稀土元素在光催化剂中的应用及作用机理

稀土元素具有丰富的能级,特殊的4f电子跃迁特性和光学性质,不仅能够以离子掺杂或半导体复合的形式有效提升传统TiO2光催化剂的性能,而且可以构造出多种新型的光催化剂体系.本文在归纳近年来相关文献的基础上,综述了稀土元素在光催化剂中的应用概况及研究进展,从稀土改性TiO2基光催化剂和含稀土非TiO2基新型光催化剂两方面,探讨了稀土元素在光催化剂体系中所起的作用及其机理,并对含稀土光催化剂的设计思想、研究重点、目前效果及不足之处进行了总结和评述.     

碘硫循环中硫酸相与氢碘酸相的纯化过程

Iodine-sulfur(IS) thermochemical water-splitting cycle is the most promising massive hydrogen production process.To avoid the undesirable side reactions between hydriodic acid(HI) and sulfuric acid(H₂SO₄),it is necessary to purify the two phases formed by the Bunsen reaction.The purification process could be achieved by reverse reaction of the Bunsen reaction.In this study,the purification of the H₂SO₄ and HI Phases was studied.The purification proceeded in both batches and the continuous mode,the influences of operational parameters,including the reaction temperature,the flow rate of nitrogen gas,and the composition of the raw material solutions,on the purification effect,were investigated.Results showed that the purification of the H₂SO₄ phase was dominantly affected by the reaction temperature,and iodine ion in the sulfuric acid phase could be removed completely when the temperature was above 130℃;although,the purification effect of the HI phase improved with increasing of both the flow rate of nitrogen gas and temperature.     

碘硫循环中硫酸在铁酸铜上的催化分解

碘硫循环是目前提出的效率最高、最有希望实现工业应用的热化学分解水制氢流程。碘硫循环由Bunsen反应、氢碘酸分解反应和硫酸分解反应组成。其中,硫酸分解是碘硫循环及其他含硫热化学循环中的共同步骤,需要在高温及催化剂存在下进行。本文以铁酸铜作为硫酸分解的催化剂,考察了反应温度、硫酸进料速率以及催化剂用量等因素对硫酸分解转化效率的影响,并与Pt催化剂的效果进行了比较。在铁酸铜催化的条件下,转化率比没有催化剂时平均提高了22%。温度超过820 ℃,催化效果与负载质量分数1%的Pt/Al₂O₃相当;催化剂活性在9 h内未出现下降趋势。用X射线衍射、比表面积全分析吸附、透射电镜以及热重－差热等方法对使用前后的铁酸铜进行了表征,给出了物相参数、表面性能参数及热稳定性等数据。     

堆肥条件下多价态金属有机化合物对聚乙烯促降解规律的研究

造反爽价金属的有机化合物为降解剂,研究了基人民环境中对ＰＥ的促降解规律。通过对试样的力学性能、相对分子质量和氢过氧化物浓度进行了跟踪测试,对部分试样进行的ＦＴ－ＩＲ分析和ＴＧＡ、ＤＳＣ热分析,表征了体系的降解。实验结果表明,多价金属有机化合物降解剂在堆肥温度下对ＰＥ有明显的促降解作用,ＰＥ具体的降解程度速度又与降解剂中心离种类、含量以及配位体等因素有关。所测「ＰＯＯＨ」结果与相对分子质量变化趋势基     

高放废液除锶技术的研究进展

高放废液的处理处置是影响核能可持续发展的重要因素。从高放废液中分离出⁹⁰Sr不仅能实现高放废液的安全处置,也具有较高的经济意义。本文在早期研究的基础上,结合近些年的研究情况,从沉淀法、离子交换法、溶剂萃取法、色层分离法和膜分离法5个方面介绍了从高放废液中分离⁹⁰Sr的方法,并进行了讨论。最后指出目前研究工作中存在的不足,并对其前景进行了展望。     

单分散球形镍粉的制备与表征

采用液相化学还原法,以硫酸镍为原料、水合肼为还原剂、氢氧化钠为pH值调节剂制备了超细镍粉,并利用粉末X射线衍射、扫描电镜、热重和X射线光电子能谱对其进行了表征. 实验结果表明,所制粉末为面心立方(fcc)晶型、颗粒粒径范围约100~400 nm、纯度高、分散性好的球状镍粉,并获得优化工艺条件：[Ni2+]=0.35 mol/L, [NaOH]/[Ni2+]=2.5, [N2H4]/[Ni2+]=4.0,反应温度80℃. 镍离子初始浓度决定产品二次颗粒大小,反应温度决定体系的反应速率,氢氧化钠和水合肼用量直接影响所得镍粉的还原率.     

水合肼-甲醛复合还原法和葡萄糖预还原法制备超细铜粉的研究

分别采用水合肼-甲醛复合还原剂法以及葡萄糖预还原法制得了微米级的超细铜粉,并利用粉末X射线衍射以及扫描电镜对其进行了表征.结果表明采用水合肼-甲醛复合还原剂法可得纯净的铜粉,它是由平均粒径为1 μm的Cu单晶构成,具有较好的分散性及稳定性.采用葡萄糖预还原可进一步增大产物中Cu一次粒子的尺寸,并改善颗粒的均匀性和分散性.     

AsPen辅助下的碘硫循环制氢工艺物料衡算

选择Aspen10.1软件进行碘硫循环整体流程的模拟计算.结合碘硫循环的基本原理,对制氢台架的闭合运行进行深入讨论,并分析流程模拟的关键点,在参考实验数据的基础上,完成了10L/h制氢台架的物料衡算和工艺优化.     

Recovery of valuable metals from anode material of hydrogen-nickel battery

Simultaneous recovery of rare earth, nickel and cobalt resources from the anode material of hydrogen-nickel battery was performed through a hydrometallurgical process. Most of rare earth elements are separated from nickel and cobalt in the form of sulfates when the anode material is firstly leached with sulfuric acid. Then, the precipitated rare earth sulfates are dissolved with sodium hydroxide to form rare earth hydroxides. The rare earth element, zinc and manganese ions in the lixivium are also separated from nickel and cobalt by using PC-88A extractant system, and the organic phase loaded rare earth is stripped with hydrochloric acid. By neutralizing the stripping solution with rare earth hydroxide, the rare earth chloride is obtained. Under the suitable leaching conditions of sulfuric acid 3 mol/L, leaching time 4 h and temperature 95 ℃, 94.5% of rare earth in the anode material is transformed into the sulfate precipitates, and the leaching ratios of nickel and cobalt can approach 99.5%. When the pH value of the extractive system is controlled in the range of 3.0-3.5, the rare earth elements in the lixivium can be extracted completely into the organic phase, and the stripping recovery of the rare earth can reach 98% in the extraction stage. The total recoveries of rare earth, nickel and cobalt are 98.9%, 98.4% and 98.5%, respectively.