Ashutosh Agarwal, Hashan Nuwantha Thenuwara and Ping Wu
{"title":"Novel, facile, and scalable synthesis of magnesium based adsorbents via the freeze-drying technique for CO2 capture†","authors":"Ashutosh Agarwal, Hashan Nuwantha Thenuwara and Ping Wu","doi":"10.1039/D4SE00802B","DOIUrl":null,"url":null,"abstract":"<p >In this study, MgO/Mg(OH)<small><sub>2</sub></small> based adsorbents were prepared <em>via</em> freeze-drying and electrospinning techniques, and their CO<small><sub>2</sub></small> adsorption capacities were investigated. The synthesized adsorbents were characterized by XRD, N<small><sub>2</sub></small>-Ads–Des, FESEM, XPS, and CO<small><sub>2</sub></small>-TPD, while their CO<small><sub>2</sub></small> capture efficiency and mechanism were evaluated by TGA and FTIR spectroscopy, respectively. The adsorbent prepared <em>via</em> freeze-drying displayed nearly 6.2 wt% CO<small><sub>2</sub></small> adsorption at room temperature compared to only 5.4 wt% by the adsorbent prepared <em>via</em> electrospinning. This adsorbent's superior CO<small><sub>2</sub></small> capture capacity was attributed to the high basic strength of the active sites and the presence of a substantial amount of surface oxygen vacancies/defects. The adsorbent prepared <em>via</em> freeze-drying exhibited abundant surface basic sites, which led to enhanced CO<small><sub>2</sub></small> molecule interaction with the O<small><sup>2−</sup></small> (strong sites), Mg–O pairs (medium sites), and OH group (weak sites) forming firmly fixed unidentate/monodentate, bidentate chelate and bidentate bridged carbonates, respectively. Although both physical and chemical adsorption coexisted in the process, the CO<small><sub>2</sub></small> adsorption was mainly presided over by the chemisorption sites. The high surface basicity of the adsorbents dominated BET surface area in governing the CO<small><sub>2</sub></small> capture capacity. For the first time in this research, the freeze-drying technique was applied to enlighten the facile, sustainable, and scalable synthesis of magnesium-based adsorbents for efficient CO<small><sub>2</sub></small> capture at room temperature.</p>","PeriodicalId":104,"journal":{"name":"Sustainable Energy & Fuels","volume":null,"pages":null},"PeriodicalIF":5.0000,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Sustainable Energy & Fuels","FirstCategoryId":"88","ListUrlMain":"https://pubs.rsc.org/en/content/articlelanding/2024/se/d4se00802b","RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
In this study, MgO/Mg(OH)2 based adsorbents were prepared via freeze-drying and electrospinning techniques, and their CO2 adsorption capacities were investigated. The synthesized adsorbents were characterized by XRD, N2-Ads–Des, FESEM, XPS, and CO2-TPD, while their CO2 capture efficiency and mechanism were evaluated by TGA and FTIR spectroscopy, respectively. The adsorbent prepared via freeze-drying displayed nearly 6.2 wt% CO2 adsorption at room temperature compared to only 5.4 wt% by the adsorbent prepared via electrospinning. This adsorbent's superior CO2 capture capacity was attributed to the high basic strength of the active sites and the presence of a substantial amount of surface oxygen vacancies/defects. The adsorbent prepared via freeze-drying exhibited abundant surface basic sites, which led to enhanced CO2 molecule interaction with the O2− (strong sites), Mg–O pairs (medium sites), and OH group (weak sites) forming firmly fixed unidentate/monodentate, bidentate chelate and bidentate bridged carbonates, respectively. Although both physical and chemical adsorption coexisted in the process, the CO2 adsorption was mainly presided over by the chemisorption sites. The high surface basicity of the adsorbents dominated BET surface area in governing the CO2 capture capacity. For the first time in this research, the freeze-drying technique was applied to enlighten the facile, sustainable, and scalable synthesis of magnesium-based adsorbents for efficient CO2 capture at room temperature.
期刊介绍:
Sustainable Energy & Fuels will publish research that contributes to the development of sustainable energy technologies with a particular emphasis on new and next-generation technologies.