TiO2纳米管阵列电极电催化降解甲基橙的研究

采用阳极氧化法制备了TiO2纳米管阵列电极。采用场发射扫描电子显微镜(FESEM)和X-射线衍射仪(XRD)表征了电极的表面形貌和晶体结构,应用电化学阻抗谱(EIS)技术研究了不同阳极极化电位下电极的导电性能,应用荧光光谱法研究了电极产生羟基自由基(·OH)的活性,考察了3种支持电解质(Na2SO4、NaNO3和NaCl)对甲基橙(MO)电催化降解效率的影响,通过加入捕获剂探讨了MO分子的降解机理。结果表明,TiO2纳米管阵列电极电极的导电性随阳极极化电位的升高而增强;在电场作用下,TiO2纳米管阵列电极表面生成大量·OH;Na2SO4和NaNO3不参与MO分子的氧化反应,MO的降解符合一级反应动力学模型,而NaCl参与了TiO2纳米管阵列电极电催化降解MO的过程,呈现出复杂的动力学行为;在捕获剂存在的情况下,MO分子仍能发生降解,显示MO分子可在TiO2纳米管阵列电极表面直接氧化。     

硫化黑2BR 200%在石墨镀银电极上的电催化还原

采用涂附法制备了石墨镀银电极。用配有EDS的扫描电子显微镜(FE-SEM)对石墨镀银电极表面结构进行了表征,以石墨镀银电极和石墨电极为工作电极,采用线性扫描法研究了硫化黑在NaOH溶液中的电化学还原行为,探讨了溶液pH值对硫化黑2BR 200%电还原反应的影响。实验结果表明：用涂附法制备得到的石墨镀银电极表面分布了大量金属银颗粒,该石墨镀银电极对硫化黑2BR 200%的还原反应显示了很高的电催化活性,其电催化活性高于石墨电极;电解液的pH值越大,硫化黑的电还原反应就越容易。在恒电流电解中,以镀银石墨电极为阴极,电流密度为6.25 mA•cm^-2,反应温度为(27±2)℃时,硫化黑的电解实验的电流效率可达92.2%。     

TiO2纳米管阵列电极电催化降解甲基橙的研究

采用阳极氧化法制备了TiO2纳米管阵列电极.采用场发射扫描电子显微镜（FESEM）和X-射线衍射仪（XRD）表征了电极的表面形貌和晶体结构,应用电化学阻抗谱（EIS）技术研究了不同阳极极化电位下电板的导电性能,应用荧光光谱法研究了电极产生羟基自由基（·OH）的活性,考察了3种支持电解质（Na2SO4、NaNO3和NaCl）对甲基橙（MO）电催化降解效率的影响,通过加入捕获剂探讨了MO分子的降解机理.结果表明,TiO2纳米管阵列电极电极的导电性随阳极极化电位的升高而增强;在电场作用下,TiO2纳米管阵列电极表面生成大量·OH;Na2SO4和NaNO3不参与MO分子的氧化反应,MO的降解符合一级反应动力学模型,而NaCl参与了TiO2纳米管阵列电极电催化降解MO的过程,呈现出复杂的动力学行为;在捕获剂存在的情况下,MO分子仍能发生降解,显示MO分子可在TiO2纳米管阵列电极表面直接氧化.     

TiO2纳米管阵列电催化降解甲基橙

采用阳极氧化法制备了TiO2纳米管阵列电极,通过考察其对模拟染料废水甲基橙(MO)的光催化降解效率来优化制备条件。研究了TiO2纳米管阵列电极电催化降解MO的活性及其影响因素,并考察了MO降解反应动力学。结果表明,MO溶液pH、电解槽压、支持电解质浓度等是TiO2纳米管阵列电极催化效率的重要影响因素。TiO2纳米管阵列电催化降解MO的反应遵守一级反应动力学规律,与TiO2纳米管阵列光催化降解MO的行为一致,且表观反应速率常数不随MO溶液浓度不同而发生改变。     

