Sustainable biosorption of Methylene Blue using highly-efficient activated Mediterranean macroalgae: a comparative mechanistic study

Sustainable biosorption of Methylene Blue using highly-efficient activated Mediterranean macroalgae: a comparative mechanistic study | 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 Article Sustainable biosorption of Methylene Blue using highly-efficient activated Mediterranean macroalgae: a comparative mechanistic study Ali Jaber, Loubna Bitar, Mohammad Mazloum, Leila Ghannam, Walid Malaeb, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9313150/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 14 You are reading this latest preprint version Abstract Synthetic dyes, for instance methylene blue, are persistent water pollutants that withstand conventional methods applied for water treatment. This poses a high risk to ecosystems and public health. In this study, we investigated the biosorption efficiency of four marine macroalgae species, Ulva lactuca , Ulva prolifera , Bryopsis , and Corallina , collected from the Lebanese coastline, as low-cost local adsorbents for the removal of methylene blue from aqueous solutions. The algal biomasses were chemically pretreated with either CaCl₂, NaOH, or HCl to enhance their stability and adsorption performance. Batch experiments were conducted to evaluate the influence of pH, initial dye concentrations, biomass dosage, and contact time. Adsorption isotherms, described in terms of Langmuir and Freundlich, and kinetic models ( pseudo -first-order, pseudo -second-order, and intraparticle diffusion) were used to analyze the data. All four algae exhibited efficient dye removal, with the maximum Langmuir adsorption capacity (Q max ) reaching an impressive 653 mg/g for Ulva prolifera . The optimal conditions were within pH ranges of 5 to 12, biosorbent dosage of 100 mg/L, and contact time of 90 min. Kinetic modeling revealed strong conformity with pseudo -first- and pseudo -second-order mechanisms of adsorption. Our work further highlights that marine macroalgae, particularly CaCl 2 –treated Ulva prolifera , and to a lesser extent Ulva lactuca , demonstrate an outstanding potential as sustainable and low-cost biosorbent material for the removal of cationic dyes. These findings support their application in phycoremediation strategies for industrial wastewater treatment. Earth and environmental sciences/Environmental sciences Physical sciences/Materials science Phycoremediation Biosorption Marine macroalgae Methylene blue Water treatment Full Text Additional Declarations No competing interests reported. Supplementary Files SupportingInformation.docx Cite Share Download PDF Status: Under Revision Version 1 posted Editorial decision: Revision requested 11 May, 2026 Reviews received at journal 10 May, 2026 Reviews received at journal 06 May, 2026 Reviews received at journal 05 May, 2026 Reviewers agreed at journal 04 May, 2026 Reviewers agreed at journal 04 May, 2026 Reviewers agreed at journal 02 May, 2026 Reviewers agreed at journal 30 Apr, 2026 Reviewers agreed at journal 30 Apr, 2026 Reviewers agreed at journal 30 Apr, 2026 Reviewers invited by journal 30 Apr, 2026 Editor assigned by journal 16 Apr, 2026 Submission checks completed at journal 09 Apr, 2026 First submitted to journal 09 Apr, 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-9313150","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":635751790,"identity":"3d616878-aff1-44d6-831e-7a8b515e8c70","order_by":0,"name":"Ali Jaber","email":"","orcid":"","institution":"Lebanese American University","correspondingAuthor":false,"prefix":"","firstName":"Ali","middleName":"","lastName":"Jaber","suffix":""},{"id":635751791,"identity":"fb6b69ec-b1bc-4e6f-8d20-70ec075872d9","order_by":1,"name":"Loubna Bitar","email":"","orcid":"","institution":"Lebanese University","correspondingAuthor":false,"prefix":"","firstName":"Loubna","middleName":"","lastName":"Bitar","suffix":""},{"id":635751792,"identity":"d5b84cee-2965-42e6-8d67-fdca9784630b","order_by":2,"name":"Mohammad Mazloum","email":"","orcid":"","institution":"Lebanese American University","correspondingAuthor":false,"prefix":"","firstName":"Mohammad","middleName":"","lastName":"Mazloum","suffix":""},{"id":635751793,"identity":"5e934fd5-5482-4229-a727-76a944ed1ea8","order_by":3,"name":"Leila