Biochar Production From Plastic‐Contaminated Biomass

ABSTRACT Anaerobic digestion and composting of biowastes are vital pathways to recycle carbon and nutrients for agriculture. However, plastic contamination of soil amendments and fertilizers made from biowastes is a relevant source of (micro‐) plastics in (agricultural) ecosystems. To avoid this con...

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Main Authors: Isabel Hilber, Nikolas Hagemann, José María de laRosa, Heike Knicker, Thomas D. Bucheli, Hans‐Peter Schmidt
Format: Article
Language:English
Published: Wiley 2024-11-01
Series:GCB Bioenergy
Subjects:
Online Access:https://doi.org/10.1111/gcbb.70005
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author Isabel Hilber
Nikolas Hagemann
José María de laRosa
Heike Knicker
Thomas D. Bucheli
Hans‐Peter Schmidt
author_facet Isabel Hilber
Nikolas Hagemann
José María de laRosa
Heike Knicker
Thomas D. Bucheli
Hans‐Peter Schmidt
author_sort Isabel Hilber
collection DOAJ
description ABSTRACT Anaerobic digestion and composting of biowastes are vital pathways to recycle carbon and nutrients for agriculture. However, plastic contamination of soil amendments and fertilizers made from biowastes is a relevant source of (micro‐) plastics in (agricultural) ecosystems. To avoid this contamination, plastic containing biowastes could be pyrolyzed to eliminate the plastic, recycle most of the nutrients, and create carbon sinks when the resulting biochar is applied to soil. Literature suggests plastic elimination mainly by devolatilization at co‐pyrolysis temperatures of > 520°C. However, it is uncertain if the presence of plastic during biomass pyrolysis induces the formation of organic contaminants or has any other adverse effects on biochar properties. Here, we produced biochar from wood residues (WR) obtained from sieving of biowaste derived digestate. The plastic content was artificially enriched to 10%, and this mixture was pyrolyzed at 450°C and 600°C. Beech wood (BW) chips and the purified, that is, (macro‐) plastic‐free WR served as controls. All biochars produced were below limit values of the European Biochar Certificate (EBC) regarding trace element content and organic contaminants. Under study conditions, pyrolysis of biowaste, even when contaminated with plastic, can produce a biochar suitable for agricultural use. However, thermogravimetric and nuclear magnetic resonance spectroscopic analysis of the WR + 10% plastics biochar suggested the presence of plastic residues at pyrolysis temperatures of 450°C. More research is needed to define minimum requirements for the pyrolysis of plastic containing biowaste and to cope with the automated identification and determination of plastic types in biowaste at large scales.
format Article
id doaj-art-d0cd04d355fe412ebcb8677f7016d6cc
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spelling doaj-art-d0cd04d355fe412ebcb8677f7016d6cc2025-08-20T02:12:10ZengWileyGCB Bioenergy1757-16931757-17072024-11-011611n/an/a10.1111/gcbb.70005Biochar Production From Plastic‐Contaminated BiomassIsabel Hilber0Nikolas Hagemann1José María de laRosa2Heike Knicker3Thomas D. Bucheli4Hans‐Peter Schmidt5Environmental Analytics Agroscope Zürich SwitzerlandEnvironmental Analytics Agroscope Zürich SwitzerlandInstituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS‐CSIC) Seville SpainInstituto de la Grasa Consejo Superior de Investigaciones Científicas IG‐CSIC Seville SpainInstituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS‐CSIC) Seville SpainIthaka Institute Arbaz SwitzerlandABSTRACT Anaerobic digestion and composting of biowastes are vital pathways to recycle carbon and nutrients for agriculture. However, plastic contamination of soil amendments and fertilizers made from biowastes is a relevant source of (micro‐) plastics in (agricultural) ecosystems. To avoid this contamination, plastic containing biowastes could be pyrolyzed to eliminate the plastic, recycle most of the nutrients, and create carbon sinks when the resulting biochar is applied to soil. Literature suggests plastic elimination mainly by devolatilization at co‐pyrolysis temperatures of > 520°C. However, it is uncertain if the presence of plastic during biomass pyrolysis induces the formation of organic contaminants or has any other adverse effects on biochar properties. Here, we produced biochar from wood residues (WR) obtained from sieving of biowaste derived digestate. The plastic content was artificially enriched to 10%, and this mixture was pyrolyzed at 450°C and 600°C. Beech wood (BW) chips and the purified, that is, (macro‐) plastic‐free WR served as controls. All biochars produced were below limit values of the European Biochar Certificate (EBC) regarding trace element content and organic contaminants. Under study conditions, pyrolysis of biowaste, even when contaminated with plastic, can produce a biochar suitable for agricultural use. However, thermogravimetric and nuclear magnetic resonance spectroscopic analysis of the WR + 10% plastics biochar suggested the presence of plastic residues at pyrolysis temperatures of 450°C. More research is needed to define minimum requirements for the pyrolysis of plastic containing biowaste and to cope with the automated identification and determination of plastic types in biowaste at large scales.https://doi.org/10.1111/gcbb.70005biocharNMRPAHPCDD/Fpolymerpyrolysis
spellingShingle Isabel Hilber
Nikolas Hagemann
José María de laRosa
Heike Knicker
Thomas D. Bucheli
Hans‐Peter Schmidt
Biochar Production From Plastic‐Contaminated Biomass
GCB Bioenergy
biochar
NMR
PAH
PCDD/F
polymer
pyrolysis
title Biochar Production From Plastic‐Contaminated Biomass
title_full Biochar Production From Plastic‐Contaminated Biomass
title_fullStr Biochar Production From Plastic‐Contaminated Biomass
title_full_unstemmed Biochar Production From Plastic‐Contaminated Biomass
title_short Biochar Production From Plastic‐Contaminated Biomass
title_sort biochar production from plastic contaminated biomass
topic biochar
NMR
PAH
PCDD/F
polymer
pyrolysis
url https://doi.org/10.1111/gcbb.70005
work_keys_str_mv AT isabelhilber biocharproductionfromplasticcontaminatedbiomass
AT nikolashagemann biocharproductionfromplasticcontaminatedbiomass
AT josemariadelarosa biocharproductionfromplasticcontaminatedbiomass
AT heikeknicker biocharproductionfromplasticcontaminatedbiomass
AT thomasdbucheli biocharproductionfromplasticcontaminatedbiomass
AT hanspeterschmidt biocharproductionfromplasticcontaminatedbiomass