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1.
Int J Biol Macromol ; 256(Pt 2): 128499, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38048932

RESUMO

Wounds were considered as defects in the tissues of the human skin and wound healing is said to be a tedious process as there are possibilities of infection or inflammation due to microorganisms. Modern moisture-retentive wound dressing (MMRWD) is opening a new window toward wound therapy. It comprises different types of wound dressing that has classified based on their functionality. Selective polysaccharide-polypeptide fiber composite materials such as hydrogels, hydrocolloids, hydro fibers, transparent-film dressing, and alginate dressing are discussed in this review as a type of MMRWD. The highlight of this polysaccharide and polypeptide based MMRWD is that it supports and enhances the healing of different types of wounds by moisture absorption thus preventing infection. This study has given enlightenment on the application of selected polysaccharide and polypeptide based MMRWD that enhances wound healing actions still it has been observed that the composite wound healing dressing is more effective than the single one. The nano-sized materials (synthetic nano drugs and phyto drugs) were found to increase the efficiency of healing action while coated in the wound dressing material. Future research is required to find out more possibilities of the different composite types of wound dressing in the healing action.


Assuntos
Bandagens , Queimaduras , Humanos , Cicatrização , Alginatos/uso terapêutico , Queimaduras/tratamento farmacológico , Curativos Oclusivos
2.
J Environ Manage ; 351: 119830, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38141340

RESUMO

Cyclodextrin (CD) and its derivatives are receiving attention as a new-generation adsorbent for water pollution treatment due to their external hydrophilic and internal hydrophobic properties. Among types of CD, ß-Cyclodextrin (ßCD) has been a material of choice with a proven track record for a range of utilities in distinct domains, owing to its unique cage-like structural conformations and inclusion complex-forming ability, especially to mitigate emerging contaminants (ECs). This article outlines ßCD composites in developing approaches of their melds and composites for purposes such as membranes for removal of the ECs in aqueous setups have been explored with emphasis on recent trends. Electrospinning has bestowed an entirely different viewpoint on polymeric materials, comprising ßCD, in the framework of diverse functions across a multitude of niches. Besides, this article especially discusses ßCD polymer composite membrane-based removal of contaminants such as pharmaceutical substances, endocrine disruptors chemicals, and dyes. Finally, in this article, the challenges and future directions of ßCD-based adsorbents are discussed, which may shed light on pragmatic commercial applications of ßCD polymer composite membranes.


Assuntos
Celulose , Ciclodextrinas , Disruptores Endócrinos , beta-Ciclodextrinas , Polímeros , Corantes , beta-Ciclodextrinas/química , Ciclodextrinas/química , Preparações Farmacêuticas
3.
Sci Total Environ ; 904: 166563, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37647970

RESUMO

The growing concentrations of micropollutants in aquatic ecosystems are a global water quality issue. Understanding micropollutants varied chemical composition and potency is essential to solving this complex issue. Micropollutants management requires identifying contaminants to reduce, optimal reduction targets, and the best wastewater recycling locations. Management requires appropriate technological measures. Pharmaceuticals, antibiotics, hormones, and other micropollutants can enter the aquatic environment from point and diffuse sources, with wastewater treatment plants (WWTPs) distributing them in urban areas. Micropollutants like pharmaceuticals and hormones may not be removed by conventional WWTPs. Micropollutants affect the EU, especially in densely populated areas where surface water is consumed. This review examines several technological options that can be integrated into existing treatment methods to address this issue. In this work, oxidation, activated carbon, and their combinations as potential solutions, considering their efficacy and cost were evaluated. This study illuminates micropollutants origin and physico-chemical properties, which affect distribution, persistence, and environmental impacts. Understanding these factors helps us develop targeted micropollutant mitigation strategies to protect water quality. This review can inform policy and decision-making to reduce micropollutant impacts on aquatic ecosystems and human health.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Humanos , Eliminação de Resíduos Líquidos/métodos , Ecossistema , Relação Quantitativa Estrutura-Atividade , Poluentes Químicos da Água/análise , Águas Residuárias , Purificação da Água/métodos , Hormônios , Preparações Farmacêuticas
4.
J Environ Manage ; 332: 117382, 2023 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-36753844

