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1.
J Environ Manage ; 360: 121161, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38761626

RESUMO

Recent attention on the detrimental effects of pharmaceutically active compounds (PhACs) in natural water has spurred researchers to develop advanced wastewater treatment methods. Carbamazepine (CBZ), a widely recognized anticonvulsant, has often been a primary focus in numerous studies due to its prevalence and resistance to breaking down. This study aims to explore the effectiveness of a bio-electrochemical system in breaking down CBZ in polluted water and to assess the potential harmful effects of the treated wastewater. The results revealed bio-electro degradation process demonstrated a collaborative effect, achieving the highest CBZ degradation compared to electrodegradation and biodegradation techniques. Notably, a maximum CBZ degradation efficiency of 92.01% was attained using the bio-electrochemical system under specific conditions: Initial CBZ concentration of 60 mg/L, pH level at 7, 0.5% (v/v) inoculum dose, and an applied potential of 10 mV. The degradation pathway established by identifying intermediate products via High-Performance Liquid Chromatography-Mass Spectrometry, revealed the complete breakdown of CBZ without any toxic intermediates or end products. This finding was further validated through in vitro and in vivo toxicity assays, confirming the absence of harmful remnants after the degradation process.


Assuntos
Biodegradação Ambiental , Carbamazepina , Poluentes Químicos da Água , Carbamazepina/toxicidade , Poluentes Químicos da Água/toxicidade , Águas Residuárias/química , Animais
2.
Int Microbiol ; 2023 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-37659056

RESUMO

Bisphenol A (BpA) is an endocrine-disrupting substance commonly found in plastics and resins. It is reported that BpA exposure induces lipid accumulation in humans, similar to obesogenic compounds. The main objective of this study is to investigate the removal of BpA using Lactiplantibacillus sp. D10-2, and to examine its potential for reducing BpA-induced lipid accumulation in 3T3-L1 cell line model. The heat-dried cells of Lactiplantibacillus sp. D10-2 showed 69.7% removal efficiency for initial BpA concentration of 10 µg/mL, which was 30.5% higher than the live cells. The absence of metabolites or intermediates in BpA removal studies indicates that the Lactiplantibacillus sp. D10-2 strain removed BpA by adsorption process. The hydrophobic interactions of heat-dried Lactiplantibacillus sp. D10-2 cells were observed to be higher with 33.7% compared to live cells (15.0%), suggesting a stronger ability to bind with BpA. Although the BpA binding onto Lactiplantibacillus sp. D10-2 was not affected by pH, it was confirmed that as the temperature increases, the binding ability got decreased due to mass transfer and diffusion of BpA molecules. Treatment with Lactiplantibacillus sp. D10-2 (0.1, 0.25, 0.5, 1%) reduced lipid accumulation by 61.7, 58.0, 52.7 and 60.4% in 3T3-L1 cells exposed with BpA. In addition, it was confirmed that Lactiplantibacillus sp. D10-2 treatment suppressed the protein expression levels of lipogenesis-related PPARγ and C/EBPα in 3T3-L1 cells. The results of the study suggest that the Lactiplantibacillus sp. D10-2 strain can remove BpA and reduce BpA-accelerated lipid accumulation in 3T3-L1 cells.

3.
J Appl Microbiol ; 134(12)2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37989872

RESUMO

AIM: To assess the effectiveness of Lentilactobacillus parafarraginis A6-2 cell lysate for the removal of aluminum (Al), which induces neurotoxicity, and its protective effect at cellular level. METHODS AND RESULTS: The cell lysate of the selected L. parafarraginis A6-2 strain demonstrated superior Al removal compared to live or dead cells. The Al removal efficiency of L. parafarraginis A6-2 cell lysate increased with decreasing pH and increasing temperature, primarily through adsorption onto peptidoglycan. Neurotoxicity mitigation potential of L. parafarraginis A6-2 was evaluated using C6 glioma cells. C6 cells exposed with increasing concentration of Al led to elevated toxicity and inflammation, which were gradually alleviated upon treatment with L. parafarraginis A6-2. Moreover, Al-induced oxidative stress in C6 cells showed a concentration-dependent reduction upon treatment with L. parafarraginis A6-2. CONCLUSIONS: This study demonstrated that L. parafarraginis A6-2 strain, particularly in its lysate form, exhibited enhanced capability for Al removal. Furthermore, it effectively mitigated Al-induced toxicity, inflammation, and oxidative stress.


