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1.
Bioresour Technol ; 320(Pt A): 124284, 2020 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-33137640

RESUMO

Biohydrogen production in Microbial Electrolysis Cell (MEC) had inspired the researchers to overcome the challenges associated towards sustainability. Despite microbial community and various substrates, economical cathode catalyst development is most significant factor for enhancing hydrogen production in the MEC. Hence, in this study, the performance of MEC was investigated with a sugar industry effluent (COD 4200 ± 20 mg/L) with graphite anode and modified Nickel foam (NF) cathode. Nickel molybdate (NiMoO4) coated NF achieved a higher hydrogen production rate 0.12 ± 0.01 L.L-1D-1 as compared to control under favorable conditions. Electrochemical characterizations demonstrated that the improved catalytic activity of novel nanocatalyst with lower impedance favoring faster hydrogen evolution kinetics. The MEC with the novel catalyst performed with 58.2% coloumbic efficiency, 20.36% cathodic hydrogen recovery, 11.96% overall hydrogen recovery and 54.38% COD removal efficiency for a 250 mL substrate during 5 days' batch cycle. Hence, the potentiality of modified cathode was established with the real time industrial effluent highlighting the waste to wealth bio-electrochemical technology.

2.
ACS Omega ; 5(37): 23502-23509, 2020 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-32984668

RESUMO

Glucose monitoring devices for diabetes mellitus, which is a worldwide significant health issue, have attracted attention of many researchers. Herein, we report a hollow Mn-Cu-Al oxide nanocomposite (HMCA) by a microwave-assisted technique showing excellent sensing abilities toward glucose. Also, it possesses a superb supercapacitor activity described in our previous paper. The sensitivity value of the nanocomposite is 2.194 mA mM-1 cm-2 with a low detection limit of 0.43 µM (S/N = 3). The high sensitivity and low detection limit were the results of the large surface area of the nanocomposite and the redox nature of CuO and MnO2. It shows a selective detection of glucose levels in blood serum. The hollow nanocomposite has been useful for monitoring the glucose level in blood serum and holds great potential for diabetes mellitus and clinical diagnosis.

3.
Chemosphere ; 205: 610-617, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29715675

RESUMO

Recently, the incorporation of metal oxide nanoparticles into polymers has gained great attention owing to their ample of applications. The green mediated synthesis Fe-doped ZnO nanoparticles have been incorporated into PVA nanofibers through electro spinning for the application of photocatalytic degradation. The PVA polymer concentration was optimized to obtain uniform fibers without beads. The Fe-doped ZnO nanofibers were characterized by various analyzing techniques. The results show that good physicochemical with high surface area, uniformity in fiber with an average diameter ranges from 150 to 300 and 50-200 nm for un-calcined and calcined Fe-doped ZnO nanofiber respectively. The photocatalytic activity of nanofibers was examined by the degradation of naphthalene. The efficiency was observed 96 and 81% for calcined and un-calcined nanofibers, respectively. The reusable efficacy of Fe-doped ZnO calcined nanofiber as a catalyst was studied. These studies corroborated that the calcined Fe-doped ZnO nanofiber as promising material for catalytic applications.


Assuntos
Nanofibras/química , Naftalenos/química , Polímeros/química , Óxido de Zinco/química , Catálise , Ferro/química , Nanopartículas Metálicas
4.
Bioresour Technol ; 195: 242-7, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26212679

RESUMO

The effect of various system parameters such as wastewater Chemical Oxygen Demand (COD) concentration, pH, conductivity, membrane size and thickness on efficient energy production using mixed isolated culture from the distillery wastewater in the MFC was studied. The power density increased with increase in the anolyte pH from 6 to 8. The peak power density and COD removal efficiency was observed as 63.8±0.65 mW/m(2) and 63.5±1.5% at pH 8, respectively. The MFC performance increased with increasing COD concentration (800-3200 mg/l), conductivity (1.1-9.7 mS/cm) and membrane area (8-24 cm(2)). The MFC operating with wastewater COD concentration of 3200 mg/l and its conductivity of 9.7 mS/cm produced the highest power density of 202±6 mW/m(2) with a corresponding current density of 412±12 mA/m(2). The results showed that the efficient electricity generation and simultaneous treatment of distillery wastewater can be attained in the MFC.


