Circular economy approach to eggshell waste utilisation: Insoluble protein extraction and CaCO3 upcycling for carbonated hydroxyapatite (cHAP)-based fire-resistant wood

PLOS ONE

卷:21

Research Article

Edita Garskaite^1,2  Stephen R. Euston^3,4  Jozef Martinka⁵  Peter Rantuch⁵  Konrad Wilkens Flecknoe-Brown⁶  Patrick van Hees⁶  Michael Försth⁷  Alexandra Byström⁸  Dietrich Buck⁹  Dick Sandberg¹⁰ 

[1] Institute of Chemistry, Faculty of Chemistry and Geosciences, Vilnius University, Vilnius, Lithuania

[2] Faculty of Materials Science and Technology in Trnava, Slovak University of Technology in Bratislava, Trnava, Slovakia

[3] SWECO, Luleå, Sweden

[4] Wood Science and Engineering, Department of Engineering Sciences and Mathematics, Luleå University of Technology, Skellefteå, Sweden

[5] Department of Manufacturing and Civil Engineering, Norwegian University of Science and Technology, Gjøvik, Norway

[6] Division of Structural and Fire Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden

[7] Department of Physics, Toronto Metropolitan University, Toronto, Canada

[8] Division of Fire Safety Engineering, Department of Building and Environmental Technology, Faculty of Engineering, LTH, Lund University, Lund, Sweden

[9] Division of Building Materials, Department of Building and Environmental Technology, Faculty of Engineering, LTH, Lund University, Lund, Sweden

[10] Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, United Kingdom

关键词: Chicken eggs;    Bird eggs;    Protein extraction;    Scottish people;    Aqueous solutions;    Eggs;    Wood;    Sustainability science;   

DOI  :  10.1371/journal.pone.0351943

 received in 2026-03-17, accepted in 2026-06-03,  发布年份 2026

来源: PLOS

【 摘 要 】

Transitioning to a resource-efficient and sustainable circular economy is vital for tackling climate- and environmental-related challenges. This study demonstrates a closed-loop strategy for upcycling agricultural biowaste eggshells. Water-insoluble proteins were extracted from both shell membranes and shell fragments by boiling in water using protein denaturants. The ground eggshells also were used to prepare calcium acetate (Ca(CH3COO)2) and to treat Scots pine (Pinus sylvestris L.) sapwood. Mineralisation of the wood was achieved by performing a two-step impregnation process using aqueous solutions of ammonium dihydrogen phosphate (NH4H2PO4) and Ca(CH3COO)2 salts. Morphological studies revealed the relatively low saturation of wood matrix with mineral, with cell lumina mostly unfilled, while elemental mapping confirmed homogeneous distribution of Ca and P within the wood matrix. Powder X-ray diffraction (XRD) analysis revealed that wood treatment resulted in the in-situ co-precipitation of low-crystallinity hydroxyapatite (Ca10(PO4)6(OH)2), and spectroscopic analysis indicated carbonate substitution within the Ca10(PO4)6(OH)2 crystal lattice, suggesting the formation of carbonated hydroxyapatite (Ca10-x(PO4)6-x(CO3)x(OH)2-x-2y(CO3)y). Microscale combustion calorimeter (MCC) and cone calorimeter (CC) measurements of mineralised wood revealed a reduction in the total heat release (THR) compared with untreated wood, indicating potential for further optimisation of wood modification process. Results suggest that the proposed aqueous solution-based processing approach for converting an abundant resource, chicken eggshells, into value-added products has potential for new technology and bioeconomy development and represents a promising pathway towards improved sustainability.

【 授权许可】

CC BY   
Garskaite et al 2026

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