A dedicated sorption science agenda

Sorption Science Symposium 2021 will feature a niche, focused sorption science agenda exploring a range of topics within the spheres of DVS, iGC, and everything in between.

Register now to learn the latest insights, case studies, and applications from leading sorption science experts.

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Poster Sessions

The Poster Sessions are a great and efficient way to gain insights from fresh research and applications. You will be able to view the poster presentations from the beginning of the early access period (Friday 17th September). You will then have the opportunity to discuss them with the author in detail in the Poster Sessions, taking place on the afternoon of both days. These live sessions will take place:

Wednesday 22 September 2021: 14:45 – 15:05 CET
Thursday 23 September 2021: 14:35 – 14:55 CET

by Elizabeth Denis, Pacific Northwest National Laboratory

Elizabeth H. Denis, Anjelica Bautista, Guohui Wang, Signe K. White, Nicholas L. Huggett, Carlos G. Fraga, April J. Carman
Pacific Northwest National Laboratory, Richland, WA, USA

Abstract:
The goal of this work is to better understand the chemistry of gas-solid interactions and how volatile compounds are transported through geological materials under different temperature and humidity conditions. Inverse gas chromatography (iGC) allows us to characterize and quantify the physicochemical sorption properties of geologic materials using probe gases, such as volatile organic compounds and noble gases. Complementary to our commercial SMS iGC with a flame ionization detector, we developed an in-house iGC coupled to a mass spectrometer that enables us to evaluate compounds that are in the gas phase at room temperature and non-carbon probe gases.

Geologic materials can be very heterogeneous both physically and chemically. Characterizing the properties of individual organic and inorganic components can help elucidate the primary factors influencing volatile interactions in more complex mixtures. This presentation builds upon our publication in Langmuir (Denis et al., 2021, https://doi.org/10.1021/acs.langmuir.0c03676) and highlights recent work including zeolite characterization and noble gas adsorption and diffusion. A suite of geologic materials, including soil, clay, sand, and salt, can be differentiated based on heat of adsorption (kJ/mol) and Henry’s constant (partition coefficient, μmol/g·Pa). The interactivity of soils and clays are likely heightened by the variety of bonding sites in the complex structures compared to the simpler single mineral media (e.g., salt). For diffusion coefficient (cm2/s), material differences are less pronounced, but particle size may be more influential. Diffusion coefficient tends to decrease with smaller particle sizes. The work has demonstrated that iGC is effective in analyzing key physicochemical parameters used for modeling subsurface gas transport.

by Yang Ding, University of Namur

Abstract:

The three-dimensional ordered macroporous TiO2 were originally synthesized for photocatalytic degradation and water splitting. Through optimizing the loading amounts of Pt, it was found that the sample exhibited the highest PEC water splitting activity, which were 2.2 times higher than that of the original catalyst. A series of characterizations demonstrated that the improved activities were attributed to the slow photon effect, efficient charges pair separation and the Pt surface plasmonresonance (SPR) effect [1-2].

 

Figure1. SEM image of 3DOM structure

References

[1] Xu, J, Wang, W, Sun, S, Wang, L, Enhancing Visible-Light-Induced Photocatalytic Activity by Coupling with WideBand-Gap Semiconductor. Appl. Catal., B 2012, 111-112, 126-132.

[2] Chen, H, Nanayakkara, Titanium Dioxide Photocatalysis in Atmospheric Chemistry. Chem Rev 2012, 112, 5919- 5948.

by Jinfeng Liu, Sun Yat-Sen University

Abstract:
Sorption processes play a key role in determining the capacity of coal, shale and claystone formations as sources of natural gas and as CO2 storage reservoirs. Unlike granular solids subject to gas/fluid sorption measurements familiar in surface chemistry, geomaterials buried in the subsurface support a general tensorial stress state, in excess of the gas/fluid pressure within the pores, and cannot freely expand. Accordingly, sorption-induced swelling requires stress-strain work to be done against the applied stress. This is not considered in classical sorption theories (e.g. Langmuir-type models) and, relative to these, changes the free energy of sorption, thus leading to a change in sorption capacity of geomaterials in the subsurface. This work discusses a thermodynamic model describing monolayer sorption of a gas or fluid, at pressure P, by an anisotropic micro/nanoporous solid subjected to a general, 3Dstress state (sij) at isothermal conditions. Our model demonstrates that applied stress reduces the sorption capacity of any solid sorbent, by an amount that strongly depends on the partial molar volume of the adsorbed molecules. The model has been verified against experiments performed at 40℃ on solid coal samples exposed to CO2 and CH4 at 10 and 15 MPa pressure, and subjected to additional isotropic stresses varied in the range 1-33MPa, using a specially designed apparatus. The experiments show that the sorption capacity of the coal samples investigated was reduced by ~10% for CO2 at 25 MPa applied stress, and by ~6% for CH4 at 33 MPa applied stress. This implies that predictions of coalbed methane content or CO2 storage capacity based on classical sorption experiments and Langmuir-type isotherm fits are overestimated. More importantly, the mechanical effects addressed here should be quite general, applying to any solid sorbent and any sorbate whose uptake produces a volumetric response – from clays and cements to rubbers, plastics, woods and absorbent gels.

