Adsorption of [formula omitted] from dry gases on MCM-41 silica at ambient temperature and high pressure. 1: Pure [formula omitted] adsorption

Adsorption of CO 2 from dry gases on MCM-41 silica at ambient temperature and high pressure. 2: Adsorption of CO 2/N 2, CO 2/CH 4 and CO 2/H 2 binary mixtures

A high capacity, water tolerant adsorbent for CO2: diethanolamine supported on pore-expanded MCM-41

The capture of CO2 under high pressure and temperature is challenging and is required in a number for industrial applications including natural gas processing. In this work, we examine the use of benchmark hybrid ultraporous materials HUMs for their potential use in CO2 adsorption processes under high-pressure conditions, with three varying temperatures (283, 298 and 318 K). NbOFFOVE-1-Ni and SIFSIX-3-Ni were the selected HUMs given their established superior CO2 capacity under low pressure (0–1 bar). Both are microporous with highly ordered crystalline structures as compared to the mesoporous hexagonal silica (Santa Barbara Anhydrous-15 (SBA-15)). SBA-15 was previously tested for both low and high-pressure applications and can serve as a benchmark in this study. Sorbent characterization using XRD, SEM, FTIR and N2 adsorption were conducted to assure the purity and structure of the sorbents. TGA analysis were conducted to establish the thermal stability of the sorbents under various temperatures. High-pressure CO2 adsorption was conducted from 0–35 bar using magnetic suspension balance (Rubotherm). Although the SBA-15 had the highest surface (527 m3/g) are of the three adsorbents, the CO2 adsorption capacity (0.42 mmol/g) was an order of magnitude less than the studies HUMs with SIFSIX-3-Ni having 2.6 mmol/g, NbOFFIVE-1-Ni achieving 2.5 mmol/g at 298 K. Multistage adsorption isotherms were obtained at different pressures. In addition, results indicate that electrostatics in HUMs are most effective at improving isosteric heat of adsorption Qst and CO2 uptake. Higher temperatures had negative effect on adsorption capacity for the HUMs and SBA-15 at pressures between 7–9 bar. In SAB-15 the effect of temperature is reversed in what is known as a cross over phenomena.

The excess adsorption of CO2 on 13X zeolite and of N2O on silica gel has been studied at high pressure using a magnetic suspension balance, i.e. a gravimetric method. Recently, a detailed study on the density distribution in the measuring cell of the magnetic suspension balance showed that a proper approach to thermostatting the unit should be used in order to obtain reliable and accurate excess adsorption measurements. This is particularly important in the vicinity of the critical point of the fluid, where the density is strongly dependent on pressure and temperature. In the past, several effects were observed in our laboratory when measuring near-critical adsorption on 13X zeolite and on silica gel, namely critical adsorption and critical depletion. In the present study, these effects have been checked using the balance in the new thermostatting configuration, and the conclusion can be drawn that the accuracy of the measurement is not sufficient to prove that they indeed occur. More accurate adsorption data for the two systems have been measured and reported.

The potential of direct air capture using adsorbents in cold climates.

Effects of amino functionality on uptake of CO2, CH4 and selectivity of CO2/CH4 on titanium based MOFs

Experimental analysis of the efficiency on charge/discharge cycles in natural gas storage by adsorption

This reference is for an abstract only. A full paper was not submitted for this conference. Abstract The use of vessels filled with porous materials to store and transport natural gas at moderate pressures (about 3.5 MPa) and ambient temperature (about 298 K) has been studied as a potential alternative to compressed natural gas storage at high pressures (ca. 20 MPa). The present study provides an experimental investigation of charge and discharge cycles of natural gas in a prototype storage vessel filled with activated carbon and analyses the effect of the gas composition on the adsorption capacity. The adsorption properties were evaluated by measuring isotherms for each component of natural gas in a magnetic suspension balance and compared with the isotherms measured in a storage vessel using natural gas. The selectivities of the main constituents of natural gas in relation to methane were determined and the influence of the pressure on the selectivity was also observed. Although natural gas is composed mainly of methane (ca. 90% vol.), our experimental results indicate that the preferential adsorption of the heavier hydrocarbons and CO2 should be properly taken into account for the evaluation of the behavior of adsorbed natural gas systems along several charge and discharge cycles.

This paper investigates the potential of pristine and acid-treated olivine as a substrate for CO2 capture using a vacuum swing adsorption (VSA) process from the gas-solid phase. The experiments tested the isotherm of pure CO2 adsorption with partial pressure from 10−5 to 1 bar at ambient temperature. The CO2 adsorption capacity and actual expected working capacity (EWC) curves of pristine and acid-treated olivine were determined. Isotherm studies predict that physisorption dominates chemisorptions at ambient temperatures. The adsorption capacity enhances with the increase of specific surface area, pore volume, and the appearance of Mg complexed on the mineral’s surface. Actual EWC studies showed that acid-treated olivine is an adsorbent choice for the VSA process, due to enhanced CO2 adsorption capacities compared to olivine and the potential for 100% recovery of CO2 during the regeneration process. Pristine olivine is not suitable for the VSA process because of bad regenerability, but it can be used in capturing and sequestering dilute CO2 in process streams. Our research reveals excellent viability for the application of VSA in the area of CO2 capture using pristine olivine and acid-treated olivine.

Selective adsorption of CO2 on a regenerable amine-bentonite hybrid adsorbent

Performance evaluation of clinoptilolite and 13X zeolites in CO2 separation from CO2/CH4 mixture

Adsorption and separation of CO2 from N2-rich gas on zeolites: Na-X faujasite vs Na-mordenite

Hypercrosslinked polymers (HCPs) synthesized by copolymerisation of p-dichloroxylene (p-DCX) and 4,4′-bis(chloromethyl)-1,1′-biphenyl (BCMBP) constitute a family of low density porous materials with excellent textural development. Such polymers show microporosity and mesoporosity and exhibit Brunauer–Emmett–Teller (BET) surface areas of up to 1970 m2 g−1. The CO2 adsorption capacity of these polymers was evaluated using a thermogravimetric analyser (atmospheric pressure tests) and a high-pressure magnetic suspension balance (high pressure tests). CO2 capture capacities were related to the textural properties of the HCPs. The performance of these materials to adsorb CO2 at atmospheric pressure was characterized by maximum CO2 uptakes of 1.7 mmol g−1 (7.4 wt%) at 298 K. At higher pressures (30 bar), the polymers show CO2 uptakes of up to 13.4 mmol g−1 (59 wt%), superior to zeolite-based materials (zeolite 13X, zeolite NaX) and commercial activated carbons (BPL, Norit R). In addition, these polymers showed low isosteric heats of CO2 adsorption and good selectivity towards CO2. Hypercrosslinked polymers have potential to be applied as CO2 adsorbents in pre-combustion capture processes where high CO2 partial pressures are involved.

Mesocellular silica foam supported polyamine adsorbents for dry CO2 scrubbing: Performance of single versus blended polyamines for impregnation

Carbon dioxide adsorption isotherm study on mine waste for integrated CO2 capture and sequestration processes