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2.
Molecules ; 26(5)2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33668169

RESUMO

A series of fifteen silver (I) quinoline complexes Q1-Q15 have been synthesized and studied for their biological activities. Q1-Q15 were synthesized from the reactions of quinolinyl Schiff base derivatives L1-L5 (obtained by condensing 2-quinolinecarboxaldehyde with various aniline derivatives) with AgNO3, AgClO4 and AgCF3SO3. Q1-Q15 were characterized by various spectroscopic techniques and the structures of [Ag(L1)2]NO3Q1, [Ag(L1)2]ClO4Q6, [Ag(L2)2]ClO4Q7, [Ag(L2)2]CF3SO3Q12 and [Ag(L4)2]CF3SO3Q14 were unequivocally determined by single crystal X-ray diffraction analysis. In vitro antimicrobial tests against Gram-positive and Gram-negative bacteria revealed the influence of structure and anion on the complexes' moderate to excellent antibacterial activity. In vitro antioxidant activities of the complexes showed their good radical scavenging activity in ferric reducing antioxidant power (FRAP). Complexes with the fluorine substituent or the thiophene or benzothiazole moieties are more potent with IC50 between 0.95 and 2.22 mg/mL than the standard used, ascorbic acid (2.68 mg/mL). The compounds showed a strong binding affinity with calf thymus-DNA via an intercalation mode and protein through a static quenching mechanism. Cytotoxicity activity was examined against three carcinoma cell lines (HELA, MDA-MB231, and SHSY5Y). [Ag(L2)2]ClO4Q7 with a benzothiazole moiety and [Ag(L4)2]ClO4Q9 with a methyl substituent had excellent cytotoxicity against HELA cells.


Assuntos
Antibacterianos/farmacologia , Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Complexos de Coordenação/farmacologia , DNA/química , Antibacterianos/síntese química , Antibacterianos/química , Antineoplásicos/síntese química , Antineoplásicos/química , Antioxidantes/síntese química , Antioxidantes/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Ensaios de Seleção de Medicamentos Antitumorais , Compostos Férricos/antagonistas & inibidores , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Oxirredução , Quinolinas/química , Quinolinas/farmacologia , Bases de Schiff/química , Bases de Schiff/farmacologia , Prata/química , Prata/farmacologia
3.
Bioresour Technol ; 330: 125011, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33773268

RESUMO

Biomass chemical looping gasification (CLG) technology is an important utilization form of renewable energy. In order to obtain high-quality syngas, CaO/Fe2O3 was used as a composite oxygen carrier for biomass CLG in this study. The CLG experiment of corn straw and the study of oxygen carrier recycling were carried out, simultaneously, the reaction mechanism was further discussed. Results shown adding CaO to oxygen carrier could significantly improve the quality of syngas through increasing the H2 and reduce Greenhouse gas (CO2 and CH4, about 14% reduction). Besides, the ratio of Fe2O3 to CaO, steam to biomass, and oxygen carrier to biomass all affected the syngas composition (the H2/CO variation from 1.82 to 2.19), while the temperature had obvious influence on the gas yield of CLG. The most possible reaction mechanism shown that the variation of Ca might be the main factor of gas composition fluctuation.


Assuntos
Oxigênio , Zea mays , Biomassa , Compostos de Cálcio , Compostos Férricos , Gases , Óxidos , Vapor
4.
Nat Biomed Eng ; 5(3): 252-263, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33686281

RESUMO

Contrast agents for magnetic resonance imaging (MRI) improve anatomical visualizations. However, owing to poor image resolution in whole-body MRI, resolving fine structures is challenging. Here, we report that a nanoparticle with a polysaccharide supramolecular core and a shell of amorphous-like hydrous ferric oxide generating strong T1 MRI contrast (with a relaxivity coefficient ratio of ~1.2) facilitates the imaging, at resolutions of the order of a few hundred micrometres, of cerebral, coronary and peripheral microvessels in rodents and of lower-extremity vessels in rabbits. The nanoparticle can be synthesized at room temperature in aqueous solution and in the absence of surfactants, has blood circulation and renal clearance profiles that prevent opsonization, and leads to better imaging performance than Dotarem (gadoterate meglumine), a clinically approved gadolinium-based MRI contrast agent. The nanoparticle's biocompatibility and imaging performance may prove advantageous in a broad range of preclinical and clinical applications of MRI.


