{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,6]],"date-time":"2026-03-06T13:57:06Z","timestamp":1772805426388,"version":"3.50.1"},"reference-count":52,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2021,10,28]],"date-time":"2021-10-28T00:00:00Z","timestamp":1635379200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100005632","name":"National Centre for Research and Development","doi-asserted-by":"publisher","award":["NOR\/POLNORCCS\/PhotoRed\/0007\/2019-00"],"award-info":[{"award-number":["NOR\/POLNORCCS\/PhotoRed\/0007\/2019-00"]}],"id":[{"id":"10.13039\/501100005632","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>This paper examines the synthesis of the ZnO\/carbon spheres composites using resorcinol\u2014formaldehyde resin as a carbon source and zinc nitrate as a zinc oxide source in a solvothermal reactor heated with microwaves. The influence of activation with potassium oxalate and modification with zinc nitrate on the physicochemical properties of the obtained materials and CO2 adsorption capacity was investigated. It was found that in the case of nonactivated material as well as activated materials, the presence of zinc oxide in the carbon matrix had no effect or slightly increased the values of CO2 adsorption capacity. Only for the material where the weight ratio of carbon:zinc was 2:1, the decrease of CO2 adsorption capacity was reported. Additionally, CO2 adsorption experiments on nonactivated carbon spheres and those activated with potassium oxalate with different amounts of zinc nitrate were carried out at 40 \u00b0C using thermobalance. The highest CO2 adsorption capacity at temperature 40 \u00b0C (2.08 mmol\/g adsorbent) was achieved for the material after activation with potassium oxalate with the highest zinc nitrate content as ZnO precursor. Moreover, repeated adsorption\/desorption cycle experiments revealed that the as-prepared carbon spheres were very good CO2 adsorbents, exhibiting excellent cyclic stability with a performance decay of less than 10% over up to 25 adsorption-desorption cycles.<\/jats:p>","DOI":"10.3390\/ma14216478","type":"journal-article","created":{"date-parts":[[2021,10,28]],"date-time":"2021-10-28T23:51:36Z","timestamp":1635465096000},"page":"6478","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":13,"title":["ZnO\/Carbon Spheres with Excellent Regenerability for Post-Combustion CO2 Capture"],"prefix":"10.3390","volume":"14","author":[{"given":"Iwona","family":"Pe\u0142ech","sequence":"first","affiliation":[{"name":"Department of Inorganic Chemical Technology and Environment Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Pulaskiego 10, 70-322 Szczecin, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Daniel","family":"Sibera","sequence":"additional","affiliation":[{"name":"Department of Inorganic Chemical Technology and Environment Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Pulaskiego 10, 70-322 Szczecin, Poland"},{"name":"Department of General Civil Engineering, Faculty of Civil and Environmental Engineering, West Pomeranian University of Technology in Szczecin, Piastow 50a, 70-311 Szczecin, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Piotr","family":"Staciwa","sequence":"additional","affiliation":[{"name":"Department of Inorganic Chemical Technology and Environment Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Pulaskiego 10, 70-322 Szczecin, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ewelina","family":"Kusiak-Nejman","sequence":"additional","affiliation":[{"name":"Department of Inorganic Chemical Technology and Environment Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Pulaskiego 10, 70-322 Szczecin, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Joanna","family":"Kapica-Kozar","sequence":"additional","affiliation":[{"name":"Department of Inorganic Chemical Technology and Environment Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Pulaskiego 10, 70-322 Szczecin, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7240-4499","authenticated-orcid":false,"given":"Agnieszka","family":"Wanag","sequence":"additional","affiliation":[{"name":"Department of Inorganic Chemical Technology and Environment Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Pulaskiego 10, 70-322 Szczecin, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2443-1510","authenticated-orcid":false,"given":"Urszula","family":"Narkiewicz","sequence":"additional","affiliation":[{"name":"Department of Inorganic Chemical Technology and Environment Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Pulaskiego 10, 70-322 Szczecin, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2606-4104","authenticated-orcid":false,"given":"Antoni W.","family":"Morawski","sequence":"additional","affiliation":[{"name":"Department of Inorganic Chemical Technology and Environment Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Pulaskiego 10, 70-322 Szczecin, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,10,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"110261","DOI":"10.1016\/j.micromeso.2020.110261","article-title":"Synthesis of hierarchical porous Zeolite-Y for enhanced CO2 capture","volume":"303","author":"Dabbawala","year":"2020","journal-title":"Microporous Mesoporous Mater."