Ghannam","email":"","orcid":"","institution":"Lebanese University","correspondingAuthor":false,"prefix":"","firstName":"Leila","middleName":"","lastName":"Ghannam","suffix":""},{"id":635751794,"identity":"854ed22c-7655-465d-acf6-7f06151cae1e","order_by":4,"name":"Walid Malaeb","email":"","orcid":"","institution":"Lebanese American University","correspondingAuthor":false,"prefix":"","firstName":"Walid","middleName":"","lastName":"Malaeb","suffix":""},{"id":635751795,"identity":"2a14b11e-007a-4787-8752-327fb6083380","order_by":5,"name":"Ali Yassin","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA/0lEQVRIiWNgGAWjYDACdsYGMM3GwNj44EMBmG3AwFBwALcWZrgW5sOGMwxgWgzwaYGz2NKkeYjRwt/M3MDMU1NnzyfdYyBtY2CX2MDevE2CweAOTi0ShxmBWo4dTmyTOWNgnGOQnNjAc6wMqOUZboeBtbAdSGCTAKrPMWBObJDIMQNqOYxThzxYy786e5CWwxYG9YkN8m/wazEAaeFtY2Zsk0hLbAZygbbw4NdiCNRycG4f0C8SyYcZewyOG7fxpBVbJODxi9zx9ocP3nyrs5efkdj+40dFtWw/++GNNz5U4A4xEDjEg8xjAxEJeDUwMDD+IKBgFIyCUTAKRjgAAKePTmezUexnAAAAAElFTkSuQmCC","orcid":"","institution":"Lebanese American University","correspondingAuthor":true,"prefix":"","firstName":"Ali","middleName":"","lastName":"Yassin","suffix":""},{"id":635751796,"identity":"97473541-ac50-4a3c-9767-55282712777c","order_by":6,"name":"Ahmad Houri","email":"","orcid":"","institution":"Lebanese American University","correspondingAuthor":false,"prefix":"","firstName":"Ahmad","middleName":"","lastName":"Houri","suffix":""}],"badges":[],"createdAt":"2026-04-03 13:08:17","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9313150/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9313150/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":108807670,"identity":"bd1cefb1-8f95-4104-9b70-73672c6c521d","added_by":"auto","created_at":"2026-05-08 15:31:07","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1241518,"visible":true,"origin":"","legend":"","description":"","filename":"BiosorptionofMBusingAlgaeAYf2.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9313150/v1_covered_27942530-132e-4cf5-bb0b-6c97bec8e825.pdf"},{"id":108781534,"identity":"3b6569f8-98e8-485a-83dd-b33080c6ebc3","added_by":"auto","created_at":"2026-05-08 10:22:07","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":94036,"visible":true,"origin":"","legend":"","description":"","filename":"SupportingInformation.docx","url":"https://assets-eu.researchsquare.com/files/rs-9313150/v1/ef1fb07e5668cf6cae5c09a3.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Sustainable biosorption of Methylene Blue using highly-efficient activated Mediterranean macroalgae: a comparative mechanistic study","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Phycoremediation, Biosorption, Marine macroalgae, Methylene blue, Water treatment","lastPublishedDoi":"10.21203/rs.3.rs-9313150/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9313150/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSynthetic dyes, for instance methylene blue, are persistent water pollutants that withstand conventional methods applied for water treatment. This poses a high risk to ecosystems and public health. In this study, we investigated the biosorption efficiency of four marine macroalgae species, \u003cem\u003eUlva lactuca\u003c/em\u003e, \u003cem\u003eUlva prolifera\u003c/em\u003e, \u003cem\u003eBryopsis\u003c/em\u003e, and \u003cem\u003eCorallina\u003c/em\u003e, collected from the Lebanese coastline, as low-cost local adsorbents for the removal of methylene blue from aqueous solutions. The algal biomasses were chemically pretreated with either CaCl₂, NaOH, or HCl to enhance their stability and adsorption performance. Batch experiments were conducted to evaluate the influence of pH, initial dye concentrations, biomass dosage, and contact time. Adsorption isotherms, described in terms of Langmuir and Freundlich, and kinetic models (\u003cem\u003epseudo\u003c/em\u003e-first-order, \u003cem\u003epseudo\u003c/em\u003e-second-order, and intraparticle diffusion) were used to analyze the data. All four algae exhibited efficient dye removal, with the maximum Langmuir adsorption capacity (Q\u003csub\u003emax\u003c/sub\u003e) reaching an impressive 653 mg/g for \u003cem\u003eUlva