Assuntos
Dextranos/química , Compostos Férricos/química , Imagem por Ressonância Magnética/métodos , Nanopartículas/química , Animais , Materiais Biocompatíveis/química , Meios de Contraste/química , Gadolínio/química , Meglumina/química , Camundongos , Camundongos Endogâmicos BALB C , Microvasos/patologia , Compostos Organometálicos/química , Tamanho da Partícula , Polissacarídeos/química , Coelhos , Ratos , Ratos Sprague-Dawley
5.
Food Chem ; 352: 129330, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-33657486

RESUMO

Pregnancy test strips are one of the most mature and widely used commercial lateral flow devices used to determine pregnancy. Being a simple and rapid detection method, human chorionic gonadotropin (hCG) was used with different aptamers (hCG-apt) as probes for the detection of metal ions, small organic molecules, and proteins. Quantitative detection of target analytes was achieved using a smartphone app and a portable device developed in our laboratory. The results showed detection ranges of 1 nM-1 µM, 0.1 nM-10 µM and 32 nM-500 nM for Pb2+, chloramphenicol, and ß-lactoglobulin, respectively, and the corresponding visual detection limits in dairy products were 5 nM, 1 nM and 50 nM, respectively. Based on these results, rapid detection of multiple analytes can be realized through aptamer modification, thereby broadening the application range of commercial lateral flow devices for analysis of food chemistry.


Assuntos
Aptâmeros de Nucleotídeos/metabolismo , Laticínios/análise , Compostos Férricos/química , Análise de Alimentos/instrumentação , Grafite/química , Testes de Gravidez/instrumentação , Smartphone , Animais , Feminino , Ouro/química , Humanos , Limite de Detecção , Gravidez
6.
Int J Nanomedicine ; 16: 2271-2282, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33776432

RESUMO

Background: Contrast-enhanced magnetic resonance imaging (MRI) is a powerful diagnostic tool for many diseases. In many situations, the contrasts are repeatedly administrated in order to monitor and assess the disease progression. Objective: To investigate and compare the biological effects of γ-Fe2O3 nanoparticle (NP) and gadolinium dimeglumine (Gd-DTPA) with high and multiple doses on the kidney of healthy mice. Methods: Polydextrose sorbitol carboxymethyl ether coated γ-Fe2O3 NP with hydrodynamic size of 68.2 nm and clinically applied Gd-DTPA were employed on healthy mice with the repeatedly intravenous administration of high doses. The cell viability of human umbilical vein endothelial cells (HUVEC) in high doses of these two contrast agents were measured using the xCELLigence Real-Time Cell Analysis (RTCA) S16 Instrument. The biological effects of γ-Fe2O3 NP and Gd-DTPA on the kidney were obtained using a biochemical automatic analyzer and multiple proinflammatory factor kit on the serum. Histopathological and immunohistochemistry analysis were taken on kidney tissues. Results: It showed that the proinflammatory responses elicited by the γ-Fe2O3 NPs were weaker than that by Gd-DTPA, evidenced by the relatively much lower level of IL-1ß, IL-6, IL-18, TNF-α, C-reactive protein (CRP) and Ferritin. At the same time, the γ-Fe2O3 NPs did not have the biochemical index elevated, while the Gd-DTPA did. Conclusion: The γ-Fe2O3 NPs induced weaker proinflammatory effects in reference to the Gd-DTPA, indicating better renal safety. Therefore, it is suggested that γ-Fe2O3 NPs should be safer and optional choice when repeated contrast-enhanced MRI is necessary.