Assuntos
Bactérias/isolamento & purificação , Fontes de Energia Bioelétrica/microbiologia , Eletricidade , Resíduos Industriais , Águas Residuárias/microbiologia , Biofilmes , Análise da Demanda Biológica de Oxigênio , Condutividade Elétrica , Técnicas Eletroquímicas , Concentração de Íons de Hidrogênio , Membranas Artificiais
5.
Ecotoxicol Environ Saf ; 121: 135-41, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25982731

RESUMO

Green synthesis of nanoparticles with low range of toxicity and conjugation to antibiotics has become an attractive area of research for several biomedical applications. Nanoconjugates exhibited notable increase in biological activity compared to free antibiotic molecules. With this perception, we report the biosynthesis of silver nanoparticles using aqueous extract of leaves of Mukia maderaspatana and subsequent conjugation of the silver nanoparticles to antibiotic ceftriaxone. The leaves of this plant are known to be a rich source of phenolic compounds with high antioxidant activity that are used as reducing agents. The size, morphology, crystallinity, composition of the synthesized silver nanoparticles and conjugation of ceftriaxone to silver nanoparticles were studied using analytical techniques. The activity of the conjugates against Bacillus subtilis (MTCC 1790), Klebsiella pneumoniae (MTCC 3384), Staphylococcus aureus (ATCC 25923), and Salmonella typhi (MTCC 3224) was compared to ceftriaxone and unconjugated nanoparticles using disc diffusion method. The effect of silver nanoparticles on the reduction of biofilms of Pseudomonas fluorescens (MTCC 6732) was determined by micro plate assay method. The antioxidant activities of extract, silver nitrate, silver nanoparticles, ceftriaxone and conjugates of nanoparticles were evaluated by radical scavenging 1, 1- diphenyl-2-picrylhydrazyl test. Ultraviolet visible spectroscopy and Fourier transform infrared spectroscopy confirmed the formation of metallic silver nanoparticles and conjugation to ceftriaxone. Atomic force microscopy, transmission electron microscopy and particle size analysis showed that the formed particles were of spherical morphology with appreciable nanosize and the conjugation was confirmed by slight increase in surface roughness. The results thus showed that the conjugation of ceftriaxone with silver nanoparticles has better antioxidant and antimicrobial effects than ceftriaxone and unconjugated nanoparticles. It can be suggested that M. maderaspatana mediated nanoparticle-ceftriaxone conjugate can be used effectively in the production of potential antioxidant and antimicrobial agents. The present study offers a significant overview to the development of novel antimicrobial nanoparticles.


Assuntos
Antibacterianos/farmacologia , Ceftriaxona/farmacologia , Cucumis/química , Nanoconjugados/química , Prata/farmacologia , Antibacterianos/química , Antioxidantes/farmacologia , Ceftriaxona/química , Química Verde , Klebsiella pneumoniae/efeitos dos fármacos , Nanopartículas Metálicas/química , Microscopia Eletrônica de Transmissão , Extratos Vegetais/farmacologia , Folhas de Planta/química , Pseudomonas fluorescens/efeitos dos fármacos , Prata/química , Nitrato de Prata/química , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos
6.
Bioresour Technol ; 136: 407-12, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23567709

RESUMO

Energy generation from dairy industry wastewater was investigated using a dual chambered Microbial Fuel Cell by aerobic and anaerobic anodic metabolism, operating with initial COD concentration of 1600 mg/L and anolyte pH of 7 produced highest power density of 192, 161 mW/m(2) and volumetric power of 3.2, 2.7 W/m(3) with COD removal efficiency of 91% and 90%, respectively. The columbic efficiency was 3.7-folds lower for aerobic metabolism compared to anaerobic metabolism with 17.17%. Effect of operating parameters such as anolyte pH and COD concentration on MFC performance was also evaluated. Anaerobic metabolism operated with COD concentration of 1600 mg/L and anolyte pH 7 showed best performances. Biofilm formation by inherent microbes of wastewater on anode was visualized by instrumental techniques. Milk processing operation runs almost through the year, hence MFC utilizing dairy industry wastewater would be a sustainable and reliable source of bio-energy generation.