RESUMO

Currently, international development requires innovative solutions to address imminent challenges like climate change, unsustainable food system, food waste, energy crisis, and environmental degradation. All the same, addressing these concerns with conventional technologies is time-consuming, causes harmful environmental impacts, and is not cost-effective. Thus, biotechnological tools become imperative for enhancing food and energy resilience through eco-friendly bio-based products by valorisation of plant and food waste to meet the goals of circular bioeconomy in conjunction with Sustainable Developmental Goals (SDGs). Genome editing can be accomplished using a revolutionary DNA modification tool, CRISPR-Cas9, through its uncomplicated guided mechanism, with great efficiency in various organisms targeting different traits. This review's main objective is to examine how the CRISPR-Cas system, which has positive features, could improve the bioeconomy by reducing food loss and waste with all-inclusive food supply chain both at on-farm and off-farm level; utilising food loss and waste by genome edited microorganisms through food valorisation; efficient microbial conversion of low-cost substrates as biofuel; valorisation of agro-industrial wastes; mitigating greenhouse gas emissions through forestry plantation crops; and protecting the ecosystem and environment. Finally, the ethical implications and regulatory issues that are related to CRISPR-Cas edited products in the international markets have also been taken into consideration.


Assuntos
Eliminação de Resíduos , Sistemas CRISPR-Cas , Ecossistema , Produtos Agrícolas
5.
Chemosphere ; 312(Pt 1): 137319, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36410505

RESUMO

Water treatment is a worldwide issue. This review aims to present current problems and future challenges in water treatments with the existing methodologies. Carbon nanotube production, characterization, and prospective uses have been the subject of considerable and rigorous research around the world. They have a large number of technical uses because of their distinct physical characteristics. Various catalyst materials are used to make carbon nanotubes. This review's primary focus is on integrated and single-treatment technologies for all kinds of drinking water resources, including ground and surface water. Inorganic non-metallic matter, heavy metals, natural organic matter, endocrine-disrupting chemicals, disinfection by-products and microbiological pollutants are among the contaminants that these treatment systems can remediate in polluted drinking water resources. Significant advances in the antibacterial and adsorption capabilities of carbon-based nanomaterials have opened up new options for excluding organic/inorganic and biological contaminants from drinking water in recent years. The advancements in multifunctional nanocomposites synthesis pave the possibility for their use in enhanced wastewater purification system design. The adsorptive and antibacterial characteristics of six main kinds of carbon nanomaterials are single-walled carbon nanotubes, multi-walled carbon nanotubes, graphene, graphene oxide, fullerene and single-walled carbon nanohorns. This review potentially addressed the essential metallic and polymeric nanocomposites, are described and compared. Barriers to use these nanoparticles in long-term water treatment are also discussed.


Assuntos
Água Potável , Nanocompostos , Nanotubos de Carbono , Poluentes Químicos da Água , Purificação da Água , Nanotubos de Carbono/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Antibacterianos , Águas Residuárias
6.
Chemosphere ; 310: 136836, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36243089

RESUMO

Peroxidase (POX) is a heme-containing oxidoreductase, its voluminous immuno-diagnostic and bioremediatory intuitions have incited optimization and large scale-generation from novel microbial repertoires. Azo dyes are the most detrimental classes of synthetic dyes and they are the common ecotoxic industrial pollutants in wastewater. In addition, azo dyes are refractory to degradation owing to their chemical nature, comprising of azoic linkages, amino moieties with recalcitrant traits. Moreover, they are major carcinogenic and mutagenic on humans and animals, whereby emphasizing the need for decolorization. In the present study, a novel POX from Streptomyces coelicolor strain SPR7 was investigated for the deterioration of ecotoxic dyestuffs. The initial medium component screening for POX production was achieved using, One Factor at a Time and Placket-Burman methodologies with starch, casein and temperature as essential parameters. In auxiliary, Response Surface Methodology (RSM) was recruited and followed by model validation using Back propagation algorithm (BPA). RSM-BPA composite approach prophesied that combination of starch, casein, and temperature at optimal values 2.5%, 0.035% and 35 °C respectively, has resulted in 7 folds enhancement of POX outturn (2.52 U/mL) compared to the unoptimized media (0.36 U/mL). The concentrated enzyme decolorized 75.4% and 90% of the two azo dyes with lignin (10 mM), respectively. Hence, this investigation confirms the potentiality of mangrove actinomycete derived POX for elimination of noxious azo dyes to overcome their carcinogenic, mutagenic and teratogenic effects on humans and aquatic organisms.


