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The potential of ferrihydrite-synthetic humic-like acid composite as a soil amendment for metal-contaminated agricultural soil: Immobilization mechanisms by combining abiotic and biotic perspectives.
- Source :
-
Environmental Research . Jun2024, Vol. 250, pN.PAG-N.PAG. 1p. - Publication Year :
- 2024
-
Abstract
- In-situ passivation technique has attracted increasing attention for metal-contaminated agricultural soil remediation. However, metal immobilization mechanisms are mostly illustrated based on metal speciation changes and alterations in soil physicochemical properties from a macroscopic and abiotic perspective. In this study, a ferrihydrite-synthetic humic-like acid composite (FH-SHLA) was fabricated and applied as a passivator for a 90-day soil incubation. The heavy metals immobilization mechanisms of FH-SHLA were investigated by combining both abiotic and biotic perspectives. Effects of FH-SHLA application on soil micro-ecology were also evaluated. The results showed that the 5%FH-SHLA treatment significantly decreased the DTPA-extractable Pb, Cd and Zn by 80.75%, 46.82% and 63.63% after 90 days of incubation (P < 0.05), respectively. Besides, 5% FH-SHLA addition significantly increased soil pH, soil organic matter content and cation exchange capacity (P < 0.05). The SEM, FTIR, and XPS characterizations revealed that the abiotic metal immobilization mechanisms by FH-SHLA included surface complexation, precipitation, electrostatic attraction, and cation-π interactions. For biotic perspective, in-situ microorganisms synergistically participated in the immobilization process via sulfide precipitation and Fe mineral production. FH-SHLA significantly altered the diversity and composition of the soil microbial community, and enhanced the intensity and complexity of the microbial co-occurrence network. Both metal bioavailability and soil physiochemical parameters played a vital role in shaping microbial communities, while the former contributed more. Overall, this study provides new insight into the heavy metal passivation mechanism and demonstrates that FH-SHLA is a promising and environmentally friendly amendment for metal-contaminated soil remediation. [Display omitted] • FH-SHLA significantly decreased the bioavailability of Pb, Cd and Zn in soil. • Four abiotic passivation mechanisms were involved (e.g. surface complexation, etc). • In-situ microorganisms synergistically participated in the immobilization process. • Both FH-SHLA addition and metal bioavailability could shape microbial communities. [ABSTRACT FROM AUTHOR]
- Subjects :
- *SOIL amendments
*ACID soils
*AGRICULTURE
*CHEMICAL speciation
*SOIL remediation
Subjects
Details
- Language :
- English
- ISSN :
- 00139351
- Volume :
- 250
- Database :
- Academic Search Index
- Journal :
- Environmental Research
- Publication Type :
- Academic Journal
- Accession number :
- 177316080
- Full Text :
- https://doi.org/10.1016/j.envres.2024.118470