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"6078","DOI":"10.1021\/acs.iecr.7b00890","article-title":"Amine-Modified Mesoporous Silica for CO2 Adsorption: The Role of Structural Parameters","volume":"56","author":"Kishor","year":"2017","journal-title":"Ind. Eng. Chem. Res."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Chiang, Y.-C., Yeh, C.-Y., and Weng, C.-H. (2019). Carbon Dioxide Adsorption on Porous and Functionalized Activated Carbon Fibers. Appl. Sci., 9.","DOI":"10.3390\/app9101977"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"75","DOI":"10.1016\/j.matlet.2017.07.100","article-title":"Facile synthesis of a nitrogen-doped carbon membrane for CO2 capture","volume":"209","author":"Qin","year":"2017","journal-title":"Mater. Lett."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Alghamdi, A.A., Alshahrani, A.F., Khdary, N.H., Alharthi, F.A., Alattas, H.A., and Adil, S.F. (2018). Enhanced CO2 Adsorption by Nitrogen-Doped Graphene Oxide Sheets (N-GOs) Prepared by Employing Polymeric Precursors. Materials, 11.","DOI":"10.3390\/ma11040578"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1099","DOI":"10.1021\/jp2100446","article-title":"Significantly increased CO2 adsorption performance of nanostructured templated carbon by tuning surface area and nitrogen doping","volume":"116","author":"Wang","year":"2012","journal-title":"J. Phys. Chem. C"},{"key":"ref_7","first-page":"1","article-title":"Preparation and characterisation of carbon spheres for carbon dioxide capture","volume":"26","author":"Sibera","year":"2018","journal-title":"J. Porous Mater."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1849","DOI":"10.1021\/am400112m","article-title":"Activated carbon spheres for CO2 adsorption","volume":"5","author":"Wickramaratne","year":"2013","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"169","DOI":"10.17512\/ios.2016.2.1","article-title":"Preparation and Studies of Adsorption Properties of Microporous Carbon Spheres","volume":"19","author":"Choma","year":"2016","journal-title":"Eng. Prot. Environ."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"6426","DOI":"10.1002\/cssc.202002230","article-title":"Polyvinyl Chloride-Derived Carbon Spheres for CO2 Adsorption","volume":"13","author":"Wang","year":"2020","journal-title":"ChemSusChem"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"426","DOI":"10.1016\/j.carbon.2020.08.056","article-title":"Facile and environmentally friendly synthesis of ultramicroporous carbon spheres: A significant improvement in CVD method","volume":"171","author":"Khodabakhshi","year":"2021","journal-title":"Carbon"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"193","DOI":"10.1016\/j.carbon.2020.07.064","article-title":"Soft templating production of porous carbon adsorbents for CO2 and H2S capture","volume":"169","author":"Nicolae","year":"2020","journal-title":"Carbon"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1016\/j.jcou.2016.05.004","article-title":"Developing microporosity in Kevlar1-derived carbon fibers by CO2 activation for CO2 adsorption","volume":"16","author":"Choma","year":"2016","journal-title":"J. CO2 Util."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1269","DOI":"10.1080\/10962247.2018.1460282","article-title":"Preparation and characterisation of activated carbon from waste tea by physical activation using steam","volume":"68","author":"Zhou","year":"2018","journal-title":"J. Air Waste Manag. Assoc."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"403","DOI":"10.1016\/j.electacta.2017.01.194","article-title":"Excellent electrochemical properties and large CO2 capture of nitrogen-doped activated porous carbon synthesised from waste longan shells","volume":"231","author":"Wei","year":"2017","journal-title":"Electrochim. Acta"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"259","DOI":"10.1016\/j.jcis.2017.09.040","article-title":"CO2 adsorption at nitrogen-doped carbons prepared by K2CO3 activation of urea-modified coconut shell","volume":"511","author":"Yue","year":"2018","journal-title":"J. Colloid Interface Sci."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1783","DOI":"10.1007\/s10008-015-2789-8","article-title":"Mesoporous activated carbon spheres derived from resorcinol-formaldehyde resin with high performance for supercapacitors","volume":"19","author":"Wang","year":"2015","journal-title":"J. Solid State Electrochem."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"297","DOI":"10.1016\/j.carbon.2014.10.074","article-title":"Potassium salt-assisted synthesis of highly microporous carbon spheres for CO2","volume":"82","author":"Ludwinowicz","year":"2015","journal-title":"Carbon"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"90","DOI":"10.1016\/j.jssc.2014.06.005","article-title":"Effect of ZnCl2 activation on CO2 adsorption of N-doped nanoporous carbons from polypyrrole","volume":"218","author":"Meng","year":"2014","journal-title":"J. Solid State Chem."