新型负载型粒子电极的制备及处理二氯喹啉酸农药废水的效能

以高阻抗多孔陶瓷材料为基体、Sb掺杂SnO2为活性组分,采用浸渍-焙烧法制备新型负载型粒子电极。借助于扫描电子显微镜、能量色散X射线能谱和X射线衍射等分析手段对粒子电极的形貌及晶相组成进行了表征,通过三维电催化氧化降解二氯喹啉酸废水实验研究粒子电极的电催化反应效能。结果表明,所制备的粒子电极表面积增加,孔道增多,负载了Sb掺杂SnO2晶体,因而提高了电催化氧化反应的效率。当槽电压为15V,电极间距为7cm,电解质投加量为0.1mol/L,反应120min后,采用所建立的三维电极体系处理二氯喹啉酸废水,COD去除率达到64.3%,相应的能耗为14.4kWh·(kg COD)-1,与二维电极体系相比,COD去除率提高了26.9%,低耗降低了99.3%。     

电催化氧化处理难降解废水用电极材料的研究进展

随着石油化工、医药等工业的迅速发展,工业废水中难降解物质与日俱增,采用传统的水处理方法已难以达到环保要求。电催化氧化技术主要利用电极表面产生的活性物质羟基自由基进行氧化降解,具有氧化能力强、无需添加化学药剂、无二次污染的优势,而且电催化氧化工艺操作简单、处理条件温和,在处理难降解废水方面具有诸多优势。电催化氧化技术的核心部件是阳极,因此阳极材料的开发一直是研究人员关注的重点。一般要求阳极材料具有析氧电位高、电催化活性高、耐腐蚀、稳定性好、价格低廉等特点。目前常用的阳极材料有钛基金属氧化物阳极(SnO_2电极和PbO_2电极)和合成掺硼金刚石薄层电极,但是这些材料存在使用寿命短、制作成本高等问题。通过改性制备复合金属氧化物阳极可以改善上述问题,常用的改性方法包括掺杂离子、引入中间层、掺杂纳米颗粒、调控电极材料的微观形貌等。改性可以提高电极电催化性能、导电性及稳定性,增大电极的反应面积,延长电极寿命。因此复合金属氧化物阳极的制备是阳极材料研究的重点。在二维电极的基础上引入粒子电极可以构成三维电极系统。在三维电极系统中,粒子电极在电场作用下,会极化形成一个个微型电解槽,极大地增加了反应面积。因而三维电极相比于二维电极具有面体比大、电催化效率更高、能耗更低的优势,因此高催化活性、高稳定性的粒子电极的研制成为了电催化氧化技术领域新的研究方向。目前,常用的粒子电极材料主要有碳材料(活性炭、炭气凝胶等)、金属氧化物(Al_2O_3、Fe_3O_4等)、陶瓷和矿物类等。本文从电催化氧化的机理以及三维电极的工作原理出发,综述了在电催化氧化处理废水中广泛应用的电极材料,包括钛基金属氧化物阳极、合成掺硼金刚石薄层电极,重点介绍了在三维电极系统中使用的粒子电极。并对今后废水处理中电催化氧化电极材料的研究趋势进行了展望,指出提高电催化氧化效率不仅需改进电极材料,还需改善反应器构型及与其他工艺的耦合等,以实现电催化氧化技术的推广应用。     

TiO2掺杂PbO2电极及其在电解法制臭氧中的应用研究

为了提高电极对臭氧生成反应的电催化活性,采用纳米复合电镀技术制备了TiO2改性PbO2电极.分别采用X射线衍射和X射线荧光光谱分析了其晶体结构和组分含量。将该电极用于电解法制备臭氧,并考察了电流密度、电镀极间距、电镀液pH值以及TiO2颗粒粒径对电极性能的影响.实验结果表明,改性后的PbO2电极使臭氧生成反应的电流效率由11.9%提高到了12.9%.电镀电流密度和电镀极间距的提高有利于提高电极催化活性.TiO2的掺杂会降低PbO2电极的晶胞粒径,有利于提高电极的电催化活性.     

Au/Fe3O4磁性纳米粒子的合成及表征

报道了一种合成具有巯基官能团修饰的Au/Fe_3O_4磁性纳米粒子的新方法。采用共沉淀法制备Fe_3O_4磁性纳米颗粒,并在此基础上用聚(烯丙胺)溶液还原HAuCl4,制得Au/Fe_3O_4磁性核壳纳米颗粒,再用3-巯基-1-丙磺酸钠修饰Au/Fe_3O_4磁性纳米粒子,最后得到具有巯基官能团稳定的Au/Fe_3O_4磁性纳米粒子。通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线能谱仪(EDS)、X射线衍射仪(XRD)、X射线光电子能谱(XPS)、振动样品磁强计(VSM)分别对产物的微观结构及磁性特征进行表征。     