Assuntos
Alumínio , Estresse Oxidativo , Humanos , Alumínio/toxicidade , Inflamação , Anti-Inflamatórios/farmacologia
4.
Environ Res ; 239(Pt 1): 117367, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37827364

RESUMO

In today's industrialized world, contamination of soil and water with various substances has emerged as a pressing concern. Bioremediation, with its advantages of degradation or detoxification, non-polluting nature, and cost-effectiveness, has become a promising method due to technological advancements. Among the bioremediation agents, bacteria have been highly explored and documented as a productive organism. Recently, few studies have reported on the significance of Herbaspirillum sp., a Gram-negative bacterium, in bioremediating herbicides, pesticides, polycyclic aromatic hydrocarbons, metalloids, and heavy metals, as well as its role in augmenting phytoremediation efforts. Herbaspirillum sp. GW103 leached 66% of Cu from ore materials and significantly enhanced the phytoaccumulation of Pb and Zn in plumule and radical tissues of Zea mays L. plants. Additionally, Herbaspirillum sp. WT00C reduced Se6+ into Se0, resulting in an increased Se0 content in tea plants. Also, Herbaspirillum sp. proved effective in degrading 0.6 mM of 4-chlorophenol, 92.8% of pyrene, 77.4% of fluoranthene, and 16.4% of trifluralin from aqueous solution and soil-water system. Considering these findings, this review underscores the need for further exploration into the pathways of pollutant degradation, the enzymes pivotal in the degradation or detoxification processes, the influence of abiotic factors and pollutants on crucial gene expression, and the potential toxicity of intermediate products generated during the degradation process. This perspective reframes the numerical data to underscore the underutilized potential of Herbaspirillum sp. within the broader context of addressing a significant research gap. This shift in emphasis aligns more closely with the problem-necessity for solution-existing unexplored solution framework.


Assuntos
Poluentes Ambientais , Herbaspirillum , Herbicidas , Metais Pesados , Praguicidas , Biodegradação Ambiental , Herbaspirillum/genética , Hidrocarbonetos , Metais Pesados/toxicidade , Solo , Água
5.
Environ Res ; 231(Pt 3): 116289, 2023 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-37263467

RESUMO

Enterococcus gallinarum (JT-02) isolated and identified from the animal farm waste sludge was found to be capable of biodegrading p-nitrophenol (PNP), an organic compound used to manufacture drugs, fungicides, insecticides, dyes, and to darken leather. The intention of this study was to optimize the biodegradation by finding the optimal conditions for the specific strain through single-factor experiments. The bacterial strain was grown in Luria Bertani broth and various parameters were optimized to achieve the prime settings for the p-nitrophenol (PNP) biodegradation. The results indicated that the best setups for the biodegradation by the strain JT-02 was 100 mg/L of PNP; pH 7; 30 °C; 150 rpm in a shaker incubator and 3% (v/v) of inoculum dose. Once the optimal conditions were found, the bacteria were capable of degrading p-nitrophenol (98.21%) in 4 days. Intermediates produced during PNP biodegradation were identified using High Performance Liquid Chromatography (HPLC) analysis and the biodegradation pathway was elucidated. Phytotoxicity studies were carried out with Vigna radiata seeds to confirm the applicability and efficiency of PNP biodegradation.


Assuntos
Enterococcus , Esgotos , Animais , Esgotos/microbiologia , Fazendas , Bactérias/metabolismo
6.
Environ Res ; 212(Pt A): 113136, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35351453

RESUMO

WO3/Zeolite/V2O5 (TZV) composite synthesized through co-precipitation was used for the degradation of Bisphenol-A (BpA). XRD and Raman spectra were employed to ascertain the crystallinity of the composite. The pristine nature of the compound without any free particles over the zeolite surface was established through FESEM, thus, substantiating the composite character of the material. The enhancement in activity after doping with WO3 was ascertained by DRS-UV. Photocatalytic degradation studies clearly established the superiority of TZV 10 over bare V2O5. Complete BpA degradation (100%) was attained at 50 min of incubation with 0.75 g/L TZV-10 in acidic medium (pH 3) for an initial BpA concentration of 100 mg/L. HPLC-MS/MS analysis was used to decipher the degradation pathway. The catalyst was stable even after 9 cycles. Phytotoxicity studies and lake water treatment results proved the environmental efficiency of the synthesized material.


