Phosphorus-doped graphene supported palladium (Pd/PG) electrocatalyst for the hydrogen evolution reaction in PEM water electrolysis

PEM water electrolysis is one of the most efficient methods for the production of hydrogen because of produced high purity of the gases and environmentally friendly. In the present study, Phosphorus-doped Graphene (PG) was synthesized by thermal annealing of triphenylphosphine (TPP) and graphene oxide (GO). The PG supported palladium (Pd/PG) electrocatalysts were synthesized by chemical reduction method and used as the cathode for hydrogen evolution reaction (HER) electrode. Structural properties and electrochemical performances of the synthesized Pd/PG electrocatalyst were studied by FE-SEM, EDS, ICP, FT-IR, XRD, and Cyclic voltammetry (CV) methods, respectively. The membrane electrode assemblies (MEA’s) were fabricated using Pd/PG as cathode for HER electrode and RuO₂ as anode for OER electrode. Also, their electrochemical performances along with the corresponding hydrogen yields were evaluated in single cell PEM water electrolyzer at various experimental conditions such as different current densities from 0.1 to 2.0 A cm^?2 and temperatures (28–80°C). The synthesized Pd/PG electrocatalyst was observed a current density of 1 A cm^?2 with 1.95 V at 80°C. Further, long-term stability studies were carried out continuously up to 2000 h which showed a reasonable stability. Hence, the synthesized Pd/PG can be used as an alternative to Pt-based electrocatalysts for the HER in PEM water electrolysis.     

含硫油品储罐腐蚀产物自燃及其防治理论研究

含硫油品储罐内壁腐蚀产物(Fe2O3、Fe3O4、Fe(OH)3)与H2S反应生成硫化铁,硫化铁的氧化放热是引起储罐火灾的主要原因.实验模拟了油品储罐中硫化铁的生成,研究了在无氧条件下H2S气体与油品储罐内壁腐蚀产物的反应以及生成的硫化铁在自然环境下的氧化自燃性.结果表明,Fe2O3、Fe3O4、Fe(OH)3,以及它们的混合物经硫化后生成的硫化铁具有很高的自然氧化活性,在自然环境中,常温下能迅速和空气中的氧气反应并放出大量的热,热量积聚引起储罐火灾爆炸事故.在实验结论的基础上,提出了一些行之有效的安全防范措施.     

亚甲基蓝褪色催化动力学光度法测定痕量Cu~(2+)

研究了在聚乙二醇-200(PEG-200)活化下,Cu2+催化H2O2氧化亚甲基蓝的褪色反应,建立了亚甲基蓝褪色催化动力学光度法测定痕量Cu2+的方法。在25mL容量瓶中,加入1.00mL pH为11.68的氨水溶液、2.00mL H2O2溶液(质量分数15%)、1.00mL亚甲基蓝溶液(质量浓度0.20mg/mL)、3.00mL PEG-200溶液,76℃恒温反应5min后冷却,测定吸光度,根据加Cu2+溶液和不加Cu2+溶液的吸光度差值与Cu2+质量浓度绘制了工作曲线,并由试样的吸光度差值确定痕量Cu2+含量。该法的测定波长为664nm,检出限为5.4×10-6g/L,最大相对标准偏差为2.58%,回收率为97.5%~104.5%。     

氢同位素组成及光合特征对梵净山珙桐水源的解析

珙桐(Davidia involucrata)系我国特有的单科单属植物,为第三纪孑遗种,被列为我国一级珍稀濒危植物。贵州省梵净山地区气候常年温凉湿润,在梵净山国家级自然保护区内,选取人工种植及天然分布的珙桐为研究对象,通过测定珙桐的光合参数,比较阴天和晴天珙桐光合日变化,分析生长地大气降水、土壤水分、地下水以及珙桐树枝水分氢同位素组成,研究了梵净山珙桐的水分利用状况和不同水源利用份额。结果表明,珙桐幼树为阳生植物,蒸腾速率较低,适宜在阴凉的环境生长,且温度不宜超过30℃。人工林种植和天然生长的珙桐利用大气降水分别为76%和58%。低蒸腾速率导致根部对土壤水的拉力小,因此,利用土壤深层水分的份额小。阴凉、多雨、云雾缭绕的环境为梵净山的珙桐生存提供良好的水分条件。     