Assuntos
Meios de Contraste/química , Compostos Férricos/química , Gadolínio DTPA/química , Inflamação/patologia , Rim/fisiopatologia , Nanopartículas/química , Animais , Biomarcadores/sangue , Proteína C-Reativa/metabolismo , Proliferação de Células , Sobrevivência Celular , Ferritinas/sangue , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Rim/patologia , Imagem por Ressonância Magnética , Masculino , Camundongos , Espectrometria por Raios X , Fator de Crescimento Transformador beta/metabolismo
7.
Water Res ; 195: 116977, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33684677

RESUMO

Anaerobic digestion (AD) is an essential process in wastewater treatment plants as it can reduce the amount of waste activated sludge (WAS) for disposal, and also enables the recovery of bioenergy (i.e. methane). Here, a new pretreatment method to enhance anaerobic digestion was achieved by treating thickened WAS (TWAS) with ferric (as FeCl3) and nitrite simultaneously for 24-hour at room temperature. Biochemical methane potential tests showed markedly improved degradability in the pretreated TWAS, with a relative increase in hydrolysis rate by 30%. A comparative experiment with the operation of two continuous-flow anaerobic digesters further demonstrated the improvement in biogas quantity and quality, digestate disposal, and phosphorus recovery in the experimental digester. The dosed FeCl3 (i.e. ~6 mM) decreased the pH of TWAS to ~5, which led to the formation of free nitrous acid (FNA, HNO2) at parts per million levels (i.e. ~6 mg N/L), after dosing nitrite at 250 mg NO2--N/L. This FNA treatment caused a 26% increase in methane yield and volatile solids destruction, 55% reduction in the viscosity of sludge in digester, and 24% less polymer required in further digestate dewatering. In addition, the dosed Fe(III) was reduced to Fe(II) which precipitated sulfide and phosphorus, leading to decreased hydrogen sulfide concentration in biogas, and increased percentage of vivianite in the total crystalline iron species in digested sludge. Our study experimentally demonstrated that combined dosing of FeCl3 and nitrite is a useful pretreatment strategy for improving anaerobic digestion of WAS.


Assuntos
Esgotos , Eliminação de Resíduos Líquidos , Anaerobiose , Reatores Biológicos , Compostos Férricos , Metano
8.
Int J Nanomedicine ; 16: 1709-1724, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33688187

RESUMO

Background: Manganese Ferrite Nanoparticles (Mn-IONPs) are widely used in biomedical field and their cytotoxicity has been initially explored, but the mechanism remains obscure. The nano-bio interactions are believed to be crucial for cytotoxicity mechanism, while little data have been acquired. Methods: Mn-IONPs were synthesized by thermal decomposition of acetylacetonate precursor. After physicochemical characterization, we analyzed the metabolic conversion and removal of Mn-IONPs in RAW264.7 cells by Prussian blue staining, TEM, HRTEM and elemental quantitative analysis, followed by gene expression evaluation using quantitative RT-PCR. Results: Mn-IONPs were successfully synthesized. Both the uptake and cytotoxicity of Mn-IONPs on RAW264.7 cells were time- and dose-dependent. After internalized, Mn-IONPs were passed to daughter cells with passages on. Meanwhile, Mn-IONPs were exocytosed and digested to metal ions and further excreted out, resulted in the labeling rate and ions contents decreased gradually. As ion influx related genes, the expressions of ZIP14, IRP2, FtH and DMT1 were suppressed within 24 hours but overexpressed to a plateau at the 48th hour in a dose-dependent manner. At the 72nd hour, ZIP14 and DMT1 mRNA levels decreased toward normal, while IRP2 and FtH kept up-regulated. As efflux related genes, FPN, SLC30A10 and Hamp2 genes were up-regulated within 24-72 hours; SPCA1 was suppressed at the 24th and 72nd hour, while overexpressed at the 48th hour. All the efflux related genes' mRNA had a dose-dependent increasing manner at the corresponding time points. Conclusion: Mn-IONPs showed time- and dose-dependent cytotoxicity and cell labeling rate in RAW264.7 cells. Accompanying with the intracellular catabolic breakdown and exocytosis of Mn-IONPs, RAW264.7 cells also secreted and re-uptook manganese and iron ions to maintain intracellular homeostasis in the succeeding passages. And the metabolic conversion of Mn-IONPs in RAW264.7 cells can affect the expression of ZIP14, DMT1, FPN, SLC30A10, IRP2, FtH, Hamp2 and SPCA1 genes.