Assuntos
Zeolitas , Compostos Benzidrílicos/toxicidade , Catálise , Fenóis/química , Espectrometria de Massas em Tandem
7.
J Basic Microbiol ; 55(10): 1232-8, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25903936

RESUMO

This study aimed to understand the influence of heavy metals on 1-aminocyclopropane-1-carboxylate deaminase activity (ACCD) and acdS gene expression in Herbaspirillium sp. GW103. The GW103 strain ACCD activity decreased in cells grown in a medium supplemented with Pb and As, whereas cells grown in medium supplemented with Cu showed increase in enzyme activity. The GW103 strain produced 262.2 ± 6.17 µmol of α-ketobutyrate per milligram of protein per hour during ACC deamination at 25 °C after 24 h incubation. Using a PCR approach, an acdS coding-gene of 1.06 kbp was amplified in isolate GW103, showing 92% identity with Herbaspirillum seropedicae SmR1 acdS gene. Real time quantitative polymerase chain reaction results indicate that the acdS expression rate was increased (7.1-fold) in the presence of Cu, whereas it decreased (0.2- and 0.1-fold) in the presence of As and Pb.


Assuntos
Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Herbaspirillum/enzimologia , Herbaspirillum/genética , Metais Pesados/metabolismo , Microbiologia do Solo , Arsênio , Carbono-Carbono Liases/genética , Cobre , DNA Bacteriano/genética , Herbaspirillum/isolamento & purificação , Chumbo , Raízes de Plantas , Reação em Cadeia da Polimerase em Tempo Real , Rizosfera , Análise de Sequência de DNA
8.
Chemosphere ; 324: 138368, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36905999

RESUMO

The doping of noble metals onto the semiconductor metal oxides has a great impact on the intrinsic properties of the materials. This present work reports the synthesis of noble metals doped BiOBr microsphere by a solvothermal method. The various characteristic findings reveal the effective incorporation of Pd, Ag, Pt, and Au onto the BiOBr and the performance of synthesized samples was test for the degradation of phenol over visible light. The Pd-doped BiOBr material showed enhanced phenol degradation efficacy, which is ∼4-fold greater than pure BiOBr. This improved activity was on reason of good photon absorption, lower recombination rate, and higher surface area facilitated by surface plasmon resonance. Moreover, Pd-doped BiOBr sample displayed good reusability and stability after 3 cycles of run. A plausible charge transfer mechanism for phenol degradation is disclosed in detail over Pd-doped BiOBr sample. Our findings disclose that the incorporation of noble metal as the electron trap is a feasible approach to enhance visible light activity of BiOBr photocatalyst used in phenol degradation. This work represents new vision interested in the outline and development of noble metal doped semiconductor metal oxides as a visible light material for the elimination of colorless toxins from untreated wastewater.


Assuntos
Bismuto , Fenol , Catálise , Luz , Óxidos
9.
Chemosphere ; 313: 137485, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36526143

RESUMO

Prolonged exposure to antibiotics would likely favor the development of antibiotic resistance and their gene transfer among bacterial communities that are responsible for enriched antibiotic resistant microbes. Sulfamethoxazole (SFM) is a commonly used antibiotic that is released into the environment through human and animal wastes. Improper degradation of SFM poses severe threats to mankind and all life forms. The present study aims in analyzing the process and the probability of utilizing bio-electrokinetic degradation for elimination of SFM from artificially contaminated soil employing Enterobacter hormaechei HaG-7. The desired optimal conditions for SFM degradation (∼98%) were observed at SFM initial concentration (100 mg/L) with an inoculum dose (1% v/v) and applied potential voltage (1.5 V) at pH (7). The results indicated efficient and complete degradation of SFM when compared with the conventional biodegradation.


Assuntos
Enterobacter , Sulfametoxazol , Animais , Humanos , Sulfametoxazol/toxicidade , Antibacterianos/toxicidade , Biodegradação Ambiental
10.
Chemosphere ; 343: 140230, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37734496

RESUMO

Antibiotics have revolutionized modern day living with their ability to effectively treat infectious diseases in humans and animals. However, the release of antibiotic compounds into the environment has led to toxic consequences. To reduce this environmental impact, it is important to employ an inexpensive and rational technology to reduce the amount of antibiotics released into the ecosystem. This study aims to explore the potential of using a bio-electrochemical system (BES) to remove Amoxicillin (AMX) from artificially contaminated soil using a microbial consortium and pure culture isolates. Under desired conditions, including an initial AMX concentration of 150 mg/L, 5 mg/L tryptone as the nitrogen source, pH of 7, temperature of 29 °C, an applied potential of 0.8 V, and an inoculum dose of 1% w/v, the BES showed a maximum degradation of 97.9% of AMX with the microbial consortium (HP03, HP09, and HP10). High performance liquid chromatography-mass spectrometry was used to analyse the intermediates formed during the degradation process, and the pathway elucidated revealed complete degradation of AMX. Phytotoxicity studies and degradation efficiency against multiple antibiotics confirmed the environmental significance of the BES with microbial consortium. Overall, this study highlights the potential of BES as a cost-effective and efficient method for reducing the release of antibiotics into the environment and provides valuable insights into the mechanisms and pathways of antibiotic degradation.


