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1.
Chemosphere ; 363: 142977, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39084306

RESUMEN

Microbially induced carbonate precipitation (MICP) is a common biomineralization method, which is often used for remediation of heavy metal pollution such as hexavalent chromium (Cr(VI)) in recent years. Calcium sources are essential for the MICP process. This study investigated the potential of MICP technology for Cr(VI) remediation under the influence of three calcium sources (CaCl2, Ca(CH3COO)2, Ca(C6H11O7)2). The results indicated that CaCl2 was the most efficient in the mineralization of Cr(VI), and Ca(C6H11O7)2 could significantly promote Cr(VI) reduction. The addition of different calcium sources all promoted the urease activity of Sporosarcina saromensis W5, in which the CaCl2 group showed higher urease activity at the same Ca2+ concentration. Besides, with CaCl2, Ca(CH3COO)2 and Ca(C6H11O7)2 treatments, the final fraction of Cr species (Cr(VI), reduced Cr(III) and organic Cr(III)-complexes) were mainly converted to the carbonate-bound, cytoplasm and cell membrane state, respectively. Furthermore, the characterization results revealed that three calcium sources could co-precipitate with Cr species to produce Ca10Cr6O24(CO3), and calcite and vaterite were present in the CaCl2 and Ca(CH3COO)2 groups, while only calcite was present in the Ca(C6H11O7)2 group. Overall, this study contributes to the optimization of MICP-mediated remediation of heavy metal contaminated soil. CaCl2 was the more suitable calcium source than the other two for the application of MICP technology in the Cr(VI) reduction and mineralization.


Asunto(s)
Calcio , Carbonatos , Cromo , Sporosarcina , Cromo/metabolismo , Cromo/química , Calcio/metabolismo , Sporosarcina/metabolismo , Carbonatos/química , Carbonatos/metabolismo , Precipitación Química , Ureasa/metabolismo , Biodegradación Ambiental , Cloruro de Calcio/química , Contaminantes del Suelo/metabolismo
2.
Environ Sci Pollut Res Int ; 31(9): 13523-13534, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38253835

RESUMEN

Biomineralization by phosphate minerals and phosphate solubilizing fungi (PSF) has attracted great interest as a novel remediation method for heavy metal(loid) co-contaminated soil. It was very essential to investigate the microenvironment response with the application of amendments. In this study, three grain sizes of hydroxyapatites (HAP) and Phanerochaete chrysosporium (P. chrysosporium) were used to investigate the change in heavy metal(loid) fractions, soil physicochemical properties, and bacterial community during the remediation of Mangchang and Dabaoshan acidic mine soils. The results showed that the residual fractions in the two soils increased significantly after 35 days of remediation, especially that of As and Zn in Dabaoshan soils were presented at over 87%. In addition, soil pH, organic matter (OM), and available phosphorous (AP) were almost improved. 16S rRNA sequencing analysis indicated that the introduction of culture medium and P. chrysosporium alone changed bacterial abundance, but the addition of HAP changed the bacterial diversity and community composition by altering environmental conditions. The amendments in the research showed good performance on immobilizing heavy metal(loid)s and reducing their bioavailability. Moreover, the research suggested that environmental factors and soil inherent properties could influence the microbial community structure and composition.


Asunto(s)
Metales Pesados , Phanerochaete , Contaminantes del Suelo , Suelo/química , Fosfatos/análisis , ARN Ribosómico 16S , Metales Pesados/análisis , Contaminantes del Suelo/análisis
3.
Environ Sci Pollut Res Int ; 30(38): 89355-89368, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37442938

