{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T23:32:23Z","timestamp":1788910343519,"version":"build-2803163510"},"reference-count":26,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2022,12,25]],"date-time":"2022-12-25T00:00:00Z","timestamp":1671926400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["22206130"],"award-info":[{"award-number":["22206130"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Secondary problems, such as the occurrence of side reactions and the accumulation of by-products, are a major challenge in the application of wet denitrification technology through urea solution. We revealed the formation mechanism of urea nitrate and clarified the main and side reaction paths and key intermediates of denitrification. Urea nitrate would be separated from urea absorption solution only when the concentration product of [urea], [H+] and [NO3\u2212] was greater than 0.87~1.22 mol3\/L3. The effects of the urea concentration (5\u201320%) and reaction temperature (30\u201370 \u00b0C) on the denitrification efficiency could be ignored. Improving the oxidation degree of the flue gas promoted the removal of nitrogen oxides. The alkaline condition was beneficial to the dissolution process, while the acidic condition was beneficial to the reaction process. As a whole, the alkaline condition was the preferred process parameter. The research results could guide the optimization of process conditions in theory, improve the operation efficiency of the denitrification reactor and avoid the occurrence of side reactions.<\/jats:p>","DOI":"10.3390\/molecules28010162","type":"journal-article","created":{"date-parts":[[2022,12,27]],"date-time":"2022-12-27T02:55:07Z","timestamp":1672109707000},"page":"162","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Reaction Mechanism for the Removal of NOx by Wet Scrubbing Using Urea Solution: Determination of Main and Side Reaction Paths"],"prefix":"10.3390","volume":"28","author":[{"given":"Lina","family":"Gan","sequence":"first","affiliation":[{"name":"School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yang","family":"Liu","sequence":"additional","affiliation":[{"name":"School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peng","family":"Ye","sequence":"additional","affiliation":[{"name":"School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hejingying","family":"Niu","sequence":"additional","affiliation":[{"name":"School of Environmental & Chemical Engineering, Shanghai University, Shanghai 200444, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7783-0673","authenticated-orcid":false,"given":"Kezhi","family":"Li","sequence":"additional","affiliation":[{"name":"Institute of Engineering Technology, Sinopec Catalyst Co., Ltd., Beijing 101111, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,12,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"221","DOI":"10.1016\/S0926-860X(01)00832-8","article-title":"Present status and perspectives in de-NOx SCR catalysis","volume":"222","author":"Forzatti","year":"2001","journal-title":"Appl. Catal. A Gen."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1080\/01614940500439891","article-title":"Recent advances in catalytic DeNOx science and technology","volume":"48","author":"Liu","year":"2006","journal-title":"Catal. Rev. Sci. Eng."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1016\/j.cattod.2011.03.034","article-title":"Low-temperature selective catalytic reduction of NOxwith NH3 over metal oxide and zeolite catalysts-A review","volume":"175","author":"Li","year":"2011","journal-title":"Catal. Today"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Gan, L., Guo, F., Yu, J., and Xu, G. (2016). Improved low-temperature activity of V2O5-WO3\/TiO2 for denitration using different vanadium precursors. 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Interfaces"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"623","DOI":"10.1016\/j.chemosphere.2016.11.015","article-title":"Nitric oxide removal by combined urea and FeII EDTA reaction systems","volume":"168","author":"He","year":"2017","journal-title":"Chemosphere"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"16","DOI":"10.1016\/j.jiec.2008.07.010","article-title":"Removal of NO from flue gas by wet scrubbing with NaClO2\/(NH2)2CO solutions","volume":"15","author":"Wei","year":"2009","journal-title":"J. Ind. Eng. Chem."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1016\/j.jhazmat.2016.03.034","article-title":"Combination of complex adsorption and anammox for nitric oxide removal","volume":"312","author":"Wang","year":"2016","journal-title":"J. Hazard. Mater."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"52","DOI":"10.1016\/j.cej.2010.12.030","article-title":"Simultaneous removal of SO2 and NOx by wet scrubbing using urea solution","volume":"168","author":"Fang","year":"2011","journal-title":"Chem. Eng. J."