Synergistic Corrosion Inhibition of Mild Steel in 0.5 M H₂SO₄ by Sodium Benzoate, Onion Extract, and Chitosan: Mechanistic and Electrochemical Insights

Synergistic Corrosion Inhibition of Mild Steel in 0.5 M H₂SO₄ by Sodium Benzoate, Onion Extract, and Chitosan: Mechanistic and Electrochemical Insights | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Synergistic Corrosion Inhibition of Mild Steel in 0.5 M H₂SO₄ by Sodium Benzoate, Onion Extract, and Chitosan: Mechanistic and Electrochemical Insights Ameena Kousar, Sowmya P T, Anitha Sudhir, Giridarshan S K, Bhavana V This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8583014/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 14 You are reading this latest preprint version Abstract The corrosion inhibition performance of eco-friendly hybrid inhibitors based on benzoate, onion extract, and chitosan for mild steel in 0.5 M H₂SO₄ was investigated using OCP, Tafel polarization, and EIS techniques. The ternary Benzoate–Onion extract–Chitosan (BOC) system exhibited the most positive and stable OCP, indicating effective surface passivation. Polarization studies showed a pronounced reduction in corrosion current density with a shift of E ₍corr₎ toward nobler potentials, confirming strong inhibition. EIS results revealed substantially increased charge-transfer resistance for chitosan-containing systems, with BOC showing the largest Nyquist semicircle. The inhibition efficiency followed the order: BOC > BC > OC > BO > blank. The superior performance of BOC arises from synergistic adsorption of benzoate carboxylates, chitosan amino groups forming a polymeric barrier, and sulfur- and phenolic-rich compounds from onion extract that enhance film stability. The BOC hybrid system offers an efficient, biodegradable, and sustainable solution for mild steel protection in acidic environments. Mild Steel corrosion Green corrosion inhibitor Electrochemical impedance spectroscopy (EIS) Tafel polarization Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 06 Feb, 2026 Reviews received at journal 02 Feb, 2026 Reviews received at journal 02 Feb, 2026 Reviewers agreed at journal 01 Feb, 2026 Reviews received at journal 30 Jan, 2026 Reviewers agreed at journal 28 Jan, 2026 Reviewers agreed at journal 28 Jan, 2026 Reviewers agreed at journal 27 Jan, 2026 Reviewers agreed at journal 27 Jan, 2026 Reviewers agreed at journal 27 Jan, 2026 Reviewers invited by journal 27 Jan, 2026 Editor assigned by journal 14 Jan, 2026 Submission checks completed at journal 14 Jan, 2026 First submitted to journal 12 Jan, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8583014","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":581950240,"identity":"c08fa302-f293-4798-be29-413843450de9","order_by":0,"name":"Ameena Kousar","email":"","orcid":"","institution":"Vidyavardhaka College of Engineering","correspondingAuthor":false,"prefix":"","firstName":"Ameena","middleName":"","lastName":"Kousar","suffix":""},{"id":581950241,"identity":"00230b6b-9b25-4f01-a5e5-c1afd3a393dd","order_by":1,"name":"Sowmya P T","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA2ElEQVRIiWNgGAWjYDADfvYGIGlgQYRSNigt2XMApEWCBC0GNxJAFBFazOXbHz7mzTksLznz+dUNPwokGPjbuxPwarFs4zE25t122LBfOqfsZg/QYRJnzm7Aq8XgGA+bdO62w4wzZ+ek3eABajGQyCWkhf0ZSIv9hptn0m7+IU4LgxlIS+KGG+zHbhNli2VbjrHx323pyTN7cthuyxhI8BD0iznz8YcPZ26ztu1nP/7s5ps/NnL87b0EHAahmoGYB8zmwascSUsdELM/IKh6FIyCUTAKRiYAACCSSOmdc362AAAAAElFTkSuQmCC","orcid":"","institution":"Vidyavardhaka College of Engineering","correspondingAuthor":true,"prefix":"","firstName":"Sowmya","middleName":"P","lastName":"T","suffix":""},{"id":581950242,"identity":"6dafe22c-0d0b-429e-a628-8d2de9a3d723","order_by":2,"name":"Anitha Sudhir","email":"","orcid":"","institution":"Vidyavardhaka College of Engineering","correspondingAuthor":false,"prefix":"","firstName":"Anitha","middleName":"","lastName":"Sudhir","suffix":""},{"id":581950243,"identity":"905d52b9-dc59-4b41-b9b9-5e8fed0200ad","order_by":3,"name":"Giridarshan S K","email":"","orcid":"","institution":"Vidyavardhaka College of Engineering","correspondingAuthor":false,"prefix":"","firstName":"Giridarshan","middleName":"S","lastName":"K","suffix":""},{"id":581950244,"identity":"72a45014-54b1-4d8a-8c93-bceb6afe8f93","order_by":4,"name":"Bhavana V","email":"","orcid":"","institution":"Vidyavardhaka College of Engineering","correspondingAuthor":false,"prefix":"","firstName":"Bhavana","middleName":"","lastName":"V","suffix":""}],"badges":[],"createdAt":"2026-01-12 14:53:26","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8583014/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8583014/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":101456419,"identity":"09b901b2-10b7-4366-87f9-e231a75f2e3e","added_by":"auto","created_at":"2026-01-29 23:19:04","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2830449,"visible":true,"origin":"","legend":"","description":"","filename":"Corrosionpaper1.6version.