Site metadata: {"title":"Leachate Analysis of Heavy Metals in Cigarette Butts and Bricks Incorporated with Cigarette Butts","description":"Billions of cigarette butts (CBs) are discarded as litter in the environment every year worldwide. As CBs have poor biodegradability, it can take several years for them to break down while leaching toxic chemicals and heavy metals. Mohajerani et al. (2016), based on long-term research, developed a method for the recycling of CBs in fired clay bricks with promising results. This paper presents and discusses the leaching behavior of potentially hazardous metals from used, unused, and shredded used CBs, and unfired and fired clay bricks incorporating CBs. The leachate analysis was conducted according to the Australian Bottle Leaching Procedure (ABLP) for pH values 2.9, 5.0, and 9.2. The aim was to quantify the amount of heavy metals leached, determine the relationship between the metal concentration leachate, pH of the solution and condition of the sample, and examine the effect of firing on the leaching capability of bricks. The leachate results were then compared to the concentration limits for heavy metals set by the United States Environmental Protection Authority (USEPA) national primary drinking water and the Environmental Protection Authority (EPA) solid industrial waste hazard categorization thresholds to assess the suitability of fired clay bricks incorporating CBs. Metals Cu, Zn, Mn, Al, Fe, Ti, and Ba demonstrated the highest leachate concentrations for pH 2.9 and pH 5.0 for used CBs. This suggests that used CBs are more prone to leaching heavy metals in areas with highly acidic rain compared to the natural range of precipitation. The leaching behavior of fired bricks incorporating CBs was considerably lower than that for the unfired bricks due to the immobilization of heavy metals during the firing process. However, the leaching of Cr and Ni was almost completely impeded after the firing of the bricks, and more than 50% of all the tested heavy metals were hindered.","favicon":"https://pub.mdpi-res.com/img/mask-icon-128.svg?c1c7eca266cd7013?1737539732","language":"en","ogTitle":"Leachate Analysis of Heavy Metals in Cigarette Butts and Bricks Incorporated with Cigarette Butts","ogDescription":"Billions of cigarette butts (CBs) are discarded as litter in the environment every year worldwide. As CBs have poor biodegradability, it can take several years for them to break down while leaching toxic chemicals and heavy metals. Mohajerani et al. (2016), based on long-term research, developed a method for the recycling of CBs in fired clay bricks with promising results. This paper presents and discusses the leaching behavior of potentially hazardous metals from used, unused, and shredded used CBs, and unfired and fired clay bricks incorporating CBs. The leachate analysis was conducted according to the Australian Bottle Leaching Procedure (ABLP) for pH values 2.9, 5.0, and 9.2. The aim was to quantify the amount of heavy metals leached, determine the relationship between the metal concentration leachate, pH of the solution and condition of the sample, and examine the effect of firing on the leaching capability of bricks. The leachate results were then compared to the concentration limits for heavy metals set by the United States Environmental Protection Authority (USEPA) national primary drinking water and the Environmental Protection Authority (EPA) solid industrial waste hazard categorization thresholds to assess the suitability of fired clay bricks incorporating CBs. Metals Cu, Zn, Mn, Al, Fe, Ti, and Ba demonstrated the highest leachate concentrations for pH 2.9 and pH 5.0 for used CBs. This suggests that used CBs are more prone to leaching heavy metals in areas with highly acidic rain compared to the natural range of precipitation. The leaching behavior of fired bricks incorporating CBs was considerably lower than that for the unfired bricks due to the immobilization of heavy metals during the firing process. However, the leaching of Cr and Ni was almost completely impeded after the firing of the bricks, and more than 50% of all the tested heavy metals were hindered.","ogUrl":"https://www.mdpi.com/1996-1944/13/12/2843","ogImage":"https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g001-550.jpg?1593333301","ogLocaleAlternate":[],"ogSiteName":"MDPI","dcDate":"2020-06-25","dcType":"Article","dcSubject":"leachate analysis","dcDescription":"Billions of cigarette butts (CBs) are discarded as litter in the environment every year worldwide. As CBs