Jinfeng Liu*1, 2, 3, Christopher J. Spiers4

1School of Earth Sciences and Engineering, Sun Yat-Sen University, Zhuhai, 519082, China

2Guangdong Provincial Key Lab of Geodynamics and Geohazards, Sun Yat-Sen University, Zhuhai, 519082, China

3Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, 519082, China

4Department of Earth Sciences, Utrecht University, Utrecht, 3584 CB, The Netherlands

by Jun Sian Lee, UBC Biomass and Bioenergy Research Group

Abstract:
The province of British Columbia is a major producer of wood pellets in Canada, produced 4 million tonnes of pellets in 2020. Wood pellets are made by compacting wood particles through a 6-mm diameter die at a temperature around 100 °C and under a force over 5000 N. The pressure and heat may change the sorption characteristics of wood particles in the pellets. We showed that the adsorption isotherm of commercial compressed softwood pellets at 25 °C is slightly lower than published adsorption isotherm of un-compressed softwood particles, likely due to the heat and pressure applied during pellet formation. Desorption and adsorption isotherm of softwood pellets display hysteresis. In an adsorption test in a humidity chamber at 95% RH, the adsorption curves approached higher equilibrium moisture content as the temperature increases. This result indicates that moisture adsorption in a pellet may be a bulk water movement-driven phenomenon instead of a hygroscopic layered water deposition phenomenon.

by Susannah Molisso, Imperial College London

Susannah Molissoa, Ylang Ylang Lub, Robert V Lawa, Oscar Cesa, Jennifer M Marshc & Daryl R Williamsb*

Abstract:

The fundamental physical processes behind the hysteresis phenomena in keratin water sorption isotherms is still uncertain.

Complex keratins such as hair have a type II isotherm which is typical for microporous materials. Materials which exhibit type II behaviour, often have their hysteresis accounted for by pore filling, where water becomes trapped and is therefore not released during the desorption process.

This explanation cannot be used however to describe hysteresis in hair, as it is non-porous material. The physics of this process is therefore not well understood. In other proteins which also exhibit hysteresis, the cause of hysteresis has been suggested to originate from protein-water interactions at charged and polar amino acid residues [1], or more vaguely, the sorption kinetics of the protein itself [2].

For keratins, the cause of hysteresis has been linked to the swelling ability of the fibre. As the fibre swells in the sorption stage, active sites not previously accessible in the dry state become available for binding resulting in high water sorption behaviour. During the desorption phase, as the fibres reduces in swelling with the loss of water, water present at some active sites are retained, resulting in the hysteresis loop [3].

To examine the role of swelling in this process, hair was damaged via reduction and dying to measure the impact of reduced inter-keratin bonding on hysteresis. Water sorption isotherms were measured using Dynamic Vapour Sorption demonstrating that  samples with low disulphide bond content showed maximum hysteresis occurring at lower relative humidity’s (%RH). Diffusional analysis further supported the conclusion that increased swelling ability at higher %RH results in hysteresis becoming more apparent at low %RH. This work concludes that hysteresis is dependent on the swelling ability of keratin, which is strongly governed by disulphide bond content.

[1]      S.B. Kim, E.M. Sparano, R.S. Singh, P.G. Debenedetti, Microscopic Origin of Hysteresis in Water Sorption on Protein Matrices, The Journal of Physical Chemistry Letters. 8 (2017) 1185–1190. https://doi.org/10.1021/acs.jpclett.7b00184.

[2]      C.A.S. Hill, Y. Xie, The dynamic water vapour sorption properties of natural fibres and viscoelastic behaviour of the cell wall: Is there a link between sorption kinetics and hysteresis?, Journal of Materials Science. 46 (2011) 3738–3748. https://doi.org/10.1007/s10853-011-5286-1.

[3]      S.E. Smith, S.E. Smith, The Sorption of Water Vapor by High Polymers, Journal of the American Chemical Society. 69 (1947) 646–651. https://doi.org/10.1021/ja01195a053.

by Paola Alejandra Saenz Cavazos, Imperial College London

Abstract:
Carbon capture utilisation and storage (CCUS) using solid sorbents such as zeolites, activated carbon, Metal Organic Frameworks (MOFs) and Polymers of Intrinsic Microporosity (PIMs) could facilitate the reduction of anthropogenic CO2 concentration. Developing efficient and stable adsorbents, understanding their transport diffusion limitations, and assessing their performance for industrial CO2 capture plays a crucial role in CCUS technology development. However, experimental data available under relevant industrial conditions is scarce, particularly for novel materials like MOFs or PIMs.