Fe/CHI-MWNTs修饰石墨阴极电Fenton氧化4-硝基酚

采用硫酸亚铁溶液浸渍经壳聚糖(CHI)修饰的多壁碳纳米管(MWNTs)制备Fe/CHI-MWNTs粉末,并与石墨粉、聚四氟乙烯以一定比例混合制成Fe/CHI-MWNTs修饰石墨电极,用作电Fenton体系的阴极氧化降解4-硝基酚,探讨了浸渍FeSO4溶液的含量、反应初始pH、电流密度对电Fenton降解4-硝基酚的影响,同时考察了电极的稳定性。结果表明,用质量浓度10.0g/L的FeSO4溶液浸渍制得的Fe/CHI-MWNTs修饰石墨电极,在4-硝基酚初始质量浓度为100mg/L、初始pH为3.0、电流密度为3.0mA/cm2、电解质Na2SO4浓度为0.05 mol/L、空气曝气体积流量为0.1 m3/h的条件下,60 min时4-硝基酚的去除率达89.98%;在该体系下,90 min阴极产生的H2O2可达148μmol/L,Fe3+质量浓度为1.52 mg/L;电极可重复使用,连续使用810 min后电极的催化活性才逐渐降低。     

石墨烯修饰石墨电极制备及在高氨氮废水中的应用

采用改进Hummers法制备氧化石墨烯,用水合肼将其还原制成石墨烯,并通过FTIR、XRD、FESEM、循环伏安法进行表征。以自制石墨烯修饰的石墨电极(RCE)为阳极,纯石墨电极为阴极,构建二维电极体系电催化氧化处理高氨氮垃圾渗滤液生化出水。在电流为15 A、极板间距为1.5 cm、pH=7、反应时间为45 min的实验条件下,氨氮去除率为98%,其主要转化为氮气而被去除,符合零级反应动力学模型;COD去除率为88%,降解过程符合一级反应动力学模型。     

有机污染物的脱色率与COD值的关系研究

采用阳极氧化法制备了TiO2纳米管阵列电极,采用场发射扫描电子显微镜(FESEM)和X-射线衍射(XRD)对电极的表面形貌和晶型进行了表征,并以其为阳极对模拟染料废水甲基橙(MO)和亚甲基蓝(MB)溶液进行电化学氧化降解。研究了MB溶液的电化学氧化降解反应动力学,考察了MO和MB溶液脱色率与COD值之间的关系。结果表明,MB溶液在TiO2纳米管阵列电极表面发生电化学氧化降解反应动力学为一级反应;MO和MB溶液的脱色率与其COD值之间均呈良好的线性关系,可通过测定溶液脱色率来了解COD值的去除情况。     

两种不同石墨电极上溴离子电氧化的研究

通过测定溴离子在两种不同石墨电极上的循环伏安曲线及电流效率,探索了溴离子在石墨电极上氧化的电解条件,比较了两种石墨电极对溴离子电氧化的影响。研究发现,由于电极材料的不同和析氧反应的存在,两种电极材料对溴离子氧化的催化作用有一定差别。溴离子在石墨电极上氧化的电流效率一般在80％以上,最高可达88.5％。     

泡沫镍和泡沫铜阴极电类Fenton氧化降解对硝基酚的比较

选用两种常见的泡沫金属材料——泡沫镍(NF)和泡沫铜(CF)作为电类Fenton氧化体系的阴极,分别从电极的形貌、结构、电类Fenton氧化降解对硝基酚(p-NP)和稳定性能等方面进行了比较分析。结果表明,NF和CF均为三维多孔网络结构,CF电极表面有少量铜氧化物颗粒沉积;NF和CF阴极均能催化O_2原位两电子还原产H_2O_2,当阴极电位为-0.9V,180min时H2O_2的累积质量浓度达最大值,分别为64.2mg/L和56.5mg/L,电流效率分别为14.1%和14.3%;NF和CF阴极可拓宽电类Fenton氧化法的pH适用范围,在不调节电解液初始pH条件下p-NP均有较好的降解效果,当阴极电位为-0.9V,180min时p-NP去除率分别为72.9%和80.7%,反应过程均符合一级动力学模型,CF电极体系p-NP的降解速率高于其在NF电极体系中的降解速率;NF电极相对CF电极的稳定性较好,重复使用8次后,p-NP去除率和电极形貌均没有明显变化,但仍有少量的镍离子溶出。     

光电催化氧化法降解杀菌剂废水的研究

采用光电催化氧化法降解季铵盐类杀菌剂十二烷基二甲基苄基氯化铵(1227)废水.以紫外灯为光源,DSA电极为阳极,石墨电极为阴极,考察了阳极材料、光催化剂投加量、外加电场强度、极板间距、初始pH对COD去除率的影响.结果表明:光电催化氧化过程的最佳外加偏压为20V,光催化剂最佳投加质量浓度为0.3 g/L,极板间距为0....     