have poor biodegradability, it can take several years for them to break down while leaching toxic chemicals and heavy metals. Mohajerani et al. (2016), based on long-term research, developed a method for the recycling of CBs in fired clay bricks with promising results. This paper presents and discusses the leaching behavior of potentially hazardous metals from used, unused, and shredded used CBs, and unfired and fired clay bricks incorporating CBs. The leachate analysis was conducted according to the Australian Bottle Leaching Procedure (ABLP) for pH values 2.9, 5.0, and 9.2. The aim was to quantify the amount of heavy metals leached, determine the relationship between the metal concentration leachate, pH of the solution and condition of the sample, and examine the effect of firing on the leaching capability of bricks. The leachate results were then compared to the concentration limits for heavy metals set by the United States Environmental Protection Authority (USEPA) national primary drinking water and the Environmental Protection Authority (EPA) solid industrial waste hazard categorization thresholds to assess the suitability of fired clay bricks incorporating CBs. Metals Cu, Zn, Mn, Al, Fe, Ti, and Ba demonstrated the highest leachate concentrations for pH 2.9 and pH 5.0 for used CBs. This suggests that used CBs are more prone to leaching heavy metals in areas with highly acidic rain compared to the natural range of precipitation. The leaching behavior of fired bricks incorporating CBs was considerably lower than that for the unfired bricks due to the immobilization of heavy metals during the firing process. However, the leaching of Cr and Ni was almost completely impeded after the firing of the bricks, and more than 50% of all the tested heavy metals were hindered.","scrapeId":"c8183a24-92e4-4b71-a723-5968c78ee955","sso-service":"mdpi","viewport":"width=device-width, initial-scale=1.0","theme-color":"#ffffff","application-name":" ","msapplication-TileImage":"https://pub.mdpi-res.com/img/journals/materials-logo-sq.png?8600e93ff98dbf14","dc.title":"Leachate Analysis of Heavy Metals in Cigarette Butts and Bricks Incorporated with Cigarette Butts","dc.creator":["Halenur Kurmus","Abbas Mohajerani"],"dc.type":"Article","dc.source":"Materials 2020, Vol. 13, Page 2843","dc.date":"2020-06-25","dc.identifier":"10.3390/ma13122843","dc.publisher":"Multidisciplinary Digital Publishing Institute","dc.rights":"http://creativecommons.org/licenses/by/3.0/","dc.format":"application/pdf","dc.language":"en","dc.description":"Billions of cigarette butts (CBs) are discarded as litter in the environment every year worldwide. As CBs have poor biodegradability, it can take several years for them to break down while leaching toxic chemicals and heavy metals. Mohajerani et al. (2016), based on long-term research, developed a method for the recycling of CBs in fired clay bricks with promising results. This paper presents and discusses the leaching behavior of potentially hazardous metals from used, unused, and shredded used CBs, and unfired and fired clay bricks incorporating CBs. The leachate analysis was conducted according to the Australian Bottle Leaching Procedure (ABLP) for pH values 2.9, 5.0, and 9.2. The aim was to quantify the amount of heavy metals leached, determine the relationship between the metal concentration leachate, pH of the solution and condition of the sample, and examine the effect of firing on the leaching capability of bricks. The leachate results were then compared to the concentration limits for heavy metals set by the United States Environmental Protection Authority (USEPA) national primary drinking water and the Environmental Protection Authority (EPA) solid industrial waste hazard categorization thresholds to assess the suitability of fired clay bricks incorporating CBs. Metals Cu, Zn, Mn, Al, Fe, Ti, and Ba demonstrated the highest leachate concentrations for pH 2.9 and pH 5.0 for used CBs. This suggests that used CBs are more prone to leaching heavy metals in areas with highly acidic rain compared to the natural range of precipitation. The leaching behavior of fired bricks incorporating CBs was considerably lower than that for the unfired bricks due to the immobilization of heavy metals during the firing process. However, the leaching of Cr and Ni was almost completely impeded after the firing of the bricks, and more than 50% of all the tested heavy metals were hindered.","dc.subject":["leachate analysis","cigarette butts","recycling","fired clay bricks","waste