In this study we evaluate recently developed adsorbents on their capabilities for CCUS under pertinent industrial conditions. Usually, new generation adsorbents are tuned to enhance their adsorption capacity, selectivity, and stability. Here, we explore the modification of MIL-101(Cr) by incorporation of fluorine atoms to enhance the material hydrophobicity. We evaluated its potential use for CCUS by measuring CO2 adsorption and kinetics in the presence of different water vapour concentrations (0.0, 0.05, 0.10, 0.15 and 0.20). All experiments were carried out at ambient pressure and temperature to resemble economically feasible industrial conditions.

Our results show that at low and moderate water loadings the total CO2 uptake capacity of MIL-101(Cr)-4F(1%) improved, with the best uptake (0.097 CO2 mmol g-1) at P/P0= 0.15. However, higher partial pressures seem to inhibit CO2 uptake. As for the pristine material, the highest water loading decreases it’s overall CO2 capacity by 18% compared to its dry form. Both materials present a stable behaviour in moist environments when compared to other commercial adsorbents with higher CO2 capacity such as HKUST-1 and MIL-53(Al) under the same conditions. Desorption results of CO2 with different water loadings at ambient pressure and temperature suggest that the fluorinated material would have a minimum energy penalty during the regeneration step. CO2 diffusion coefficients at different water partial pressures were extracted from the mass uptake curves of the co-adsorption experiments. For both materials, CO2 diffusion occurs faster when water is introduced; this is because water is responsible for providing a more homogeneous surface and permits an easier movement for CO2. For water concentrations from P/P0 = 0.05 to 0.15 the CO2 diffusion coefficients of both materials remain stable, however, at the maximum water partial pressure studied P/P0 = 0.2 a drop in the diffusion coefficient in the fluorinated material can be observed, coinciding with a drop in CO2 uptake. This data suggests that certain water vapour concentrations of up to 0.15 P/P0 can promote CO2 diffusion which coincidentally corresponds to the water concentrations of most industrial importance for CCS. Above these conditions, a compromise between uptake and transport kinetics should be considered. Additionally, MIL-101(Cr)-4F(1%) showed high SO2 capture under humid conditions and an outstanding cycling performance up to 50 cycles with facile regeneration.

1, 2

References

  1. P. A. Sáenz Cavazos, M. L. Díaz-Ramírez, E. Hunter-Sellars, S. R. McIntyre, E. Lima, I. A. Ibarra and D. R. Williams, RSC Advances, 2021, 11, 13304-13310.
  1. M. L. Díaz-Ramírez, E. Sánchez-González, J. R. Álvarez, G. A. González-Martínez, S. Horike, K. Kadota, K. Sumida, E. González-Zamora, M.-A. Springuel-Huet, A. Gutiérrez-Alejandre, V. Jancik, S. Furukawa, S. Kitagawa, I. A. Ibarra and E. Lima, Journal of Materials Chemistry A, 2019, 7, 15101-15112.

by Maha Al-Khalili, Sultan Qaboos University

Abstract:
Measurement of water activity and moisture sorption isotherms of foods and biomaterials are important to determine the state of water. In this work, a dynamic temperature-humidity (DTH) controlled chamber was used to measure water sorption isotherm and compared with the conventional isopiestic method. Temperature and relative humidity of DTH chamber can be controlled in the range of -15 to 100oC and 0 to 98%, respectively, thus measurement of water activity at any point can be measured within the above ranges. DTH chamber method showed high reproducibility as compared with the conventional isopiestic method when measured isotherm of cellulose, lignin and hemicellulase were compared at 30oC. Finally, isotherm data of cellulose, lignin and hemicellulase were generated in the temperature range of 10-90oC using DTH chamber, and these were modelled by BET and GAB equations. The model parameters were correlated with the temperature.

by Amina Bekhoukh, Université de Mascara

Amina Bekhoukh1, Imane Moulefera1,2, S. Daikh1 and A. Benyoucef1,2

1Department of science and technology, University of Mascara, Algeria

2University of Malaga, Facultad de Ciencias, Spain

Abstract:

