Comadran-Casas, Carla and Unluer, Cise and Bass, Adrian M. and Macdonald, John and Khaksar Najafi, Elmira and Spruzeniece, Liene and Gauchotte-Lindsay, Caroline (2025) Bioremediation of multiple heavy metals through biostimulation of Microbial-Induced Calcite Precipitation at varying calcium-to-urea concentrations. Journal of Hazardous Materials, 491: 137691. ISSN 0304-3894
AI Summary:
The study investigated the efficiency of soils autochthonous ureolytic bacteria to simultaneously remediate multiple heavy metals and sequester carbon through urea hydrolysis and microbial-induced calcite precipitation (MICP). The results showed that biostimulation approaches can effectively remediate multiple contaminants simultaneously, with optimal conditions achieved at an equimolar calcium-to-urea ratio of 333 mM.AI Topics:
Studies on heavy metal bioremediation through microbial-induced calcite precipitation (MICP) typically involve bioaugmentation approaches that use low calcium-to-urea ratios and target single contaminants. We present an investigation on the efficiency of soils’ autochthonous ureolytic bacteria to simultaneously remediate multiple heavy metals and sequester carbon through urea hydrolysis and MICP on an urban soil containing excess Pb, Zn, Mn, Sr, Ba and Al. Soils were treated at a fixed urea concentration of 333 mM and increasing calcium content of 0, 50 and 333 mM to provide a range of carbonation potential. Urea hydrolysis (Ca2+ = 0 mM) did not produce quantifiable soil carbonation and mobilised Mn into the exchangeable fraction. Ca2+ at 50 mM delayed soils’ autochthonous ureolytic activity and produced limited carbon and heavy metal mineralisation (CaCO3 = 0-0.7%). 333 mM of Ca2+ inhibited urea hydrolysis however, if applied following urea hydrolysis, both carbon (CaCO3 = 4-7%) and heavy metal (Pb, Zn, Mn, Sr and Ba) mineralisation were maximised. Urea hydrolysis and MICP were most successful in removing Pb and Zn from the exchangeable fraction (>85%). However, the higher pH induced by urea hydrolysis at Ca2+ = 0-50 mM (~9) compared to 333 mM (~8.5) favoured partition of Pb into the oxyhydroxide fraction. Instead, partition of Zn, Mn, Sr and Ba into the soil carbonate fraction increased with increasing calcium, whilst there was no evidence of Al carbonation. The results of this study evidence the feasibility of biostimulation approaches to remediate multiple contaminants simultaneously through MICP, provide insights into multiple element’s behaviour during urea hydrolysis and MICP and demonstrate carbon and element mineralisation are maximised at equimolar calcium-to-urea ratio of 333 mM.
Title | Bioremediation of multiple heavy metals through biostimulation of Microbial-Induced Calcite Precipitation at varying calcium-to-urea concentrations |
---|---|
Creators | Comadran-Casas, Carla and Unluer, Cise and Bass, Adrian M. and Macdonald, John and Khaksar Najafi, Elmira and Spruzeniece, Liene and Gauchotte-Lindsay, Caroline |
Identification Number | 10.1016/j.jhazmat.2025.137691 |
Date | 5 July 2025 |
Divisions | College of Science and Engineering > School of Engineering College of Science and Engineering > School of Engineering > Infrastructure and Environment College of Science and Engineering > School of Geographical and Earth Sciences |
Publisher | Elsevier |
URI | https://pub.demo35.eprints-hosting.org/id/eprint/2 |
---|
Item Type | Article |
---|---|
Depositing User | Unnamed user with email ejo1f20@soton.ac.uk |
Date Deposited | 11 Jun 2025 16:34 |
Revision | 30 |
Last Modified | 12 Jun 2025 13:13 |
![]() |