Assuntos
Proteínas de Transporte de Cátions/genética , Compostos Férricos/metabolismo , Regulação da Expressão Gênica , Compostos de Manganês/metabolismo , Nanopartículas/química , Animais , Proteínas de Transporte de Cátions/metabolismo , Morte Celular/genética , Proliferação de Células/genética , Camundongos , Nanopartículas/ultraestrutura , Tamanho da Partícula , Células RAW 264.7
9.
Water Res ; 195: 116988, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33714011

RESUMO

Microbial dissimilatory iron reduction and aerobic oxidation affect the biogeochemical cycles of many elements. Although the processes have been widely studied, the underlying mechanisms, and especially how the surface structures of iron oxides affect these redox processes, are poorly understood. Therefore, {001} facet-dominated hematite nanoplates (HNP) and {100} facet-dominated hematite nanorods (HNR) were used to explore the effects of surface structure on the microbial dissimilatory iron reduction and aerobic oxidation processes. During the reduction stage, the production of total Fe(II) normalized by specific surface area (SSA) was higher for HNP than HNR due to steric effects and the ligand-bound conformation of the connection between iron on different exposed facets and electron donors from microorganisms. However, during the aerobic oxidation stage, both the SSA- and Fe(II)-normalized reactive oxygen species (ROS), including hydrogen peroxide (H2O2) and hydroxyl radical (•OH), were higher for HNR than HNP. Theoretical calculation results showed that the {100} facets exhibited a lower activation energy barrier for oxygen reduction reaction than {001} facets, supporting the experimental observation that {100} facet-dominated HNR had a higher ROS production efficiency than {001} facet-dominated HNP. These results indicated that surface characteristics not only mediated the microbial reduction of Fe(III) but also affected the aerobic oxidation of microbially reduced Fe(II). Accessibility of electron donors to surface iron atom determined the reduction of Fe(III), and activation energy barrier for oxygen reduction by surface Fe(II) dominated the ROS production during the redox processes. This study advances our understanding of the mechanisms through which ROS are produced by iron (oxyhydr)oxides during microbial dissimilatory iron reduction and aerobic oxidation processes.


Assuntos
Compostos Férricos , Shewanella , Peróxido de Hidrogênio , Ferro , Oxirredução , Espécies Reativas de Oxigênio
10.
Carbohydr Polym ; 260: 117777, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33712133

RESUMO

The combination of alginate, hyaluronic acid and multivalent ions have been reported to form alginate-hyaluronic acid ionic-crosslinking hydrogels for biomedical applications. However, injectable alginate-hyaluronic acid ionic-crosslinking hydrogels with satisfactory shear-thinning property have rarely been reported. In this study, we successfully developed an ionic-crosslinked alginate-hyaluronic acid hydrogel by simple assembly of alginate-hyaluronic acid mixture and Fe3+ complex. This hydrogel could fully recover within seconds after damaged, while displayed shear thinning behavior and good injectability which were contributed by the reversible and dynamic metal-ligand interactions formed via ferric ions and carboxyl groups of the polymers. Moreover, the local degradation of this hydrogel giving the hydrogel sustained ferric ions release property, of which led to potential long-term antibacterial activities against multiple types of bacteria including gram-negative Escherichia coli and gram-positive Staphylococcus aureus, as well as representative oral pathogenic bacteria Streptococcus mutans and Porphyromonas gingivalis.


Assuntos
Alginatos/química , Anti-Infecciosos/química , Compostos Férricos/química , Ácido Hialurônico/química , Hidrogéis/química , Animais , Anti-Infecciosos/farmacologia , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Feminino , Compostos Férricos/metabolismo , Humanos , Hidrogéis/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Porphyromonas/efeitos dos fármacos , Reologia , Pele/efeitos dos fármacos , Pele/patologia , Staphylococcus aureus/efeitos dos fármacos , Streptococcus mutans/efeitos dos fármacos
11.
J Environ Manage ; 287: 112302, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33714045

