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A systematic measurement of H2 adsorption on activated carbon over a wide scope of conditions was completed for the first time using a novel cryostat developed by the present authors. The equilibrium temperatures covered 77-298 K with the space of about 20 K, and the equilibrium pressures increased from 0 to about 7MPa. A set of adsorption/desorption isotherms was obtained by a standard volumetric method. This set of experimental data was fitted to all the well-known models of type-I isotherms, and Dubinin-Astakhov (D-A) equation was found to be the best-fit one On the basis of D-A model one can predict adsorption with relative error of ±4%. A 3-dimensional adsorption surface was also constructed, and the isosteric heat of adsorption was analytically determined. Except in the low pressure area, the calculated values agreed well with the experimental ones. Finally, the troubles encountered in applying D-A equation to supercritical adsorption is discussed. 相似文献
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关于氢在活性炭上高压吸附特性的实验研究 总被引:15,自引:1,他引:15
利用研制的大容量超级低温恒温槽,以20K为步长,首次在298K至77K,0到7MPa的大范围内系统地研究了氢在活性炭上的吸附特性。采用容积法测定了氢在AX-21活性炭上的一组吸/脱附等温线。通过将该组数据拟合到描述I-型等温线的诸理论模型,发现Dubinin-Astakhov方程在整个实验范围内与实验数据较好地吻合。由非线性回归定出的参数值,使该方程可以±4%的误差预测吸附量。根据该模型作出了三维吸附面,并解析地计算出等量吸附热。除低压部分外,计算值与实验值符合良好。最后讨论了D-A方程在超临界领域遇到的问题。 相似文献
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超临界甲烷在高表面活性炭上的吸附测量及其理论分析 总被引:22,自引:0,他引:22
实验测定了0~10
MPa,233~333 K (20 K间隔)范围内超临界甲烷在高表面活性炭上的吸/脱附等温线,确定了此物理吸附过程的可逆性,并从实验数据计算出吸附热为16.5
kJ/mol. 建立了描述具有最大点的吸附等温线模型,其总体偏差为±2%. 模型保持了特征吸附能恒定的性质,方程指数亦反映了吸附剂的微孔分布特征,模型参数给出了超临界甲烷的吸附相密度. 将超临界吸附极限态引入等温线模型中,经典的吸附理论亦可解释超临界吸附现象. 相似文献
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大气颗粒物重金属元素分析技术研究进展 总被引:3,自引:0,他引:3
大气颗粒物已经成为当前大气环境首要污染物,而其中重金属由于具有非降解性和滞后性,严重威胁人类生命和自然环境,已成为当前研究热点。对分析大气颗粒物中重金属元素所用原子吸收光谱法、电感耦合等离子体原子发射光谱法、电感耦合等离子体质谱法、荧光光谱法、中子活化法、辉光放电原子发射光谱法、微波等离子体原子发射光谱法和激光诱导击穿光谱法进行了综述,并尝试对这些技术的不足之处提出一些改进建议:连续光源原子吸收光谱法同时测定多种元素,原子发射光谱法直接测定颗粒物,高分辨率激光剥蚀电感耦合等离子质谱法测定固体样品,低散射同步加速荧光法测定大气颗粒物和k0中子活化法测定对流层发射性元素。大气颗粒物重金属元素的时空分布差异和人类对环境空气质量要求的提高以及现代仪器科学技术的高速发展促使大气颗粒物重金属元素分析技术朝着实时、快速、检出限低、直接测定和操作简便的方向发展。 相似文献
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Measurement and theoretical analysis of the adsorption of supercritical methane on superactivated carbon 总被引:3,自引:0,他引:3
Adsorption/desorption isotherms of supercritical methane on superactivated carbon have been measured in the range of 0-10 MPa and 233-333 K (20 K interval). The reversibility of the physical adsorption process is acknowledged. The heat of adsorption of 16.5 kJ/mol is determined from the isotherms, and a new modeling strategy for isotherms with maximum is presented. The model yields fits to the experimental isotherms with precision of ?%, maintaining the constancy of the characteristic energy of adsorption. The exponent of the model equation expresses the pore size distribution feature of the adsorbent. The density of the supercritical adsor-bate is evaluated as a parameter of the model. It is shown that the conventional isotherm theory works too at supercritical condition if the limit state of supercritical adsorption is introduced into isotherm modeling. 相似文献
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超临界氢在活性炭上的吸附等温线研究 总被引:17,自引:0,他引:17
通过77-298K范围内氢在AX-21活性炭上的吸附数据,探讨如何用普通I-型等温线模型处理超临界条件下的吸附等温线,以获取关于超临界吸附系统的正确信息,结果表明,Langmuir方程虽然可用来表达实验数据,但不能提供关于该吸附系统的任何可靠信息,Virial方程虽不是整组数据的最好模型,但却能够可靠地确定Henry定律常数,然后可从vantHoff标绘决定等量吸附热,通过将实验数据拟合到Dubi 相似文献
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