management"],"prism.issn":"1996-1944","prism.publicationName":"Materials","prism.publicationDate":"2020-06-25","prism.volume":"13","prism.number":"12","prism.section":"Article","prism.startingPage":"2843","citation_issn":"1996-1944","citation_journal_title":"Materials","citation_publisher":"Multidisciplinary Digital Publishing Institute","citation_title":"Leachate Analysis of Heavy Metals in Cigarette Butts and Bricks Incorporated with Cigarette Butts","citation_publication_date":"2020/1","citation_online_date":"2020/06/25","citation_volume":"13","citation_issue":"12","citation_firstpage":"2843","citation_author":["Kurmus, Halenur","Mohajerani, Abbas"],"citation_doi":"10.3390/ma13122843","citation_id":"mdpi-ma13122843","citation_abstract_html_url":"https://www.mdpi.com/1996-1944/13/12/2843","citation_pdf_url":"https://www.mdpi.com/1996-1944/13/12/2843/pdf?version=1593333198","fulltext_pdf":"https://www.mdpi.com/1996-1944/13/12/2843/pdf?version=1593333198","citation_fulltext_html_url":"https://www.mdpi.com/1996-1944/13/12/2843/htm","fulltext_html":"https://www.mdpi.com/1996-1944/13/12/2843/htm","fulltext_xml":"https://www.mdpi.com/1996-1944/13/12/2843/xml","citation_xml_url":"https://www.mdpi.com/1996-1944/13/12/2843/xml","twitter:card":"summary","twitter:site":"@MDPIOpenAccess","twitter:image":"https://pub.mdpi-res.com/img/journals/materials-logo-social.png?8600e93ff98dbf14","fb:app_id":"131189377574","og:site_name":"MDPI","og:type":"article","og:url":"https://www.mdpi.com/1996-1944/13/12/2843","og:title":"Leachate Analysis of Heavy Metals in Cigarette Butts and Bricks Incorporated with Cigarette Butts","og:description":"Billions of cigarette butts (CBs) are discarded as litter in the environment every year worldwide. As CBs have poor biodegradability, it can take several years for them to break down while leaching toxic chemicals and heavy metals. Mohajerani et al. (2016), based on long-term research, developed a method for the recycling of CBs in fired clay bricks with promising results. This paper presents and discusses the leaching behavior of potentially hazardous metals from used, unused, and shredded used CBs, and unfired and fired clay bricks incorporating CBs. The leachate analysis was conducted according to the Australian Bottle Leaching Procedure (ABLP) for pH values 2.9, 5.0, and 9.2. The aim was to quantify the amount of heavy metals leached, determine the relationship between the metal concentration leachate, pH of the solution and condition of the sample, and examine the effect of firing on the leaching capability of bricks. The leachate results were then compared to the concentration limits for heavy metals set by the United States Environmental Protection Authority (USEPA) national primary drinking water and the Environmental Protection Authority (EPA) solid industrial waste hazard categorization thresholds to assess the suitability of fired clay bricks incorporating CBs. Metals Cu, Zn, Mn, Al, Fe, Ti, and Ba demonstrated the highest leachate concentrations for pH 2.9 and pH 5.0 for used CBs. This suggests that used CBs are more prone to leaching heavy metals in areas with highly acidic rain compared to the natural range of precipitation. The leaching behavior of fired bricks incorporating CBs was considerably lower than that for the unfired bricks due to the immobilization of heavy metals during the firing process. However, the leaching of Cr and Ni was almost completely impeded after the firing of the bricks, and more than 50% of all the tested heavy metals were hindered.","og:image":"https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g001-550.jpg?1593333301","google-site-verification":"PxTlsg7z2S00aHroktQd57fxygEjMiNHydKn3txhvwY","facebook-domain-verification":"mcoq8dtq6sb2hf7z29j8w515jjoof7","sourceURL":"https://www.mdpi.com/1996-1944/13/12/2843","url":"https://www.mdpi.com/1996-1944/13/12/2843","statusCode":200} Next Article in Journal [Flame-Retardant and Sound-Absorption Properties of Composites Based on Kapok Fiber](https://www.mdpi.com/1996-1944/13/12/2845) Next Article in Special Issue [Quicklime and Calcium Sulfoaluminate Cement Used as Mineral Accelerators to Improve the Properties of Cemented Paste Backfill with a High Volume of Fly Ash](https://www.mdpi.com/1996-1944/13/18/4018) Previous Article in Journal [Influence of the Acoustic Cover of the Modular Expansion Joint on the Acoustic Climate in the Bridge Structure Surroundings](https://www.mdpi.com/1996-1944/13/12/2842) ## Journals [Active Journals](https://www.mdpi.com/about/journals) [Find a