Agenda:
-STFI Textile Essential
-Introduction to iGC
-Surface Energy and Heterogeneity -Sized and Unsized Fibres
-Effect of relative humidity
-Analysis of biomedical polymers
-Analysis of Cellulose fibres of different types
-Prediction of nanofiller-polyurethane composite interactions
-Q&A Discussion
Abstract:
Crystalline solids with controllable structures possess tailored porosity and large surface areas. This is particularly attractive for gas storage and separation applications. Physisorption of gases is a technique applied for the characterization of porous solids, such as zeolites and metal-organic frameworks (MOFs). Gravimetric vapor sorption and gas adsorption techniques measure promising functionalities such as removal of carbon dioxide (CO2) from the atmosphere or stability of sorbents in humid environments. Currently, both techniques are routinely applied for the characterization of porous solids to explore adsorption capacities and porosity. However, only a few studies focus on the pre-experimental conditions for the determination of gas/vapor sorption isotherms. Details of outgassing conditions, despite their importance, are often lacking in research publications. Outgassing at low temperatures of thermally stable material provides an incomplete cleaning of the porous surface. As a result, the ability of sorbents to store CO2 or water molecules is underestimated based on adsorption data. Contrary, outgassing of temperature-sensitive sorbent at elevated temperatures can cause irreversible structural changes which will have profound effects on the adsorption capacities. The impact of water adsorption on the structure was isolated by introducing partial pressures of water under a vacuum. Such measurements provided a true water adsorption isotherm without unnecessary interference from a carrier gas. CO2 adsorption data were measured from low pressures up to 1bar. CO2 adsorption in the presence of water on the sorbent was collected in a system under a vacuum. The results show that the performance of the sorbent can be significantly modified depending on outgassing conditions.
Oil pollution, from anthropogenic exploration activities, constitutes a serious risk to water resources globally. Different conventional sorbents have been used to remove oily contaminants from affected water bodies with varying degrees of success. In recent years, natural sorbents such as kapok fibres, rice husks, and chicken feathers have been explored as a substitute for conventional sorbents because they are cheaper, abundantly available and provide a means to develop a circular economy. The oil sorption capacity of these fibres is determined by their surface chemistry and microstructure–surface properties.
In this study, Inverse Gas Chromatography (IGC-SEA) was utilized to evaluate the surface properties of chicken feather mat – a natural sorbent and polypropylene pad – a synthetic organic sorbent. The BET, dispersive/specific (acid-base) surface energies, specific free energies of adsorption, and thermodynamic work of cohesion and adhesion for chicken feather mat and polypropylene pad were measured. The surface profiles demonstrated that both sorbents were energetically heterogeneous. However, the chicken feather mat surface energy profiles showed comparable values to the conventional polypropylene pad, widely used as an oil sorbent.
The vapor pressure of material is an important physical property that defines the amount of vapor molecules generated at its surfaces. Materials have tendency to enter the vapor phase by sublimation (solid-gas) or evaporation (liquid–gas). The vapor pressure of material at the thermodynamic equilibrium is only a function of temperature.
The knowledge of vapor pressure is highly desirable for liquids, oils, pesticides, fertilizers, and various substances in order to avoid the atmospheric accumulation of toxic compounds with low vapor pressure. The US Environmental Protection Agency (EPA) and the European Chemicals Agency (ECH) mandate the registration of vapor pressure of certain materials, because of the impact on the environment.
Furthermore, the vapor pressure can play a vital role in manufacturing, for example, organic solar films, where the progressive reduction of additives like plasticizers and UV absorbers as a result of evaporation from the surface can cause an unwanted decrease in their efficiency.
In this webinar, Knudsen Effusion Method and Static Method for determining the vapor pressure of materials will be discussed.
