JOURNAL OF HAZARDOUS MATERIALS
·
2021
·
IF 10.588
Quanfeng Wang,Haoxuan Wei,Wenbo Liu,Jun Zhai
Forty strains of Mn-oxidizing microalgae (MnOMs) with different Mn 2+ oxidation mechanisms were identified from two aquatic environments. Among them, three strains of isolates ( Chlamydomonas sp. WH1–1, Chlamydomonas sp. WH1–4 , and Chlorella sp. WH2–5) oxidize Mn 2+ by increasing the ambient pH and by secreting Mn oxidation factors (e.g., superoxide-production enzymes and/or other Mn oxidases) into the extracellular environment at the same time. In carbamazepine (CBZ) removal by MnOMs and/or Bio-MnOx, the combination of MnOMs and Bio-MnOx significantly increased the CBZ (1 mg/L) removal efficiency from 36.05% (by MnOMs alone) and 20.11% (by Bio-MnOx alone) to 80.13% by two synergistic mechanisms. One of the synergistic mechanisms was confirmed as that the Mn 2+ was re-oxidized by MnOMs to Bio-MnOx, which can promote the CBZ removal, and another was the mutual exchange of degradation products of CBZ as shared reactants between MnOMs and Bio-MnOx. The degradation intermediates of CBZ were analyzed using high-performance liquid chromatography-tandem mass spectrometry , based on which the CBZ degradation pathway by MnOMs and Bio-MnOx was proposed. These findings expand existing knowledge on the Mn 2+ oxidation mechanisms of MnOMs, and indicate that MnOMs and their generated Bio-MnOx are promising for the removal of CBZ or other pharmaceutical contaminants from wastewater.
研究领域:
环境科学
·
微生物学
·
制药工程
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
PROTEINS-STRUCTURE FUNCTION AND BIOINFORMATICS
·
2024
·
IF 3.2
Wenwei Tang,Zuxun Huang,Yunying Liu,Xinping Zeng
The microbial manganese removal process is believed to consist of the catalytic oxidation of Mn(II) by manganese oxidase. In this study, the multicopper oxidase CopA was purified and exhibited high manganese oxidation activity in vitro, and it was found that Cu(II) can significantly enhance its manganese oxidation activity. Gene site-directed mutagenesis was used to mutate four conserved copper binding sites of CopA to obtain four mutant strains. The manganese removal efficiencies of the four strains were determined, and it was found that H120 is the catalytically active site of CopA. The loss of Cu(II) and the mutation of the conserved copper binding site H120 resulted in the loss of ethoxyformyl and quinone modifications, a reduction in the number of modifications, and a change in the position of modifications, eventually causing a decrease in protein activity from 85.87% to 70.1%. These results reveal that Cu(II) and H120 play an indispensable role in manganese oxidation by the multicopper oxidase CopA. X-ray photoelectron spectroscopy (XPS) analysis indicates that biogenic manganese oxides produced by strains and by CopA were both composed of MnO 2 and Mn 3 O 4 and that the average valence of Mn was 3.2.
研究领域:
微生物学
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
GEOCHIMICA ET COSMOCHIMICA ACTA
·
2021
·
IF 5.01
Jing Liu,Sayako Inoué,Runliang Zhu,Hongping He,Michael F. Hochella
It is recognized that different facets of minerals vary distinctively in their chemical reactivity with aqueous solutions. However, detailed molecular and atomistic understandings of these phenomena are relatively limited. This study investigated the interaction of aqueous Mn 2+ and dissolved oxygen on various facets of two morphology-types of iron oxide (hematite) nanocrystals. These interactions result in the oxidation of Mn(II) and heterogeneous growth of Mn(II)/Mn(III) and Mn(III) oxides. The nanoscale morphology and atomic structure of the manganese oxide products were characterized in detail. Our results, for the first time, directly demonstrate the facet-specific oxidation of Mn(II) and nucleation of Mn(II/III) oxides, followed by their epitaxial growth on hematite. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron diffraction measurements reveal the growth of MnO x nanowires on {1 1 3} of hematite nanoplates (HNP) and {0 1 2} facets of hematite nanocubes (HNC), while the basal {0 0 1} facets on the HNP particles do not produce precipitates. The average oxidation states of the MnO x on HNP and HNC determined using electron energy-loss spectroscopy (EELS) show that both Mn(II) and Mn(III) are present. The mineral composition and growth mechanisms of MnO x catalyzed by HNP and HNC are similar. High-resolution TEM analysis reveals the presence of both hausmannite and manganite on HNP and HNC. The crystallographic relationship between the heterogeneously formed manganite with hematite, which has not been reported before, proves that hematite provides reaction sites and can function as an atomic template for the formation of MnO x nanowires. These findings advance our understanding of the redox chemistry and heterogeneous growth of minerals as controlled by the surficial structure of the substrate mineral. This has important geochemical implications as the catalytic growth of less common, highly reactive phases like MnO x are known to be consequential in complex natural and anthropogenic environments.