RESUMO

Fly ash and arsenic species have been regarded as contaminants that pollute the environment. Herein, low alumina fly ash (LAFA) was utilized to fabricate the As(V) and As(III) adsorbent via combining the routes of alkali fusion and incipient-wetness impregnation. The characterization results suggested that the grafted ferric citrate was coordinated to LAFA by substituting a Si4+ to a Fe3+, and the compound monosodium citrate was observed. Based on the XPS analysis, the C-O and -COO- groups of monosodium citrate played the significant role in uptaking As(V) and As(III) species by chemical complexation, the FeOOH adsorbed As(V) and As(III) species via ion-exchange, and the Fe2O3 oxidize As(III) into As(V). Additionally, it was observed that the As(V) removal performance by adsorbent prepared with different modifiers was in the order of FeC6H5O7 (ca. 93.7%) > C6H8O7 (84%) > HCl (73%). And then, the optimal adsorbent synthesis condition for As(V) uptake was explored at ferric citrate loaded LAFA with 1:1 mass ratio (fly ash to NaOH) under temperature 923 K. The maximum monolayer adsorption capacities of the optimal adsorbent were 2725.0 µgAs(V)/g and 2281.9 µgAs(III)/g, and the removal efficiency of As(V) and As(III) was near 100% for their initial concentrations below 500 ppb, where the residual arsenic concentration met the required standard in drinking water (lower than 10 ppb).


Assuntos
Arsênico , Poluentes Químicos da Água , Purificação da Água , Adsorção , Óxido de Alumínio , Arsênico/análise , Cinza de Carvão , Compostos Férricos , Concentração de Íons de Hidrogênio , Cinética , Citrato de Sódio , Poluentes Químicos da Água/análise
12.
J Clin Pediatr Dent ; 45(1): 22-28, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33690822

RESUMO

OBJECTIVE: To determine the clinical and radiographic success of Biodentine® (BD) and Ferric Sulfate (FS) as primary molar pulpotomy materials and to compare their outcomes. STUDY DESIGN: Retrospective data was obtained from the electronic health records (EHR) of a university-based pediatric dental clinic. Participants were enrolled according to specified inclusion and exclusion criteria. Two trained and calibrated examiners evaluated the EHR using validated criteria for clinical and radiographic outcomes. Study data was numerically coded and analyzed. Cohen's Kappa and Chi-square tests were used (p<0.05). RESULTS: Eighty-three participants (62.7% females, age range two to eight years, average age of 4.5 years) with 102 pulpotomies were enrolled. FS was used in 78% (n=79) and BD in 22% (n=23) of the cases. Follow-up periods ranged from six to 36 months (mean of 17 months). BD showed 100% clinical and radiographic success, while FS demonstrated 84% clinical and 70% radiographic success. The two groups were compared at one year with no statistically significant differences. At 18 months, BD outperformed FS clinically (p=.012) and radiographically (p=.001). Intra-rater and inter-rater agreement were κ>0.88. CONCLUSIONS: Both materials can be recommended for clinical practice, however BD may be the preferred choice for its better outcomes at 18 months.


Assuntos
Compostos de Cálcio , Pulpotomia , Criança , Pré-Escolar , Combinação de Medicamentos , Feminino , Compostos Férricos/uso terapêutico , Humanos , Masculino , Dente Molar/diagnóstico por imagem , Dente Molar/cirurgia , Estudos Retrospectivos , Silicatos/uso terapêutico , Dente Decíduo , Resultado do Tratamento
13.
J Biomed Nanotechnol ; 17(2): 205-215, 2021 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-33785092

RESUMO

Imaging-guided cancer theranostic is a promising strategy for cancer diagnostic and therapeutic. Photodynamic therapy (PDT), as an approved treatment modality, is limited by the poor solubility and dispersion of photosensitizers (PS) in biological fluids. Herein, it is demonstrated that superparamagnetic iron oxide (SPIO)-based nanoparticles (SCFs), prepared by conjugated with Chlorin e6 (Ce6) and modified with folic acid (FA) on the surface, can be used as versatile drug delivery vehicles for effective PDT. The nanoparticles are great carriers for photosensitizer Ce6 with an extremely high loading efficiency. In vitro fluorescence imaging and in vivo magnetic resonance imaging (MRI) results indicated that SCFs selectively accumulated in tumor cells. Under near-infrared laser irradiation, SCFs were confirmed to be capable of inducing low cell viability of RM-1 cells In vitro and displaying efficient tumor ablation with negligible side effects in tumor-bearing mice models.