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"112","DOI":"10.1039\/C2TA00388K","article-title":"Importance of small micropores in CO2 capture by phenolic resin-based activated carbon spheres","volume":"1","author":"Wickramaratne","year":"2013","journal-title":"J. Mater. Chem. A"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"320","DOI":"10.1016\/j.jcou.2019.06.021","article-title":"One step N-doping and activation of biomass carbon at low temperature through NaNH2: An effective approach to CO2 adsorbents","volume":"33","author":"Yang","year":"2019","journal-title":"J. CO\u2082 Util."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"064306","DOI":"10.1063\/1.4892458","article-title":"Enhanced CO2 capture in Fe3O4-graphene nanocomposite by physicochemical adsorption","volume":"116","author":"Mishra","year":"2014","journal-title":"J. Appl. Phys."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1966","DOI":"10.1021\/acsomega.9b03806","article-title":"Nanocomposite Titania\u2212Carbon Spheres as CO2 and CH4 Sorbents","volume":"5","author":"Morawski","year":"2020","journal-title":"ACS Omega"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"113e124","DOI":"10.1016\/j.carbon.2015.08.015","article-title":"Atomically homogeneous dispersed ZnO\/N-doped nanoporous carbon composites with enhanced CO2 uptake capacities and high efficient organic pollutants removal from water","volume":"95","author":"Chen","year":"2015","journal-title":"Carbon"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"55","DOI":"10.1016\/j.jcis.2016.05.008","article-title":"Revisiting the St\u00f6ber method: Design of nitrogen-doped porous carbon spheres from molecular precursors of different chemical structures","volume":"476","author":"Tian","year":"2016","journal-title":"J. Colloid Interface Sci."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"2820","DOI":"10.1021\/cm5001895","article-title":"Nitrogen enriched porous carbon spheres: Attractive materials for supercapacitor electrodes and CO2 adsorption","volume":"26","author":"Wickramaratne","year":"2014","journal-title":"Chem. Mater."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"155","DOI":"10.1016\/j.carbon.2014.05.017","article-title":"Highly porous carbon spheres for electrochemical capacitors and capacitive flowable suspension electrodes","volume":"77","author":"Zhang","year":"2014","journal-title":"Carbon"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"110829","DOI":"10.1016\/j.micromeso.2020.110829","article-title":"Effect of microwave assisted solvothermal process parameters on carbon dioxide adsorption properties of microporous carbon materials","volume":"314","author":"Staciwa","year":"2021","journal-title":"Microporous Mesoporous Mater."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Staciwa, P., Narkiewicz, U., Sibera, D., Moszy\u0144ski, D., Wr\u00f3bel, R.J., and Cormia, R.D. (2019). Carbon Spheres as CO2 Sorbents. Appl. Sci., 9.","DOI":"10.3390\/app9163349"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"D\u0105browska, S., Chudoba, T., Wojnarowicz, J., and \u0141ojkowski, W. (2018). Current Trends in the Development of Microwave Reactors for the Synthesis of Nanomaterials in Laboratories and Industries: A Review. Crystals, 8.","DOI":"10.3390\/cryst8100379"},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Wojnarowicz, J., Chudoba, T., and Lojkowski, W. (2020). A Review of Microwave Synthesis of Zinc Oxide Nanomaterials: Reactants, Process Parameters and Morphologies. Nanomaterials, 10.","DOI":"10.3390\/nano10061086"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Wojnarowicz, J., Chudoba, T., Gierlotka, S., and Lojkowski, W. (2018). Effect of Microwave Radiation Power on the Size of Aggregates of ZnO NPs Prepared Using Microwave Solvothermal Synthesis. Nanomaterials, 8.","DOI":"10.3390\/nano8050343"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"2797","DOI":"10.1021\/acssuschemeng.7b04634","article-title":"Revealing the dynamic formation process and mechanism of hollow carbon spheres: From bowl to sphere","volume":"6","author":"Liu","year":"2018","journal-title":"ACS Sustain. Chem. Eng."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Kukulka, W., Wenelska, K., Baca, M., Chen, X., and Mijowska, E. (2018). From hollow to solid carbon spheres: Time-dependent facile synthesis. Nanomaterials, 8.","DOI":"10.3390\/nano8100861"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1229","DOI":"10.3762\/bjnano.7.114","article-title":"Mesoporous hollow carbon spheres for lithium\u2013sulfur batteries: Distribution of sulfur and electrochemical performance","volume":"7","author":"Juhl","year":"2016","journal-title":"Beilstein J. Nanotechnol."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"154","DOI":"10.1016\/j.micromeso.2017.06.018","article-title":"Microporous carbon spheres derived from resorcinol-formaldehyde solutions. A New Approach Coat Supports","volume":"252","author":"Villanueva","year":"2017","journal-title":"Microporous Mesoporous Mater."