Assuntos
Amoxicilina , Ecossistema , Humanos , Animais , Amoxicilina/análise , Antibacterianos/química , Bactérias/metabolismo , Instalações de Eliminação de Resíduos
11.
Int J Biol Macromol ; 250: 126193, 2023 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-37562468

RESUMO

Recent efforts on the expansion of sustainable and commercial primal matters are essential to enhance the knowledge of their hazards and noxiousness to humans and their environments. For example, polysaccharide materials are widely utilized in food, wound dressing, tissue engineering, industry, targeted drug delivery, environmental, and bioremediation due to their attractive degradability, nontoxicity and biocompatibility. There are numerous easy, quick, and efficient ways to manufacture these materials that include cellulose, starch, chitosan, chitin, dextran, pectin, gums, and pullulan. Further, they exhibit distinctive properties when combined favourably with raw materials from other sources. This review discusses the synthesis and novel applications of these carbohydrate polymers in industrial, environmental and biomedical sciences.

12.
Food Sci Biotechnol ; 32(9): 1257-1268, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37362805

RESUMO

The limited yield of Ulmus davidiana var. japonica root bark (URB) extract is considered an economic loss to the food industry. Improving extraction yield and bioactivity through fermentation increase the industrial usage of URB. The study aims to optimize the fermentation with cellulolytic and pectinolytic bacteria and evaluate the bioactivity and anti-Helicobacter pylori activity of the fermented URB extract. URB fermentation with the Bacillus licheniformis FLa3, isolated from salted seafood (Sardinella zunasi), under optimal conditions (37 °C, pH 6, 10% inoculum dose, and 36 h) improved the extraction yield by 36% compared to the control. The antioxidant and antimicrobial activity of the fermented extract were significantly higher than non-fermented extract. High-performance liquid chromatography results confirmed that the fermentation increased the proportion of bioactive components such as catechin (171.7%), epicatechin (144.3%), quercetin (27.3%), and kaempferol (16.7%). The results confirmed that the fermentation increased both the extraction yield and bioactivity.

13.
Chemosphere ; 303(Pt 2): 135121, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35623428

RESUMO

Development of novel and eco-friendly composite photocatalysts for the efficient removal of contaminants from wastewater is the need of the hour. In this study, visible light responsive novel graphene aerogel/bismuth oxyiodide (GA/BiOI) composite was synthesized via low-temperature solvothermal method. The synthesized GA/BiOI composite was tested for methyl orange (MO) azo-dye degradation under visible light. The graphene aerogel nanosheets were wrapped onto the surface of the each individual BiOI microsphere, which encourages the interconnection charge transfer process. The light absorption properties of GA/BiOI composite were increased with the addition of graphene aerogel. The optimal 5%-GA/BiOI composite displayed higher MO removal efficiency, which is ∼2 fold more than the bare BiOI photocatalyst. This enhanced photocatalytic activity was on account of lower recombination rate of charge carriers, improved light absorption, and the high surface area. In addition, the 5%-GA/BiOI composite showed good stability until 3 cycles without deactivation. The plausible MO degradation mechanism was also proposed over GA/BiOI under visible light. This work provides a new perspective on the design and synthesis of graphene aerogel-based composite for environmental applications.


Assuntos
Bismuto , Grafite , Compostos Azo , Catálise , Luz
14.
Chemosphere ; 303(Pt 2): 135091, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35644242

RESUMO

The wide use of antibiotics has caused their continual release and persistence in the eco-system, subsequently giving birth to antibiotic resistant bacterial species in the aquatic environment, thereby necessitating immediate and efficient remediation of the contaminated environment. In the present study, we synthesized Ag/Ag2S@BiOI nanowires with an average diameter of ∼150 nm and length of 3-5 µm using a hydrothermal method and employed them as photocatalysts for photocatalytic degradation of tetracycline as a model antibiotic. The nanowire achieved nearly complete degradation of tetracycline (∼99%) within 60 min at the optimal condition of 100 mg/L TC concentration and pH 2. The degradation followed pseudo-first order kinetics, with a rate constant of 0.06228 min- 1. Our toxicity tests showed that the nanowire has negligible toxicity towards PBMC cells, suggesting it as a promising photocatalyst.


