LaNi5氚老化效应的实验研究

测定了老化LaNi5料的解吸等温线及去氘化热力学参数.评价了氚老化对LaNi5贮氢性能的影响.结果表明,氚老化使LaNi5解吸等温线形貌发生重大改变.与新鲜材料相比,老化2140天后,在373 K下,坪台压力降低了约50%,坪斜由0.033到0.130,可逆吸氢容量减少了约1.3 mmol.g-1.老化LaNi5料去氘化反应热力学焓变ΔH和熵变ΔS分别由30.1 kJ.mol-1和105 J.mol-1.K-1增加到44.5 kJ.mol-1和128 J.mol-1.K-1.     

临界点附近H2气体的焓和熵的热力学计算

采用热力学方法和Benedict-Webb-Rubin(BWR)方程及相应的参数,计 算了临界温度附近H2气体的绝对焓和熵值,同时拟合了一组高准确度的定压比热容与温度 关联式参数.通过计算值与实验值的比较发现:在临界温度以上,计算值与实验值符合良好 ,对低于临界温度的未饱和H2气体也能计算出较好了结果.但对临界点和温度低于临界温 度、压强高于临界压强的过饱和H2气体的计算误差比较大,说明此时的H2气体的热力学性质特别,应当专门处理.     

Atomic Structural Origin of Fictive Temperature Revealed by AZnP3O9 (A=K,Rb) Glasses

The fictive temperature (T_f) is widely applied to understand the relaxation thermodynamics of a glass; however, its atomic structural origin is still unclear. Here, we report two novel AZnP₃O₉ glasses obtained by melting the composition identical single crystals. These glasses exhibit structural inheritance within 5 Å from the single crystal counterparts that is quantified by δ=n_glass/n_cry (0≤δ≤1, n is the number of pair correlation functions). Among the available glass-formers, ^glassKZnP₃O₉ exhibits the highest structural inheritance (δ=1, n_glass=8). More insightfully, a reverse correlation between δ and the relaxation thermodynamic parameters is observed in ^glassAZnP₃O₉, revealing for the first time the atomic structural origin of fictive temperature.     

Xanthan or esterified xanthan/cobalt ferrite-lignin hybrid materials for methyl blue and basic fuchsine dyes removal: equilibrium,kinetic and thermodynamic studies

In this study, new adsorbents based on xanthan (XG) or esterified xanthan (XGAC) and ferrite-lignin hybrids were obtained and characterized by using the dynamic vapor sorption (DVS) method, infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The porosity, swelling ratio and point of zero charge (PZC) of the adsorbents were also evaluated. Batch adsorption experiments have been performed to determine the adsorption capacity of the adsorbents for Methyl Blue (MB) and Basic Fuchsine (BF). Ferrite-Lignoboost® lignin and ferrite-organosolv lignin hybrid materials (CFLB and CFLO) presented the highest adsorption capacity for MB dye (44.73 and 37.54 mg/g), while the adsorbents based on xanthan and ferrite-lignin hybrids (XG/CFLO and XG/CFLB) retained the highest quantities of BF dye (36.23 and 33.33 mg/g). The chemical nature of the adsorption process was determined, the analyzed data being better fitted to the pseudo second order (PSO) kinetic model. The data analysis showed that the adsorption process followed Langmuir, Dubinin-Radushkevich and Jovanovi? isotherm models. All the studied adsorption processes were endothermic (ΔH^o > 0) and the positive values of the entropy (ΔS^o > 0) indicated disorder at the interface between the adsorbent and the dye solutions.