偶氮荧光桃红-溴酸钾体系阻抑动力学光度法测定金矿石中的痕量金

在磷酸介质中, 金能阻抑溴酸钾氧化偶氮荧光桃红的褪色反应, 据此建立了一种测定痕量金的新方法。探讨了该阻抑褪色反应的最佳反应条件并测定了动力学参数。结果表明, 金的质量浓度在2.00~20.0 μg/L范围与阻抑反应和非阻抑反应的吸光度差(ΔA)有良好的线性关系, 线性相关系数为0.997 8, 方法的检出限为5.74×10^-7 g/L。测得反应速率常数为1.60×10^-3/s, 表观活化能为202.91 kJ/mol。方法用于金矿石标准物质中金的测定, 测定值与认定值一致, 相对标准偏差(RSD, n=6)小于2.5%, 加标回收率为98%~106%。     

分光光度法测定铁的研究进展

综述了近年来(2000～2012年)分光光度法测定痕量铁的研究进展。内容包括:直接显(褪)色光度法、催化动力学光度法、阻抑动力学光度法、荧光光度法、化学发光分析法以及相关联用技术。对不同分析方法的反应介质、检出限、线性范围、实际应用对象等方面进行了归纳和概述, 并对分光光度法测定铁的发展提出了提高仪器性能, 以增强灵敏度和减少测量误差;开发灵敏度高、选择性强、稳定性好、绿色环保的显色剂, 以改善检测方法;加强与高效分离、富集检测技术的联用, 以降低测定干扰, 提高方法准确度等建议。     

镁铝水滑石焙烧产物对甲基橙溶液的吸附性能

本文研究了Mg-Al-LDHs焙烧产物(LDO)对甲基橙的吸附性能并讨论了焙烧温度和吸附温度对反应的影响.结合XRD表征结果得到450℃焙烧产物在吸附甲基橙溶液后,恢复为LDHs层状结构;其对甲基橙溶液的吸附主要是层间吸附,即甲基橙可进入Mg-Al水滑石层间;此外,还对吸附动力学进行了讨论,结果表明:LDO对甲基橙的吸附符合准二级动力学模型.     

Selective removal of phenol by spherical particles of α-, β- and BoldItalic-cyclodextrin polymers: kinetics and isothermal equilibrium

Spherical particles of α-, β- and γ-cyclodextrin (CD) polymers to efficiently remove phenol from waste water were prepared by reverse suspension polymerization with epichlorohydrin as crosslinker in liquid paraffin. By controlling the amounts of crosslinker and water, well-defined spherical polymer particles with controllable size were obtained. Due to the selective inclusion associations between CD groups and phenol, these CD spherical polymer particles were demonstrated to be ideal candidates for removal of phenol. Among them β-CD polymer particles showed the best performance. The kinetics and isothermal equilibrium models were used to fit the experimental data of phenol removal from aqueous solution using these CD polymer particles. It was found that the kinetics followed the Ho and Mckay equation, suggesting that the adsorption process of phenol was controlled by diffusion and the host-guest interaction between CD and phenol. Equilibrium isothermal data can be well fitted by the Freundlich equation. The negative free energy change indicated the spontaneous nature of adsorption of phenol by α-, β- and γ-CD spherical polymer particles, while the lowest free energy for β-CD polymer reflected its best adsorption ability, compared to α- and γ-CD polymer particles.     

聚合物粉体动摩擦因数的影响实验研究

设计了一套自动化实验数据采集程序,实现了对于压力、扭矩和温度的多参数、在线数据采集,并基于LabVIEW数学函数功能计算出粉体物料动摩擦因数。研究了在不同压力、温度、转速和材料种类时,其动摩擦因数的变化情况,并分析不同压力、温度、转速和材料种类等因素对动摩擦因数的影响。结果表明,动摩擦因数随着压力的增大而降低,且压力、温度和转速这些因素是相互影响的;不同粉体材料的性质对动摩擦因数有着很大影响,其中聚四氟乙烯粉体动摩擦因数最低,并且橡胶粉体动摩擦因数随着颗粒的增大而增大;动摩擦因数测试结果证明所设计的测试系统是切实可行的,而且数值的准确度和精度都比较高。     

软性磨粒流精密加工工艺参数优化方法

针对固-液两相软性磨粒流加工中随着磨粒流温度的升高而导致流体黏度下降,进而导致湍动能和动压力分布不均匀的问题,提出一种新型的加工方法,即通过改变流速来补偿温度变化对湍动能和动压力的影响。基于对加工机理的研究,认为湍动能和动压力分别影响加工表面的加工纹理和材料去除率,确定了一种评价湍流形态的标准。对同一速度下不同温度时的湍动能和动压力的大小分布进行对比,研究了温度对湍动能和动压力大小和分布的影响;对同一温度下不同速度时的湍动能和动压力的大小分布进行对比,研究了速度对湍动能和动压力大小和分布的影响。通过大量仿真求得了9个不同温度下的最优温度,并作出了温度-速度曲线,为以后的湍流调控和自动控制系统的设计提供参考。实验结果表明,调速后工件表面的加工均匀度有明显的提升。     