Assuntos
Nanofios , Antibacterianos/toxicidade , Catálise , Feminino , Humanos , Leucócitos Mononucleares , Gravidez , Tetraciclina/toxicidade
15.
Chemosphere ; 301: 134699, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35483659

RESUMO

Pharmaceuticals and personal care products occupy a predominant position with respect to both utility and release into the ecosystem, thereby contributing to environmental pollution at alarming rates. Of the several methods identified to minimize the concentration of PPCPs, nanomaterial based photocatalysis seems to be a potential alternative for it being highly economical and eco-friendly. In this study, we synthesized Nickel zinc ferrite (Ni-ZF) [Nix Zn1-x Fe2O4 (x = 0, 0.3, 0.7)] nanoparticles with an average diameter of ∼400 nm by a co-precipitation method towards diclofenac degradation. The composite showed greater degrees of crystallinity devoid of any impurities. Nearly complete DCF degradation (∼99%) was achieved after 50 min reaction time with the nanoparticles at pH 7 for an initial DCF concentration of 50 mg/L. The degradation process followed a pseudo first-order rate law with the rate constant of 0.1657 min- 1. Microbial toxicity and phytotoxicity studies demonstrated negligible toxicity imposed by the contaminated water treated with the prepared composite, suggesting it as a promising photocatalyst benefitting in all aspects.


Assuntos
Diclofenaco , Nanopartículas , Catálise , Diclofenaco/toxicidade , Ecossistema , Luz , Zinco
16.
J Hazard Mater ; 416: 126209, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492970

RESUMO

In this present study, spherical shaped zinc ferrite (Zn/Fe2O4) was prepared as uniformly sized (65 ± 0.5 nm) nanoparticles with band gap (2.00 eV) in a visible light regime and employed for the photocatalytic degradation of carbamazepine (CBZ). The doping of Zn decreased the band gap (from 2.00 to 1.98 eV) and enhanced the absorption of visible light. Zinc doping also induced effective separation of photogenerated carriers and subsequent charge migration to the surface of the Zn/Fe2O4 nanoparticle. On account of the advantages of the material, a high removal efficiency (~ 100%) of CBZ through photocatalytic degradation was achieved. Kinetics of CBZ degradation follows a pseudo first-order with the rate constant 0.0367 min-1. In-vitro and in-vivo toxicity of the nanoparticles were examined promoting the environmental implications.


Assuntos
Carbamazepina , Zinco , Carbamazepina/toxicidade , Catálise , Compostos Férricos , Luz , Zinco/toxicidade
17.
Chemosphere ; 264(Pt 1): 128481, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33045558

RESUMO

Reduced graphene oxide/cadmium sulfide (RGOCdS) nanocomposite synthesized through solvothermal process was used for methylparaben (MeP) degradation. The crystallinity of the nanocomposite was ascertained through X-ray diffraction. High resolution transmission electron microscope (HRTEM) results proved the absence of any free particle beyond the catalyst surface ensuring the composite nature of the prepared material. The enhancement in the activity on doping with RGO was substantiated by diffuse reflectance spectroscopy (DRS-UV). It is evident from the photocatalytic degradation experiments that RGOCdS is more efficient than pure CdS. Maximum MeP degradation (100%) was achieved after 90 min of irradiation with 750 mg/L RGOCdS dosage at an acidic pH of 3, for an initial MeP concentration of 30 mg/L. The degradation mechanism substantiated through HPLC-MS/MS analysis showed the complete degradation of MeP without any residual intermediaries. The catalyst could be sustained and reused for up to 9 cycles of usage. Phytotoxicity and mycotoxicity results evidently ascertain the environmental implications of the photocatalyst material.


