CO2 adsorption–desorption performance of mesoporous zirconium hydroxide with robust water durability

2016 ◽  
Vol 18 (4) ◽  
pp. 2699-2709 ◽  
Author(s):  
Y. Kamimura ◽  
A. Endo

The present study demonstrates for the first time, the development of mesoporous zirconium hydroxide with high CO2 capacity and sustainable adsorption–desorption performance within a broad range of pressures (100–3000 kPa).

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1301
Author(s):  
Zully J. Suárez Montenegro ◽  
Gerardo Álvarez-Rivera ◽  
Jose A. Mendiola ◽  
Elena Ibáñez ◽  
Alejandro Cifuentes

This work reports the use of GC-QTOF-MS to obtain a deep characterization of terpenoid compounds recovered from olive leaves, which is one of the largest by-products generated by the olive oil industry. This work includes an innovative supercritical CO2 fractionation process based on the online coupling of supercritical fluid extraction (SFE) and dynamic adsorption/desorption for the selective enrichment of terpenoids in the different olive leaves extracts. The selectivity of different commercial adsorbents such as silica gel, zeolite, and aluminum oxide was evaluated toward the different terpene families present in olive leaves. Operating at 30 MPa and 60 °C, an adsorbent-assisted fractionation was carried out every 20 min for a total time of 120 min. For the first time, GC-QTOF-MS allowed the identification of 40 terpenoids in olive leaves. The GC-QTOF-MS results indicate that silica gel is a suitable adsorbent to partially retain polyunsaturated C10 and C15 terpenes. In addition, aluminum oxide increases C20 recoveries, whereas crystalline zeolites favor C30 terpenes recoveries. The different healthy properties that have been described for terpenoids makes the current SFE-GC-QTOF-MS process especially interesting and suitable for their revalorization.


Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3371 ◽  
Author(s):  
Svensson ◽  
Grins ◽  
Eklöf ◽  
Eriksson ◽  
Wardecki ◽  
...  

The CO2 adsorption on various Prussian blue analogue hexacyanoferrates was evaluated by thermogravimetric analysis. Compositions of prepared phases were verified by energy-dispersive X-ray spectroscopy, infra-red spectroscopy and powder X-ray diffraction. The influence of different alkali cations in the cubic Fm3m structures was investigated for nominal compositions A2/3Cu[Fe(CN)6]2/3 with A = vacant, Li, Na, K, Rb, Cs. The Rb and Cs compounds show the highest CO2 adsorption per unit cell, 3.3 molecules of CO2 at 20 C and 1 bar, while in terms of mmol/g the Na compound exhibits the highest adsorption capability, 3.8 mmol/g at 20 C and 1 bar. The fastest adsorption/desorption is exhibited by the A-cation free compound and the Li compound. The influence of the amount of Fe(CN)6 vacancies were assessed by determining the CO2 adsorption capabilities of Cu[Fe(CN)6]1/2 (Fm3m symmetry, nominally 50% vacancies), KCu[Fe(CN)6]3/4 (Fm3m symmetry, nominally 25% vacancies), and CsCu[Fe(CN)6] (I-4m2 symmetry, nominally 0% vacancies). Higher adsorption was, as expected, shown on compounds with higher vacancy concentrations.


2021 ◽  
Author(s):  
Shiva Chahardahmasoumi ◽  
Seyed Amir Hossein Jalali ◽  
Mehdi Nasiri Sarvi

Abstract The adsorption and photo-Fenton degradation of tetracycline (TC) over Fe saturated nanoporous montmorillonite was analyzed. The synthesized samples were characterized using XRD, FTIR, SEM, and XRF analysis, and the adsorption and desorption of TC onto these samples as well as the antimicrobial activity of TC during these processes were analyzed at different pH. The results indicated that the montmorillonite is a great adsorbent for the separation of the TC from aqueous solutions, however, after increasing the amount of TC adsorbed, the desorption process started, and up to 50% of TC adsorbed onto non-modified montmorillonite was released back to the solution with almost no changes in its antimicrobial activity. After acid treatment (for creation of nanoporous layers) and Fe saturation of the montmorillonite, almost similar great separation was achieved compared to non-modified montmorillonite. In addition, the desorption of TC from modified montmorillonite was still high up to 40% of adsorbed TC. However, simultaneous adsorption and photodegradation of TC were detected and almost no antimicrobial activity was detected after 180 min of visible light irradiation, which could be due to the photo-Fenton degradation of TC on the modified montmorillonite surface. In the porous structures of modified montmorillonite high ˙OH radicals were created in the photo-Fenton reaction and were measured using the Coumarin technique. The ˙OH radicals help the degradation of TC as proposed in an oxidation process. Surprisingly, more than 90 % of antimicrobial activity of the TC decreased under visible light (after 180 min) when desorbed from nanoporous Fe-saturated montmorillonite compared to natural montmorillonite. To the best of our knowledge, this is the first time that such a high TC desorption rate from an adsorbent with the least remained antimicrobial activity is reported which makes nanoporous Fe-saturated montmorillonite a perfect separation substance of TC from the environment.


Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 4013 ◽  
Author(s):  
Norbert Skoczylas ◽  
Anna Pajdak ◽  
Mariusz Młynarczuk

The paper presents the results of studies on sorption and CO2 desorptions from coals from two Polish mines that differed in petrographic and structural properties. The tests were carried out on spherical and plane sheet samples. On the basis of the sorption tests, the effective diffusion coefficient was calculated on the plane sheet samples based on a proper model. Similar tests were performed on the spherical samples. Mathematical model results for plane sheet samples were compared with the most frequently chosen model for spherical samples. The kinetics of CO2 desorption from plane sheet samples were compared with the kinetics of sample shrinkage. In both samples, the shrinkage was about 0.35%. The size change kinetics and CO2 desorption kinetics significantly differed between the samples. In both samples, the determined shrinkage kinetics was clearly faster than CO2 kinetics.


Author(s):  
Sayuri Chong-Canto ◽  
Efrén V. García-Báez ◽  
Francisco J. Martínez-Martínez ◽  
Ángel Ramos-Organillo ◽  
Itzia I. Padilla-Martínez

A new cocrystal salt of metformin, an antidiabetic drug, and N,N’-(1,4-phenylene)dioxalamic acid, was synthesized by mechanochemical synthesis, purified by crystallization from solution and characterized by single X-ray crystallography. The structure revealed a salt-type cocrystal composed of one dicationic metformin unit, two monoanionic units of the acid and four water molecules namely H2Mf(HpOXA)2∙4H2O. X-ray powder, IR, 13C-CPMAS, thermal and BET adsorption-desorption analyses were performed to elucidate the structure of the molecular and supramolecurar structure of the anhydrous microcrystalline mesoporous solid H2Mf(HpOXA)2. The results suggest that their structures, conformation and hydrogen bonding schemes are very similar between them. To the best of our knowledge, the selective formation of the monoanion HpOXA⁻, as well as its structure in the solid, is herein reported for the first time. Regular O(-)∙∙∙C(), O(-)∙∙∙N+ and bifacial O(-)∙∙∙C()∙∙∙O(-) of n→* charge-assisted interactions are herein described in H2MfA cocrystal salts which could be responsible of the interactions of metformin in biologic systems. The results, support the participation of n→* charge-assisted interactions independently, and not just as a short contact imposed by the geometric constraint due to the hydrogen bonding patterns.


2013 ◽  
Vol 702 ◽  
pp. 56-61 ◽  
Author(s):  
Rahmatollah Rahimi ◽  
Masoumeh Mahjoub Moghaddas ◽  
Solmaz Zargari ◽  
Rahim Rahimi

Mesoporous vanadium doped titania (V-TiO2) photocatalyst was synthesized with the use of a new surfactant (Gemini) for the first time. In order to investigate the surfactant effect on the photocatalytic activity of catalysts, different surfactants containing Gemini, pluronic F127, pluronic P123, CTAB, Hexadecylamine and PEG 6000 were used in the preparation of mesoporous V-TiO2photocatalyst as a templating agent. The catalysts were characterized by FT-IR, XRD, SEM, EDX, nitrogen adsorption-desorption isotherm, and DRS. The nanosized V-TiO2 with Gemini surfactant (V-TiO2(G)) exhibited the highest visible light driven photocatalytic efficiency for degrading MO dye. The results showed that the surfactant type played an important role on the structure and photocatalytic activity of the samples.


Clean Energy ◽  
2020 ◽  
Vol 4 (2) ◽  
pp. 120-131 ◽  
Author(s):  
Pailin Muchan ◽  
Chintana Saiwan ◽  
Manit Nithitanakul

Abstract Mesoporous silicas with hexagonal structure (MCM-41 and SBA-15) and cubical interconnected pore structure (KIT-6) were synthesized and modified with aminopropyltriethoxysilane (APTES) for using as adsorbents in carbon-dioxide (CO2)-adsorption application. The CO2-adsorption experiment was carried out at room temperature and atmospheric pressure using 15% CO2 with a flow rate of 20 mL/min and the desorption experiment was carried out at 100°C under N2 balance with a flow rate of 20 mL/min. The adsorption capacity and adsorption rate of all modified mesoporous silicas were enhanced due to the presence of primary amine in the structure, which was able to form a fast chemical reaction with CO2. All adsorbents showed good adsorption performance stability after using over five adsorption/desorption cycles. Due to the effect of the adsorbents’ porous structure on the adsorption/desorption process, an adsorbent with sufficient pore-size diameter and pore volume together with interconnected pore, KIT-6, represents a promising adsorbent that gave the optimum adsorption/desorption performance among others. It showed reasonable adsorption capacity with a high rate of adsorption. In addition, it could also be regenerated with 99.72% efficiency using 12.07 kJ/mmolCO2 of heat duty for regeneration.


2018 ◽  
Vol 54 (75) ◽  
pp. 10602-10605 ◽  
Author(s):  
Li Peng ◽  
Shuliang Yang ◽  
Daniel T. Sun ◽  
Mehrdad Asgari ◽  
Wendy L. Queen

A double solvent method is for the first time used to synthesize polymer composites showing enhanced water and CO2 adsorption properties.


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