研究领域:
矿物学
·
地球化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Rui Wang,Huizhi Hu,Danting Shi,Jinsong Liang,Senlin Shao
Biogenic manganese oxides (BioMnO x ) can effectively remove Mn(II) from drinking water. In the gravity-driven membrane (GDM) system for Mn(II)-containing water treatment, both BioMnO x and Mn(II)-oxidizing bacteria (MnOB) present in the cake layer, and their role in Mn(II) oxidation is still controversial. To address this issue, in this study, we naturally formed a cake layer containing BioMnO x and MnOB using the GDM process and identified the different roles of BioMnO x and MnOB in the removal of Mn(II). The experimental results showed that the BioMnO x accounted for a major proportion of the cake layer of GDM, and it played a principal role in the removal of Mn(II) through the combination of adsorption and catalytic oxidation. However, this removal efficiency would be continuously reduced in the absence of MnOB, while stabilized in the presence of MnOB. XPS analysis revealed that the proportion of Mn(III) and Mn(IV) in BioMnO x with MnOB reached 64.1% and 35.8%, respectively, while BioMnO x without MnOB did not contain Mn(IV). These findings suggest that BioMnO x may be the primary catalyst for Mn(II) oxidation, but its long-term activity is dependent on MnOB, which can maintain the catalytic activity by 1) producing new BioMnO x and 2) sustaining the high valence state of MnO x .
研究领域:
环境科学
·
水处理
·
微生物学
·
催化
✓ 已验证
产品关联
DOI
高影响因子
IONICS
·
2023
·Vol. 29
·期 7
·2853-2864
·
IF 2.8
Wang Wenping,Zhao Zhiyi,Deng Jiayao,Lang Wei,Zhen Lipeng,Lu Huimin
The oxygen reduction reaction of the cathode in an Al-air battery plays a key role in the performance of the entire battery. Generally, Pt and its alloys are recognized as catalysts with high oxygen reduction catalytic performance, but their application is limited by the rare earth content and high cost. In this paper, α-MnO 2 nanotubes are prepared using a hydrothermal method and used as a template. Nano-Ni–Mn bimetallic oxides with different compositions are prepared with different NiO and α-MnO 2 ratios by calcination. The effects of morphology, phase, and Mn 3+ /Mn 4+ and Ni 3+ /Ni 2+ ratios on electrochemical performance and battery discharge performance are analyzed. The results show that the contents of α-MnO 2 and Ni 6 MnO 8 in NM-12 catalyst are low, and the molar ratio of Mn 3+ /Mn 4+ and Ni 3+ /Ni 2+ is high. Also, the specific surface area of NM-12 is relatively high. Finally, the catalyst prepared with a NiO to α-MnO 2 ratio of 1:2 shows better electrochemical catalytic performance and battery discharge performance that is comparable to that obtained for a commercial 20 wt% Pt/C catalyst.
研究领域:
材料科学
·
电化学
·
能源存储与转换
✓ 已验证
产品关联
DOI
高影响因子
Frontiers of Environmental Science & Engineering
·
2022
·Vol. 17
·期 2
·1-11
·
IF 6.048
Yang Fan,Li Junpeng,Wang Huan,Xiao Xiaofeng,Bai Rui,Zhao Feng
Manganese oxides are widely distributed in soils and sediments, affecting the migration and transformation of heavy metals and organic pollutants. The microbial conversion of soluble Mn(II) into insoluble Mn(III/IV) oxides is considered to be the initial source of manganese oxides in the environment; however, whether this process is related to a physiological role remains unclear. Here, we explored the microbial manganese oxidation process under visible light by using coastal surface seawater microorganisms. Visible light greatly promotes the oxidation rate of Mn(II), and the average rate reaches 64 µmol/(L·d). The generated manganese oxides were then conducive to Mn(II) oxidation, thus the rapid manganese oxidation was the result of the combined action of biotic and abiotic, and biological function accounts for 88 % ± 4 %. Extracellular superoxide produced by microorganisms induced by visible light is the decisive factor for the rapid manganese oxidation in our study. But the production of these superoxides does not require the presence of Mn(II) ions, the Mn(II) oxidation process was more like an unintentional side reaction, which did not affect the growth of microorganisms. More than 70 % of heterotrophic microorganisms in nature are capable of producing superoxide, based on the oxidizing properties of free radicals, all these bacteria can participate in the geochemical cycle of manganese. What’s more, the superoxide oxidation pathway might be a significant natural source of manganese oxide.
