碱性燃料电池产过氧化氢的外部影响因素

以持续注入的KOH水溶液为电解质,在燃料电池反应器中进行了H2O2合成工艺研究. 结果表明,KOH溶液浓度及流量、H2O, O2和H2流量对电池电流、H2O2浓度和电流效率等均有较大影响. 其中KOH浓度为2 mol/L, H2O, KOH和O2, H2的流量分别为80, 150 mL/h和60, 20 mL/min时,反应体系获得了较高的H2O2产量(0.225 mol/L)和电流效率(接近100%),可望应用于水中污染物的处理.     

燃料电池型反应器生产过氧化氢的研究进展

燃料电池型反应器合成过氧化氢是一种环境友好的制备方法.详细地介绍了其工作原理和特点,并阐述了催化剂、电极制备、反应工艺的研究进展,提出了今后工作重点,展望了其发展前景.     

燃料电池反应器中过氧化氢的生产I 实验研究

以循环流动的盐酸和硫酸水溶液为电解质,在燃料电池反应器中进行了过氧化氢和电能共生的研究.结果表明,石墨可作为共生的适宜催化剂,生成过氧化氢的电流效率可达42%.氧气分压是影响反应速率的主要因素,pH值对反应速率影响小,但对生成过氧化氢的电流效率影响大,特别是当pH＜1时,随pH值减小,电流效率明显下降.     

碱性燃料电池产过氧化氢阴极C/PTFE的制备及性能表征

研究了碱性燃料电池合成过氧化氢阴极碳/聚四氟乙烯(C/PTFE)的制备方法,考察了制备过程中的主要影响因素,并通过伏安曲线和过氧化氢浓度曲线及交流阻抗图谱,对不同条件下制备的阴极性能进行了评价.结果表明,压力、整平层碳含量及聚四氟乙烯含量对阴极性能均有较大影响,其中压力为10.0 MPa、碳含量为0.2 g及聚四氟乙烯含量为50%条件下制备的阴极能获得最大电流,过氧化氢的产量最高,2.5 h后过氧化氢浓度达到56 mmol/L.     

多壁碳纳米管为阴极材料的单室过氧化氢燃料电池

以多壁碳纳米管负载在碳纸上作为阴极材料,镍网作为阳极材料,在酸性电解质中,构成了一个单室过氧化氢燃料电池。该过氧化氢燃料电池的最大功率密度为4080mW/m2,高于仅以碳纸作为阴极材料(28mW/m2)的电池。结果表明,该单室过氧化氢燃料电池有潜力发展成为便携式和小型化的应用电源。     

制备过氧化氢的新方法

<正> 氢和氧在常温下用燃料电池反应合成过氧化氢的小试验由日本东京工学院的 Otsu-ka,K.和 Yamanaka,Ⅰ.获得成功。这种合成方法的优点是:(1)不消耗电能,还可产生少量电能。(2)氢和氧用固体聚合物电解质膜分隔,组成两个电极室,避免了氢氧的混合,形成爆炸性气体的危险。     

十二烷基苯磺酸钠对铜绿微囊藻光合作用的影响

以各项表征光合作用的叶绿素荧光参数(Y、Y'、qP、qN、NPQ、φPSII、rETR)为观测指标,研究了不同质量浓度(0、0.05 mg/L、0.5 mg/L、5 mg/L、10 mg/L和20 mg/L)的十二烷基苯磺酸钠(LAS)对铜绿微囊藻光合作用的影响.结果表明,小于0.05 mg/L的LAS对该藻细胞生理生长不仅未产生胁迫作用,反而能提高PSII(光合反应中心)系统的光能捕获效率、光能转化效率和电子传递速率,从而促进光合作用的进行;0.5 mg/L～5 mg/L的LAS对该藻细胞的光合作用具有一定的促进作用,但程度较0.05 mg/L弱;10 mg/L的LAS对该藻的生理生长具有一定的胁迫作用,导致PSII系统的光能捕获效率、光能转化效率及电子传递速率均受影响,藻细胞无法进行正常的光合作用;高于20 mg/L的LAS对该藻具有剧烈毒性,严重胁迫其生理生长,致使光合作用完全终止.     

燃料电池反应器中过氧化氢的生产——Ⅰ 实验研究

以循环流动的盐酸和硫酸水溶液为电解质,在燃料电池反应器中进行了过氧化氢和电能共生的研究.结果表明,石墨可作为共生的适宜催化剂,生成过氧化氢的电流效率可达42%.氧气分压是影响反应速率的主要因素,pH值对反应速率影响小,但对生成过氧化氢的电流效率影响大,特别是当pH＜1时,随pH值减小,电流效率明显下降.     