Electrolyte wetting effects in the comparative polarization behaviour of the hydrogen evolution reaction at Ni-Mo-Cd electrodes in KF · 2HF and KOH · 2H2O melts

In the electrolyte process of fluorine production from KF · 2HF melts at 85° C, unusually high polarization arises both at the cell anodes (carbon) and cathodes (mild steel) at moderate current densities. The anomalous polarization behaviour in fluorine evolution at carbon anodes has been extensively studied but much less is known about the origin of hyperpolarization in hydrogen evolution at the cathodes. Here, the results of comparative polarization studies at a Ni-Mo-Cd composite cathode material in a KF · 2HF melt and a corresponding aquo-analogue melt of KOH · 2H₂O are reported. Large differences are observed which are attributed to the different wetting characteristics of these two melts at the interface of the Ni-Mo-Cd cathodes that are microporous. Such electrode material also offers a major improvement of cathode polarization over that at mild steel surfaces. Conclusions on wetting effects are based on: (i) a comparative determination of hydrogen-bubble contact angles at the electrode in the two melts and (ii) an evaluation of the double-layer capacitances of the electrode interfaces with the two melts as determined by the fast potential-relaxation method, at short times after current interruption. The apparent double-layer capacitances at a given electrode are very different in the two melts.     

Effect of the oxygen reduction catalyst loading method on the performance of air breathable cathodes for microbial fuel cells

This paper presents three different methods of hydrothermal (HT), microwave (MW), and cyclic voltammetry (CV) used to load a catalyst on a cathode surface. In the HT and MW methods, a multiwall carbon nanotube (MWCNT) is used as a support material to fix the catalyst, while Nafion solution is used as a binder to load the catalyst on the cathode surface. For the third option, the CV method is used to directly load the catalysts on the cathode surface without any support material. The performances of the three cathodes are tested in an air breathable batch microbial fuel cell (MFC) and compared to that of a commercial carbon cloth cathode with platinum (Pt). The maximum power density of the MFC with the HT cathode is measured as 833 mW m^?2, which is higher than those of the CV and MW cathodes and slightly smaller than the MFC with the Pt cathode. The open circuit voltage of the MFC with the HT cathode is 610 mV, which is higher than those of MFCs with other cathodes, while the power density is higher than the MFCs of the MW and CV cathodes. In the case of the HT cathode, a conductive MWCNT network is well formed and entangled with the catalyst nanostructure of the cathode surface while the small ohmic and activation resistances of the HT cathode contribute to the good MFC performance.     

新型直接碳燃料电池阴极材料及其性能

考察了Ni-CeO2复合阴极对直接碳燃料电池(DCFC)输出性能的影响. 使用不同组成的Ni-CeO2复合阴极对DCFC性能进行了测试. 结果表明,使用Ni-CeO2复合阴极可显著提高DCFC在500和630℃工作时的电流密度、功率密度和燃料转化效率,500℃下DCFC最大电流密度、功率密度分别为328 mA/cm2和72 mW/cm2. 630℃下DCFC最大电流密度、功率密度分别为474 mA/cm2和108 mW/cm2,电流密度50 mA/cm2时燃料转化效率为70%. 用XRD和SEM对Ni-CeO2复合阴极材料进行了表征,并对Ni-CeO2复合阴极可能的作用机制进行了研究.     

隔膜电解槽纳米活性阴极的开发与应用

介绍了氯碱工业隔膜电解槽活性阴极的开发研究背景、研究意义和研究现状。通过电沉积法制备了纳米晶Ni-X合金电极,阴极极化过电位较碳钢电极低约160 mV(i=500 A/m2时),性能稳定,抗反向电流及耐蚀性好。由正交实验考察了镀液组成、镀液温度及pH值对电极催化活性的影响,确定了最佳工艺条件,并进行了中试和生产实验。     

