a global 98 % TOC removal, decreasing from 1,062 to <30 mg L^?1.     

钛基IrO2-SnO2电极在烟气海水脱硫恢复系统中的应用

采用浸渍-热分解法制备了含IrOx-TiO2中间层的IrO2-SnO2电极,得到的电极具有较高的析氯电催化活性和较强的稳定性,并通过电化学氧化法对Na2SO3海水脱硫模拟液进行处理,考察了电流密度、温度、pH值和电解时间等电解工艺参数对Na2SO3去除率和化学需氧量COD的影响.结果表明,在电流密度为200 mA/cm...     

Kinetic behavior of anti-inflammatory drug ibuprofen in aqueous medium during its degradation by electrochemical advanced oxidation

The electrochemical abatement of the drug ibuprofen (2-(4-isobutylphenyl)propionic acid) from aqueous solution has been carried out by anodic oxidation. The electrolyses have been performed at constant current using a small, undivided cell equipped with a Pt or thin-film boron-doped diamond (BDD) anode and a carbon-felt cathode. The results have shown that ibuprofen has been destroyed under all the conditions tested, following pseudo-first-order kinetics; however, BDD enables higher removal rates than Pt, because the former produces greater quantity of ^?OH. Using BDD anode, the pseudo-first-order rate constant increased with applied current and when NaCl replaced Na₂SO₄ as supporting electrolyte, while it is almost unaffected by ibuprofen concentration. Mineralization of ibuprofen aqueous solutions was followed by total organic carbon (TOC) measurements. After 8 h of electrolysis, TOC removal varied from 91 % to 96 % applying a current in the range of 50–500 mA. The reaction by-products were quantified by chromatographic techniques, and in particular, aliphatic acids (oxalic, glyoxylic, formic, acetic, and pyruvic) have been the main intermediates formed during the electrolyses. The absolute rate constant for the oxidative degradation of ibuprofen have also been determined, by competition kinetic method, as 6.41?×?10⁹ M^?1?s^?1.     

A GC-TCD method for measuring the liquid water mass of collected aerosols

This work presents a gas chromatographic method that uses a thermal conductivity detector (GC-TCD) to measure the liquid water mass (LWM) of collected aerosols. The method is a modification of the previously developed EA-TCD method (Journal of Aerosol Science 29, 827). A microcomputer was incorporated into the system to control the analytical procedures, improve the measurement precision, and make possible a continuous operation. To validate the method, the aerosol LWMs of NaCl, Na₂SO₄, NH₄NO₃, (NH₄)₂SO₄, NH₄Cl, and Na₂CO₃ were measured at room temperature under relative humidities (RHs) varying between 20% and 90%, in both humidifying and dehumidifying conditions. Estimates of aerosol LWMs for varying aerosol chemical compositions and RHs by various measurement methods and predictive models are comprehensively compared. The comparison shows that the GC-TCD measurements agree closely with those of the other methods. The GC-TCD measurements are closer to the ISORROPIA model predictions than those of the AIM2 model. Most notably, our method determines, for the first time, the hygroscopic behavior of Na₂CO₃ aerosol yielding the deliquescence relative humidity and crystallization relative humidity at 78% and 39% RH, respectively. The hygroscopic characteristics of various NaCl mole fractions in mixed NaCl–Na₂SO₄ aerosols, determined by GC-TCD, are used to show the discrepancy between the measurements and the model's prediction.     

Electrochemical degradation of Acid Blue and Basic Brown dyes on Pb/PbO2 electrode in the presence of different conductive electrolyte and effect of various operating factors

Electrocatalytic degradation of Acid Blue and Basic Brown dyes from simulated wastewater on lead dioxide anode was investigated in different conductive electrolytes. It was shown that complete degradation of these dyes is dependent primarily on type and concentration of the conductive electrolyte. The highest electrocatalytic activity was achieved in the presence of NaCl (2g/l) and could be attributed to indirect oxidation of the investigated dyes by the electrogenerated hypochlorite ions formed from the chloride oxidation. In addition, contribution from direct oxidation could also be possible via reaction of these organic compounds with the electrogenerated hydroxyl radicals adsorbed on the lead dioxide surface. In the presence of NaOH, the electrocatalytic activity of the employed anode was not comparable to that in NaCl due primarily to the absence of chloride. This indicates that dyes degradation in NaOH occurs exclusively via direct electrochemical process. However, in H2SO4, the electrode performance was poor due partially to the absence of chloride from the conductive solution. The possibility of electrode poisoning as a result of growth of adherent film on the anode surface or production of stable intermediates not easily further oxidized by direct electrolysis in H2SO4 might also be accountable for the poor performance observed in this conductive electrolyte. Optimizing the conditions that ensure effective electrochemical degradation of Acid Blue and Basic Brown dyes on lead dioxide electrode necessitates the control of all the operating factors.     

MnO2催化Fenton试剂降解苯酚废水

实验对MnO2催化Fenton试剂氧化高浓度苯酚废水的动力学特性和去除效果进行了研究。结果表明,MnO2可以提高Fenton试剂体系对苯酚的降解率以及COD的去除率;Fenton试剂以及MnO2催化Fenton试剂氧化苯酚废水体系中苯酚的降解都符合拟一级动力学模型。在MnO2催化Fenton试剂氧化体系中,苯酚的降解速率常数有明显提高,反应活化能也有所降低,说明MnO2的加入可以使反应容易进行。废水降解前后紫外可见吸收光谱和红外谱图表明,Fenton试剂法将苯酚可能降解为羧酸、烯烃等有机物中间体。