Assuntos
Fontes de Energia Bioelétrica/microbiologia , Indústria de Laticínios , Eletricidade , Águas Residuárias/microbiologia , Purificação da Água/métodos , Biodegradação Ambiental , Análise da Demanda Biológica de Oxigênio , Biomassa , Tampões (Química) , Técnicas Eletroquímicas , Eletrodos , Concentração de Íons de Hidrogênio
7.
Ultrason Sonochem ; 19(4): 803-11, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22261471

RESUMO

The decolorization and degradation of Reactive Red 195 (RR 195) is studied using sonoelectrochemical and electrochemical oxidation. Sonoelectrochemical oxidation was found to be more efficient than electrochemical oxidation. The efficiency of decolorization was found to be 91% and 99% in the case of electrochemical and sonoelectrochemical process, respectively. The effect of different supporting electrolytes and ultrasonic power on decolorization and COD removal has been studied. The decolorization was found to be maximum in the KCl and NaCl as electrolytes. The color removal decreased with increasing ultrasonic power. Response surface methodology was used to assess optimal condition for decolorization and COD removal of RR 195. A Central Composite Design in five most important operating variables; current density, electrolyte concentration, dye concentration, time and sonication power was employed for experimental design and optimization of results. The significance of independent variables and their interactions were tested by means of the analysis of variance with 95% confidence limits. There was good agreement between the experimental and predicated values. Sonoelectrochemical degradation was found to be efficient in decolorizing simulated textile effluent. The results show that ultrasound was significantly enhanced in the electrochemical oxidation.


Assuntos
Compostos Azo/química , Corantes/química , Naftalenossulfonatos/química , Sonicação , Cor , Eletroquímica , Estrutura Molecular , Oxirredução
8.
J Hazard Mater ; 150(3): 596-603, 2008 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-17590271

RESUMO

The mediated electrochemical oxidation (MEO) process with cerium(IV) and nitric acid as the oxidizing medium was employed for the destruction of various model organic pollutants in continuous organic feeding mode. A near complete destruction was observed for all the organics studied. The effects of various experimental conditions were evaluated with respect to EDTA mineralization. The key parameters varied in the process were concentration of EDTA (67-268 mM), temperature (70, 80 and 95 degrees C), concentrations of Ce(IV) (0.7, 0.8 and 0.95 M), nitric acid (2, 3 and 4M) and duration of organic addition (30 and 120 min). Under the experimental conditions of 80 degrees C and 0.95 M Ce(IV) in 3 M nitric acid, nearly 90% destruction was achieved based on CO(2) production and 95% based on TOC analyses for all the organic compounds studied. The in situ regeneration of mediator ion by the electrochemical cell was found to be good during the organic destruction within the range of experimental conditions studied. In the case of long term organic feeding (120 min) the destruction was calculated after the CO(2) evolution attained the steady state and under this condition the destruction efficiency was found to be 85% based on CO(2) evolution.


