多孔化和活性炭的吸附性质:一项比较研究
Christian Bläker1, Tim Jähnichen2, Jan Hojak1
1Chair of Thermal Process Engineering, University of Duisburg-Essen, Duisburg 47057, Germany.
ACS omega
|October 28, 2024
概括
多孔化与活性炭相比,对极性和芳香化合物的吸附性更强. 它们的高热稳定性也使得它们对先进的吸附技术具有前景.
科学领域:
- 材料科学 材料科学 材料科学
- 吸附科学 吸附科学
- 化学工程是化学工程的重要组成部分.
背景情况:
- 多孔材料对于吸附过程至关重要,因为它们的表面积和稳定性很高.
- 化 (BN) 材料具有出色的热和化学稳定性,这表明吸附应用的潜力.
- 活性炭是广泛使用的吸附剂,但在特定应用中可能存在局限性.
研究的目的:
- 为了比较合成多孔化的吸附性能与各种碳化合物的商业活性碳.
- 研究吸附性质 (微孔表面积,极性) 对吸附行为的影响.
- 评估化的热稳定性和吸附剂-吸附剂相互作用,用于技术应用.
主要方法:
- 在多孔化和活性炭上对不同碳化合物的吸附异热测量.
- 通过微孔表面积对吸附负载的规范化,以进行性能比较.
- 热量测量实验用于研究吸附剂-吸附剂相互作用和吸附热量.
- 使用自发点火温度和氧化点进行热稳定性评估.
主要成果:
- 多孔化对极性和芳香碳化合物具有优越的吸附性,其负载比活性炭高出50%.
- 活性炭在非极性碳化合物中表现出更高的特异性负荷.
- 非极性化合物的吸附行为是由微孔表面积和极性/芳香化合物的化极性决定的.
- 化的热稳定性明显更高,氧化温度高于900°C.
结论:
- 多孔化是极性和芳香碳化合物的高效吸附剂,在这些方面表现优于活性碳.
- 吸附剂的选择取决于特定的吸附剂的极性和应用的要求.
- 多孔化的特殊热稳定性使其适用于苛刻的吸附技术.
相关概念视频
02:19Physical Properties Affecting Solubility
Solutions of Gases in Liquids
As for any solution, the solubility of a gas in a liquid is affected by the attractive intermolecular forces between solute and solvent species. Unlike solid and liquid solutes, however, there is no solute-solute intermolecular attraction to overcome when a gaseous solute dissolves in a liquid solvent since the atoms or molecules comprising a gas are far separated and experience negligible interactions. Consequently, solute-solvent interactions are the sole...
As for any solution, the solubility of a gas in a liquid is affected by the attractive intermolecular forces between solute and solvent species. Unlike solid and liquid solutes, however, there is no solute-solute intermolecular attraction to overcome when a gaseous solute dissolves in a liquid solvent since the atoms or molecules comprising a gas are far separated and experience negligible interactions. Consequently, solute-solvent interactions are the sole...
01:28Adsorption of Gases on Solids
Adsorption is a process where molecules, known as the adsorbates, accumulate on a surface, which is referred to as the adsorbent or substrate. Occurring at the solid-gas interface, this phenomenon is crucial in various scientific and industrial contexts. The reverse of adsorption is desorption.Two types of adsorptions exist: physical (physisorption) and chemical (chemisorption). Physisorption involves gas molecules held to the solid's surface by relatively weak intermolecular van der Waals...
01:29Adsorption Isotherms I
Adsorption isotherms are mathematical models that describe how molecules in a gas or liquid phase interact with surfaces. Two of the most common isotherm models are the Langmuir and Freundlich isotherms, which relate to Type I monolayer chemisorption. The Langmuir model is based on four key assumptions:• Adsorption cannot exceed monolayer coverage.• All surface sites are equivalent.• Molecules adsorb only at vacant sites.• There are no interactions between adsorbed molecules.Consider the...
01:25Adsorption Isotherms II
Brunauer, Emmett, and Teller (BET) introduced a theory in 1938 that modified Langmuir's assumptions to explain multilayer physical adsorption. This theory is applicable to Type II isotherms and provides a more realistic picture of adsorption processes. The BET theory assumes a uniform solid surface with localized adsorption sites, where adsorption at one site doesn't affect adsorption at neighboring sites. This theory also allows for the possibility of additional molecules being adsorbed on top...
01:22Heterogeneous Catalysis
Heterogeneous catalysis involves a catalyst in a different phase from the reactants. It is a process where the catalyst and the reactants are in distinct phases, typically solid and gas or liquid.Most heterogeneous catalysts are metals, metal oxides, or acids. The list includes transition metals like iron (Fe), cobalt (Co), nickel (Ni), palladium (Pd), platinum (Pt), chromium (Cr), manganese (Mn), tungsten (W), silver (Ag), and copper (Cu). These metals possess partially vacant d orbitals that...
01:20Porosity and Absorption of Aggregate
Aggregates contain pores of varying sizes; while some are completely enclosed within the particles, others open onto the surface, allowing water to penetrate. The porosity of aggregates is a major factor contributing to the overall porosity of concrete, given that aggregates constitute about three-quarters of concrete's volume.
When all pores in an aggregate are filled with water, the aggregate is considered saturated and surface-dry. If left in dry air, water will evaporate until the aggregate...
When all pores in an aggregate are filled with water, the aggregate is considered saturated and surface-dry. If left in dry air, water will evaporate until the aggregate...