},{"key":"ref_37","first-page":"147","article-title":"Preparation of various morphologies of ZnO nanostructure through wet chemical methods","volume":"4","author":"Dien","year":"2019","journal-title":"Adv. Mater. Sci."},{"key":"ref_38","first-page":"608183","article-title":"Kinetic Study of Organic Dye Degradation Using ZnO Particles with Different Morphologies as a Photocatalyst","volume":"2012","author":"Pung","year":"2012","journal-title":"Int. J. Inorg. Chem."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.colsurfa.2016.11.070","article-title":"Alkali-assisted hydrothermal route to control submicron-sizednanoporous carbon spheres with uniform distribution","volume":"515","author":"Xu","year":"2017","journal-title":"Colloids Surf. A Physicochem. Eng. Asp."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1016\/j.jaap.2011.12.020","article-title":"BET, TG\u2013DTG, FT-IR, SEM, iodine number analysis and preparation of activated carbon from acorn shell by chemical activation with ZnCl2","volume":"95","author":"Saka","year":"2012","journal-title":"J. Anal. Appl. Pyrolysis"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"37604","DOI":"10.1039\/C7RA04984F","article-title":"Sintered metal fibers@carbon molecular sieve membrane (SMFs@CMSM) composites for the adsorptive removal of low concentration isopropanol","volume":"7","author":"Shao","year":"2017","journal-title":"RSC Adv."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"484","DOI":"10.1021\/cm802141h","article-title":"Carboxylate-rich carbonaceous materials via one-step hydrothermal carbonization of glucose in the presence of acrylic acid","volume":"21","author":"Baccile","year":"2009","journal-title":"Chem. Mater."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1727","DOI":"10.1246\/bcsj.44.1727","article-title":"The Differential Thermal Analysis of Potassium Oxalate","volume":"44","author":"Higashiyama","year":"1971","journal-title":"Bull. Chem. Soc. Jap."},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Pe\u0142ech, I., Sibera, D., Staciwa, P., Narkiewicz, U., and Cormia, R. (2020). Pressureless and Low-Pressure Synthesis of Microporous Carbon Spheres Applied to CO2 Adsorption. Molecules, 25.","DOI":"10.3390\/molecules25225328"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"2297","DOI":"10.1007\/BF01911893","article-title":"On the thermal decomposition of Zn(NO3)2\u00b76H2O and its deuterated analogue","volume":"35","author":"Maneva","year":"1989","journal-title":"J. Therm. Anal."},{"key":"ref_46","first-page":"1","article-title":"Structural Morphological Properties of Nanostructured","volume":"2014","author":"Rabanal","year":"2014","journal-title":"Adv. Mat. Sci. Eng."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"3059","DOI":"10.1039\/c1ee01176f","article-title":"Effect of pore size on carbon dioxide sorption by carbide derived carbon","volume":"4","author":"Presser","year":"2011","journal-title":"Energy Environ. Sci."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"133","DOI":"10.1016\/j.cej.2013.06.085","article-title":"The role of different properties of activated carbon in CO2 adsorption","volume":"230","author":"Yin","year":"2013","journal-title":"Chem. Eng. J."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"6058","DOI":"10.1002\/anie.201000431","article-title":"Carbon dioxide capture: Prospects for new materials","volume":"49","author":"Smit","year":"2010","journal-title":"Ang. Chem. Int. Ed."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"230","DOI":"10.1016\/j.carbon.2013.09.086","article-title":"Effect of the porous structurein carbon materials for CO2 capture at atmospheric and high-pressure","volume":"67","author":"Casco","year":"2014","journal-title":"Carbon"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1016\/j.fuel.2013.10.042","article-title":"Granular KOH-activated carbons from coal based cokes and their CO2 adsorption capacity","volume":"118","author":"Labus","year":"2014","journal-title":"Fuel"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"5223","DOI":"10.1039\/C5TA09908K","article-title":"Pine cone shell-based activated carbon used for CO2 adsorption","volume":"4","author":"Li","year":"2016","journal-title":"J. Mater. Chem. A"}],"container-title":["Materials"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1996-1944\/14\/21\/6478\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T07:22:03Z","timestamp":1760167323000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1996-1944\/14\/21\/6478"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,10,28]]},"references-count":52,"journal-issue":{"issue":"21","published-online":{"date-parts":[[2021,11]]}},"alternative-id":["ma14216478"],"URL":"https:\/\/doi.org\/10.3390\/ma14216478","relation":{},"ISSN":["1996-1944"],"issn-type":[{"value":"1996-1944","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,10,28]]}}}