Journal](https://www.mdpi.com/about/journalfinder) [Journal Proposal](https://www.mdpi.com/about/journals/proposal) [Proceedings Series](https://www.mdpi.com/about/proceedings) [**Topics**](https://www.mdpi.com/topics) ## Information [For Authors](https://www.mdpi.com/authors) [For Reviewers](https://www.mdpi.com/reviewers) [For Editors](https://www.mdpi.com/editors) [For Librarians](https://www.mdpi.com/librarians) [For Publishers](https://www.mdpi.com/publishing_services) [For Societies](https://www.mdpi.com/societies) [For Conference Organizers](https://www.mdpi.com/conference_organizers) [Open Access Policy](https://www.mdpi.com/openaccess) [Institutional Open Access Program](https://www.mdpi.com/ioap) [Special Issues Guidelines](https://www.mdpi.com/special_issues_guidelines) [Editorial Process](https://www.mdpi.com/editorial_process) [Research and Publication Ethics](https://www.mdpi.com/ethics) [Article Processing Charges](https://www.mdpi.com/apc) [Awards](https://www.mdpi.com/awards) [Testimonials](https://www.mdpi.com/testimonials) [**Editing Services**](https://www.mdpi.com/authors/english) ## Initiatives [Sciforum](https://sciforum.net/) [MDPI Books](https://www.mdpi.com/books) [Preprints.org](https://www.preprints.org/) [Scilit](https://www.scilit.com/) [SciProfiles](https://sciprofiles.com/) [Encyclopedia](https://encyclopedia.pub/) [JAMS](https://jams.pub/) [Proceedings Series](https://www.mdpi.com/about/proceedings) ## About [Overview](https://www.mdpi.com/about) [Contact](https://www.mdpi.com/about/contact) [Careers](https://careers.mdpi.com/) [News](https://www.mdpi.com/about/announcements) [Press](https://www.mdpi.com/about/press) [Blog](http://blog.mdpi.com/) [Sign In / Sign Up](https://www.mdpi.com/user/login) ## Notice You can make submissions to other journals [here](https://susy.mdpi.com/user/manuscripts/upload). _clear_ ## Notice You are accessing a machine-readable page. 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[Get Information](https://www.mdpi.com/authors) _clear_ ## JSmol Viewer _clear_ _first\_page_ [Download PDF](https://www.mdpi.com/1996-1944/13/12/2843/pdf?version=1593333198) _settings_ [Order Article Reprints](https://www.mdpi.com/1996-1944/13/12/2843/reprints) Font Type: _Arial__Georgia__Verdana_ Font Size: AaAaAa Line Spacing: ______ Column Width: ______ Background: Open AccessArticle # Leachate Analysis of Heavy Metals in Cigarette Butts and Bricks Incorporated with Cigarette Butts by Halenur Kurmus ![](https://www.mdpi.com/bundles/mdpisciprofileslink/img/unknown-user.png)Halenur Kurmus [SciProfiles](https://sciprofiles.com/profile/author/clpZZ0ttMzRTcUx6K1RSa1FleVpWRnhjcmhueVE3N3p2OWg4dExxM0xvVk5laTNsZFU1WjRhZjdEUEJkU1BrSw==?utm_source=mdpi.com&utm_medium=website&utm_campaign=avatar_name) [Scilit](https://scilit.com/scholars?q=Halenur%20Kurmus) [Preprints.org](https://www.preprints.org/search?search1=Halenur%20Kurmus&field1=authors) [Google Scholar](https://scholar.google.com/scholar?q=Halenur%20Kurmus) \* [![](https://pub.mdpi-res.com/img/design/orcid.png?0465bc3812adeb52?1737539732)](https://orcid.org/0000-0003-2628-5035) and Abbas Mohajerani ![](https://www.mdpi.com/profiles/570639/thumb/Abbas_Mohajerani.png)Abbas Mohajerani [SciProfiles](https://sciprofiles.com/profile/570639?utm_source=mdpi.com&utm_medium=website&utm_campaign=avatar_name) [Scilit](https://scilit.com/scholars?q=Abbas%20Mohajerani) [Preprints.org](https://www.preprints.org/search?search1=Abbas%20Mohajerani&field1=authors) [Google Scholar](https://scholar.google.com/scholar?q=Abbas%20Mohajerani) \* [![](https://pub.mdpi-res.com/img/design/orcid.png?0465bc3812adeb52?1737539732)](https://orcid.org/0000-0001-9495-9535) School of Engineering, RMIT University, Melbourne 3000, Australia \* Authors to whom correspondence should be addressed. _Materials_ **2020**, _13_(12), 2843; [https://doi.org/10.3390/ma13122843](https://doi.org/10.3390/ma13122843) Submission received: 14 May 2020 / Revised: 21 June 2020 / Accepted: 23 June 2020 / Published: 25 June 2020 (This article belongs to the Special Issue [Advances in Green Construction Materials](https://www.mdpi.com/journal/materials/special_issues/Green_Construct_Material)) Download _keyboard\_arrow\_down_ [Download PDF](https://www.mdpi.com/1996-1944/13/12/2843/pdf?version=1593333198) [Download PDF with Cover](https://www.mdpi.com/1996-1944/13/12/2843#) [Download XML](https://www.mdpi.com/1996-1944/13/12/2843#) [Download Epub](https://www.mdpi.com/1996-1944/13/12/2843/epub) [Browse Figures](https://www.mdpi.com/1996-1944/13/12/2843#) [\ Figure 1
\