Assuntos
Nanopartículas , Fotoquimioterapia , Porfirinas , Animais , Linhagem Celular Tumoral , Compostos Férricos , Ácido Fólico , Imagem por Ressonância Magnética , Camundongos , Camundongos Endogâmicos BALB C , Fármacos Fotossensibilizantes/farmacologia , Medicina de Precisão , Nanomedicina Teranóstica
14.
Medicine (Baltimore) ; 100(11): e25104, 2021 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-33725987

RESUMO

ABSTRACT: Our aim in this study was to investigate the relationship between serum ischemia modified albumin (IMA) levels with oxidative stress parameters [protein carbonyl (PCO), advanced protein oxidation products (AOPPs), malondialdehyde (MDA), total nitric oxide (NOx), prooxidant-antioxidant balance (PAB), and ferric reducing of antioxidant power (FRAP)] in breast cancer (BC) and colon cancer (CC).In total, 90 patients undergoing surgical treatment for BC (n = 45) or CC (n = 45) and 35 healthy controls were included in this cross-sectional study.The serum PCO, AOPPs, MDA, NOx, PAB, and IMA levels were all statistically significantly higher in the cancer patients than in the control group. MDA, NOx, and PAB levels were significantly lower in the BC group than in the CC group. FRAP values were statistically significantly lower in both the CC group and the BC group compared to the control. IMA showed a weak positive correlation with CA-19.9 (r = 0.423 P = .007) but a moderate positive correlation with tumor size in the CC group. IMA showed a positive correlation with metastasis, grade, and HER2 and a negative correlation with ER and PR in the BC group.Oxidative stress is a key player in the development of solid malignancies. Cancer development is a multistage process, and oxidative stress caused by the production of ROS/RNS in the breast and colon may predispose individuals to BC and CC. Patients with BC and CC had an impaired oxidative/antioxidant condition that favored oxidative stress. The ROC analysis indicated that IMA sensitivity above 80% could be used as a secondary biomarker in diagnosis.


Assuntos
Neoplasias da Mama/sangue , Neoplasias do Colo/sangue , Estresse Oxidativo , Espécies Reativas de Nitrogênio/sangue , Espécies Reativas de Oxigênio/sangue , Produtos da Oxidação Avançada de Proteínas/sangue , Antioxidantes/metabolismo , Biomarcadores Tumorais/sangue , Neoplasias da Mama/patologia , Estudos de Casos e Controles , Neoplasias do Colo/patologia , Estudos Transversais , Feminino , Compostos Férricos/sangue , Humanos , Masculino , Malondialdeído/sangue , Pessoa de Meia-Idade , Gradação de Tumores/métodos , Estadiamento de Neoplasias/métodos , Óxido Nítrico/sangue , Oxirredução , Carbonilação Proteica , Curva ROC , Albumina Sérica/análise
15.
Sci Total Environ ; 768: 144477, 2021 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-33736314

RESUMO

Copper ferrite/reduced graphene oxide (CF/rGO) nanocomposites (NCs) was synthesized using the bio-combustion method and applied as a cathode catalyst in the microbial reduction of CO2 to volatile fatty acids (VFAs) in a single chamber microbial electrosynthesis system (MES). The synthesized NCs exhibited a porous network-like structure with a high surface area of CF/rGO (158.22 m2/g), which was 2.24 folds higher than that of CF. The Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) analysis for CF/rGO/Carbon cloth (Cc) revealed a high reduction current density of -7.3 A/m2 and a low charge transfer resistance of 2.8 Ω. The isobutyrate and acetate in MES-2 (Cu/rGO/Cc) were produced at 35.37 g/m2/d, which was 1.53 folds higher than that of MES-1 (bare Cc: 23.10 g/m2/d). The columbic efficiency (77.78%) and total VFA concentration (1941.13 ± 83 mg COD/L) were noted to be 1.97 and 1.6 folds higher for MES-2 than MES-1, respectively. The Tafel plot drawn from the CV curves exhibited an exchange current density value of MES-2 that was 3.46 A/m2, and this value was 1.19 and 33.92 folds higher than that of MES-1 and abiotic CF/rGO/Cc, respectively. Field emission scanning electron microscopy (FESEM) observations revealed enhanced rod-shaped bacteria had grown on the cathode suggesting excellent biocompatible and multi-length scale porosity of CF/rGO catalysts for enhanced colonization of microbes. The phyla Proteobacteria (Betaproteobacteria), Bacteroidetes, and Firmicutes were highly abundant as the dominant microbial communities on the cathode, which might played a major role in bioelectrochemical CO2 reduction to VFAs. The results from this study clearly demonstrate that the CF/rGO/Cc electrode could serve as a conductive element between microbes and bactericidal electrodes with excellent electrochemical properties to enable performance of the MES.


