Online Workshop: Innovative Sorption Technology Solutions for Porous Materials

 

 

Date:
Thurs 10 June 2021
Time:
10 am BST | 11 am CEST
Duration:
2 hours incl. Q&A

Register free here

Co-organized with:

Text

Dr. Giulio Santori
Professor
University of Edinburgh
(Click here for bio)

Speakers:

Elwin Hunter Sellar
PhD Student
Imperial College London
(Click here for bio)

 

Paola Saenz Cavazos
PhD Student
Imperial College London
(Click here for bio)

We are excited to invite you to this in-depth online workshop exploring innovative sorption techniques, technology and appications for the study of porous materials. Employing recent research and case studies, attendees will gain a keen understanding of the groundbreaking DVS technique, and the unparalleled detail and accuracy it grants in the study of porous materials, VOCs and MOFs.

Agenda:

Ionic liquids and ionogels for water sorption in low-grade heat driven applications

with Dr. Giulio Santori, Senior Lecturer, University of Edinburgh

Sorption Heat Transformation (AHT) processes can convert low-grade heat into diverse useful effects such as cooling, pure water and drying. AHT mainly relies on the utilization of nanoporous physisorbents of water such as crystalline zeolites, zeotypes, metal-organic framework or amorphous silica. Here we show that some ionic liquids and their solid phase version (ionogels) have promising features for application in low-grade heat powered devices. We show an insight into the properties of acetate ionic liquids and ionogels and highlight how water can be retained at amounts well above the best advanced competitor sorption materials, achieving equilibrium uptakes >1 gwater/gsorbent. Experiments confirm that the material can be regenerated at temperatures < 40 °C. Ionic liquids and ionogels are setting off as novel, high performance water sorptive emerging fluids and materials.

Impact of relative humidity on hydrophobicity and selectivity of porous adsorbents for VOC capture

with Elwin Hunters Sellars, PhD Student, Imperial College London

Volatile organic compounds (VOCs) are a broad class of chemicals, elevated levels of which have been associated with a number of health problems as well as ‘sick building syndrome’. Removal of VOCs is typically carried out using porous adsorbents such as zeolites and activated charcoal. However, the high concentrations of water vapour relative to VOCs makes selectivity a key parameter in the effectiveness of the adsorbent.

This work explores the impact of relative humidity on the selectivity of porous adsorbents (specifically charcoals, zeolites, and MOFs) using three approaches:

  • Humidity-dependant hydrophobicity indexes, calculated using single-component isotherms
  • Gravimetric ‘wet adsorbent’ experiments to assess the impact of pre-adsorbed water vapour
  • Fixed-bed ‘wet adsorbate’ experiments to gain insight into the mechanism of competition at realistic concentration levels

The findings from this work that while many adsorbents are described as ‘hydrophobic’, this property is not immutable, and depends largely on the adsorbent’s environment. The mode of adsorption of water vapour by porous adsorbents was found to have a significant impact not only on the extent of competition, but also the mechanism by which it occurs.

Novel Porous Materials for Carbon Capture Utilisation and Storage: Studies Under Relevant Industrial Conditions

with Paola Saenz Cavazos, PhD Student, Imperial College London

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) and SO2 adsorption and stability in the presence of water. 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 exceptionally high SO2 capture under humid conditions and an outstanding cycling performance up to 50 cycles with facile regeneration.

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