Some of the prepared brick samples with different percentages of cigarette butts (CBs).

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g001.png?1593333301 " Figure 1

Some of the prepared brick samples with different percentages of cigarette butts (CBs).

")[\ Figure 2
\

Leaching procedure for leachates derived from (a) used, unused, and shredded used CBs and (b) fired clay bricks and (c) unfired clay bricks incorporating 0%, 0.5%, 1%, 1.5%, and 2% CBs by mass.

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g002a.png?1593333300 " Figure 2

Leaching procedure for leachates derived from (a) used, unused, and shredded used CBs and (b) fired clay bricks and (c) unfired clay bricks incorporating 0%, 0.5%, 1%, 1.5%, and 2% CBs by mass.

")[\ Figure 2 Cont.
\

Leaching procedure for leachates derived from (a) used, unused, and shredded used CBs and (b) fired clay bricks and (c) unfired clay bricks incorporating 0%, 0.5%, 1%, 1.5%, and 2% CBs by mass.

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g002b.png?1593333300 " Figure 2 Cont.

Leaching procedure for leachates derived from (a) used, unused, and shredded used CBs and (b) fired clay bricks and (c) unfired clay bricks incorporating 0%, 0.5%, 1%, 1.5%, and 2% CBs by mass.

")[\ Figure 3
\

Flow chart of the leachate analysis procedure followed in this study.

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g003.png?1593333300 " Figure 3

Flow chart of the leachate analysis procedure followed in this study.

")[\ Figure 4
\

Particle size distribution (PSD) curve of brick soil used in this study.

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g004.png?1593333301 " Figure 4

Particle size distribution (PSD) curve of brick soil used in this study.

")[\ Figure 5
\

Brick soil chemical properties.

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g005.png?1593333300 " Figure 5

Brick soil chemical properties.

")[\ Figure 6
\

X-ray diffraction (XRD) patterns of brick soil.

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g006.png?1593333301 " Figure 6

X-ray diffraction (XRD) patterns of brick soil.

")[\ Figure 7
\

Leachate concentrations of unused CBs.

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g007.png?1593333300 " Figure 7

Leachate concentrations of unused CBs.

")[\ Figure 8
\

Leachate concentrations of used CBs.

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g008.png?1593333301 " Figure 8

Leachate concentrations of used CBs.

")[\ Figure 9
\

Leachate concentrations of shredded used CBs.

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g009.png?1593333300 " Figure 9

Leachate concentrations of shredded used CBs.

")[\ Figure 10
\

Al, Mn, Fe, and Zn leachate concentrations for pH 5.0.

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g010.png?1593333300 " Figure 10

Al, Mn, Fe, and Zn leachate concentrations for pH 5.0.

")[\ Figure 11
\

Leachate concentrations for crushed bricks with 0% CB content.

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g011.png?1593333301 " Figure 11

Leachate concentrations for crushed bricks with 0% CB content.

")[\ Figure 12
\

Leachate concentrations for crushed bricks with 0.5% CB content.

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g012.png?1593333300 " Figure 12

Leachate concentrations for crushed bricks with 0.5% CB content.

")[\ Figure 13
\

Leachate concentrations for crushed bricks with 1% CB content.

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g013.png?1593333301 " Figure 13

Leachate concentrations for crushed bricks with 1% CB content.

")[\ Figure 14
\

Leachate concentrations for crushed bricks with 1.5% CB content.

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g014.png?1593333300 " Figure 14

Leachate concentrations for crushed bricks with 1.5% CB content.

")[\ Figure 15
\

Leachate concentrations for crushed bricks with 2% CB content.

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g015.png?1593333300 " Figure 15

Leachate concentrations for crushed bricks with 2% CB content.

")[\ Figure 16
\

Variable relationship observed between metal concentrations leached from 1% CB bricks and pH value.

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g016.png?1593333301 " Figure 16

Variable relationship observed between metal concentrations leached from 1% CB bricks and pH value.