RESUMEN

The microbial reduction of Cr(VI) to Cr(III) is widely applied, but most studies ignored the stability of reduction products. In this study, the Cr(VI)-reducing bacterium of Sporosarcina saromensis combined with microbially induced carbonate precipitation (MICP) was used to explore the reduction and mineralization mechanisms of Cr(VI). The results indicated that the high concentration of Ca2+ could significantly enhance the reduction and mineralization of Cr(VI). The highest reduction and mineralization efficiencies of 99.5% and 55.9% were achieved at 4 g/L Ca2+. Moreover, the urease activity of S. saromensis in the experimental group was up to 13.28 U/mg NH3-N. Besides, the characteristic results revealed that Cr(VI) and reduced Cr(III) were absorbed on the surface or got into the interspace of CaCO3, which produced a new stable phase (Ca10Cr6O24(CO3)). Overall, the combination of S. saromensis and MICP technology might be a high-efficiency and environmentally friendly strategy for further application in the Cr(VI)-containing groundwater.


Asunto(s)
Cromo , Sporosarcina , Carbonatos , Carbonato de Calcio
4.
J Hazard Mater ; 445: 130465, 2023 03 05.
Artículo en Inglés | MEDLINE | ID: mdl-36436453

RESUMEN

Phosphate solubilizing bacteria (PSB) induced phosphate precipitation is considered as an effective method for Pb(II) removal through the formation of stable Pb(II)-phosphate compound, but the location of end-products is still unclear. Herein, the PSB strain of Burkholderia cepacia (B. cepacia) coupled with the hydroxyapatite (HAP) was used in this study to investigate the Pb(II) removal mechanism and the biomineralization location. The dissolving phosphate of three particle sizes of HAP and Pb(II) resistant capabilities, and the effect factors such as HAP dosage, initial concentrations of Pb(II), pH, temperature, and different treatments were determined. The results indicated that the highest soluble phosphate could reach 224.85 mg/L in a 200 nm HAP medium and the highest removal efficiency of Pb(II) was about 96.32 %. Additionally, it was interesting that Pb(II) was mainly located in the periplasmic space through the cellular distribution experiment, which was further demonstrated by scanning electron microscope (SEM) and transmission electron microscopy (TEM). Besides, the characterization results showed that the functional groups such as amide, hydroxy, carboxy and phosphate played an important role in Pb(II) biomineralization, and the free Pb(II) in aqueous solution could be transformed into pyromorphite through phosphate dissolution, extracellular adsorption/complexation, and intracellular precipitation.


Asunto(s)
Burkholderia cepacia , Plomo , Periplasma , Biomineralización , Bacterias , Durapatita/química
5.
Sci Total Environ ; 850: 157995, 2022 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-35964759

RESUMEN

Microbial induced phosphate precipitation (MIPP) is an advanced bioremediation technology to reduce the mobility and bioavailability of heavy metals (HMs), but the high level of HMs would inhibit the growth of phosphate solubilizing microbes. This study proposed a new combination system for the remediation of multiple HMs contaminated acidic mine soil, which included hydroxyapatite (HAP) and Phanerochaete chrysosporium (P. chrysosporium, PC) that had high phosphate solubilizing ability and HMs tolerance. Experimental data suggested that in HAP/PC treatment after 35 d of remediation, labile Cr, Zn and As could be transformed into the stable fraction with the maximum immobilization efficiencies increased by 53.01 %, 22.43 %, and 35.65 %, respectively. The secretion of organic acids by P. chrysosporium was proved to promote the dissolution of HAP. Besides, the pH value, available phosphorus (AP) and organic matter (OM) increased in treated soil than in original soil, which also indicated the related dissolution-precipitation mechanism of HMs immobilization. Additionally, characterization results revealed that adsorption and ion exchange also played an important role in the remediation process. The overall results suggested that applying P. chrysosporium coupled with HAP could be considered as an efficient strategy for the remediation of multiple HMs contaminated mine soil and laid a foundation for the future exploration of soil microenvironment response during the remediation process.


Asunto(s)
Arsénico , Metales Pesados , Phanerochaete , Contaminantes del Suelo , Antimonio , Cromo , Hidroxiapatitas , Plomo , Metales Pesados/química , Compuestos Orgánicos , Fosfatos/química , Fósforo , Suelo/química , Contaminantes del Suelo/análisis , Zinc/química
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