Assuntos
Compostos Azo , Peroxidases , Streptomyces coelicolor , Compostos Azo/química , Biodegradação Ambiental , Bioprospecção , Carcinógenos , Caseínas , Corantes/química , Amido , Streptomyces coelicolor/enzimologia
7.
Arch Microbiol ; 205(1): 29, 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36522563

RESUMO

Bioremediation of heavy metals and dyes is one of the emerging techniques globally as it is evident from the numerous publications made by various research groups. Biofilm-assisted bioremediation is one of the trending approaches as it facilitates negatively charged extracellular polymeric substances which makes the bacteria resistant to the toxic chemicals. Genetic engineering of microbes will make them unique in the bioremediation process. This mini-review concentrates on source and toxic effects of heavy metals and dyes on aqueous and living beings. Further, the genetic improvement strategies for effective bioremediation are described. However, the gap between practicability and real-time applicability needs to test with real-time wastewater in the industrial scale.


Assuntos
Metais Pesados , Águas Residuárias , Biodegradação Ambiental , Corantes/toxicidade , Metais Pesados/toxicidade , Metais Pesados/análise , Bactérias/genética
8.
Environ Monit Assess ; 194(12): 886, 2022 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-36239825

RESUMO

Bisphenol-A (BPA) is a monomer found in polycarbonate plastics, food cans, and other everyday chemicals; this monomer and its counterparts are widely used, culminating in its presence in water, soil, sediment, and the atmosphere. Furthermore, because of its estrogenic and genotoxic properties, it has been acknowledged as an endocrine disruptor; contamination of BPA in the environment is becoming a growing concern, and ways to effectively mitigate BPA from the environment are currently explored. Hence, the focal point of the review is to collate the bacterial degradation of BPA with the proposed degradation mechanism, explicitly focusing on researches published between 2017 and 2022. BPA breakdown is dependent primarily on bacterial metabolism, although numerous factors influence its fate in the environment. The metabolic routes for BPA breakdown in crucial bacterial strains were postulated, sourced on the transformed metabolite-intermediates perceived through degradation; enzymes and genes associated with the bacterial degradation of BPA have also been included in this review. This review will be momentous to generate a conceptual strategy and stimulate the progress on bacterial mitigation of BPA as a path to a sustainable cleaner environment.


Assuntos
Disruptores Endócrinos , Bactérias/metabolismo , Compostos Benzidrílicos/toxicidade , Disruptores Endócrinos/análise , Monitoramento Ambiental , Fenóis , Plásticos , Solo , Água
9.
Chemosphere ; 307(Pt 4): 136008, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35985386

RESUMO

The ever-exploding global population coupled with its anthropogenic impact has imparted unparalleled detrimental effects on the environment and mitigating them has emerged as the prime challenge and focus of the current century. The niche of nanotechnology empowered by composites of biopolymers in the handling of xenobiotics and environmental clean-up has an unlimited scope. The appositeness of biopolymer-nanoparticles (Bp-NPs) for environmental contaminant mitigation has received unique consideration due to its exclusive combination of physicochemical characteristics and other attributes. The current review furnishes exhaustive scrutiny of the current accomplishments in the development of Bp-NPs and biopolymer nanomaterials (Bp-NMs) from various polymeric biomolecules. Special attention was provided for polymeric biomolecules such as cellulose, lignin, starch, chitin, and chitosan, whereas limited consideration on gelatin, alginate, and gum for the development of Bp-NPs and Bp-NMs; together with coverage of literature. Promising applications of tailored biopolymer hybrids such as Bp-NPs and Bp-NMs on environmentally hazardous xenobiotics handling and pollution management are discussed as to their notable environmental applications.