")[\ Figure 17
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Variable relationship observed between metal concentrations leached from 2% CB bricks and pH value.

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g017.png?1593333300 " Figure 17

Variable relationship observed between metal concentrations leached from 2% CB bricks and pH value.

")[\ Figure 18
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Heavy metal concentration of 0.5% CB content bricks before and after firing.

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g018.png?1593333300 " Figure 18

Heavy metal concentration of 0.5% CB content bricks before and after firing.

")[\ Figure 19
\

Heavy metal concentration of 1% CB content bricks before and after firing.

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g019.png?1593333300 " Figure 19

Heavy metal concentration of 1% CB content bricks before and after firing.

")[\ Figure 20
\

Heavy metal concentration of 1.5% CB content bricks before and after firing.

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g020.png?1593333300 " Figure 20

Heavy metal concentration of 1.5% CB content bricks before and after firing.

")[\ Figure 21
\

Heavy metal concentration of 2% CB content bricks before and after firing.

\ ](https://pub.mdpi-res.com/materials/materials-13-02843/article_deploy/html/images/materials-13-02843-g021.png?1593333300 " Figure 21

Heavy metal concentration of 2% CB content bricks before and after firing.

") [Versions Notes](https://www.mdpi.com/1996-1944/13/12/2843/notes) ## Abstract **:** Billions of cigarette butts (CBs) are discarded as litter in the environment every year worldwide. As CBs have poor biodegradability, it can take several years for them to break down while leaching toxic chemicals and heavy metals. Mohajerani et al. (2016), based on long-term research, developed a method for the recycling of CBs in fired clay bricks with promising results. This paper presents and discusses the leaching behavior of potentially hazardous metals from used, unused, and shredded used CBs, and unfired and fired clay bricks incorporating CBs. The leachate analysis was conducted according to the Australian Bottle Leaching Procedure (ABLP) for pH values 2.9, 5.0, and 9.2. The aim was to quantify the amount of heavy metals leached, determine the relationship between the metal concentration leachate, pH of the solution and condition of the sample, and examine the effect of firing on the leaching capability of bricks. The leachate results were then compared to the concentration limits for heavy metals set by the United States Environmental Protection Authority (USEPA) national primary drinking water and the Environmental Protection Authority (EPA) solid industrial waste hazard categorization thresholds to assess the suitability of fired clay bricks incorporating CBs. Metals Cu, Zn, Mn, Al, Fe, Ti, and Ba demonstrated the highest leachate concentrations for pH 2.9 and pH 5.0 for used CBs. This suggests that used CBs are more prone to leaching heavy metals in areas with highly acidic rain compared to the natural range of precipitation. The leaching behavior of fired bricks incorporating CBs was considerably lower than that for the unfired bricks due to the immobilization of heavy metals during the firing process. However, the leaching of Cr and Ni was almost completely impeded after the firing of the bricks, and more than 50% of all the tested heavy metals were hindered. Keywords: [leachate analysis](https://www.mdpi.com/search?q=leachate+analysis); [cigarette butts](https://www.mdpi.com/search?q=cigarette+butts); [recycling](https://www.mdpi.com/search?q=recycling); [fired clay bricks](https://www.mdpi.com/search?q=fired+clay+bricks); [waste management](https://www.mdpi.com/search?q=waste+management) ## 1\. Introduction The littering of cigarette butts (CBs) has become a critical environmental issue around the world. In Australia, 20 billion filtered cigarettes are consumed annually, and it is predicted that over 7 billion are thrown into the environment \[ [1](https://www.mdpi.com/1996-1944/13/12/2843#B1-materials-13-02843)\]. In 2016, 5.7 trillion cigarettes were consumed worldwide, and it is estimated that by 2025, cigarette production will increase by 50% \[ [2](https://www.mdpi.com/1996-1944/13/12/2843#B2-materials-13-02843)\]. Over 97% of cigarettes have cellulose acetate filters \[ [2](https://www.mdpi.com/1996-1944/13/12/2843#B2-materials-13-02843)\], which are designed to partially preserve particulate smoke components. The major toxic agents include nicotine, polycyclic aromatic hydrocarbons (PAHs), compounds specific to Solanaceae, nicotiana alkaloids, and catechols \[ [3](https://www.mdpi.com/1996-1944/13/12/2843#B3-materials-13-02843), [4](https://www.mdpi.com/1996-1944/13/12/2843#B4-materials-13-02843)\]. Cellulose acetate filters have poor biodegradability, and, under normal environm