Assuntos
Dióxido de Carbono , Cobre , Eletrodos , Ácidos Graxos Voláteis , Compostos Férricos , Grafite
16.
Sci Total Environ ; 768: 144709, 2021 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-33736355

RESUMO

Understanding the biogeochemical processes controlling arsenic (As) mobilization under bacterial sulfate reduction (BSR) in aquifer sediments is essential for the remediation of high As groundwater. Here, we conducted microcosm experiments with shallow aquifer sediments from the Jianghan Plain (central Yangtze River Basin) under the stimulation of exogenous sulfate. Initially, co-increases of As(III) (from 0.0 to 88.5 µg/L), Fe(II) (from 0.5 to 6.0 mg/L), and S(-II) (from 0.0 to 90.0 µg/L) indicated the concurrent occurrence of sulfate, Fe(III), and arsenate reduction. The corresponding increase of the relative abundance of OTUs classified as sulfate-reducing bacteria, Desulfomicrobium (from 0.5 to 30.6%), and dsrB gene abundance indicated the strong occurrence of BSR during the incubation. The underlying mechanisms of As mobilization could be attributed to the biotic and abiotic reduction of As-bearing iron (hydro)oxides either through the iron-reducing bacteria or the bacterially generated sulfide, which were supported by the variations in solid speciation of Fe, S, and As. As the incubation progressed, we observed a transient attenuation followed by a re-increase of aqueous As, due to the limited abundance of newly-formed Fe-sulfide minerals with a weak ability of As sequestration. Moreover, the formation of thioarsenate (H2AsS4-) during the mobilization of As from the sediments was observed, highlighting that BSR could facilitate As mobilization through multiple pathways. The present results provided new insights for the biogeochemical processes accounting for As mobilization from sediments under BSR conditions.


Assuntos
Arsênico , Água Subterrânea , Poluentes Químicos da Água , Arsênico/análise , Bactérias , Compostos Férricos , Sedimentos Geológicos , Oxirredução , Sulfatos , Poluentes Químicos da Água/análise
17.
J Environ Sci (China) ; 103: 80-92, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33743921

RESUMO

In this study, transport behaviors of graphene oxide (GO) in saturated uncoated (i.e., clean sand) and goethite-coated sand porous media were examined as a function of the phosphate. We found that phosphate enhanced the transport of GO over a wide range of solution chemistry (i.e., pH 5.0-9.0 and the presence of 10 mmol/L Na+ or 0.5 mmol/L Ca2+). The results were mainly ascribed to the increase of electrostatic repulsion between nanoparticles and porous media. Meanwhile, deposition site competition induced by the retained phosphate was another important mechanism leading to promote GO transport. Interestingly, when the phosphate concentration increased from 0.1 to 1.0 mmol/L, the transport-enhancement effect of phosphate in goethite-coated sand was to a much larger extent than that in clean sand. The observations were primarily related to the difference in the total mass of retained phosphate between the iron oxide-coated sand and clean sand columns, which resulted in different degrees of the electrostatic repulsion and competitive effect of phosphate. When the background solution contained 0.5 mmol/L Ca2+, phosphate could be bind to sand/ goethite-coated sand surface by cation bridging; and consequently, promoted competition between phosphate and nanoparticles for deposition sites, which was an important mechanism for the enhanced effect of phosphate. Moreover, the DLVO theory was applicable to describe GO transport behaviors in porous media in the absence or presence of phosphate. Taken together, these findings highlight the important status and role of phosphate on the transport and fate of colloidal graphene oxide in the subsurface environment.