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8583014/v1_covered_9a0f4a1d-b595-4615-95ba-107f486b9837.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Synergistic Corrosion Inhibition of Mild Steel in 0.5 M H₂SO₄ by Sodium Benzoate, Onion Extract, and Chitosan: Mechanistic and Electrochemical Insights","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"chemical-papers","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"chpa","sideBox":"Learn more about [Chemical Papers](http://link.springer.com/journal/11696)","snPcode":"11696","submissionUrl":"https://www.editorialmanager.com/CHPA/default.aspx","title":"Chemical Papers","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Mild Steel corrosion, Green corrosion inhibitor, Electrochemical impedance spectroscopy (EIS), Tafel polarization","lastPublishedDoi":"10.21203/rs.3.rs-8583014/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8583014/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe corrosion inhibition performance of eco-friendly hybrid inhibitors based on benzoate, onion extract, and chitosan for mild steel in 0.5 M H₂SO₄ was investigated using OCP, Tafel polarization, and EIS techniques. The ternary Benzoate\u0026ndash;Onion extract\u0026ndash;Chitosan (BOC) system exhibited the most positive and stable OCP, indicating effective surface passivation. Polarization studies showed a pronounced reduction in corrosion current density with a shift of \u003cem\u003eE\u003c/em\u003e₍corr₎ toward nobler potentials, confirming strong inhibition. EIS results revealed substantially increased charge-transfer resistance for chitosan-containing systems, with BOC showing the largest Nyquist semicircle. The inhibition efficiency followed the order: BOC\u0026thinsp;\u0026gt;\u0026thinsp;BC\u0026thinsp;\u0026gt;\u0026thinsp;OC\u0026thinsp;\u0026gt;\u0026thinsp;BO\u0026thinsp;\u0026gt;\u0026thinsp;blank. The superior performance of BOC arises from synergistic adsorption of benzoate carboxylates, chitosan amino groups forming a polymeric barrier, and sulfur- and phenolic-rich compounds from onion extract that enhance film stability. The BOC hybrid system offers an efficient, biodegradable, and sustainable solution for mild steel protection in acidic environments.\u003c/p\u003e","manuscriptTitle":"Synergistic Corrosion Inhibition of Mild Steel in 0.5 M H₂SO₄ by Sodium Benzoate, Onion Extract, and Chitosan: Mechanistic and Electrochemical Insights","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-29 23:18:44","doi":"10.21203/rs.3.rs-8583014/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-02-06T05:37:21+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-02T11:27:14+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-02T10:18:13+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"27168163789615922529631777464178705381","date":"2026-02-02T01:07:17+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-30T22:48:53+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"264789348985854532991644621769726903601","date":"2026-01-28T16:35:27+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"132856441221058334998047370015502453476","date":"2026-01-28T16:20:48+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"178298765754896198525356587171848598014","date":"2026-01-28T04:14:58+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"40683048749311140386838591033416669005","date":"2026-01-28T02:56:57+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"227161028205467573295945459824172498848","date":"2026-01-27T21:34:12+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-01-27T21:24:34+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-01-14T09:17:26+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-01-14T08:21:01+00:00","index":"","fulltext":""},{"type":"submitted","content":"Chemical Papers","date":"2026-01-12T14:36:01+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"chemical-papers","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"chpa","sideBox":"Learn more about [Chemical Papers](http://link.springer.com/journal/11696)","snPcode":"11696","submissionUrl":"https://www.editorialmanager.com/CHPA/default.aspx","title":"Chemical Papers","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"eed36717-e9a6-4940-bcc7-f7968c002fa4","owner":[],"postedDate":"January 29th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-30T16:53:54+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-29 23:18:44","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8583014","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8583014","identity":"rs-8583014","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}