银纳米粒子-锌(Ⅱ)协同双催化动力学荧光法测定电镀工业废水中痕量锌

在含有十六烷基三甲基溴化胺(CTMAB)的磷酸盐(PBS)缓冲溶液中,Zn²⁺对高碘酸钠氧化荧光桃红的反应具有显著的催化效应,催化的结果是导致其荧光强度显著减弱。据此建立了基于Zn²⁺和银纳米粒子协同双催化效应动力学荧光法测定痕量Zn²⁺的新方法。实验结果表明pH 7.8的磷酸盐缓冲溶液中,当荧光桃红、NaIO₄、银纳米粒子、CTMAB溶液浓度分别为2.0×10^-6 mol/L,5.0×10^-3 g/L,5.0×10^-6 mol/L ,1.5×10^-3 g/L时,Zn²⁺的浓度在5×10^-8 ~ 100×10^-8 g/L范围内与体系的荧光强度改变值呈良好的线性关系,检出限为1.88×10^-8 g/L。应用于电镀工业废水中Zn²⁺的检测,测定值与双硫腙光度法基本一致,相对标准偏差(RSD,n=6)≤2.5%。     

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Experiments of combustion and granularity analysis as well as infrared spectroscopy were carried out on the investigation of raw and microwave irradiated pulverized coal (PC). It is indicated in the results that combustion properties of PC under different heating rates are ameliorated after irradiation. Meanwhile, a small decrease in granularity of PC is noticed after microwave treatment, which can prove to be invalid in optimizing the combustion performance of PC in the combustion of devolatilized PC. Simultaneously, radicals of high activity in PC are found to be increased, namely the superior combustion of irradiated PC is due to the activation of volatiles by microwave. Flynn-Wall-Ozawa (FWO) model is adopted to investigate the kinetics of PC combustion, it is indicated that the activation energy of irradiated PC is lower than that of raw PC under the conversion rate of 50%. After microwave treatment, the activation energy of Yungang and Yangquan PC is reduced by 20. 37 and 26. 91J??mol-1 respectively at the conversion rate of 20%. However, the difference in activation energy between raw and irradiated PC is reduced with the increasing of conversion rate. The activation energy of Yungang and Yangquan irradiated PC respectively returns to the level of raw PC at conversion rate of 50% and 60%. When conversion rate of two PC exceeds this level, the activation energy of irradiated PC becomes slightly higher than that of raw PC while the extent was not that significant.     

铁基复合载氧体煤化学链气化反应特性及机理

以水蒸气作为气化/流化介质,在流化床中研究了两种铁基复合载氧体的化学链气化反应特性及循环特性,并对气化过程中的反应机理、动力学方程进行了推断。结果表明:温度为920℃时,添加不同修饰物的铁基复合载氧体与煤焦气化的反应活性依次为Fe4Al6K1>Fe4Al6>Fe4Al6Ni1。在多次循环实验过程中,合成气成分保持稳定,表明Fe4Al6K1复合载氧体循环特性良好。XRD谱图分析表明,六次氧化还原实验后的铁基载氧体氧化态仍为Fe₂O₃。K⁺主要以铁酸钾形态存在,该结构有利于促进化学链气化反应。利用高斯函数对气化反应速率进行了峰拟合,拟合结果表明化学链气化主要分为3个阶段:化学链作用阶段、煤气化阶段以及Fe₃O₄向FeO转变的气化阶段。     

CaO-Ca9Al6O18吸收剂的碳酸化反应动力学

以柠檬酸钙和硝酸铝为前体,采用湿法混合法制备了CaO质量分数为80%的CaO-Ca₉Al₆O₁₈吸收剂,并对其CO₂吸收性能进行了研究。结果表明,CaO-Ca₉Al₆O₁₈具有优异的CO₂吸收容量和长周期循环使用稳定性,经过50次循环使用后,其转化率仍保持在78%以上,远优于传统的CaO吸收剂。在500～700℃和CO₂分压为0.005～0.015 MPa条件下,研究了CaO-Ca₉Al₆O₁₈吸收剂的碳酸化反应动力学,分别采用离子反应模型和表观模型描述化学反应动力学控制阶段(快反应段)和产物层扩散阶段(慢反应段)。实验测得的吸收剂转化率与模型预测值吻合较好,快慢反应段的活化能分别为25.6、57.7 kJ·mol^-1。该动力学模型可准确模拟CaO-Ca₉Al₆O₁₈吸收剂在长周期循环使用条件下的碳酸化反应。