Linking experimental H2O vapor adsorption on biomass char with physicochemical char properties and MD simulation

IF 2.8 3区工程技术 Q3 CHEMISTRY, PHYSICAL

Fluid Phase Equilibria Pub Date : 2025-05-13 DOI:10.1016/j.fluid.2025.114460

Tim Eisenbach , Babak Farhadi Jahromi , Vanessa Angenent , Christin Pflieger , Martin Muhler , Rochus Schmid , Carsten Wedler , Roland Span

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引用次数: 0

Abstract

The adsorption of H₂O vapor on biomass char particles is gravimetrically measured in a temperature range of 298.15 K to 323.15 K. The results are correlated to results of a comprehensive structural and chemical char analysis using N₂ and CO₂ physisorption measurements with corresponding 2D-NLDFT models and temperature-programmed desorption measurements (TPD) for the detection of oxygen-containing functional groups (OFG). The adsorption isotherms of a highly porous and unfunctionalized model char show a distinct type V shape for hydrophobic, microporous materials, which is in accordance with its structural and chemical properties. In contrast, results for a highly functionalized model char show type II isotherm characteristics with high adsorption capacity at low H₂O concentrations. The adsorption behavior of a beechwood char with a conversion history aligns more closely with that of the unfunctionalized model char, exhibiting differences that correlate with its less pronounced pore structure and higher proportion of OFG. Molecular dynamics (MD) simulations of ideal slit pores were conducted to confirm distinct effects and tendencies found in the H₂O adsorption measurements with respect to outstanding char properties. The simulations confirm a strong binding tendency of H₂O molecules to OFG, especially for comparably low H₂O densities as well as a contribution of the confinement effect in small pores to the overall adsorption capacity.

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生物质炭上实验水蒸汽吸附与炭理化性质的联系及MD模拟

在298.15 ~ 323.15 K的温度范围内，用重量法测定了生物质炭颗粒对水蒸汽的吸附。该结果与利用N2和CO2物理吸附测量（相应的2D-NLDFT模型）和温度编程解吸测量（TPD）检测含氧官能团（OFG）的综合结构和化学碳分析结果相关。高孔非功能化模型炭对疏水微孔材料的吸附等温线表现出明显的V型，这与其结构和化学性质相一致。相比之下，高功能化模型炭在低水浓度下具有高吸附容量的II型等温线特征。具有转化历史的山毛榉炭的吸附行为与未功能化模型炭的吸附行为更为接近，其差异与其不太明显的孔隙结构和较高的OFG比例有关。对理想狭缝孔进行了分子动力学（MD）模拟，以证实在水吸附测量中发现的明显的影响和趋势。模拟结果证实了H2O分子对OFG的强结合倾向，特别是在相对较低的H2O密度下，以及小孔隙中的约束效应对总体吸附能力的贡献。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Fluid Phase Equilibria 工程技术-工程：化工

CiteScore

5.30

自引率

15.40%

发文量

223

审稿时长

53 days

期刊介绍： Fluid Phase Equilibria publishes high-quality papers dealing with experimental, theoretical, and applied research related to equilibrium and transport properties of fluids, solids, and interfaces. Subjects of interest include physical/phase and chemical equilibria; equilibrium and nonequilibrium thermophysical properties; fundamental thermodynamic relations; and stability. The systems central to the journal include pure substances and mixtures of organic and inorganic materials, including polymers, biochemicals, and surfactants with sufficient characterization of composition and purity for the results to be reproduced. Alloys are of interest only when thermodynamic studies are included, purely material studies will not be considered. In all cases, authors are expected to provide physical or chemical interpretations of the results. Experimental research can include measurements under all conditions of temperature, pressure, and composition, including critical and supercritical. Measurements are to be associated with systems and conditions of fundamental or applied interest, and may not be only a collection of routine data, such as physical property or solubility measurements at limited pressures and temperatures close to ambient, or surfactant studies focussed strictly on micellisation or micelle structure. Papers reporting common data must be accompanied by new physical insights and/or contemporary or new theory or techniques.