Assuntos
Quitosana , Poluentes Ambientais , Alginatos , Celulose/química , Quitosana/química , Gelatina , Lignina , Polímeros , Amido , Xenobióticos
10.
Microbiol Res ; 263: 127135, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35926259

RESUMO

Antimicrobial resistance (AMR) with the ability to thwart clinical therapies and escalate mortality rates is emerging as one of the most pressing global health and environmental concerns. Urban rivers as an important subsystem of the environment offer galore of ecological services which benefit the city dwellers. However, with increased urbanization, industrialization, and heavy discharge of anthropogenic waste harboring antibiotics, heavy metals, pesticides, antibiotic resistance genes (ARGs), antibiotic resistant bacteria (ARB), urban rivers are becoming major reservoirs of ARGs and a hotspot for accelerated selection of ARB. These ARGs in urban rivers have the potential of being transferred to clinically important pathogens. In addition, urban rivers also act as important vectors for AMR spread. This is mainly due to the direct exposure of humans and animals to the heavily contaminated river water and high mobility of organisms (aquatic animals, pathogenic, non-pathogenic bacteria) as well as the genetic elements including ARGs and mobile genetic elements (MGEs) in the river. However, in spite of recent advocacy for comprehensive research programs aimed to investigate the occurrence, extent and major drivers of AMR in urban rivers globally, such studies are missing largely. This review encompasses the issues of AMR, major drivers and their vital roles in the evolution and spread of ARB with an emphasis on sources and hotspots of diverse ARGs in urban rivers contributing to co-occurrence of ARGs and MGEs. Further, the causal factors leading to adverse effects of antibiotic-load to river organisms with an elaboration on the current measures to eradicate the ARB, ARGs, and remove antibiotics from the urban river ecosystems are also discussed. A perspective review of current and emerging strategies with potentials of combating AMR in urban river ecosystems including advanced water treatment methodologies and floating islands or constructed wetlands.


Assuntos
Antibacterianos , Rios , Antagonistas de Receptores de Angiotensina/farmacologia , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Animais , Antibacterianos/farmacologia , Farmacorresistência Bacteriana/genética , Ecossistema , Genes Bacterianos , Humanos , Rios/microbiologia
11.
Sci Total Environ ; 845: 157168, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-35817120

RESUMO

Nanoplastics are drawing a significant attention as a result of their propensity to spread across the environment and pose a threat to all organisms. The presence of nanoplastics in water is given attention nowadays as the transit of nanoplastics occurs through the aquatic ecosphere besides terrestrial mobility. The principal removal procedures for macro-and micro-plastic particles are effective, but nanoparticles escape from the treatment, increasing in the water and significantly influencing the society. This critical review is aimed to bestow the removal technologies of nanoplastics from aquatic ecosystems, with a focus on the treatment of freshwater, drinking water, and wastewater, as well as the importance of transit and its impact on health concerns. Still, there exists a gap in providing a collective knowledge on the methods available for nanoplastics removal. Hence, this review offered various nanoplastic removal technologies (microorganism-based degradation, membrane separation with a reactor, and photocatalysis) that could be the practical/effective measures along with the traditional procedures (filtration, coagulation, centrifugation, flocculation, and gravity settling). From the analyses of different treatment systems, the effectiveness of nanoplastics removal depends on various factors, source, size, and type of nanoplastics apart from the treatment method adopted. Combined removal methods, filtration with coagulation offer great scope for the removal of nanoplastics from drinking water with >99 % efficiency. The collected data could serve as base-line information for future research and development in water nanoplastics cleanup.


