{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,4]],"date-time":"2026-08-04T14:03:31Z","timestamp":1785852211890,"version":"3.56.0"},"reference-count":49,"publisher":"MDPI AG","issue":"24","license":[{"start":{"date-parts":[[2025,12,13]],"date-time":"2025-12-13T00:00:00Z","timestamp":1765584000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000780","name":"European Union-NextGenerationEU","doi-asserted-by":"publisher","award":["BG-RRP-2.004-0008-C01"],"award-info":[{"award-number":["BG-RRP-2.004-0008-C01"]}],"id":[{"id":"10.13039\/501100000780","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>A multi-stage TG-DSC approach consisting of five heating\/holding and five cooling\/holding stages within one experiment in the temperature range 20\u2013320 \u00b0C was applied to investigate the dehydration\/hydration processes in K+, Na+, Ca2+, and Mg2+ clinoptilolite forms. The influence of extra-framework cations on the parameters characterizing these processes (such as mass changes, dehydration and hydration heats calculated per gram zeolite, amounts of water molecules leaving and entering the structure, and enthalpy values calculated per mol water) was established. The values of molar enthalpy of dehydration for different cationic clinoptilolite forms increase in different ways with temperature increasing (within the framework of 50\u2013120 kJ mol\u22121). The data on the molar enthalpy are in good agreement with the distributions of the two types of water molecules\u2014weakly bound to cations and water molecules coordinating cations in the applied crystal chemical models of the cationic exchange samples. The data obtained for water molecules and their molar enthalpies of dehydration for the various cationic forms are useful in studying the sorption of water vapor and other sorbates, in choosing a desiccant and an object to dry at room conditions, etc. The first data on the hydration energy of sequentially added water molecules in a dynamic cooling mode in the temperature range 320\u201320 \u00b0C were obtained.<\/jats:p>","DOI":"10.3390\/molecules30244770","type":"journal-article","created":{"date-parts":[[2025,12,15]],"date-time":"2025-12-15T15:15:08Z","timestamp":1765811708000},"page":"4770","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Comparative Multi-Stage TG-DSC Study of K+, Na+, Ca2+ and Mg2+-Exchanged Clinoptilolite Forms"],"prefix":"10.3390","volume":"30","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2624-309X","authenticated-orcid":false,"given":"Tsveta","family":"Stanimirova","sequence":"first","affiliation":[{"name":"Faculty of Geology and Geography, Sofia University \u201cSt. Kliment Ohridski\u201d, 15 Tzar Osvoboditel Blvd., 1540 Sofia, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2559-017X","authenticated-orcid":false,"given":"Nadia","family":"Petrova","sequence":"additional","affiliation":[{"name":"Institute of Mineralogy and Crystallography\u2014Bulgarian Academy of Sciences, 107 Acad. G. Bonchev Str., 1113 Sofia, Bulgaria"},{"name":"PERIMED, Central District, Vasil Aprilov Blvd. 15A, 4002 Plovdiv, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Georgi","family":"Kirov","sequence":"additional","affiliation":[{"name":"Faculty of Geology and Geography, Sofia University \u201cSt. Kliment Ohridski\u201d, 15 Tzar Osvoboditel Blvd., 1540 Sofia, Bulgaria"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,12,13]]},"reference":[{"key":"ref_1","unstructured":"Breck, D.W. (1974). Zeolite Molecular Sieves: Structure, Chemistry and Use, Waley and Sons."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Gottardi, G., and Galli, E. (1985). Natural Zeolites, Springer.","DOI":"10.1007\/978-3-642-46518-5"},{"key":"ref_3","unstructured":"Tsitsishvili, G.V., Andronikashvili, T.G., Kirov, G.N., and Filizova, L.D. (1992). Natural Zeolites, Ellis Harwood Ltd."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1016\/S0167-2991(01)81183-6","article-title":"Clinoptilolite-heulandite: Applications and basic research","volume":"135","author":"Armbruster","year":"2001","journal-title":"Stud. Surf. Sci. Catal."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Rodr\u00edguez-Iznaga, I., Shelyapina, M.G., and Petranovskii, V. (2022). Ion exchange in natural clinoptilolite: Aspects related to its structure and applications. Minerals, 12.","DOI":"10.3390\/min12121628"},{"key":"ref_6","unstructured":"Baerlocher, C., McCusker, L.B., and Olson, D.H. (2007). Atlas of Zeolite Framework Types, Elsevier."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"533","DOI":"10.1180\/002646198547800","article-title":"Recommended nomenclature for zeolite minerals: Report of the International Mineralogical Association, Commission of New Minerals and Mineral names","volume":"62","author":"Coombs","year":"1998","journal-title":"Miner. Mag."},{"key":"ref_8","first-page":"1120","article-title":"Determination and refinement of the structure of heulandite","volume":"53","author":"Merkle","year":"1968","journal-title":"American Mineralogist. Am. Miner."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"216","DOI":"10.1524\/zkri.1977.145.3-4.216","article-title":"Clinoptilolite: The distribution of potassium atoms and its role in thermal analysis","volume":"145","author":"Koyama","year":"1977","journal-title":"Z. Kristallogr."