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"6600","DOI":"10.1021\/acs.energyfuels.9b01184","article-title":"Experimental Study on the NOx Removal by Scrubbing with Urea-H2O2 Solution after NO Partial Preoxidation","volume":"33","author":"Wen","year":"2019","journal-title":"Energy Fuel"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"645","DOI":"10.1016\/j.fuproc.2012.09.060","article-title":"Simultaneous removal of SO2, NO and Hg0 by wet scrubbing using urea+KMnO4 solution","volume":"106","author":"Fang","year":"2013","journal-title":"Fuel Process. Technol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1536","DOI":"10.1016\/j.cjche.2018.02.026","article-title":"A study on simultaneous removal of NO and SO2 by using sodium persulfate aqueous scrubbing","volume":"26","author":"Kang","year":"2018","journal-title":"Chin. J. Chem. Eng."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"42","DOI":"10.1016\/j.cej.2010.02.060","article-title":"Simultaneous removal of SO2 and NO using M\/NaClO2 complex absorbent","volume":"160","author":"Zhao","year":"2010","journal-title":"Chem. Eng. J."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"912","DOI":"10.1016\/j.cej.2016.10.125","article-title":"Applications of high gravity technologies for wastewater treatment: A review","volume":"313","author":"Jiao","year":"2017","journal-title":"Chem. Eng. J."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"405","DOI":"10.1016\/j.powtec.2017.11.036","article-title":"Efficient preparation of monodisperse CaCO3 nanoparticles as overbased nanodetergents in a high-gravity rotating packed bed reactor","volume":"325","author":"Kang","year":"2018","journal-title":"Powder Technol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"2869","DOI":"10.1016\/j.watres.2012.02.041","article-title":"Adsorption behavior of pesticide methomyl on activated carbon in a high gravity rotating packed bed reactor","volume":"46","author":"Chang","year":"2012","journal-title":"Water Res."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"777","DOI":"10.1021\/ie00003a020","article-title":"Removal of nitrogen oxides (NOx) from flue gases using the urea acidic process: Kinetics of the chemical reaction of nitrous acid with urea","volume":"31","author":"Lasalle","year":"1992","journal-title":"Ind. Eng. Chem. Res."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"582","DOI":"10.1520\/JFS2004278","article-title":"A field diagnostic test for the improvised explosive urea nitrate","volume":"50","author":"Almog","year":"2005","journal-title":"J. Forensic Sci."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1016\/j.tca.2011.04.004","article-title":"Analyses of the thermal decomposition of urea nitrate at high temperature","volume":"521","author":"Brousseau","year":"2011","journal-title":"Thermochim. Acta"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"2759","DOI":"10.1021\/jp0564647","article-title":"Urea and Urea Nitrate Decomposition Pathways:\u2009 A Quantum Chemistry Study","volume":"110","author":"Tokmakov","year":"2006","journal-title":"J. Phys. Chem. A"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"572","DOI":"10.1107\/S0567740869002573","article-title":"The crystal structure of uronium nitrate (urea nitrate) by neutron diffraction","volume":"25","author":"Worsham","year":"1969","journal-title":"Acta Crystallogr. Sect. B"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"3477","DOI":"10.1007\/s10924-021-02154-x","article-title":"Composite of Natural Polymers and Their Adsorbent Properties on the Dyes and Heavy Metal Ions","volume":"29","author":"Kayan","year":"2021","journal-title":"J. Polym. Environ."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"187","DOI":"10.1016\/j.apenergy.2014.05.006","article-title":"Nitrogen oxide absorption and nitrite\/nitrate formation in limestone slurry for WFGD system","volume":"129","author":"Zheng","year":"2014","journal-title":"Appl. Energy"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1016\/S1383-5866(99)00049-0","article-title":"Analysis and prediction of the liquid phase composition for the absorption of nitrogen oxides into aqueous solutions","volume":"18","author":"Thomas","year":"1999","journal-title":"Sep. Purif. Technol."}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/28\/1\/162\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:50:36Z","timestamp":1760147436000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/28\/1\/162"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,12,25]]},"references-count":26,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2023,1]]}},"alternative-id":["molecules28010162"],"URL":"https:\/\/doi.org\/10.3390\/molecules28010162","relation":{},"ISSN":["1420-3049"],"issn-type":[{"value":"1420-3049","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,12,25]]}}}