添加剂对十二烷基苯磺酸钠溶液cmc的影响

在25℃时利用电导法测定了添加剂甲醇、乙醇、丙醇、PEG、β-环糊精和NaOH对十二烷基苯磺酸钠(SDBS)溶液的临界胶束浓度的影响。实验结果表明,随着甲醇、乙醇、丙醇、PEG、NaOH加入量的增加,均使SDBS溶液的cmc值降低;不同分子量的PEG对SDBS溶液cmc值的影响是相同体积分数的PEG200相似文献   

脂肪酸盐对十二烷基苯磺酸钠溶液泡沫性能的影响

研究了脂肪酸盐对十二烷基苯磺酸钠溶液泡沫性能的影响，并对其作用机理进行了讨论。     

Gemini双季铵盐表面活性剂与SDBS和SDS的复配行为

采用荧光分光光度法和Zeta电位法考察了系列Gemini双季铵盐表面活性剂与阴离子表面活性剂十二烷基苯磺酸钠(SDBS)和十二烷基磺酸钠(SDS)的复配效果。结果表明,Gemini双季铵盐表面活性剂疏水链和连接基越长,cmc越小,且疏水链长度对表面活性剂性能的影响较大;Gemini双季铵盐表面活性剂的加入可显著提高阴离子表面活性剂SDBS和SDS的表面活性,当Gemini双季铵盐表面活性剂与SDBS或SDS的摩尔比为3:7时,复配体系的cmc最小,且与SDS复配体系的性能优于与SDBS的复配体系。     

硝酸溶液中十二烷基苯磺酸钠对锌的缓蚀作用及吸附热力学研究

采用失重法研究了硝酸介质中烷基磺酸盐类阴离子表面活性剂对锌的缓蚀及吸附作用,考察了在不同温度的3%硝酸中,不同浓度的十二烷基苯磺酸钠对锌的缓蚀作用。实验结果表明,十二烷基苯磺酸钠能很好的抑制锌的腐蚀,当其含量达到一定浓度后,缓蚀作用基本保持不变,而其在锌表面上的吸附是产生缓蚀作用的重要原因。在浓度为0~300 mg/L时,十二烷基苯磺酸钠在锌表面的吸附规律服从Langmuir吸附等温式。用Sekine方法处理实验数据,从而获得了ΔH0、ΔS0和ΔG0等一系列相关的热力学参数。     

Synthesis of hydrogen peroxide in microbial fuel cell

BACKGROUND: Hydrogen peroxide (H₂O₂) is an important chemical product, and this study investigated its synthesis at the cathode of a microbial fuel cell (MFC) system using spectrographically pure graphite (SPG) rods as cathode electrode. RESULTS: Electrochemical methods showed that oxygen reduction reaction (ORR) on SPG mainly followed the two‐electron pathway yielding H₂O₂, while, the optimal condition for H₂O₂ production was in 0.1 mol L^?1 Na₂SO₄ electrolyte. When SPG was used as the cathodic electrode in the MFC system, H₂O₂ concentration reached 78.85 mg L^?1 after 12 h operation with an external resistance of 20 Ω (H₂O₂ production rate was 6.57 mg L^?1 h^?1). Coulombic efficiency, current efficiency and COD conversion efficiency were 12.26%, 69.47% and 8.51%, respectively. Repeated experiments proved this system had a stable operating performance. CONCLUSIONS: H₂O₂ was synthesized at the cathode of an MFC, and this study provides a proof‐of‐concept demonstration to realize the process of synthesizing H₂O₂ with wastewater. Copyright © 2010 Society of Chemical Industry     

Mixed-surfactant system of dodecylbenzene sulfonate and alpha-olefin sulfonate: Micellar and volumetric studies

Critical micelle concentrations of sodium salts of dodecylbenzene sulfonate, alpha-olefin (C₁₆) sulfonate, and their mixtures have been evaluated by measuring the surface tensions of solutions at 298.15 K. Interaction parameters for mixed monolayer formation (β^σ) and mixed-micelle formation (β^M) have been calculated from the critical micelle concentration data. Densities of solutions of surfactants and their mixtures were measured with a vibrating-tube densimeter at 298.15 K. Apparent and partial molar volumes have been evaluated from solution density data. Results of the micellar properties have been eplained on the basis of a nonideal multicomponent mixed-micelle model. The mixed-surfactant system exhibits synergism in all aspects when the mole fraction of alpha-olefin sulfonate in the mixture is 0.2. Volumetric properties correlate well, as the partial molar volumes also show a minimum at the same composition of the mixture. Formation of a compact mixed micelle at this composition has been envisaged.     