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"449","DOI":"10.1016\/S0167-2991(09)60906-X","article-title":"Distribution of Cations and Water Molecules in the Heulandite-Type Framework","volume":"28","author":"Sugiyama","year":"1986","journal-title":"Stud. Surf. Sci. Catal."},{"key":"ref_11","first-page":"689","article-title":"The cation sieve properties of clinoptilolite","volume":"45","author":"Ames","year":"1960","journal-title":"Am. Miner. J. Earth Planet. Mater."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"453","DOI":"10.2138\/rmg.2001.45.14","article-title":"Cation-exchange properties of natural zeolites","volume":"45","author":"Pabalan","year":"2001","journal-title":"Rev. Miner. Geochem."},{"key":"ref_13","first-page":"351","article-title":"Clinoptilolite redefined","volume":"45","author":"Mumpton","year":"1960","journal-title":"Am. Miner. J. Earth Planet. Mater."},{"key":"ref_14","first-page":"341","article-title":"Clinoptilolite from Patagonia: The relationship between clinoptilolite and heulandite","volume":"45","author":"Mason","year":"1960","journal-title":"Am. Miner."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"403","DOI":"10.2138\/rmg.2001.45.13","article-title":"Thermal behavior of natural zeolites","volume":"45","author":"Bish","year":"2001","journal-title":"Rev. Miner. Geochem."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"444","DOI":"10.1346\/CCMN.1984.0320602","article-title":"Effects of exchangeable cation composition on the thermal expansion\/contraction of clinoptilolite","volume":"32","author":"Bish","year":"1984","journal-title":"Clays Clay Miner."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"189","DOI":"10.1107\/S010876818300227X","article-title":"The structure of potassium-exchanged heulandite at 293, 373 and 593 K","volume":"B39","author":"Galli","year":"1983","journal-title":"Acta Crystallogr."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"61","DOI":"10.2465\/jmps.070306","article-title":"The partially dehydrated structure of natural heulandite: An in situ high temperature single crystal X-ray diffraction study","volume":"103","author":"Khobaer","year":"2008","journal-title":"J. Miner. Petrol. Sci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"392","DOI":"10.2465\/minerj.11.392","article-title":"Thermal stability of clinoptilolite: The crystal structure at 350 \u00b0C","volume":"11","author":"Kudoh","year":"1983","journal-title":"Miner. J."},{"key":"ref_20","first-page":"1872","article-title":"Stepwise dehydration of heulandite-clinoptilolite from Succor Creek Oregon, U.S.A.: A single-crystal X-ray study at 100 K","volume":"76","author":"Armbruster","year":"1991","journal-title":"Am. Miner."},{"key":"ref_21","first-page":"260","article-title":"Dehydration mechanism of clinoptilolite and heulandite; single-crystal X-ray study of Na-poor, Ca-, K-, Mg-rich clinoptilolite at 100 K","volume":"78","author":"Armbruster","year":"1993","journal-title":"Am. Miner."},{"key":"ref_22","unstructured":"Ming, D.W., and Mumpton, F.A. (1993). Thermal behavior of natural zeolites. Natural Zeolites\u201993: Occurrence, Properties, Use, Brockport."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"625","DOI":"10.1346\/CCMN.2003.0510605","article-title":"Thermal behavior of natural and cation-exchanged clinoptilolite from Sardinia (Italy)","volume":"51","author":"Langella","year":"2003","journal-title":"Clays Clay Miner."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1007\/s10973-009-0118-0","article-title":"Investigation of clinoptilolite rich natural zeolites from Turkey: A combined XRF, TG\/DTG, DTA and DSC study","volume":"100","author":"Alver","year":"2010","journal-title":"J. Therm. Anal. Calorim."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Dimowa, L., Petrova, N., Tzvetanova, Y., Petrov, O., and Piroeva, I. (2022). Structural features and thermal behavior of ion-exchanged clinoptilolite from Beli Plast deposit (Bulgaria). Minerals, 12.","DOI":"10.3390\/min12121576"},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Kr\u00f3l, M., Dechnik, J., Szymczak, P., Handke, B., Szumera, M., and Stoch, P. (2024). Thermal Behavior of Clinoptilolite. Crystals, 14.","DOI":"10.3390\/cryst14070646"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"952","DOI":"10.2138\/am-1996-7-817","article-title":"Equilibrium in the clinoptilolite-H2O system","volume":"81","author":"Carey","year":"1996","journal-title":"Am. Miner."},{"key":"ref_28","unstructured":"Barrer, R.M. (1978). Zeolites and Clay Minerals as Sorbates and Molecular Sieves, Academic Press."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"2523","DOI":"10.1021\/ie00060a004","article-title":"Adsorption characteristics of high-exchange clinoptilolites","volume":"30","author":"Ackley","year":"1991","journal-title":"Ind. Eng. Chem. Res."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"4827\u22124838","DOI":"10.1016\/S0009-2509(00)00122-6","article-title":"Sorbents for air prepurification in air separation","volume":"55","author":"Rege","year":"2000","journal-title":"Chem. Eng. Sci."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"475","DOI":"10.1016\/S0021-9614(05)80135-1","article-title":"Thermodynamic studies of zeolites: Clinoptilolite","volume":"23","author":"Johnson","year":"1991","journal-title":"J. Chem. Thermodyn."