厌氧流化床无膜微生物燃料电池的床层膨胀高度与产电特性

考察了厌氧流化床床层膨胀高度对电池不同阴极位置(阴极1, 2, 3分别位于分布板上方150, 250, 350 mm)产电性能的影响. 膨胀高度低于170 mm时,电池功率随阴极位置沿轴向高度增加而减小,同一流速下,阴极1的最大电极输出功率最大,为347.1 mW/m2. 膨胀高度在170~270 mm时,同一流速下,阴极2的最大产电功率高于阴极1和阴极3,当流速为8.35 mm/s 时,达361.0 mW/m2. 膨胀高度在400 mm以下,同一流速下3处阴极的最大产电功率均降低,阴极3最大产电功率降低幅度较小,为297.5 mW/m2,电池功率随阴极位置沿轴向高度增加而增大. 该结果是流速对阳极室内传质及电子传递效率、流速对微生物膜生长双重影响的结果.     

大型电除尘器的进展

刚产大型硫酸生产用电除尘器的总体结构为板卧式钢壳外保温结构,滚动式平面轴承为支撑构件。阳极均为薄钢板轧制的板状极板,框架式阴极已经取代了重锤挂线式阴极,框架上可安装不同的阴极线。承重绝缘件为95瓷绝缘套管,保温材料为复合硅酸盐毡,厚度仅需100mm。近年来的运行表明,国产大型电除尘器的设备结构和技术性能已达到国外先进水平,有些方面还优于原来进口的设备。大型电除尘器的设计制造和使用都积累了一定的经验,并且仍在不断改进和完善。     

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.     

The effect of surface roughness on the hydrogen evolution reaction kinetics with mild steel and nickel cathodes

The effect of electrode surface roughness on the kinetics of the hydrogen evolution reaction has been studied for mild steel and nickel cathodes in 10 M NaOH at 348°K. With the nickel cathodes, the Tafel slope was independent of whether the electrode surface was smooth or roughened, but the exchange current density was about twice that for the roughened electrode. With the mild steel cathodes, the roughened electrode showed a considerably lower Tafel slope than the smooth electrode with b = 51 mV for the rough electrode and b = 110 mV for the smooth one. The exchange current density was also lower for the roughened mild steel cathode than for the smooth electrode: 1.0 × 10^t-5 A/cm²vs 2.3 × 10^?5 A/cm².     

Marine microbial fuel cell: Use of stainless steel electrodes as anode and cathode materials

Numerous biocorrosion studies have stated that biofilms formed in aerobic seawater induce an efficient catalysis of the oxygen reduction on stainless steels. This property was implemented here for the first time in a marine microbial fuel cell (MFC). A prototype was designed with a stainless steel anode embedded in marine sediments coupled to a stainless steel cathode in the overlying seawater. Recording current/potential curves during the progress of the experiment confirmed that the cathode progressively acquired effective catalytic properties. The maximal power density produced of 4 mW m⁻² was lower than those reported previously with marine MFC using graphite electrodes. Decoupling anode and cathode showed that the cathode suffered practical problems related to implementation in the sea, which may found easy technical solutions. A laboratory fuel cell based on the same principle demonstrated that the biofilm-covered stainless steel cathode was able to supply current density up to 140 mA m⁻² at +0.05 V versus Ag/AgCl. The power density of 23 mW m⁻² was in this case limited by the anode. These first tests presented the biofilm-covered stainless steel cathodes as very promising candidates to be implemented in marine MFC. The suitability of stainless steel as anode has to be further investigated.     

基于阴极材料优化的微生物电解池研究进展

微生物电解池(MEC)是一种新型的废水处理和产能一体化技术,其通过微生物阳极催化氧化废水中的有机物,同时在阴极产生氢气和甲烷。近年来,寻找高性能低成本的阴极材料和催化剂、推进MEC废水处理应用是相关领域的研究热点。本文综述了目前MEC系统常见的阴极材料和催化剂,包括贵金属Pt、不锈钢网、镍金属、纳米材料、导电聚合物和复合材料以及生物阴极。着重介绍了基于生物阴极优化的MEC系统在废水处理与产能方面的应用。最后在阴极材料的布局优化、阴极复合材料合成、胞外电子传递机制三方面进行了展望,指出不锈钢网和纳米材料具有良好的性能,未来可通过优化电极材料的空间布局和电极表面催化特性来强化微生物附着,推进MEC技术工程应用。