This work investigated the elimination of Methyl Orange (MO) using a new adsorbent prepared from Activated Carbon (AC) with polyaniline reinforced by a simple oxidation chemical method. The prepared materials were characterized using XRD, TGA, FTIR and nitrogen adsorption isotherms. Furthermore, [email protected] highest specific surface area values (near 332 m2g−1) and total mesoporous volume (near 0.038 cm3g−1) displayed the better MO removal capacity (192.52 mg g−1 at 298 K and pH 6.0), which is outstandingly higher than that of PANI (46.82 mg g−1). Besides, the process’s adsorption, kinetics, and isothermal analysis were examined using various variables such as pH, MO concentration and contact time. To pretend the adsorption kinetics, various kinetics models, the pseudo first- and pseudo second- orders, were exercised to the experimental results. The kinetic analysis revealed that the pseudo second order rate law performed better than the pseudo first order rate law in promoting the formation of the chemisorption phase. In the case of isothermal studies, an analysis of measured correlation coefficient (R2) values showed that the Langmuir model was a better match to experimental results than the Freundlich model. By regeneration experiments after five cycles, acceptable results were observed.

by Muhammad Irfan Maulana Kusdhany, Stephen Matthew Lyth, Department of Automotive Science, Kyushu University

Amina Bekhoukh1, Imane Moulefera1,2, S. Daikh1 and A. Benyoucef1,2

1Department of science and technology, University of Mascara, Algeria

2University of Malaga, Facultad de Ciencias, Spain

Abstract:

Gas storage and separation is important for several critical carbon-neutral energy technologies. For example, hydrogen is generally compressed to make it portable enough to use in mobility applications. However, high pressure compression often require expensive tanks and incur large energy costs. A solution to these issues is to use physisorption of gases onto materials with high surface area, such as porous carbon. This method is ideal because it is simple, reversible, and relatively cheap. In our research, we synthesize and optimize porous carbons for this application by a combination of data mining techniques1 and direct experimental work.2 By using data mining techniques with a dataset collected from experimental work in the literature, we can identify clearly which properties of carbon are important in improving gas uptake and separation performance, such as shown in Figure 1. This is crucial because previous studies have not come to a clear consensus on which properties are important and to what extent. Following the identification of important properties, we can then rationally design porous carbon materials through experimentation. Hopefully, this can help the cheaper porous carbon materials to compete with materials such as state-of-the-art MOFs.


 

Figure 1. (a) Chart showing relative importance of each variable determining hydrogen uptake; (b) graph showing how ultramicropore (diameter <0.7 nm) volume affects hydrogen storage capacity of carbon materials.

References

  1. M. I. M. Kusdhany and S. M. Lyth, Carbon N. Y., 2021, 179, 190-201.
  2. M. I. M. Kusdhany, H. Li, A. Mufundirwa, K. Sasaki, A. Hayashi and S. M. Lyth, ECS Meeting Abstracts, 2020, MA2020-02, 1123.

by Mi Li, University of Tennessee

Mi Lia*, David Harpera, Daniel Burnettb
a Center for Renewable Carbon, Department of Forestry, Wildlife and Fisheries, The University of Tennessee, Knoxville, TN 37996, USA
b Surface Measurement Systems North America, Allentown, PA, 18103, USA

Abstract:
Lignin attracts tremendous interest due to its aromatic structure with high functional groups and carbon densities that can afford a broad array of bio-derived chemicals, polymers, and materials. Detailed insight into the chemical structure and surface energy of lignin materials is needed to devise efficient valorization strategies. In this study, we have used inverse gas chromatographic (iGC) technique to determine the structure, dispersive surface energy, and acid-base characteristics of three types of technical lignins, including industrial kraft processing (LignoBoost) and two advanced organosolv pulping technologies (ethanol and g-valerolactone) of three plant sources (pine, poplar, and switchgrass). The three selected plant sources represent softwood, hardwood, and herbaceous botanical origin featuring distinct lignin macromolecular structures. We have firstly used 2D Heteronuclear Single Quantum Coherence NMR spectroscopies to elucidate the major building units and cross-linkages, and 31P NMR to quantitate the hydroxyl functional groups of lignin. We then have used iGC to measure and compare the surface parameters and heterogeneity of the select lignins. The studied lignins have dispersive energy of 25–50 mJ/m2 and acid-base energy of 3–12 mJ/m2 varying on the isolation process and plant origin employed. We have also found that the lignin isolation process has a significant impact on the lignin surface properties. For example, lignins derived from ethanol pulping have much more heterogeneity of dispersive energy than that from g-valerolactone pulping in all three biomass origins; on the contrary, lignins derived from g-valerolactone pulping have generally higher acid-base energies than that from ethanol pulping. The results here will provide important information on the structural and isolation methodological impacts of lignin on its surface energies and interfacial process (e.g., wettability, liquid penetration, adhesion, and frictions) for lignin-based fillers, binders, composites, sorbents, carbon fibers, coatings, and drug-delivery, etc.

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