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"105","DOI":"10.1021\/ba-1971-0102.ch047","article-title":"Heats of immersion of outgassed ion-exchanged zeolites","volume":"102","author":"Barrer","year":"1971","journal-title":"Molecular Sieve Zeolites-II"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"323","DOI":"10.1007\/BF02636002","article-title":"Heats of immersion of clinoptilolite and its ion-exchanged forms: A calorimetric study","volume":"43","author":"Petrova","year":"1995","journal-title":"J. Therm. Anal. Calorim."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"826","DOI":"10.1346\/CCMN.1997.0450606","article-title":"Calorimetric measurement of the enthalpy of hydration of clinoptilolite","volume":"45","author":"Carey","year":"1997","journal-title":"Clays Clay Miner."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"157","DOI":"10.1023\/A:1011537029569","article-title":"Hydration heats of zeolites for evaluation of heat exchangers","volume":"64","author":"Petrova","year":"2001","journal-title":"J. Therm. Anal. Calorim."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"438","DOI":"10.2138\/am-2001-0407","article-title":"Thermodynamics of ion-exchanged and natural clinoptilolite","volume":"86","author":"Yang","year":"2001","journal-title":"Am. Miner."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"448","DOI":"10.2138\/am-2001-0408","article-title":"Thermochemical study of calcium zeolites\u2014Heulandite and stilbite","volume":"86","author":"Kiseleva","year":"2001","journal-title":"Am. Miner."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"226","DOI":"10.1346\/CCMN.1997.0450211","article-title":"Equilibrium modeling of clinoptilolite-analcime equilibria at Yucca Mountain, Nevada, USA","volume":"45","author":"Chipera","year":"1997","journal-title":"Clays Clay Miner."},{"key":"ref_39","first-page":"1889","article-title":"The distribution of zeolites and their effects on the performance of a nuclear waste repository at Yucca Mountain, Nevada, USA","volume":"88","author":"Bish","year":"2003","journal-title":"Am. Miner."},{"key":"ref_40","unstructured":"Sand, L.B., and Mumpton, F.A. (1978). Solar energy application of natural zeolites. Natural Zeolites\u201978: Occurrence, Properties, Use, Pergamon Press."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"2381","DOI":"10.1016\/j.rser.2007.06.005","article-title":"A review on adsorption heat pump: Problems and solutions","volume":"12","author":"Demir","year":"2008","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Ezgi, C. (2021). Design and thermodynamic analysis of waste heat-driven zeolite\u2013water continuous-adsorption refrigeration and heat pump system for ships. Energies, 14.","DOI":"10.3390\/en14030699"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"653","DOI":"10.1023\/A:1010116930852","article-title":"Measurements of heat of zeolite dehydration by scanning heating","volume":"58","author":"Drebushchak","year":"1999","journal-title":"J. Therm. Anal. Calorim."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1346\/CCMN.2007.0550302","article-title":"Isothermal measurement of heats of hydration in zeolites by simultaneous thermogravimetry and differential scanning calorimetry","volume":"55","author":"Neuhoff","year":"2007","journal-title":"Clays Clay Miner."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"69","DOI":"10.52215\/rev.bgs.2023.84.2.69","article-title":"Desorption\u2013sorption\u2013desorption profile of clinoptilolite in different air media: A DSC-TG study","volume":"84","author":"Petrova","year":"2023","journal-title":"Rev. Bulg. Geol. Soc."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"108","DOI":"10.52215\/rev.bgs.2024.85.2.108","article-title":"A multi-stage DSC-TG methodology for study of zeolite minerals","volume":"85","author":"Petrova","year":"2024","journal-title":"Rev. Bulg. Geol. Soc."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"109792","DOI":"10.1016\/j.micromeso.2019.109792","article-title":"Gallery character of porous space and local extra-framework configurations in the HEU-type structure","volume":"293","author":"Kirov","year":"2020","journal-title":"Micropor. Mesopor. Mat."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"140","DOI":"10.1006\/jssc.1996.0162","article-title":"Na, K, Rb, and Cs exchange in heulandite single-crystals: X-ray structure refinements at 100 K","volume":"123","author":"Yang","year":"1996","journal-title":"J. Solid State Chem."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"2015","DOI":"10.1080\/07373937.2017.1295386","article-title":"Matching of the water states of products and zeolite during contact adsorption drying","volume":"35","author":"Kirov","year":"2017","journal-title":"Dry. Technol."}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/30\/24\/4770\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,12,15]],"date-time":"2025-12-15T15:16:11Z","timestamp":1765811771000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/30\/24\/4770"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,12,13]]},"references-count":49,"journal-issue":{"issue":"24","published-online":{"date-parts":[[2025,12]]}},"alternative-id":["molecules30244770"],"URL":"https:\/\/doi.org\/10.3390\/molecules30244770","relation":{},"ISSN":["1420-3049"],"issn-type":[{"value":"1420-3049","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,12,13]]}}}