Assuntos
Água Potável , Poluentes Químicos da Água , Purificação da Água , Ecossistema , Microplásticos , Plásticos , Poluentes Químicos da Água/análise
12.
Environ Pollut ; 306: 119377, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35490997

RESUMO

Graphene oxide can be used to store energy, as electrodes and purify industrial and domestic wastewater as photocatalysts and adsorbents because of its remarkable thermal, electrical, and chemical capabilities. Toward understanding graphene oxide (GO) based nanomaterials considering the background factors, the present review study investigated their characteristics, preparation methods, and characterization processes. The removal of contaminants from wastewater has recently been a focus of attention for materials based on GO. Progress in GO synthesis and surface modification has shown that they can be used to immobilize enzymes. It is possible to immobilize enzymes with varying characteristics on graphene-oxide-based substrates without sacrificing their functioning, thus developing a new environmental remediation platform utilizing nano biocatalysts. GO doping and co-doping with a variety of heterogeneous semiconductor-based metal oxides were included in a brief strategy for boosting GO efficiency. A high band-gap material was also explored as a possibility for immobilization, which shifts the absorption threshold to the visible range and increases photoactivity. For water treatment applications, graphene-based nanomaterials were used in Fenton reactions, photocatalysis, ozonation, photo electrocatalysis, photo-Fenton, and a combination of photon-Fenton and photocatalysis. Nanoparticles made from GO improved the efficiency of composite materials when used for their intended applications. As a result of the analysis, prospects and improvements are clear, especially when it comes to scaling up GO-based wastewater treatment technologies.


Assuntos
Poluentes Ambientais , Grafite , Nanoestruturas , Poluentes Químicos da Água , Grafite/química , Nanoestruturas/química , Águas Residuárias , Poluentes Químicos da Água/química
13.
Environ Pollut ; 303: 119049, 2022 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35271953

RESUMO

The novel La-MOF@x%PANI composite was synthesized via a two-step procedure with ultra-sonication, and the adsorption mechanism of Pb2+ ions from synthetic aqueous solutions was systematically studied. The Pb2+ adsorption on the La-MOF@x%PANI was evaluated by the Fourier transform infrared spectroscopy, powder X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray analysis, Brunauer-Emmett-Teller analysis, X-ray photoelectron spectroscopy, and elemental mapping analyses. The effects of the adsorption-influencing parameters, including contact time, solution pH, and co-existing cations on the maximum adsorption capacity of Pb2+ onto the prepared composite material were investigated. Moreover, the adsorption of Pb2+ ions could be eliminated with rapid adsorption kinetics using the water-stable La-MOF@x%PANI composite. The as-synthesized La-MOF@50%PANI exhibited excellent adsorption performance toward Pb2+ ions with an extraordinary adsorption capacity of 185.19 mg/g at pH 6. The Pb2+ adsorption onto the La-MOF@x%PANI composite follows the pseudo-second-order kinetics and fits well with the Langmuir isotherm model, indicating the Pb2+ adsorption depended on the solution pH as the adsorption mechanism was mainly governed by the electrostatic attraction. Notably, La-MOF@x%PANI composite possesses outstanding regeneration ability and stability after up to four successive cycles. The satisfactory findings reflect that the La-MOF@50%PANI hybrid composite holds a great promise for remediating Pb2+ ions from aqueous environments.


Assuntos
Estruturas Metalorgânicas , Poluentes Químicos da Água , Adsorção , Compostos de Anilina , Concentração de Íons de Hidrogênio , Íons , Cinética , Lantânio , Chumbo , Espectroscopia de Infravermelho com Transformada de Fourier , Água/química , Poluentes Químicos da Água/análise
14.
Chemosphere ; 294: 133779, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35114262

RESUMO

This survey distinguishes understudied spaces of arising impurity research in wastewaters and the habitat, and suggests bearing for future checking. Thinking about the impeding effect of toxins on human wellbeing and biological system, their discovery in various media including water is fundamental. This review sums up and assesses the latest advances in the electrochemical detecting of emerging contaminants (ECs). This survey is expected to add to the advancement in electrochemical applications towards the ECs. Different electrochemical insightful procedures like Amperometry, Voltammetry has been examined in this overview. The improvement of cutting edge nanomaterial-based electrochemical sensors and biosensors for the discovery of drug compounds has accumulated monstrous consideration because of their benefits, like high affectability and selectivity, continuous observing, and convenience has been reviewed in this survey. This survey likewise features the diverse electrochemical treatment procedures accessible for the removal of ECs.