研究领域:
环境微生物学
·
地球化学
·
水文学与水资源
✓ 已验证
DOI
高影响因子
Environmental Technology & Innovation
·
2025
·
IF 7.1
Changsheng Jin,Yin Gao,Jingjing Lu,Yuxi Liu,Baowei Hu
Soils contain abundant organic matter (OM) and Mn(oxyhydr)oxides (MnOs) composites, which primarily control the geochemical behavior of Cd. However, the impact of manganese phase transformation on the retention and availability of Cd remains unclear. Here, four organo-mineral composites were synthesized using birnessite (δ-Mn Ⅳ O 2 ), β-Mn Ⅲ,Ⅳ O 2 , γ-Mn Ⅲ OOH, and Mn Ⅱ,Ⅲ 3 O 4 with fulvic acid (FA), during adsorption to preformed MnOs with 5 wt% organic carbon loadings. The performance and underlying Cd(II) adsorption mechanism by resulting FA-MnO composites were explored. Results showed that δ-MnO 2 transformation decreases Cd(II) adsorption capacity by 23.02–45.44 % on the resulting FA-MnOs. This reduction was attributed to increased aggregation of MnO particles and competition from generated Mn(II/III) for available vacancy sites. Cd undergoes redistribution within the FA-MnOs during the transformation of δ-MnO 2 . The amount of Cd associated with MnOs decreases by 9.46–37.08 %, while OM bound-Cd increases by 2.82–10.49 %. FAδ-MnO 2 predominantly interacted with Cd(II) through tetravalent manganese, forming stable coordination or chemical bonds. In contrast, FAγ-MnOOH and FA-Mn 3 O 4 primarily interacted with Cd(II) through divalent manganese via electrostatic attraction and ion exchange, resulting in weaker binding stability. These findings provide new insights into the roles of manganese transformation in the geochemical cycling of Cd in soils.
研究领域:
环境科学
·
土壤学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
·
2020
·Vol. 21
·期 5
·1709
·
IF 4.556
Juan Guo,Huan Guo,Jin Liu,Fangrui Zhong,Yuzhou Wu
Manganese oxidizing bacteria can produce biogenic manganese oxides (BMO) on their cell surface and have been applied in the fields of agriculture, bioremediation, and drinking water treatment to remove toxic contaminants based on their remarkable chemical reactivity. Herein, we report for the first time the synthetic application of the manganese oxidizing bacteria,Pseudomonas putidaMnB1 as a whole-cell biocatalyst for the effective oxidation of β-keto ester with excellent yield. Differing from known chemical protocols toward this transformation that generally necessitate the use of organic solvents, stoichiometric oxygenating agents and complex chemical catalysts, our strategy can accomplish it simply under aqueous and mild conditions with higher efficiency than that provided by chemical manganese oxides. Moreover, the live MnB1 bacteria are capable of continuous catalysis for this C-O bond forming reaction for several cycles and remain proliferating, highlighting the favorable merits of this novel protocol for sustainable chemistry and green synthesis.Keywords:Pseudomonas putidaMnB1;biogenic manganese oxides;abiotic manganese oxides;α-Hydroxy-β-keto esters;whole-cell biocatalysis
研究领域:
生物催化
·
绿色化学
·
有机合成
·
环境生物技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Environmental Sciences
·
2020
·
IF 4.302
Yanan Cai,Jing He,Jinkang Zhang,Jicheng Li
Antibiotic micro-pollution is usually found at the ng/L–level in drinking water sources or discharge water of wastewater treatment plants . In this study, a novel approach mediated by manganese oxidizing bacteria (MnOB) in a biofilter was developed to control the pollution. The results indicated that the biogenic manganese oxide (MnO x ) produced during the oxidation of the feeding manganese ions could coat the surface of the filtering sand effecting the simultaneous removal of antibiotics. It was found that the removal of antibiotics is insured as long as the feeding manganese was well removed and was not influenced by the hydraulic loading. The growth rate of the MnOB group revealed that the antibiotic concentration at 50 and 100 ng/L promoted their activity, but it was inhibited at 500 and 1000 ng/L. The structure of the bacterial community was stable in the presence of antibiotics (50 ng/L), but their extracellular processes changed. The removal performance of the feeding manganese seemed to relate to the extracellular processes of the dominant bacterial genus. Moreover, the freshly formed MnO x was a buserite-like material that was rich in Mn(III) and Mn(IV) (94.1%), favoring the degradation. The biofilter did not generate additional antibiotic resistant genes in the presence of antibiotics.