烟气脱硫石膏催化还原为硫化钙的研究

采用Fe-Ni复合催化剂,在温度650℃条件下即可将烟气脱硫石膏催化还原为硫化钙,还原率达95%以上。研究了反应温度、催化剂加入量及还原气体含量因素对还原反应的影响。     

硫化物在厌氧污泥中的分布和对产甲烷活性的抑制作用

在不同的pH值和温度下,对硫化物在厌氧污泥中的分布特征及对污泥产甲烷活性的抑制作用进行了研究.结果表明,硫化物浓度低于120mgS·l-1时,抑制作用主要由系统的pH值升高引起的,大于120mgS·l-1时,主要由液相中高浓度的硫化物引起;当硫化物浓度达160mgS·l-1时,H2S逸出量达到最大,污泥对硫化物的吸附也趋于饱和.pH值升高增加了污泥对硫化物的吸附,H2S逸出量降低;温度升高有利于吸附的硫化物向液相转移,并使H2S逸出量迅速增大.     

Biological elimination of H2S and NH3 from wastegases by biofilter packed with immobilized heterotrophic bacteria

Biotreatment of various ratios of H₂S and NH₃ gas mixtures was studied using the biofilters, packed with co-immobilized cells (Arthrobacter oxydans CH8 for NH₃ and Pseudomonas putida CH11 for H₂S). Extensive tests to determine removal characteristics, removal efficiency, removal kinetics, and pressure drops of the biofilters were performed. To estimate the largest allowable inlet concentration, a prediction model was also employed. Greater than 95% and 90% removal efficiencies were observed for NH₃ and H₂S, respectively, irrespective of the ratios of H₂S and NH₃ gas mixtures. The results showed that H₂S removal of the biofilter was significantly affected by high inlet concentrations of H₂S and NH₃. As high H₂S concentration was an inhibitory substrate for the growth of heterotrophic sulfur-oxidizing bacteria, the activity of H₂S oxidation was thus inhibited. In the case of high NH₃ concentration, the poor H₂S removal efficiency might be attributed to the acidification of the biofilter. The phenomenon was caused by acidic metabolite accumulation of NH₃. Through kinetic analysis, the presence of NH₃ did not hinder the NH₃ removal, but a high H₂S concentration would result in low removal efficiency. Conversely, H₂S of adequate concentrations would favor the removal of incoming NH₃. The results also indicated that maximum inlet concentrations (model-estimated) agreed well with the experimental values for space velocities of 50–150 h⁻¹. Hence, the results would be used as the guideline for the design and operation of biofilters.     

活性炭吸附硫化氢及微波辐照解吸研究

研究了两种活性炭对硫化氢的平衡吸附性能力,并对活性炭床层的穿透性进行了考察;吸附饱和和活性炭在微波辐射的作用下进行解吸。实验表明,解吸效率与微波作用时间及温度有关,在本实验条件下H2S解吸效率达90．1％。     

Photobiological production of hydrogen by the waste water treatment with anaerobic photosynthetic Purple bacteria

In this paper selected references about experience gained with photosynthetic bacteria in anaerobic process for either water treatment or hydrogen production are given. In particular experimental data about the hydrogen evolution rate, hydrogen yield and substrate efficiency in relationship to the nutrient conditions as well as about the behavior of some different species are presented. The limiting role of the nitrogen source is being discussed.     

油品储罐H_2S对铁锈腐蚀产物自燃性研究

为了分析有氧条件下H2S对铁锈腐蚀产物的自燃性,模拟含硫油品储罐中铁锈(Fe2O3:75%;Fe(OH)3:7%;Fe3O4:18%)在有氧条件下与H2S气体的反应试验。将铁锈与H2S气体、O2按不同比例混合形成的混合物进行反应,再进行所得产物的氧化反应。采用X射线衍射分析法鉴定混合气体与铁锈的反应产物,并研究不同初始O2体积分数下的混合气体与铁锈的反应及其产物的再氧化反应,通过温度变化评价铁锈与H2S气体反应产物的自燃性。结果表明,在有氧条件下,H2S对铁锈腐蚀产物主要是FeS;随着初始O2体积分数的增加,铁锈与H2S的反应伴随其产物的氧化反应,HS对铁锈腐蚀产物的量减小,这种产物再氧化自燃性降低。