Assuntos
Técnicas Biossensoriais , Nanoestruturas , Técnicas Eletroquímicas , Humanos , Nanoestruturas/química , Águas Residuárias , Água
15.
Chemosphere ; 291(Pt 1): 132680, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34715103

RESUMO

A pH change can enable high-energy-density RFB (redox flow battery) in an aqueous medium. Nevertheless, a membrane to prevent the ion crossover is needed. This study adopted cerium and polysulfide in an acid-base combined electrolyte with an MFI-Zeolite membrane as a separator. The increased potential with pH change is described by the OCP (open circuit potential) difference, which varies by 0.8 V for the combination of acid-acid and acid-base electrolyte. A decrease of 350 mV at the redox peak potential of Ce3+/Ce4+ and a 10 mV negative potential shift for S42-/2S22- highlights the pH effect between the combination of acid-acid and acid-base electrolyte indicates the influence of pH leading in half-cell of anodic than the opposite cathodic side. The UV-visible spectral analysis for Ce3+ and S42- ions displacement shows that cerium and sulfur ions do not migrate to each other half-cell through an MFI-Zeolite membrane. As a result, the current efficiency of 94%, voltage, and energy efficiency of 40%-43% were attained at a current density of 10 mA cm-2. Moreover, the acid-base composition of the Ce/S system showed an energy density of 378.3 Wh l -1.


Assuntos
Cério , Zeolitas , Eletrólitos , Oxirredução , Sulfetos
16.
Chemosphere ; 291(Pt 2): 133005, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34813845

RESUMO

The ubiquitous use of microplastics and their release into the environment especially the water bodies by anthropogenic/industrial activities are the major resources for microplastic contamination. The widespread and often injudicious use of antimicrobial drugs or antibiotics in various sectors including human health and hygiene, agriculture, animal husbandry and food industries are leading to the release of antibiotics into the wastewater/sewage and other water bodies, particularly in urban setups and thus leads to the antimicrobial resistance (AMR) in the microbes. Microplastics are emerging as the hubs as well as effective carriers of these microbial pathogens beside their AMR-genes (ARGs) in marine, freshwater, sewage/wastewater, and urban river ecosystems. These drug resistant bacteria interact with microplastics forming synthetic plastispheres, the ideal niche for biofilm formations which in turn facilitates the transfer of ARGs via horizontal gene transfer and further escalates the occurrence and levels of AMR. Microplastic-associated AMR is an emerging threat for human health and healthcare besides being a challenge for the research community for effective management/address of this menace. In this review, we encompass the increasing prevalence of microplastics in environment, emphasizing mainly on water environments, how they act as centers and vectors of microbial pathogens with their associated bacterial assemblage compositions and ultimately lead to AMR. It further discusses the mechanistic insights on how microplastics act as hosts of biofilms (creating the plastisphere). We have also presented the modern toolbox used for microplastic-biofilm analyses. A review on potential strategies for addressing microplastic-associated AMR is given with recent success stories, challenges and future prospects.


