处理苯胺废水的电化学研究

采用电化学法处理苯胺废水，系统的氧化电极以恒电位法聚合制成高导电聚苯胺并压制成颗粒填料分多级填充在塔中形成固定床式电极。实验研究了不同的电位扫描速度，苯胺浓度及温度对电化学氧化还原反应的影响，实验表明，采用导电聚苯胺作为处理苯胺废水的氧化电极，可以有效地降低电化学反应的电解电位，提高氧化电流和反应速度，它是采用铂电极处理苯胺废水消耗电能的1/2.78。     

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^-。     

对氯苯酚废水的电化学降解研究

实验利用电沉积法制备的不锈钢基PbO2电极,以对氯苯酚溶液为模型废水,通过静态实验研究外加电压、电解质浓度、曝气量及初始pH值对电化学氧化降解对氯苯酚效果的影响。结果表明,实验制备的PbO2电极具有较高的电催化活性,能够有效降解对氯苯酚;较低的操作电压有助于降低处理成本;随着电解质浓度和曝气量的增加,对氯苯酚去除率均呈...     

三维电极电化学氧化法深度处理DOP生产废水的研究

采用以铁板作阴、阳极,活性炭作填充粒子的三维电极电化学氧化法深度处理DOP生产废水。探讨了废水的pH、槽电压、极板间距、活性炭投加量和反应时间等因素对COD去除率的影响,并通过正交实验确定了处理DOP废水的最佳工艺条件,还对COD的降解动力学规律进行了初步探讨。结果表明,三维电极电化学氧化法处理DOP生产废水的最佳工艺条件为:pH值为5、电极间距为4 cm、槽电压为25 V、活性炭投加量为12 g/L、电解时间为90 min。在此条件下,COD去除率可达71.5%,出水COD浓度为50.9 mg/L,达到国家污水综合排放标准(GB8978-1996)的一级标准。三维电极电化学氧化法对COD的降解反应呈表观一级反应,降解速率方程为C=C0e-0.0124t。     

酸性橙7在PbO2/Ti和IrO2-Ta2O5/Ti电极上的电催化氧化

采用PbO2/Ti和IrO2-Ta2O5/Ti电极对酸性橙7(AO7)模拟废水进行了电解处理实验研究。考察了2种电极上不同电流密度条件下AO7的去除率、反应动力学、COD去除效果及瞬时电流效率,结果表明,在相同条件下,PbO2/Ti电极表现出更好的处理效率、更适合用于AO7的矿化。循环伏安(CV)曲线表明,PbO2/Ti电极具有更高的析氧电位且在AO7电解液中出现了氧化峰,说明PbO2/Ti电极对AO7具有更好的催化活性和直接氧化能力。紫外可见光谱对比分析表明,IrO2-Ta2O5/Ti电极对AO7的结构破坏速度缓慢且伴随苯胺等中间产物产生,对AO7的矿化程度弱。对比结果说明PbO2/Ti电极更适合于偶氮类染料废水的电催化氧化处理。     

聚苯胺修饰电极去除水中高氯酸根

在三电极体系中,研究聚苯胺修饰电极对高氯酸根离子的电化学去除。基于导电高聚物的电控离子交换特性,在其电化学扫描过程中高氯酸根能够掺杂进入到聚苯胺高分子链。在0.10 mol/L Na2SO4(p H 4.0)电解液中电化学循环伏安扫描25 min,2 mg/L高氯酸根的去除率达96.5%;在相同处理时间内,去除率随高氯酸根浓度的增加而明显降低,且溶液p H在3到5的范围内得到最优的去除效果。通过红外光谱和X射线光电子能谱表征高氯酸根掺杂前后的聚苯胺膜,结合循环伏安图的分析提出高氯酸根去除过程中可能的反应机理:高氯酸根作为掺杂离子,随电位的改变在聚苯胺链中迁移。研究表明,基于聚苯胺的电控离子交换特性,可以开发一种绿色高效的高氯酸根去除技术。     

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 30 0～ 5 0 0mV ,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 。     

三维三相流化床电极处理苯胺实验研究

使用了一种新型的电化学反应器———三维三相流化床电极用于处理苯胺的实验研究。得到了气量大小、外加电压、电介质浓度、pH值、原水浓度、反应时间等因素对苯胺溶液COD去除率的影响规律 ,并对之进行了合理的解释和分析。结果表明 ,用三维三相流化床电极 ,在一定条件下 ,苯胺可基本被全部氧化。初步论证了苯胺电解过程中有中间产物的生成。     

三维三相流化床电极处理苯胺实验研究

使用了一种新型的电化学反应器——三维三相流化床电极用于处理苯胺的实验研究。得到了气量大小、外加电压、电介质浓度、pH值、原水浓度、反应时间等因素对苯胺溶液COD去除率的影响规律，并对之进行了合理的解释和分析。结果表明，用三维三相流化床电极，在一定条件下，苯胺可基本被全部氧化。初步论证了苯胺电解过程中有中间产物的生成。     