Wavy nickel nanowires (NiNWs) were immobilized on mesoporous silica (SiO2) aerogels by the sol−gel method. The catalytic activity of pure NiNWs and NiNW−SiO2 aerogel composites toward the CO2 hydration reaction (CHR) when they are in water was measured. Dynamic Vapor Sorption (DVS Vacuum) analysis was performed at levels of 50% CO2 and 50% H2O vapor for SiO2 aerogels, immobilized nickel nanoparticles (NiNPs) on silica aerogel and NiNW−SiO2 aerogel composites, in order to determine catalytic activity for CHR in the gaseous phase. The results from DVS Vacuum analysis (gaseous phase) and CHR (aqueous phase) showed that NiNW−SiO2 aerogel composites are good heterogeneous catalysts for CHR in both gaseous and aqueous phases but they are less active than NiNP−SiO2 aerogel composites.
Moisture and organic solvent sorption have a large impact on the mechanical, physical, and chemical properties of many materials.
This webinar will highlight a series of water and organic solvent sorption characterization methods for determining the hydrate and solvate formation of different materials. During this presentation, we are going to highlight a series of examples of hydrates and solvation formation and stability. Moreover, we are going to present a case study of solvate formation performed with DVS and in situ Raman spectroscopy.
Using a novel dynamic flow configuration, this gravimetric experimental system can measure both competitive multicomponent adsorption as well as water sorption and glass transition processes. This characterization technique can not only be used across a wide range of materials at different temperatures but is well suited for adsorption studies using organic vapors at high partial pressures.
Characterizing construction and building materials? Watch this free online workshop to discover how you can maximize the accuracy and detail of your research using Vapor Sorption Techniques.
Organized in partnership with the University of Applied Sciences in Wismar, this session is a vital resource for any working in the following fields of research:
-Wood
-Cement
-Building Materials
In the real world, capture/adsorption of CO2 is often a competition with other gas-phase species, most commonly water vapor. In some cases, the concentration of H2O vapor is much higher than that of CO2 further complicating the adsorption process.
This presentation, delivered by one of the world’s leading authorities in sorption science, Dr. Daryl Williams, will compare the use of two of the most commonly used experimental approaches for studying CO2 sorption in the presence of H2O vapor; gravimetric analysis using Dynamic Vapour Sorption (DVS) and breakthrough analyzer studies. To give the audience maximum insight, experimental details and case study comparisons of adsorbent performance will also be presented.
Organized in partnership with University of Namur.
Abstract:
Hydrogen sulphide (H2S) is a harmful chemical present in natural gas, biogas and emitted by different chemical industries, e.g., oil desulfurization process at oil refineries. H2S is considered as a major air pollutant due to its negative environmental impact, mainly associated with acid rain, and to high toxicity to humans leading to severe nervous system illnesses.
On the other hand, sulphur dioxide (SO2) considered as one of the most hazardous chemicals is a colourless, non-flammable gas with a strong odour. SO2 provokes severe health issues including alterations of the respiratory system (e.g., broncho-constriction in lung function). Typically, an exposure to only 1.5 ppm of SO2 for a few minutes can cause a temporary incapability to breath normally. Moreover, this chemical is highly soluble in water and forms sulphurous acid further converted to sulfuric acid, the main component of acid rain which can damage plants, accelerate the corrosion of metals and attack limestone, marble, mortar, etc. The harmful impact of this pollutant present in the atmosphere is also catastrophic in terms of global warming, ozone depletion and climate change.
Metal-Organic Frameworks (MOF) have been envisaged for the capture of H2S and SO2 however, some of them, with the main disadvantage of showing poor chemical stability. Thus, in this talk we present two MOF materials highly chemically-stable to H2S and SO2: MIL-53(Al)-TDC7 and MFM-300(Sc), respectively.
MIL-53(Al)-TDC is demonstrated to exhibit one of the highest H2S capture (18.5 mmol g-1 at 298 K and 1 bar) ever reported for a MOF, to the best of our knowledge, along with the retention of its crystalline structure after multiple H2S adsorption/desorption cycles and an excellent regeneration at relatively low temperature. MFM-300(Sc) is demonstrated to exhibit a SO2 uptake of 9.4 mmol g-1 at 298 K and 1 bar significantly higher compared to its Al- and In-analogues, along with the retention of this level of performance after multiple SO2 adsorption/desorption cycles owing to the high stability of its crystalline structure. Advanced experimental and computational tools have been further coupled to gain insight into the molecular mechanisms responsible for the adsorption of H2S and SO2.