Co3O4纳米阵列电催化膜电极及其处理难降解废水耦合产氢性能研究(英文)

传统电化学高级氧化技术存在有机物降解效率不高、能耗大的弊端,并且平板式电极表面存在滞止边界层,严重限制了传质过程.本工作中,我们首先通过水热方法将一维Co₃O₄纳米针状阵列结构原位负载于金属钛膜电极,低压电场下,实现难降解有机物的去除,其中:对于苯酚的去除率可达≥99%,化学需氧量(COD)和总有机碳(TOC)去除率分别为9 9.5%和9 2.5%,电流效率为8 8.7%,能耗仅为0.061 kW h (kg COD)^-1. Co₃O₄纳米针的阵列式膜电极可以提供更多的CoOOH活性位,增强电场强度,而且其穿透式流体模式导致强化对流,可以明显地改善电催化反应过程的传质,因而提高膜电极的催化效率,降低能耗.最后,我们设计了H型电催化膜反应器,耦合阴极的析氢反应,降解有机物的同时制备纯氢,极大地提高了电极和膜反应器的效率.     

磁性黏土基TiO2复合材料的制备及其光催化性能

采用溶剂热法将酸改性凹凸棒黏土(AATP)和Fe_3O_4纳米粒子复合,制备出磁性凹凸棒黏土复合载体(MATP);采用水热法在MATP上负载活性组分TiO_2,制成新型磁性复合光催化剂(TiO_2/MATP)。采用X射线衍射(XRD)、透射电镜(TEM)、X射线能谱(EDS)、比表面积分析和振动磁强计(VSM)等对样品进行了表征。结果表明,TiO_2/MATP复合材料包含Fe_3O_4磁性组分和锐钛矿相TiO_2活性组分,保持了凹凸棒黏土的纳米棒状和多孔结构,BET比表面积为130.88m~2/g,饱和磁化强度为14.40emu/g。对罗丹明B染料降解实验表明,TiO_2/MATP复合材料具有较高暗吸附特征和光催化活性,20min暗吸附率可达39.0%;在紫外光照射下,50min降解率达到97.2%。     

超声协同微球型Bi2O2CO3降解罗丹明B的研究

Bi_2O_2CO_3是一种Bi类半导体催化剂,文章研究了它的超声催化性能。首先,采用水热法制备了微球型的Bi_2O_2CO_3,利用X射线衍射(X-ray Diffraction, XRD)、扫描电子显微镜(Scanning Electron Microscope, SEM)、紫外-可见漫反射光谱对样品的晶体结构、微观形貌、光学特性进行了表征。然后,以罗丹明B(Rh B)作为模型污染物,通过研究超声催化降解罗丹明B来评测Bi_2O_2CO_3的超声催化性能。研究了催化剂的浓度(Ccatalytic)、初始罗丹明B染料的浓度(CRhB)和超声功率(P)等实验因素对超声催化降解效率的影响。得出在Ccatalytic=3 g·L-1,CRhB=10 mg·L-1和P=400 W条件下降解罗丹明B的效率最高,其最高降解效率可以达到91.7%。     

{H3[PMo12O40]/Pt/PAMAM}复合膜的制备及对甲醇的电催化氧化

采用循环伏安法在玻碳电极上制备了{H3[PMo12O40]/Pt/PAMAM}复合膜,用X射线光电子能谱(XPS)、扫描电子显微镜(SEM)、电子能谱技术(EDS)、原子力显微镜(AFM)和循环伏安法(CV)研究了膜的组成、形貌及其对甲醇的电催化氧化活性。结果表明,Pt纳米粒子在PAMAM基底上分散均匀;最外层沉积H3[PMo12O40]后,与相同条件下制备的Pt/PAMAM膜相比,{H3[PMo12O40]/Pt/PAMAM}复合膜修饰电极对甲醇的氧化有更强的电催化活性。     

Fe_3O_4/G-BiOCl纳米复合光催化剂的制备及光催化性能研究

以自制的氧化石墨烯、BiOCl/Fe_3O_4为原料,以水合肼为还原剂,制备出Fe_3O_4/石墨烯(G)-BiOCl复合光催化剂。运用X射线衍射、透射电镜和扫描电镜对Fe_3O_4/G-BiOCl的组成和形貌进行了表征,运用振动样品磁强计对其磁性进行了测试;对照研究了Fe_3O_4/G-BiOCl、BiOCl/Fe_3O_4和纯BiOCl对罗丹明B的光催化降解能力以及Fe_3O_4/G-BiOCl光催化活性的循环稳定性。结果表明:Fe_3O_4/G-BiOCl复合光催化剂分布均匀,具有超顺磁性;Fe_3O_4/G-BiOCl的光催化性能优于纯BiOCl和BiOCl/Fe_3O_4,可回收再利用,并具有良好的循环稳定性。     