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。     

碳纳米管电极原位产生过氧化氢及其对亚甲基蓝脱色效果简

将碳纳米管固定化制成多孔疏水性导电薄膜构建电化学阴极还原体系，实现过氧化氢在阴极的原位产生。电极特性研究表明，电极在较宽的电压范围内均具有较好的活性。考察了阴极电位、电极成分、氧气流量和电解质浓度对过氧化氢原位产生的影响，在优化条件下经过120 min后过氧化氢达到66.17 mg/L，并探讨过氧化氢原位产生的机理。在此基础上考察原位过氧化氢氧化工艺下对亚甲基蓝的脱色效果，并分析其脱色机理。     

碳纳米管电极原位产生过氧化氢及其对亚甲基蓝脱色效果

将碳纳米管固定化制成多孔疏水性导电薄膜构建电化学阴极还原体系，实现过氧化氢在阴极的原位产生。电极特性研究表明，电极在较宽的电压范围内均具有较好的活性。考察了阴极电位、电极成分、氧气流量和电解质浓度对过氧化氢原位产生的影响，在优化条件下经过120min后过氧化氢达到66．17mg／L，并探讨过氧化氢原位产生的机理。在此基础上考察原位过氧化氢氧化工艺下对亚甲基蓝的脱色效果，并分析其脱色机理。     

Acetylcholinesterase-polyaniline biosensor investigation of organophosphate pesticides in selected organic solvents

The behavior of an amperometric organic-phase biosensor consisting of a gold electrode modified first with a mercaptobenzothiazole self-assembled monolayer, followed by electropolymerization of polyaniline in which acetylcholinesterase as enzyme was immobilized, has been developed and evaluated for organophosphorous pesticide detection. The voltammetric results have shown that the formal potential shifts anodically as the Au/MBT/PANI/AChE/PVAc thick-film biosensor responded to acetylthiocholine substrate addition under anaerobic conditions in selected organic solvent media containing 2% v/v 0.05 M phosphate buffer, 0.1 M KCl (pH 7.2) solution. Detection limits in the order of 0.147 ppb for diazinon and 0.172 ppb for fenthion in acetone-saline phosphate buffer solution, and 0.180 ppb for diazinon and 0.194 ppb for fenthion in ethanol-saline phosphate buffer solution has been achieved.     

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.     

三维电极电吸附动态反应器的除氟特征研究

采用自制的单极性复合型三维阳极作为第三维电极对含氟水进行动态电促吸附实验,通过研究不同填充床高度、阴阳极板间距、隔膜材料对电促吸附除氟效果的影响,确定反应器的最佳结构参数为:填充床高度20 cm、阴阳极板间距4 cm、隔膜为nafion117膜。工作电压、进水pH、进水流速、共存物质对氟离子去除效果的影响结果表明:在一定范围内增大工作电压,降低进水pH或进水流速均可提高除氟效果。相应的最佳操作条件为:工作电压7 V、进水流速4 mL/min、酸性pH;腐殖酸和碳酸根离子的存在会对氟离子去除产生较强抑制作用,低浓度的氯离子可促进氟离子的电促吸附。扫描电镜(SEM)-电子能谱(EDX)的表征结果显示三维颗粒电极的表面及孔隙内部均可吸附氟离子,且电吸附后并未出现电极腐蚀现象。     

Degradation of ampicillin antibiotic in aqueous solution by ZnO/polyaniline nanocomposite as photocatalyst under sunlight irradiation

PURPOSE AND METHOD: ZnO/polyaniline nanocomposite in core-shell structure was prepared by the synthesis and adsorption of polyaniline chains on the structure of ZnO nanoparticles. Fourier transform infrared and ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction patterns, field emission scanning electron microscopy, and transmission electron microscopy were used to characterize the composition and structure of the nanocomposite. The nanocomposite was used as an active photocatalyst for photodegradation and removal of ampicillin in aqueous solution. RESULTS: UV-Vis spectroscopy studies showed that ZnO/polyaniline nanocomposite absorbs visible light irradiation as well as ultraviolet spectrum, and therefore, it can be photoactivated under visible and ultraviolet lights. The photocatalytic activity of ZnO/polyaniline nanocomposite in degradation of ampicillin molecules in aqueous solution under natural sunlight irradiation was evaluated and compared with that of ZnO nanoparticles and pristine polyaniline. The ZnO/polyaniline core-shell nanocomposite exhibited higher photocatalytic activity compared to ZnO nanoparticles and pristine polyaniline. The effect of operating conditions (pH, ZnO/polyaniline nanocomposite dosage, and ampicillin concentration) in the photocatalytic degradation of ampicillin using ZnO/polyaniline nanocomposite was investigated. The optimum conditions for maximum efficiency of ampicillin degradation under 120 min sunlight irradiation were found as 10 mg L(-1) dosage of ZnO/polyaniline nanocomposite, ampicillin concentration of 4.5 mg L(-1), and solution pH?=?5. Under optimum operating conditions, degradation efficiency was reached to 41% after 120 min of exposure to the sunlight irradiation.     

