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18 pages, 4632 KiB

Open AccessArticle

Plasmonic and Photothermal Effects of CuS Nanoparticles Biosynthesized from Acid Mine Drainage with Potential Drug Delivery Applications

by Hernán Escobar-Sánchez, Claudio Carril Pardo, Noelia Benito, Jacobo Hernández-Montelongo, Iván Nancucheo and Gonzalo Recio-Sánchez

Int. J. Mol. Sci. 2023, 24(22), 16489; https://doi.org/10.3390/ijms242216489 - 18 Nov 2023

Cited by 5 | Viewed by 2240

Abstract

In this work, the plasmonic and photothermal effects of CuS nanoparticles biosynthesized from acid mine drainage (AMD) were studied. CuS were formed by delivering the H₂S generated by a sulfidogenic bioreactor to an off-line system containing the AMD. The precipitates collected after contact for an hour were washed and physico-chemically characterized, showing a nanoparticle with a mean diameter of 33 nm, crystalline nature and semiconductor behavior with a direct band gap of 2.2 eV. Moreover, the CuS nanoparticles exhibited localized surface plasmonic resonance in the near infrared range, with a high absorption band centered at 973 nm of wavelength, which allowed an increase in the temperature of the surrounding media under irradiation. Finally, the cytotoxicity of the CuS nanoparticles as well as their potential use as part of drug delivery platforms were investigated. Full article

(This article belongs to the Special Issue Advances in Synthesis of Transition-Metal-Based Nanoparticles and Their Bioapplications)

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20 pages, 24940 KiB

Open AccessArticle

Biogenic Hydrogen Sulfide Production Using Elemental Sulfur and Low-Cost Organic Substrates to Remove Metal Ions from Mining Effluents

by Cristian Martínez, Pabla Viedma, Franco Cárdenas and Davor Cotoras

Mining 2023, 3(2), 241-260; https://doi.org/10.3390/mining3020015 - 26 Apr 2023

Cited by 1 | Viewed by 2744

Abstract

One of the best technologies available for metal removal from mining effluents is the precipitation of metals as sulfides. However, the high cost and difficulty in managing reagents limit its widespread application. Recent literature suggests the use of sulfur-reducing bacteria (S°RB) as a safe and effective alternative to producing H₂S. Nevertheless, direct substrates for S°RB are high-cost low molecular compounds. This research aimed to evaluate the ability to produce sulfides by sulfur-reducing consortia in fixed-bed bioreactors using complex organic substrates. Consortia enriched using cellulose or Spirulina as electron donors were phylogenetically characterized by fluorescent in situ hybridization. Microorganisms belonging to Bacteria and Archaea were involved, being the most representative of the δ-Proteobacterias. The results obtained in test tube culture indicated that these consortia could use cellulose and Spirulina in alkaline conditions, resulting in high sulfide production. Upflowed fixed-bed bioreactors were implemented to establish optimal parameters., resulting in H₂S volumetric productivities ranging from 1.94 to 2.94 mol/m³∙day. In conclusion, an active biomass with significant sulfidogenic activity can be generated in bioreactors under an upflowed regime using cellulose or Spirulina. Full article

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14 pages, 3187 KiB

Open AccessArticle

Sulfidogenic Bioreactor-Mediated Formation of ZnS Nanoparticles with Antimicrobial and Photocatalytic Activity

by Aileen Segura, Araceli Rodriguez, Pedro Hernández, Hector Pesenti, Jacobo Hernández-Montelongo, Antonio Arranz, Noelia Benito, José Bitencourt, Luis Vergara-González, Iván Nancucheo and Gonzalo Recio-Sánchez

Nanomaterials 2023, 13(5), 935; https://doi.org/10.3390/nano13050935 - 4 Mar 2023

Cited by 8 | Viewed by 2799

Abstract

The use of sulfidogenic bioreactors is a biotechnology trend to recover valuable metals such as copper and zinc as sulfide biominerals from mine-impacted waters. In the present work, ZnS nanoparticles were produced using “green” H₂S gas generated by a sulfidogenic bioreactor. ZnS nanoparticles were physico-chemically characterized by UV-vis and fluorescence spectroscopy, TEM, XRD and XPS. The experimental results showed spherical-like shape nanoparticles with principal zinc-blende crystalline structure, a semiconductor character with an optical band gap around 3.73 eV, and fluorescence emission in the UV-visible range. In addition, the photocatalytic activity on the degradation of organic dyes in water, as well as bactericidal properties against several bacterial strains, were studied. ZnS nanoparticles were able to degrade methylene blue and rhodamine in water under UV radiation, and also showed high antibacterial activity against different bacterial strains including Escherichia coli and Staphylococcus aureus. The results open the way to obtain valorous ZnS nanoparticles from the use of dissimilatory reduction of sulfate using a sulfidogenic bioreactor. Full article

(This article belongs to the Special Issue Engineering Nanoparticles for Photocatalytic Applications)

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15 pages, 2854 KiB

Open AccessArticle

In-Situ Sludge Reduction Performance and Mechanism in Sulfidogenic Anoxic–Oxic–Anoxic Membrane Bioreactors

by Chengyue Li, Tahir Maqbool, Hongyu Kang and Zhenghua Zhang

Membranes 2022, 12(9), 865; https://doi.org/10.3390/membranes12090865 - 8 Sep 2022