新型可见光催化剂Bi6O26N5H9/AgCl的制备及其性能研究

以硝酸铋和硝酸银为主要原料,采用水解法制备了可见光响应型高效复合催化剂Bi6O26N5H9/AgCl。利用X射线仪(XRD)、扫描电镜(SEM)等手段对样品进行表征,并以碱性染料罗丹明B为目标污染物,金属卤化物灯为可见光光源测试其光催化性能,研究了初始Bi 3+/Ag+物质的量比、废水pH及浓度等对Bi6O26N5H9/AgCl光催化活性的影响,并对光催化过程中产生的活性物种进行了检测。结果表明,当罗丹明B的质量浓度为20 mg/L、AgCl/Bi6O26N5H9催化剂用量为0.5g/L、pH=4.6、光照30min条件下,罗丹明B脱色率、COD和TOC去除率分别为98.73%、88%和69%。活性物种的检测表明光催化过程产生的主要活性物种为·OH自由基,而非空穴和超氧阴离子。     

Synthesis and electrocatalytic property of mono-dispersed Ag/Fe3O4 composite micro-sphere

One-step reaction was designed to synthesize mono-dispersed Ag/Fe₃O₄ micro-sphere with different Ag content via a facile and easily controlled hydrothermal method without use of any surfactant. The phases and composition analysis of the as-prepared samples were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The morphology of the samples was observed by transmission electron microscopy (TEM) and field-emission scanning electron microscopy (FE-SEM). The results revealed that the Ag/Fe₃O₄ composite samples with different Ag content were micro-spheres with almost the identical size of 175 nm or so in diameter. The electrocatalytic activity of the resultant samples modified on a glassy carbon electrode (GCE) for p-nitrophenol reduction in a basic solution was investigated. The results indicated that all the samples exhibited enhanced electrocatalytic activity for p-nitrophenol reduction, and the sample with 3% Ag exhibited the highest electrocatalytic one.     

大比表面积、高孔隙率多孔仿生CeO2-CuO光催化剂

以富含多孔结构的纤维素为诱导体,采用浸渍法制备仿生CeO_2-CuO催化材料,通过X射线衍射(XRD)、场发射扫描电子显微镜(SEM)、透射电子显微镜(TEM)、氮气吸附-脱附(N2adsorption-desorption)、紫外-可见漫反射光谱(UV-vis)等分析手段对产物的结构和形貌进行了表征。在可见光条件下,以亚甲基蓝溶液为模拟废水,测试其TOC(Total organic carbon)去除率,并对光催化降解机理进行探讨。实验结果表明所制备的材料颗粒均匀,平均颗粒尺寸在10nm左右,并且含有丰富的介孔结构,其孔径集中分布于5~10nm。由紫外-可见漫反射吸收光谱可知,材料对可见光的吸收程度高于块状氧化铈,从而具有更高的可见光催化活性,光照2.5h后对亚甲基蓝的TOC去除率为90%。     

温度对燃烧包覆LiMn2O4/ZnO及其电性能的影响

通过葡萄糖辅助低温燃烧制备ZnO包覆型LiMn2O4,利用X射线衍射仪、扫描电子显微镜、循环伏安、交流阻抗以及恒流充放电测试等手段,研究了温度对产物晶体结构、微观形貌及电化学性能的影响。XRD结果表明所有产物均为单相尖晶石型LiMn2O4结构。SEM结果表明产物的颗粒尺寸随温度的升高而增大。电化学性能测试表明400℃和500℃制备的LiMn2O4/ZnO具有相对优异的电化学性能,室温1C条件下首次放电比容量分别为119.3mAh/g、116.3mAh/g,循环100次后容量保持率分别85.6%、87.8%。尖晶石LiMn2O4电极的阻抗谱特征与温度有关,电池的电化学性能主要受电荷转移电阻(Rct)影响。     

Electrochemical degradation of chlorobenzene on boron-doped diamond and platinum electrodes

In this paper the electrochemical degradation of chlorobenzene (CB) was investigated on boron-doped diamond (BDD) and platinum (Pt) anodes, and the degradation kinetics on these two electrodes was compared. Compared with the total mineralization with a total organic carbon (TOC) removal of 85.2% in 6 h on Pt electrode, the TOC removal reached 94.3% on BDD electrode under the same operate condition. Accordingly, the mineralization current efficiency (MCE) during the mineralization on BDD electrode was higher than that on the Pt electrode. Besides TOC, the conversion of CB, the productions and decay of intermediates were also monitored. Kinetic study indicated that the decay of CB on BDD and Pt electrodes were both pseudo-first-order reactions, and the reaction rate constant (k_s) on BDD electrode was higher than that on Pt electrode. The different reaction mechanisms on the two electrodes were investigated by the variation of intermediates concentrations. Two different reaction pathways for the degradation of CB on BDD electrode and Pt electrode involving all these intermediates were proposed.     