掺硼金刚石薄膜电极在水处理中应用的研究进展

掺硼金刚石(BDD)薄膜电极作为一种新型的电极材料,在水溶液中电解时具有较宽的电位窗口,在浓酸浓碱中具有很好的耐腐蚀性,其表面不易吸附污染物,与它的同素异构体电极及其他普通电极相比,具有更好的化学、物理性能,从而表现出潜在的功能,近年来被科研人员用于废水处理,并取得了很好的处理效果,对近期BDD薄膜电极的制备、在污水处理中的应用及其进展进行了总结与讨论.     

原位电化学杀菌技术处理循环冷却水

分别以金属氧化电极和不锈钢为阳极和阴极,在恒电流模式下,考察了电流密度、停留时间、放置时间、极间距和稀释比等因素对电厂循环冷却水杀菌效果的影响。实际现场结果表明,针对电厂循环冷却水,电化学杀菌处理是行之有效的,电流密度、停留时间、极间距、稀释比对杀菌效果影响较大;在电流密度120 A/m2、停留时间10 s、极间距1.8 cm的条件下,杀菌效果可以达到97%;在一定实验条件下及一定放置时间内,经处理后的循环冷却水异氧菌总数能得到有效抑制。     

Applicability of grid-net detection system for landfill leachate and diesel fuel release in the subsurface

The grid-net system estimating the electrical conductivity changes was evaluated as a potential detection system for the leakage of diesel fuel and landfill leachate. Aspects of electrical conductivity changes were varied upon the type of contaminant. The electrical conductivity in the homogeneous mixtures of soil and landfill leachate linearly increased with the ionic concentration of pore fluid, which became more significant at higher volumetric water contents. However, the electrical conductivity in soil/diesel fuel mixture decreased with diesel fuel content and it was more significant at lower water contents. The electrode spacing should be determined by considering the type of contaminant to enhance the electrode sensitivity especially when two-electrode sensors are to be used. The electrode sensitivity for landfill leachate was constantly maintained regardless of the electrode spacings while that for the diesel fuel significantly increased at smaller electrode spacings. This is possibly due to the fact that the insulating barrier effect of the diesel fuel in non-aqueous phase was less predominant at large electrode spacing because electrical current can form the round-about paths over the volume with relatively small diesel fuel content. The model test results showed that the grid-net detection system can be used to monitor the leakage from waste landfill and underground storage tank sites. However, for a successful application of the detection system in the field, data under various field conditions should be accumulated.     

Novel hybrid composite discharge electrode for electrostatic precipitator

Over the last few decades, electrostatic precipitators (ESPs) have emerged as effective air pollution control devices for treating coal-fired power plant exhausts. Among the components of the ESP, the discharge electrodes are extremely important in determining the collection efficiency of the ESP. Typically, in wet ESPs, the discharge electrodes used must be made of corrosion-resistant alloys, which makes them extremely expensive and heavy. Hybrid composite discharge electrodes have the potential to be lightweight and corrosion-resistant substitute for traditional metal alloy electrodes used in wet ESPs. In this experimental study, a novel hybrid composite electrode (recently patented at Ohio University) is presented as a substitute for traditional metal electrodes in wet ESPs. The samples of hybrid electrodes were fabricated by using carbon fiber composites, combined with metal mesh, in the shape of a long and thin tape. The electrode’s electrical response was evaluated in open atmospheric conditions, while connected to a transformer-rectifier unit to generate a corona current at voltages exceeding 50 kV. Results of these hybrid electrodes were compared with traditional metal electrodes. The hybrid composite discharge electrode produced a uniform corona at comparable power levels to that of metal electrodes, with additional advantages of being compact, lightweight, and highly corrosion resistant. In addition, hybrid composite electrodes exhibited lower corona onset voltage as compared with metal electrodes. The preliminary experimental data are encouraging and show significant potential for this new inexpensive hybrid electrode to replace metal electrodes in wet ESPs, providing comparable (and in some cases exceeding) collection efficiencies with lower ozone generation.

Implications: The newly invented hybrid composite electrode (HCE) performance was evaluated through experimentation with conventional metal electrodes. The HCE performance was comparable to the metal electrodes. The HCE also exhibited uniform corona fields and steady power while maintaining similar and in some cases superior electrical performance as compared with metal electrodes and thus shows a significant potential to substitute metal electrodes in wet ESP systems.