Assuntos
Nanopartículas , Dióxido de Silício , Compostos Férricos , Grafite , Fosfatos , Porosidade , Areia
18.
Bioresour Technol ; 329: 124853, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33621929

RESUMO

In this work, nickel ferrite nanoparticles (NiFe2O4 NPs) was prepared to improve hydrogen (H2) production by dark fermentation. Moderate amounts (50-200 mg/L) promoted H2 generation, while excess NiFe2O4 NPs (over 400 mg/L) lowered H2 productivity. The highest H2 yields of 222 and 130 mL/g glucose were obtained in the 100 mg/L (37 °C) and 200 mg/L NiFe2O4 NPs (55 °C) groups, respectively, and the values were 38.6% and 28.3% higher than those in the control groups (37 °C and 55 °C). Soluble metabolites showed that NiFe2O4 NPs enhanced the butyrate pathway, corresponding to the increased abundance of Clostridium butyricum in mesophilic fermentation. The endocytosis of NiFe2O4 NPs indicated that the released iron and nickel favored ferredoxin and hydrogenase synthesis and activity and that NiFe2O4 NPs could act as carriers in intracellular electron transfer. The NPs also optimized microbial community structure and increased the levels of extracellular polymeric substances, leading to increased H2 production.


Assuntos
Nanopartículas , Níquel , Suplementos Nutricionais , Fermentação , Compostos Férricos , Hidrogênio
19.
Food Chem ; 345: 128854, 2021 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-33601661

RESUMO

The changes of chemical compositions and sensory characteristics of Meili rosé wine in flint, antique green and amber bottles were studied under continuous illumination for 160 days in two light sources (white fluorescent light, UV light). The results showed that light exposure caused significant changes in free sulfur dioxide content, Fe(III):Fe(II) ratio and Malvidin-3-O-glucoside content, responsible for the accelerated color evolution of Meili rosé wine during bottle storage. Some notable aroma-related changes were also observed for sensory characteristics, particularly for wines in flint bottles, boiled-like odor and oxidized odor appeared. Bottle color played a key role in preventing rosé wine from light exposure, following the order: amber bottle > green bottle > flint bottle. Besides UV light, white fluorescent light did have negative effects on rosé wine quality, considering its ubiquitous presence and long-term exposure in practice. The underlying mechanisms related to photochemical reactions in wine were further discussed.


Assuntos
Armazenamento de Alimentos/métodos , Raios Ultravioleta , Vinho/análise , Antocianinas/análise , Cor , Compostos Férricos/química , Compostos Ferrosos/química , Odorantes , Dióxido de Enxofre/química
20.
J Environ Manage ; 283: 112004, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33529931

RESUMO

Acid mine waters (AMWs), generated in the processing of polymetallic sulphides, contain copper and zinc as the main valuable transition metal ions, which are typically removed by liming, due to their great environmental impact. In this context, this work proposes the integration of selective precipitation (SP) and ion-exchange (IX) processes for the separation and recovery of both valuable metals to encourage on-site and off-site management options promoting valorisation routes. Thus, the main objectives of this work were (i) the selective removal of Fe(III) and Al(III), using NaOH under pH control (pH < 5) to avoid the precipitation of Cu(II) and Zn(II) and (ii) the evaluation of a solvent-impregnated resin (Lewatit VP OC 1026, named VP1026) and a cation IX resin (Lewatit TP 207, named TP207) for the sequential extraction of both metal ions from AMW (batch and column experiments). Results indicated that the metallic pollution load was mostly removed during the SP process of Fe(III) (>99%) and Al(III) (>90%) as hydroxylsulphates (e.g., schwertmannite and basaluminite). The metal extraction profiles were determined for both metals from pH 1 to pH 5 by batch experiments, and indicated that the best extraction of Zn(II) was obtained using VP1026, being higher than 96% (pH = 2.6-2.8), whereas TP207 extraction performance was optimal for Cu(II) extraction (>99%) at pH = 3-4. Moreover, in dynamic experiments using a fixed-bed configuration, it was possible to separate and concentrate Zn(II) (concentration factor = 10) and Cu(II) (concentration factor = 40) using VP1026 and TP207, respectively. Overall, the integration of SP and IX processes showed a great potential in the separation and recovery of valuable metals from mine waters to promote a circular economy, based on the management proposal for non-ferrous metallurgical industries. The recovered Zn-rich and Cu-rich sulphuric concentrated streams were theoretically evaluated for further on-site or off-site re-use treatments (e.g., electrowinning, precipitation, crystallization).


Assuntos
Compostos Férricos , Metais Pesados , Cobre/análise , Concentração de Íons de Hidrogênio , Troca Iônica , Metais Pesados/análise , Mineração , Zinco/análise
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