Assuntos
Cério/química , Ácido Edético/química , Poluentes Ambientais/química , Benzoquinonas/química , Catecóis/química , Eletroquímica , Hidroquinonas/química , Maleatos/química , Ácido Nítrico/química , Ácido Oxálico/química , Oxirredução , Fenol/química , Temperatura
9.
Chemosphere ; 69(2): 325-31, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17606288

RESUMO

The mediated electrochemical oxidation (MEO) process using cerium(IV) in methanesulphonic acid (MSA) as the oxidizing medium was employed for the mineralization of phenol in batch and continuous feeding modes. Although nitric acid was an extensively studied electrolyte for organic mineralization reactions in MEO processes it does possess the problem of NO(x) gas production during the reduction of nitric acid in the cathode compartment of the electrochemical cell. This problem could be circumvented by proper choice of the electrolyte medium such as MSA. The mediator cerium in MSA solution was first oxidized to higher oxidation state using an electrochemical cell. The produced Ce(IV) oxidant was then used for the destruction of phenol. It was found that phenol could be mineralized to CO2 by Ce(IV) in MSA. The evolved CO2 was continuously measured and used for the calculation of destruction efficiency. The destruction efficiency was observed to be 85% based on CO2 evolution for 1000 ppm phenol solution at 80 degrees C in continuous feed mode.


Assuntos
Cério/química , Eletroquímica/métodos , Mesilatos/química , Minerais/química , Fenol/química , Oxirredução
10.
J Hazard Mater ; 142(1-2): 308-14, 2007 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-17023113

RESUMO

Terephthalic acid (TPA) is widely applied as a raw material in making polyester fiber, polyethylene terephthalate (PET) bottles, polyester films, etc. TPA is toxic and is known to act as endocrine disruptor. TPA wastewater is traditionally treated by biological process and this study aims to evaluate the effectiveness of several advanced oxidation processes on TPA removal. The oxidation processes studied were: UV-TiO(2), UV-H(2)O(2), UV-H(2)O(2)-Fe, O(3), O(3)/Fe, O(3)/TiO(2), UV-O(3)-H(2)O(2)-Fe and UV-O(3)-H(2)O(2)-Fe-TiO(2). The results indicate that the time required for the complete destruction of 50 ppm of TPA can be minimized from 10h using UV-TiO(2) system, to less than 10 min by UV-H(2)O(2)-Fe-O(3) system. Some of the likely organic intermediates identified during TPA destruction include, benzoquinone, benzene, maleic acid and oxalic acid. Possible destruction pathway of TPA has been proposed. TPA degradation by various systems was also analyzed based on the reaction kinetics and operating costs.


Assuntos
Ácidos Ftálicos/química , Catálise , Disruptores Endócrinos/química , Compostos Férricos/química , Peróxido de Hidrogênio/química , Cinética , Oxirredução , Ozônio/química , Titânio/química , Raios Ultravioleta , Poluentes Químicos da Água
11.
J Hazard Mater ; 145(1-2): 154-61, 2007 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-17141408

RESUMO

This investigation deals with effective utilization of fly ash as adsorbent for the removal of Chrysoidine R from the aqueous solution. The fly ash is a major byproduct generated in coal-based thermal power plants and has good potential for use as an adsorbent. A series of experiments were carried out in a batch adsorption technique to obtain the effect of process variables viz. contact time, pH (2, 4, 6 and 8) initial concentration of the dye (400, 600, 800 and 1000mgL(-1)), amount of the adsorbent (125, 250, 375 and 500mgL(-1)), and temperature (303, 313, 323 and 333K) on adsorption. The concentration of dye was determined by spectrophotometer. The results showed that as the amount of the adsorbent was increased, the percentage of dye removal increased accordingly; higher adsorption percentage was observed at lower concentration of chrysoidine. The adsorption data were analyzed using Langmuir and Freundlich isotherms. The adsorption was found to obey pseudo-first order kinetics. An intra particle diffusion model was used to fit the experimental data. The thermodynamic parameters such as standard change in free energy, enthalpy and entropy of adsorption have been calculated. Adsorption of Chrysoidine R on fly ash was found to be an exothermic reaction.


Assuntos
Carbono/química , Material Particulado/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , p-Aminoazobenzeno/análogos & derivados , Adsorção , Cinza de Carvão , Cinética , Termodinâmica , Poluentes Químicos da Água/análise , p-Aminoazobenzeno/análise , p-Aminoazobenzeno/isolamento & purificação
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