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- Pochard, Isabelle, et al.
(författare)
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Amine-functionalised mesoporous magnesium carbonate : Dielectric spectroscopy studies of interactions with water and stability
- 2018
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Ingår i: Materials Chemistry and Physics. - : ELSEVIER SCIENCE SA. - 0254-0584 .- 1879-3312. ; 216, s. 332-338
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Tidskriftsartikel (refereegranskat)abstract
- A mesoporous magnesium carbonate (MMC) material that was first described in 2013 is currently being investigated for several industrial and life-science-based applications. In this paper, the effect of functionalising the surface of MMC with amine groups on the water interaction properties of the material is investigated in detail. Amine functionalisation enhanced the stability and water sorption-release properties of the material. This is explained by the low affinity between amine-functionalised MMC and water molecules, as attested by the high free/total water ratio shown by dielectric spectroscopy. This low affinity had an impact on the total amount of adsorbed water at low relative humidities (RHs) but not at high RHs. The functionalisation of MMC with amine groups also stabilised the material in moist environments, hindering spontaneous crystallisation. These results provide a more fundamental understanding of the water interaction properties of MMC and are also expected to facilitate optimisation of the stability of materials like this for novel drug formulations and other life-science applications, as well as for their use in humidity control.
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- Vall, Maria, et al.
(författare)
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Amine-Modified Mesoporous Magnesium Carbonate as an Effective Adsorbent for Azo Dyes
- 2019
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Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 4:2, s. 2973-2979
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Tidskriftsartikel (refereegranskat)abstract
- Mesoporous magnesium carbonate (MMC) was evaluated as a potential candidate material for removal of dyes from textile industry wastewater. The adsorption property of MMC was analyzed for three different azo dyes: reactive black 5 (RB5), amaranth (AM), and acid red 183 (AR183). Further, the effect of porosity, amine modification, ionic strength, and pH was evaluated. MMC modified with 3-(aminopropyl)triethoxysilane (aMMC) showed consistently high uptake levels for all of the azo dyes tested; the uptake of RB5, AM, and AR183 was ∼360, ∼143 and ∼170 mg/g, respectively. The results demonstrated the importance of porosity and surface chemistry in the effective adsorption of the azo dye in aqueous systems. The uptake of RB5 and AM on aMMC was not significantly affected by pH (when varied between 4 and 10), although reduced uptake of RB5 and AM was observed at pH values <2 and >12. The addition of NaCl salt at concentrations up to 1000 mM had minimal effect on the high uptake of RB5 on aMMC. The uptake of AM by aMMC was reduced by approximately 20% in the presence of NaCl even at low concentrations. The uptake of AR183 by aMMC varied noticeably by changes in pH and no specific trend was observed. The presence of NaCl also adversely affected the uptake of AR183 on aMMC. The adsorption of the azo dye on aMMC was most likely driven by electrostatic interactions. We show here that aMMC is a potential candidate adsorbent for the effective removal of azo dyes from textile wastewaters.
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- Vall, Maria, et al.
(författare)
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Carbon dioxide adsorption on mesoporous magnesium carbonate
- 2019
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Ingår i: Energy Procedia. - : Elsevier. - 1876-6102. ; 158, s. 4671-4676
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Tidskriftsartikel (refereegranskat)abstract
- Mesoporous magnesium carbonate (MMC) was synthesized and tested for its ability to separate CO2 from N2. The pure gas CO2 uptake of MMC was around 1.5 mmol/g at 101 kPa, 0 °C. The N2 uptake under the same conditions was less than 0.1 mmol/g. Al(NO3)3, Al2O3, K2CO3 and KNO3 were introduced into the porous structure of MMC as additives. All of the additives tested increased the CO2 uptake of MMC and increased its selectivity towards CO2. The incorporation of 5 wt.% K2CO3 increased the CO2 uptake of MMC up to over 3.2 mmol/g. The ideally adsorbed solution theory was used to calculate the CO2 selectivity of MMC and MMC with additives for a hypothetical gas mixture that contained 15% CO2: 85% N2. The CO2 selectivity at 101 kPa (0 °C) was around 60. MMC with 5 wt.% K2CO3 had a CO2 selectivity of over 150 under the same conditions. Vacuum swing cyclic CO2 adsorption/desorption showed that the CO2 uptake on MMC with 5 wt.% K2CO3 decreased after each cycle. Heat regeneration (up to 250 °C, for 10 minutes) could recover most of the lost CO2 capacity after each cycle. Heat regeneration indicatively improved the cyclic performance of this adsorbent. MMC with 5 wt.% K2CO3 was the best performing adsorbent in this study and can potentially be further developed into a good CO2 adsorbent for temperature swing adsorption (TSA) processes.
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