研究领域:
环境工程
·
微生物学
·
水处理
·
生物修复
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Shunli Wan,Lian Qiu,Yan Li,Junjie Sun,Bin Gao,Feng He,Wubo Wan
Antimony and copper pollution pose significant threat to water quality security, and their advanced treatment is still a great challenge. In this study, we fabricated a hybrid adsorbent (denoted as MO-L-BC) through dispersing manganese oxide (MO) inside a biochar with enlarged pore structure (namely L-BC). The used carrier L-BC possessed a high proportion of large pores (>2 nm) (87%), and thus lowered the diffusion resistance of target pollutants in pore region of MO-L-BC. Consequently, Sb(III) and Cu(II) adsorption onto MO-L-BC achieved equilibrium within 15 min, and their effective coefficients of intra-particle diffusion (D) were calculated to be 8.6 × 10 −8 and 1.5 × 10 −7 cm 2 s −1 , respectively, which were only one-order magnitude lower than that in aqueous phase. XPS analysis indicated that 53.3% of the sorbed Sb(III) was oxidized to Sb(V) by the impregnated MO. Coexisting substances such as HCO 3 − , SO 4 2− , NO 3 − , Ca 2+ , Mg 2+ and humic acid up to 20 times higher concentration than target contaminants (Sb(III) or Cu(II)) caused only < 20% drop in sorption capacity of MO-L-BC, and the mutual effect of Sb(III) and Cu(II) was also not noticeable. The fixed-bed column adsorption tests showed that MO-L-BC can achieve the tertiary treatment of either the singly polluted (Sb(III) or Cu(II)) or the co-contaminated wastewater at a high flow rate of 0.27 m h −1 , with effective treatment volumes larger than400 BV, and the saturated MO-L-BC can be effectively regenerated. MO-L-BC is a promising engineered biochar to treat Sb(III) and/or Cu(II) contaminated water especially under high-flow conditions.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Jian Deng,Chunhao Wang,Shenggui Ma,Chengchao Liu,Yongtao Zheng,Haipeng Chen,Ruofei Chen,Siyu Wei,Shanbi Peng,Xia Jiang
In this study, Cu 1.5 Mn 1.5 O 4 spinel with Mn(Ⅳ)O 6 coordination was synthesized by evaporation and combustion method. CuMn-500-1 catalyst was obtained by acid etching, which significantly promotes the catalytic oxidation of toluene (lowering ≈ 30℃ regarding T 100 ). Characterization results demonstrate that the enhanced performance can be attributed to the increased exposure of (222) crystal facet of a more rod-like Cu 1.5 Mn 1.5 O 4 spinel, independent of surface area and oxygen vacancy (which remained almost unchanged). In addition, the rate-determining steps were proved to be the ring-opening reaction of phenol by in-situ DRIFTS experiment. Density functional theory calculation further shows that the Mn(Ⅳ)O₆ site exhibits stronger capacity for toluene adsorption. In addition, the main cause underlying the enhanced performance of CuMn-500-1 is further corroborated: specifically, the (222) crystal surface demonstrates stronger catalytic performance compared to other crystal faces. This strategy provides a new method in enhancing the VOCs removal efficiency of catalyst.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
Small
·
2024
·
IF 13
Cheng Gu,Shu Fang,Lin Liu,Benjin Chen,Lingling Xu,Min Shao,Jianan Sun,Haisheng Qian,Wanni Wang
The production of bacterial toxins and excessive accumulation of reactive oxygen species (ROS) can induce localized oxidative stress, triggering an exaggerated immune response that impedes wound healing and culminates in chronic wounds. To address this issue, a microneedle (MN) system loaded with copper-manganese oxide (CMO) is developed to modulate the hyperimmune response in wounds. CMO@MN exhibits excellent antimicrobial and anti-inflammatory properties by effectively killing bacteria, scavenging ROS, and modulating macrophage polarization through their multiple enzymatic activities and photothermal properties. RNA sequencing revealed that CMO@MN improved the therapeutic effect on the infected skin of mice by balancing the ratio of M1/M2 macrophages and promoting cell migration and angiogenesis through the regulation of relevant pathways. Overall, this CMO@MN patch skillfully balances the complex issues between the immune response and wound healing and has potential applications in the treatment of other serious bacterial infections.
研究领域:
生物医学工程
·
免疫学
·
药理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）