Oxidation of the pesticide atrazine at DSA electrodes

This paper presents the study of the electrochemical oxidation of the pesticide atrazine at a Ti/Ru(0.3)Ti(0.7)O(2) dimensionally stable anodes (DSA). The effect of using different supporting electrolytes (NaCl, NaOH, NaNO(3), NaClO(4), H(2)SO(4) and Na(2)SO(4)) during the galvanostatic electrolysis of atrazine was investigated. It was observed that the removal of atrazine and total organic carbon (TOC) was only achieved at appreciable rates when NaCl was used as the supporting electrolyte, due to the oxidising species formed in this electrolyte (e.g. ClO(-)). Variation of the NaCl concentration demonstrated that, although only low concentrations of NaCl are necessary to result in the complete removal of atrazine in solution, TOC removal is almost linearly dependent on the quantity of NaCl in solution. Examination of the applied current density indicates that the efficiency of TOC removal reaches a maximum at 60 mA cm(-2). Testing of alternative electrode materials containing SnO(2) did not improve the efficiency of atrazine removal in Na(2)SO(4), but in NaCl a small increase was observed. Overall there appears to be no great advantage in using SnO(2)-containing electrodes over the Ti/Ru(0.3)Ti(0.7)O(2) electrode.     

Photoelectrochemical properties of thin Bi2WO6 films

Thin Bi₂WO₆ film prepared from an amorphous heteronuclear complex via dip-coating method is investigated as a visible light-driven photoelectrode material. Photoelectrochemical properties of the resultant film are investigated on the basis of linear sweep voltammetry and current-time curves, and conduction and valence band edges of the film electrode are determined from the photocurrent voltage response. Anodic photocurrent associated with the oxidation of water is obtained under visible light irradiation. Furthermore, the film as a photoanode can degrade rhodamine B (RhB) and methylene blue (MB) in aqueous solution under visible light irradiation slowly. The application of bias potential further improves the photodegradation efficiency of RhB and MB. Based on the analytic result of current-time curve, the stability of the film electrode is confirmed.     

Electrochemical treatment of anionic surfactants in synthetic wastewater with three-dimensional electrodes

The electrochemical oxidation of anionic surfactants (sodium dodecyl benzene sulfonate, DBS) contained in simulated wastewater treated by three-dimensional electrode system with combined modified kaolin served as packed bed particle electrodes and Ti/Co/SnO(2)-Sb(2)O(3) anode was studied, the chemical oxygen demand (COD) removal of pollutants in the solutions was also investigated. The results showed that the three-dimensional electrodes in combined process could effectively decompose anionic surfactants. The COD removal efficiency can reach 86%, much higher than that of Ti/Co/SnO(2)-Sb(2)O(3) electrodes used singly or modified kaolin employed singly (graphite as anode and cathode) on the same condition of pH 3 and 38.1 mA/cm(2) current density. The current efficiency and kinetic constant were calculated and energy consumption was studied. At the same time the influence of pH and current density on COD removal efficiency with combined three-dimensional electrodes was also investigated, respectively. The optimal initial pH value of degradation is 3 (acid condition), and a minor COD removal increase follows higher current density.     

二次水热法制备鸟巢状TiO2/Co3O4纳米结构及其锂电性能

以TiO_2粉末和NaOH为原料,在机械外力场作用下,采用水热法制备TiO_2纳米线。随后将得到的TiO_2纳米线与六水合硝酸钴(Co(NO_3)_2·6H_2O)和尿素(Urea)共同水热反应制备TiO_2/Co_3O_4纳米结构材料。分别利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、电池充放电测试仪和电化学工作站等,对材料的相组成、微观形貌、锂电性能和阻抗性能进行测试。结果表明,TiO_2/Co_3O_4纳米复合材料为鸟巢状结构,其在33.5mA/g电流密度下恒电流充放电的首次放电容量为777mAh/g,充电容量为759mAh/g,100次循环后的可逆容量仍保持在663mAh/g,具有良好的循环稳定性和电化学特性。     

Ag/PANI/GCE电极的制备及对NO2-的电化学检测

亚硝酸盐是水中最常见的污染物之一,其检测长期以来一直是国内外研究的热点问题。制备了聚苯胺载银修饰玻碳电极(Ag/PANI/GCE)并将其应用于水中亚硝酸根的电化学检测。初步研究了亚硝酸根在电极表面的电化学行为的影响因素,并分析了所制备电极材料检测亚硝酸根的灵敏度、稳定性以及抗干扰性能。结果显示,所制备的Ag/PANI/GCE电极材料的电化学稳定性好,可以对水中的亚硝酸根浓度进行有效的检测,同时具有稳定性好、灵敏度较高、抗干扰性能强等优势,具有较高的研究价值和较好的应用前景。