Cited by 2 | Viewed by 2366

Abstract

The excess sludge generated from the activated sludge process remains a big issue. Sustainable approaches that achieve in situ sludge reduction with satisfactory effluent quality deserve attention. This study explored the sludge reduction performance of sulfidogenic anoxic–oxic–anoxic (AOA) membrane bioreactors. The dynamics of the microbial community and metabolic pathways were further analyzed to elucidate the internal mechanism of sludge reduction. Compared with the conventional anoxic–oxic–oxic membrane bioreactor (MBR_control), AOA_S150 (150 mg/L SO₄²⁻ in the membrane tank) and AOA_S300 (300 mg/L SO₄²⁻ in the membrane tank) reduced biomass production by 40.39% and 47.45%, respectively. The sulfide reduced from sulfate could enhance the sludge decay rate and decrease sludge production. Extracellular polymeric substances (EPSs) destruction and aerobic lysis contributed to sludge reduction in AOA bioreactors. The relative abundance of Bacteroidetes (phylum), sulfate-reducing bacteria (SRB, genus), and Ignavibacterium (genus) increased in AOA bioreactors compared with MBR_control. Our metagenomic analysis indicated that the total enzyme-encoding genes involved in glycolysis, denitrification, and sulfate-reduction processes decreased over time in AOA_S300 and were lower in AOA_S300 than AOA_S150 at the final stage of operation. The excess accumulation of sulfide in AOA_S300 may inactive the functional bacteria, and sulfide inhibition induced sludge reduction. Full article

(This article belongs to the Special Issue Honorary Issue for Professor Anthony Fane)

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15 pages, 2539 KiB

Open AccessFeature PaperArticle

Design and Operation of Empirical Manganese-Removing Bioreactors and Integration into a Composite Modular System for Remediating and Recovering Metals from Acidic Mine Waters

by Ana Laura Santos and D. Barrie Johnson

Appl. Sci. 2021, 11(9), 4287; https://doi.org/10.3390/app11094287 - 10 May 2021

Cited by 5 | Viewed by 2287

Abstract

Packed bed bioreactors were used to remove soluble manganese from a synthetic mine water as the final stage of an integrated bioremediation process. The synthetic mine water had undergone initial processing using a sulfidogenic bioreactor (pH 4.0–5.5) which removed all transition metals present in elevated concentrations (Cu, Ni, Zn and Co) apart from manganese. The aerobic bioreactors were packed with pebbles collected from a freshwater stream that were coated with black-colored, Mn(IV)-containing biofilms, and their capacity to remove soluble Mn (II) from the synthetic mine water was tested at varying hydraulic retention times (11–45 h) and influent liquor pH values (5.0 or 6.5). Over 99% of manganese was removed from the partly processed mine water when operated at pH 6.5 and a HRT of 45 h. Molecular techniques (clone libraries and T-RFLP analysis) were used to characterize the biofilms and identified two heterotrophic Mn-oxidizing microorganisms: the bacterium Leptothrix discophora and what appears to be a novel fungal species. The latter was isolated and characterized in vitro. Full article

(This article belongs to the Special Issue Microbial and Plant-Assisted Bioremediation for Eco-Sustainable Environment)

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9 pages, 2879 KiB

Open AccessArticle

Synthesis of Copper Sulfide Nanoparticles Using Biogenic H₂S Produced by a Low-pH Sulfidogenic Bioreactor

by Camila Colipai, Gordon Southam, Patricio Oyarzún, Daniella González, Víctor Díaz, Braulio Contreras and Ivan Nancucheo

Minerals 2018, 8(2), 35; https://doi.org/10.3390/min8020035 - 23 Jan 2018

Cited by 23 | Viewed by 7120

Abstract

The application of acidophilic sulfate-reducing bacteria (SRB) for the treatment of acidic mine water has been recently developed to integrate mine water remediation and selective biomineralization. The use of biogenic hydrogen sulfide (H₂S) produced from the dissimilatory reduction of sulfate to fabricate valuable products such as metallic sulfide nanoparticles has potential applications in green chemistry. Here we report on the operation of a low-pH sulfidogenic bioreactor, inoculated with an anaerobic sediment obtained from an acid river in northern Chile, to recover copper via the production of copper sulfide nanoparticles using biogenic H₂S. The laboratory-scale system was operated as a continuous flow mode for up to 100 days and the bioreactor pH was maintained by the automatic addition of a pH 2.2 influent liquor to compensate for protons consumed by biosulfidogenesis. The “clean” copper sulfide nanoparticles, produced in a two-step process using bacterially generated sulfide, were examined using transmission electron microscopy, dynamic light scattering, energy dispersive (X-ray) spectroscopy and UV-Vis spectroscopy. The results demonstrated a uniform nanoparticle size distribution with an average diameter of less than 50 nm. Overall, we demonstrated the production of biogenic H₂S using a system designed for the treatment of acid mine water that holds potential for large-scale abiotic synthesis of copper sulfide nanoparticles. Full article

(This article belongs to the Special Issue Acid Mine Drainage Recovery)

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