Assuntos
Anti-Infecciosos , Microplásticos , Animais , Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Ecossistema , Humanos , Plásticos
17.
J Hazard Mater ; 420: 126564, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34252672

RESUMO

This paper reports the sustainable and enhanced generation of a Ni(I) active electro-catalyst using AgSAE as a cathode material for the sustainable degradation of N2O, NO, dichloromethane (DCM), and chlorobenzene (CB) by electroscrubbing in a series operation. The AgSAE electrode showed 1.66 times higher Ni(I) formation than the Ag metal electrode. The AgSAE achieved 20% ± 2% Ni(I) generation in a highly concentrated alkaline medium, whereas Ag metal only achieved 12% ± 2% Ni(I) generation at the same current density. Electrochemical impedance spectroscopy and voltammetric studies determined that the kinetics of the charge-transfer reaction was also preferential at the AgSAE, with the cathodic peak at -1.26 V vs. Ag/AgCl confirming Ni(I) formation. Initially, the change in the oxygen reduction potential and reduction efficiency of Ni(I) confirmed the removal of N2O, NO, DCM and CB. In addition, the gas Fourier transform infrared (FTIR) spectrum revealed 99.8% removal efficiency of toxic pollutants. Therefore, the regeneration of Ni(I) confirmed the sustainable removal of toxic pollutants. Furthermore, the FTIR spectra revealed the formation of NH3 during the reduction of N2O and NO. On the other hand, DCM and CB were reduced to benzene derivatives in the solution phase. In addition, a plausible reduction mechanism was derived. As a result, the AgSAE cathode exhibited two-fold higher removal efficiency of N2O, NO, DCM, and CB than the previously reported electrodes.

18.
Int J Biol Macromol ; 186: 125-134, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34246666

RESUMO

Marine microorganisms are reported to produce polyhydroxybutyrate (PHB) that has wide range of medical and industrial applications with the advantage of biodegradability. PHBs are synthesized as an energy and carbon storage element under metabolic pressure. The scope of this work is enhancing PHB production using marine microbial isolate, Micrococcus luteus by selectively optimizing various growth conditions such as different media components and growth parameters that influence the cell growth and PHB production were sampled. Micrococcus luteus produced 7.54 g/L of PHB utilizing glucose as a carbon source and ammonium sulphate as a nitrogen source with maximum efficiency. The same optimized operational conditions were further employed in batch fermentation over a time span of 72 h. Interestingly higher cell dry weight of 21.52 g/L with PHB yield of 12.18 g/L and 56.59% polymer content was observed in batch fermentation studies at 64 h. The chemical nature of the extracted polymer was validated with physio-chemical experiments and was at par with the commercially available PHB. This study will spotlight M. luteus as a potential source for large-scale industrial production of PHB with reducing environmental pollutions.


Assuntos
Butiratos/metabolismo , Sedimentos Geológicos/microbiologia , Hidroxibutiratos/isolamento & purificação , Microbiologia Industrial , Micrococcus luteus/metabolismo , Butiratos/química , Fermentação , Concentração de Íons de Hidrogênio , Micrococcus luteus/crescimento & desenvolvimento , Estrutura Molecular , Temperatura , Fatores de Tempo
20.
J Hazard Mater ; 414: 125522, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-33684820

RESUMO

The present investigation describes the photocatalytic degradation of methylene blue (MB) and rhodamine-B (RhB) using molybdenum disulfide (MoS2) anchored metal-organic frameworks (MOFs) under visible light irradiation. Herein, MIL-88(Fe) was successfully modified with MoS2 to yield a novel heterogeneous MoS2@MIL-88(Fe) hybrid composite. The prepared catalyst enhances the superior photocatalytic activity than the pristine form of MoS2 and MIL-88(Fe) framework. The physico-chemical properties of the prepared catalyst were analytically investigated and the results exhibit greater photocatalytic efficiency towards the chosen dyes, with an optical band gap of 2.75 eV. The MoS2 and MIL-88(Fe) framework could act as efficient oxidation and reduction sites in the as-synthesized MoS2@MIL-88(Fe) composite, and generated the non-toxic by-products such as hydroxyl (•OH), and superoxide species (•O2-) for the mineralization of MB and RhB dyes. The degradation kinetics showed that the dye system followed a pseudo-first-order model which is well supported by the Langmuir-Hinshelwood mechanism. Moreover, the reusability studies showed excellent photocatalytic activity after five cycles. Finally, the photocatalytic degradation mechanism of MB and RhB dyes was suggested.

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