碳纸负载铅电极的制备及其催化顺丁烯二酸电还原合成丁二酸

通过一步电沉积法制备CP@Pb电极,并将其用于催化顺丁烯二酸（C₄H₄O₄）电还原反应合成丁二酸（C₄H₆O₄）。利用SEM、TEM、XRD等手段对CP@Pb电极表面结构、物相组成等进行表征,通过CV及CP等方法研究CP@Pb电极在酸性环境中对C₄H₄O₄的电还原催化行为。结果表明,CP@Pb电极对C₄H₄O₄电还原具有良好的催化性能;反应温度为318.15 K时,在0.25 mol/L H₂SO₄+0.30 mol/L C₄H₄O₄中还原电流密度达到191.3 mA/cm²（-1 V）;当还原电流密度为120 mA/cm²时,合成丁二酸的纯度为96%。     

超重力场中共存物质对O3/H2O2工艺降解硝基苯的影响

以硝基苯为模拟污染物,研究了常见无机钠盐和有机物在超重力场中对O3/H2O2工艺降解硝基苯的影响,同时考察了超重力技术强化O3/H2O2工艺降解硝基苯的作用机理。结果表明超重力技术通过强化臭氧传质速率提高臭氧溶解量进而提高硝基苯的去除率。超重力场中共存物对硝基苯的降解动力学产生不同的影响,其中碳酸钠、氢氧化钠、磷酸钠、硫酸钠和硝酸钠对硝基苯的去除具有促进作用,主要作用原理是添加物可升高溶液pH值进而促进臭氧分解产生羟基自由基(·OH)提高了氧化效率;氯化钠、碳酸氢钠、硫酸氢钠、乙醇、乙酸、甲酸和叔丁醇对硝基苯的去除具有抑制作用,其中添加硫酸氢钠、乙酸和甲酸使溶液pH值降低阻碍了自由基链反应的进行,而氯化钠、碳酸氢钠、乙醇和叔丁醇可消耗·OH,从而对硝基苯去除产生抑制作用。     

Comparison of mass transfer characteristics between countercurrent-flow and crosscurrent-flow rotating packed bed

Rotating packed bed (RPB), mainly including countercurrent-flow RPB (Counter-RPB) and crosscurrent-flow RPB (Cross-RPB) classified from the perspective of gas-liquid contact style, is a novel process intensification device. A significant measure standard to evaluate performance of RPB is mass transfer effect. In order to contrast the mass transfer characteristics of Counter-RPB and Cross-RPB that with the same size, liquid volumetric mass transfer coefficient (klae) and effective interfacial area (ae) were measured under identical operation conditions. Meanwhile, comparison of comprehensive mass transfer performance was conducted with ΔP (pressure drop)/klae as the standard. Experimental results indicated that klae and ae increased with increase of liquid spray density q, gas velocity u and high gravity factor β. Furthermore, compared with Cross-RPB, Counter-RPB has higher liquid volumetric mass transfer coefficient and slightly larger effective interfacial area. The experimental results of comprehensive mass transfer performance showed that the Counter-RPB had higher ΔP/klae than the Cross-RPB with changes of liquid spray density and high gravity factor, and there exists a turning point at 0.71 m/s accompanied by a variation with gas velocity. Moreover, the relative error of experimental values to calculated values calculated by the correlative expressions of klae was less than 5%. In conclusion, the mass transfer characteristics of RPB are deeply impacted by the manner in which the flows are established and Cross-RPB would have a great potential for industrial scale-up applications.     

直接甲醇燃料电池阳极催化剂研究进展

直接甲醇燃料电池（direct methanol fuel cells, DMFC）由于其高效、清洁等优点,成为替代化石能源的理想新能源装置。催化剂作为DMFC中重要的组成部分,通过降低反应活化能,解决甲醇需要高过电势才能被电氧化的问题。但是目前DMFC阳极催化剂存在催化活性低、抗CO毒性差以及成本较高等问题,限制了DMFC的商业化。本文介绍了甲醇的催化电氧化原理,从Pt基催化剂、非Pt基催化剂、催化剂载体三个方面对DMFC阳极催化剂国内外研究进展进行了综述。介绍了通过选择合适晶面、添加助催化剂、制备特殊形貌、选择合适的载体4种方法对提高催化剂性能、降低催化剂成本的研究现状。甲醇在Pt（100）晶面上的催化活性较好但是抗CO毒性较弱;根据双功能理论和电子调变理论,制备的Pt-M合金催化剂具有更高的抗CO毒性和甲醇催化活性;非Pt基催化剂的制备为降低催化剂成本提供了研究思路;选择合适的催化剂载体,利用载体与催化剂之间的相互作用,也成为解决DMFC阳极催化剂目前面临的易中毒、活性低、成本高等问题的解决方法。     

Ti/IrO_2-Ta_2O_5阳极催化降解鲁奇炉煤气化废水工艺的优化及动力学研究

针对鲁奇炉煤气化废水中酚类污染物难降解而无法满足生化处理的难题,采用热化学法制备钛铱钽催化电极(Ti/IrO_2-Ta_2O_5),并将其作为阳极对鲁奇炉煤气化废水进行电催化降解。结果表明,当电流密度为50 m A/cm~2、NaCl质量浓度为9.5 g/L、pH为4、降解时间为180 min时,苯酚和COD的去除率较高,分别可达92%和48%。废水色度极大降低,BOD/COD提高至0.42,降解后的废水可满足生化处理要求。动力学研究表明,废水降解过程符合表观一级反应的动力学规律。