prolifera\u003c/em\u003e. The optimal conditions were within pH ranges of 5 to 12, biosorbent dosage of 100 mg/L, and contact time of 90 min. Kinetic modeling revealed strong conformity with \u003cem\u003epseudo\u003c/em\u003e-first- and \u003cem\u003epseudo\u003c/em\u003e-second-order mechanisms of adsorption. Our work further highlights that marine macroalgae, particularly CaCl\u003csub\u003e2\u003c/sub\u003e\u0026ndash;treated \u003cem\u003eUlva prolifera\u003c/em\u003e, and to a lesser extent \u003cem\u003eUlva lactuca\u003c/em\u003e, demonstrate an outstanding potential as sustainable and low-cost biosorbent material for the removal of cationic dyes. These findings support their application in phycoremediation strategies for industrial wastewater treatment.\u003c/p\u003e","manuscriptTitle":"Sustainable biosorption of Methylene Blue using highly-efficient activated Mediterranean macroalgae: a comparative mechanistic study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-08 10:21:59","doi":"10.21203/rs.3.rs-9313150/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-05-11T17:55:08+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-10T20:34:41+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-06T20:45:00+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-05T10:59:21+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"327609670038483647929690317690812113289","date":"2026-05-04T23:30:16+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"269558443516503502756485916950259926015","date":"2026-05-04T04:49:29+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"97572063640279040761869414367180978609","date":"2026-05-02T05:57:32+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"266947247322298367874155454122446796583","date":"2026-04-30T15:09:48+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"72381518745246626242763655070764407957","date":"2026-04-30T10:56:51+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"228618682891001953153639570581325166671","date":"2026-04-30T04:58:09+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-30T04:47:36+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-04-16T14:37:31+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-04-09T16:37:54+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2026-04-09T15:30:42+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"96af53ae-95e2-4284-8b7b-f459c20dd27f","owner":[],"postedDate":"May 8th, 2026","published":true,"recentEditorialEvents":[{"type":"decision","content":"Revision requested","date":"2026-05-11T17:55:08+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-10T20:34:41+00:00","index":35,"fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-06T20:45:00+00:00","index":34,"fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-05T10:59:21+00:00","index":33,"fulltext":""},{"type":"reviewerAgreed","content":"327609670038483647929690317690812113289","date":"2026-05-04T23:30:16+00:00","index":32,"fulltext":""},{"type":"reviewerAgreed","content":"269558443516503502756485916950259926015","date":"2026-05-04T04:49:29+00:00","index":31,"fulltext":""},{"type":"reviewerAgreed","content":"97572063640279040761869414367180978609","date":"2026-05-02T05:57:32+00:00","index":30,"fulltext":""},{"type":"reviewerAgreed","content":"266947247322298367874155454122446796583","date":"2026-04-30T15:09:48+00:00","index":29,"fulltext":""},{"type":"reviewerAgreed","content":"72381518745246626242763655070764407957","date":"2026-04-30T10:56:51+00:00","index":28,"fulltext":""},{"type":"reviewerAgreed","content":"228618682891001953153639570581325166671","date":"2026-04-30T04:58:09+00:00","index":27,"fulltext":""},{"type":"reviewersInvited","content":"10","date":"2026-04-30T04:47:36+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"in-revision","subjectAreas":[{"id":67665439,"name":"Earth and environmental sciences/Environmental sciences"},{"id":67665440,"name":"Physical sciences/Materials science"}],"tags":[],"updatedAt":"2026-05-11T18:09:12+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-08 10:21:59","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9313150","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9313150","identity":"rs-9313150","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}