Sustainable nexus for treating acid mine drainage: How does bio-alkali matrix impact acidity neutralization and heavy metal removal?

Peng, C; Zeng, L; Liu, Y; Zhang, Z; Tang, J; Liu, Z; Yang, Z; Yin, H; Ibrahim, IA; Zhang, K; Yang, Z

Sustainable nexus for treating acid mine drainage: How does bio-alkali matrix impact acidity neutralization and heavy metal removal?

Peng, C Zeng, L Liu, Y Zhang, Z Tang, J Liu, Z Yang, Z Yin, H Ibrahim, IA Zhang, K Yang, Z

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Publisher:: ELSEVIER
Publication Type:: Journal Article
Citation:: ENVIRONMENTAL TECHNOLOGY & INNOVATION, 2025, 39
Issue Date:: 2025-08

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Field	Value	Language
dc.contributor.author	Peng, C
dc.contributor.author	Zeng, L
dc.contributor.author	Liu, Y
dc.contributor.author	Zhang, Z
dc.contributor.author	Tang, J
dc.contributor.author	Liu, Z
dc.contributor.author	Yang, Z
dc.contributor.author	Yin, H
dc.contributor.author	Ibrahim, IA
dc.contributor.author	Zhang, K
dc.contributor.author	Yang, Z
dc.date.accessioned	2026-02-18T05:36:46Z
dc.date.available	2026-02-18T05:36:46Z
dc.date.issued	2025-08
dc.identifier.citation	ENVIRONMENTAL TECHNOLOGY & INNOVATION, 2025, 39
dc.identifier.issn	2352-1864
dc.identifier.uri	http://hdl.handle.net/10453/193625
dc.description.abstract	Acid mine drainage (AMD), characterized by high acidity and elevated concentrations of heavy metals, poses a persistent threat to ecological systems. Conventional neutralizers (NaOH, Na2CO3, Ca(OH)2) raise pH effectively but generate large sludge volumes and incur high operating costs. Here, three urease-positive microbial consortia, enriched from soil and municipal activated sludge, were cultivated with urea to produce bio-alkali matrices (BAM-A/B/C, final pH 9.3). Abundant –CONH2, –NH2, –OH, and –COOH groups capable of chelating metal ions were found in BAM, suggesting alkaline buffering is complemented by ligand-mediated metal sequestration. When each BAM was mixed with AMD at a 3:10 vol ratio, the effluent pH stabilized at 7 and removal efficiencies reached ∼100 % for Al, Fe, Cr, Cd; > 90 % for As, V, Co, Ni; 79–80 % for Cu; and 60 – 62 % for Mn. Geochemical analysis identified Fe/Al hydroxysulfates and organo-metal complexes as dominant precipitates. A full cost comparison showed BAM-A lowered treatment expenses to 35.5 RMB per m3, which is 12 % below NaOH and 26 % below Ca(OH)2, while reducing sludge generation. Coupling BAM with sulfate-reducing bacterial systems is advisable to enhance Mn and SO4 2- removal. Overall, BAM provides an economical and environmentally sustainable alternative for AMD neutralization by uniting alkaline buffering with organic complexation.
dc.language	English
dc.publisher	ELSEVIER
dc.relation.ispartof	ENVIRONMENTAL TECHNOLOGY & INNOVATION
dc.relation.isbasedon	10.1016/j.eti.2025.104272
dc.rights	info:eu-repo/semantics/openAccess
dc.subject	0502 Environmental Science and Management, 0907 Environmental Engineering, 1002 Environmental Biotechnology
dc.title	Sustainable nexus for treating acid mine drainage: How does bio-alkali matrix impact acidity neutralization and heavy metal removal?
dc.type	Journal Article
utslib.citation.volume	39
utslib.for	0502 Environmental Science and Management
utslib.for	0907 Environmental Engineering
utslib.for	1002 Environmental Biotechnology
utslib.copyright.status	open_access	*
dc.rights.license	This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0). To view a copy of this license, visit https://creativecommons.org/licenses/by/4.0/
dc.date.updated	2026-02-18T05:36:41Z
pubs.publication-status	Published
pubs.volume	39

Abstract:

Acid mine drainage (AMD), characterized by high acidity and elevated concentrations of heavy metals, poses a persistent threat to ecological systems. Conventional neutralizers (NaOH, Na2CO3, Ca(OH)2) raise pH effectively but generate large sludge volumes and incur high operating costs. Here, three urease-positive microbial consortia, enriched from soil and municipal activated sludge, were cultivated with urea to produce bio-alkali matrices (BAM-A/B/C, final pH 9.3). Abundant –CONH2, –NH2, –OH, and –COOH groups capable of chelating metal ions were found in BAM, suggesting alkaline buffering is complemented by ligand-mediated metal sequestration. When each BAM was mixed with AMD at a 3:10 vol ratio, the effluent pH stabilized at 7 and removal efficiencies reached ∼100 % for Al, Fe, Cr, Cd; > 90 % for As, V, Co, Ni; 79–80 % for Cu; and 60 – 62 % for Mn. Geochemical analysis identified Fe/Al hydroxysulfates and organo-metal complexes as dominant precipitates. A full cost comparison showed BAM-A lowered treatment expenses to 35.5 RMB per m3, which is 12 % below NaOH and 26 % below Ca(OH)2, while reducing sludge generation. Coupling BAM with sulfate-reducing bacterial systems is advisable to enhance Mn and SO4 2- removal. Overall, BAM provides an economical and environmentally sustainable alternative for AMD neutralization by uniting alkaline buffering with organic complexation.

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http://hdl.handle.net/10453/193625