Assuntos
Espectrometria de Massas em Tandem , Titânio , Compostos de Cádmio , Grafite , Luz , Parabenos , Sulfetos
18.
Carbohydr Polym ; 258: 117718, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33593580

RESUMO

Herein, carboxymethyl chitosan and poly(vinylpyrrolidone) based hydrogels were synthesized by electron beam irradiation with dose variations (15 kGy, 30 kGy, and 45 kGy) for drug delivery applications. Irradiation crosslinked hydrogels were characterized for swellings in different medias, chemical, thermal, cell cytotoxicity, and drug release aspects. Swelling analysis was evaluated in distilled water, buffer, and saline solutions. Fourier transform infrared analysis revealed the establishment of physical interactions and confirmed the presence of functional groups present in the drug carriers. Scanning electron microscopy depicted the porous structure, which is responsible for swelling, drug loading, and release. Cell cytotoxicity assays indicated good cell viability on RAW 264.7 cells and anticancer activity on cancerous AGS cell lines. Cumulative drug release (%) of kanamycin in PBS at pH 7.4 was more than 90 % at 168 h. These drug carriers show promise to be developed as a sustained drug delivery system.


Assuntos
Antineoplásicos/administração & dosagem , Quitosana/análogos & derivados , Portadores de Fármacos , Sistemas de Liberação de Medicamentos , Hidrogéis/química , Canamicina/administração & dosagem , Povidona/química , Animais , Linhagem Celular Tumoral , Sobrevivência Celular , Quitosana/química , Reagentes de Ligações Cruzadas/química , Preparações de Ação Retardada , Difusão , Liberação Controlada de Fármacos , Elétrons , Concentração de Íons de Hidrogênio , Técnicas In Vitro , Canamicina/farmacologia , Camundongos , Microscopia Eletrônica de Varredura , Porosidade , Células RAW 264.7 , Espectroscopia de Infravermelho com Transformada de Fourier
19.
J Hazard Mater ; 412: 125330, 2021 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-33951878

RESUMO

A simulated visible light-mediated iron oxide-titania (IoT) nanocomposite was employed to degrade the antibiotic norfloxacin (NFN) photocatalytically. The photocatalyst were prepared using a sol-gel method with controlled titania loadings to iron oxide by altering the fabrications step. The nanocomposites were structurally characterized by field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), field emission high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, Diffuse reflectance UV-visible spectra (DRS-UV) spectroscopy, cyclic voltammetry, and X-ray photoelectron spectroscopy (XPS). It was observed that 100 mg/L of iron oxide doped titania loading at 1:4 (IoT-4) achieved the maximum photocatalytic activity in a 75 mg/100 mL of NFN solution within 60 min of the reaction time under visible light irradiation. The NFN degradation mechanism affirmed using HPLC-MS/MS analysis and the results confirmed the complete NFN degradation without residual intermediates. Significant, sustained recyclability was obtained by completely removing the contaminant up to 5 cycles with 90% degradation ability till nine cycles. Bacterial- and phytotoxicity data ascertain that the photocatalyzed and contaminant-free water is safe for the environment. The outstanding photocatalytic performance in removing organic pollutants indicates the potential application of IoT nanocomposites in real-time environmental remediation.


Assuntos
Norfloxacino , Espectrometria de Massas em Tandem , Catálise , Compostos Férricos , Ferro , Luz , Norfloxacino/toxicidade , Espectroscopia de Infravermelho com Transformada de Fourier , Titânio
20.
Environ Pollut ; 289: 117864, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34352631

RESUMO

In this work, we prepared nanocomposites of nickel-decorated manganese oxynitride on graphene nanosheets and demonstrated them as photocatalysts for degradation of acetylsalicylic acid (ASA). The catalyst exhibited a high degradation efficiency over ASA under visible light irradiation and an excellent structural stability after multiple uses. Compared to manganese oxide (MnO) and manganese oxynitride (MnON) nanoparticles, larger specific surface area and smaller band gap were observed for the nanocomposite accounting for the enhanced photocatalytic efficiency. Besides the compositional effect of the catalyst, we also examined the influence of various experimental parameters on the degradation of ASA such as initial concentration, catalyst dose, initial pH and additives. The best performance was obtained for the nanocomposite when the catalyst dose was 10 mg/mL and the initial pH 3. Detection of intermediates during photocatalysis showed that ASA undergoes hydroxylation, demethylation, aromatization, ring opening, and finally complete mineralization into CO2 and H2O by reactive species. For practical applications as a photocatalyst, cytotoxicity of the nanocomposite was also evaluated, which revealed its insignificant impact on the cell viability. These results suggest the nanocomposite of nickel-decorated manganese oxynitride on graphene nanosheets as a promising photocatalyst for the remediation of ASA-contaminated water.


Assuntos
Grafite , Aspirina , Luz , Manganês , Níquel
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