预碳化辅助双氧水沉淀高碱铝酸钠溶液强化薄水铝石合成工艺(英文)

Hydrogen peroxide (H2O2) precipitation from sodium aluminate (SA) solution at close-ambient temperature is an efficient method to synthesize boehmite and its derived alumina with high surface area, but the precipitation yield of Al2O3 is usually below 50% in highly alkaline SA solutions. Here the synthesis of boehmite is enhanced through a precarbonization-assisted H2O2 route in highly alkaline SA solutions. It is found that the crystal structure of the precipitation product is evidently influenced by the precipitation conditions. As the precipitation temperature increases from 273 to 325 K, a small amount of gibbsite by-product is formed. As the aging temperature increases from 301 to 333 K, the crystallinity of boehmite decreases and part of the boehmite dissolves due to an increase in the pH value. Based on the above results, a precarbonization-assisted H2O2 route is proposed to obtain pure boehmite with more complete recovery of Al2O3 from highly alkaline SA solutions. The route includes a controllable precarbonization step of SA solutions with a molar ratio of Na2O to Al2O3 higher than 2︰1, followed by the H2O2-precipitated step with a molar ratio of H2O2 to Al2O3 less than 7︰1. Because of its facile operation conditions, no extraneous impurity, time saving and a possible recycle of the filtrate, the route has great potential to be an alternative method for preparation of boehmite and its derived alumina.     

NaBH4溶液催化制氢的阴离子效应研究

研究了Cl-和NO3-阴离子对NaBH4溶液现场制氢反应的影响,发现在制氢反应过程中存在着生成金属硼化物和生成金属氢氧化物的竞争反应.当溶液中阴离子为Cl-时,金属离子在催化NaBH4溶液制氢反应时将与硼结合,促使其活化为高活性金属硼化物,能有效促进制氢反应;当溶液中的阴离子为NO3-时,将诱导金属离子生成没有催化活性的金属氢氧化物,抑制制氢反应.     

硼氢化钠制氢技术在质子交换膜燃料电池中的研究进展

硼氢化钠储氢量高达10.6%,安全、无爆炸危险,携带和运输方便;供氢系统设备简单,启动速度快,产氢速度可调,因此是一个非常良好的氢载体,是为质子交换膜燃料电池供氢的理想储氢介质。硼氢化钠供氢系统也已逐步应用于质子交换膜燃料电池电源中。介绍了这种制氢方式的几项关键技术：硼氢化钠水解制氢催化剂、硼氢化钠制氢反应器、氢气净化系统等在质子交换膜燃料电池中的研究进展,并指出了今后的研究发展方向。     

A small-scale flow alkaline fuel cell for on-site production of hydrogen peroxide

The behavior of a small-scale flow alkaline fuel cell (AFC) built-up for on-site production of HO₂⁻ using commercial gas-diffusion electrodes has been studied. It produces a spontaneous current due to the oxidation of H₂ to H₂O at the H₂-diffusion anode and the reduction of O₂ to HO₂⁻ at the O₂-diffusion cathode, while a fresh 1.0-6.0 mol dm⁻³ KOH electrolyte at 15.0-45.0 °C is injected through it. Under circulation of HO₂⁻+KOH solutions in open circuit, the flow AFC behaves as a two-electron reversible system. When it is shorted with an external load (R_ext), steady cell voltage-current density curves are found. The use of O₂/N₂ mixtures to fed the cathode causes a loss of its performance, being required to supply pure O₂ to yield a maximum HO₂⁻ electrogeneration. The current density and HO₂⁻ productivity increase with raising OH⁻ concentration, temperature and pressure of O₂ fed. At R_ext=0.10 Ω, a current efficiency close to 100% is obtained, and current densities >100 mA cm⁻² are achieved for 1.0 mol dm⁻³ KOH at 45.0 °C and for higher KOH concentrations at 25.0 °C. The flow AFC can work under optimum conditions up to 6.0 mol dm⁻³ KOH and 45.0 °C for possible industrial applications.     

惰性气体对氢氧等离子体直接合成过氧化氢的影响

在H₂/O₂体系中添加惰性气体(Ar、He、N₂)进行常压介质阻挡放电,合成了H₂O₂水溶液。系统研究了不同惰性气体对体系击穿电压及H₂O₂合成能效的影响。结果表明,添加气体对击穿电压、O₂转化率、H₂O₂选择性、H₂O₂收率及能量效率能产生较大影响。其中Ar的引入不仅降低了击穿电压,还提高了合成H₂O₂的能量效率;当Ar添加量为56.6 ml·min^-1时,击穿电压由11.8 kV降为10.2 kV;合成H₂O₂的能量效率提高51%,由3.45 g·(kW·h)^-1提高至5.20 g·(kW·h)^-1(以100%H₂O₂计)。发射光谱表征发现,在H₂-O₂-Ar放电体系中存在以亚稳态为末态的辐射Ar(696.5、794.8、811.5 nm),表明亚稳态Ar物种的潘宁电离作用可能是降低击穿电压的主要因素。由示波器测量的放电电流波形图可知,Ar的加入增大了体系电子密度,使得相同功率下O₂转化速率大幅提高,从而使合成H₂O₂能量效率显著提高。