751—Electrochemical sterilization of microbial cells

Matsunaga, Tadashi; Namba, Yoichi; Nakajima, Toshiaki

doi:10.1016/0302-4598(84)87040-3

Cited by 88 publications

(37 citation statements)

References 8 publications

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“…There have been major developments in conservation science, colloids and interface science, together with materials science, which belong to the realm of popular nanosciences [8,9]. The latter area has attracted the conservation experts, due to the increasing loss of efficacy of conventional methods to achieve higher self-cleaning, surface protection, and consolidation efficiencies [10]. Nanomaterials, such as SiO 2 nanoparticles, CaCO 3 nanoparticles, clay nanoparticles, and Ca(OH) 2 nanoparticles, are some of the most common nanomaterials used in the consolidation of archaeological stone materials [11,12].…”

Section: Introductionmentioning

confidence: 99%

Protecting of Marble Stone Facades of Historic Buildings Using Multifunctional TiO2 Nanocoatings

et al. 2017

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Stone surfaces and façades of historic buildings, due to their predominately outdoor location, suffer from many deterioration factors, including air pollution, soluble salts, relative humidity (RH)/temperature, and biodeterioration, which are the main causes of decay. In particular, the façades of the buildings deteriorate with direct exposure to these factors; deformation and disfiguration of superficial decoration and formation of black crusts are often observed on the stones. The development and application of self-cleaning and protection treatments on historical and architectural stone surfaces could be a significant improvement in the conservation, protection and maintenance of Cultural Heritage. A titanium dioxide nanoparticle has become a promising photocatalytic material, owing to its ability to catalyze the complete degradation of many organic contaminants and environmental factors. In this study, TiO 2 nanoparticles, dispersed in an aqueous colloidal suspension, were applied directly to historic marble stone surfaces, by spray-coating, in order to obtain a nanometric film over the stone surface. The study started with an investigation of some properties of TiO 2 nanoparticles, to assess the feasibility of the use of TiO 2 on historic stone and architectural surfaces. Scanning electron microscopy (SEM) was, coupled with energy dispersive X-ray (EDX) microanalysis, (SEM-EDX), in order to obtain information on coating homogeneity and surface morphology, before and after artificial aging; the activity of the coated surface was evaluated through UV-light exposure, to evaluate photo-induced effects. The changes of molecular structure occurring in treated samples were spectroscopically studied by attenuated total reflection infrared spectroscopy (ATR-FTIR); activity of the hydrophobic property of the coated surface was evaluated by Sterio microscopy, model Zeiss 2010 from Munich, Germany, equipped with photo camera S23 under 80X magnification. The efficacy of the treatments was evaluated through capillary water absorption, and colorimetric measurements, performed to evaluate the optical appearance. Results showed that TiO 2 nanoparticles are good candidates for coating applications on historic stone surfaces, where self-cleaning photo-induced effects are well evident; they enhanced the durability of stone surfaces toward UV aging, improved resistance to relative humidity (RH)/temperature and abrasion affect, reduced accumulation of dirt on stone surfaces when left in open air for 6 months, and did not alter the original features.

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Section: Introductionmentioning

confidence: 99%

Protecting of Marble Stone Facades of Historic Buildings Using Multifunctional TiO2 Nanocoatings

et al. 2017

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“…Foi observado que a morte de microorganismos era devido ao efeito sobre a coenzima-A presente nas células das bactérias. 8 Nas reações que ocorrem com a passagem da corrente elétrica nos eletrodos são gerados vários componentes tóxicos à viabilidade celular. 9 O objetivo deste trabalho foi utilizar o tratamento eletrolítico na água proveniente do Rio das Cinzas, Bandeirantes -PR, avaliando a possibilidade da retirada do gás cloro utilizado no pré-tratamento da água bruta, na ETA do Serviço Autônomo de Água e Esgoto (SAAE), onde numa primeira fase foram testados o processo eletrolítico e coadjuvantes do tratamento tradicional de água.…”

Section: Introductionunclassified

Avaliação em escala laboratorial da utilização do processo eletrolítico no tratamento de águas

Otênio¹,

Panchoni²,

Cruz³

et al. 2008

Quím. Nova

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Recebido em 4/1/07; aceito em 20/9/07; publicado na web em 10/3/08 LABORATORY SCALE ASSESSMENT OF AN ELECTROLYTIC PROCESS FOR WATER TREATMENT. Water treatment uses chlorine for disinfection causing formation of trihalomethanes. In this work, an electrolytic water pre-treatment was studied and applied to the water from a fountainhead. The action against microorganisms was evaluated using cast-iron and aluminum electrodes. Assays were made in laboratory using the electrolytic treatment. After 5 min of electrolysis the heterotrophic bacteria count was below 500 cfu/mL and complete elimination of total and fecal coliforms was observed. Using electrolytic treatment as a pretreatment of conventional tap water treatment is proposed.Keywords: electrolytic treatment; water disinfection; water quality. INTRODUÇÃOQuase que a totalidade da água consumida hoje provém de algum processo de purificação; o uso de cloro como desinfetante é bastante difundido no Brasil, sendo sua eficiência largamente conhecida. Porém, os problemas com os subprodutos gerados na cloração, como, por exemplo, os halometanos, são ainda objeto de estudos científicos recentes.1,2 A obtenção de fontes seguras para fornecimento de água para as grandes cidades tem sido considerada estratégica.A idéia principal da utilização do tratamento eletrolítico, pela sua ação bactericida, é para a substituição do cloro no pré-tratamento de águas.Este trabalho tem caráter pioneiro, sendo destacado que não se encontram, até este momento, na literatura citações que utilizem o tratamento eletrolítico aplicado em pré-tratamento de água antes do tratamento convencional de uma Estação de Tratamento de Água (ETA).Patermarakis e Fountoukidis estudaram a desinfecção de águas de abastecimento pelo tratamento eletrolítico. A água natural proveniente de uma represa situada em Atenas, Grécia, contaminada por coliformes e estreptococos fecais, foi eletrolisada utilizando eletrodos de titânio e corrente de 2,5 mAcm -2 e se obteve uma redução do número de microorganismos que dependia do tempo de eletrólise utilizado. 4 propuserem a desinfecção de água de abastecimento com eletrodos de fibra de carbono ativado. Uma corrente alternada entre os potenciais de 1,0 e -0,8 V foi usada em sistema de fluxo e de batelada na água a ser tratada, obtendo-se não só a desinfecção como o bloqueio da adsorção das células bacterianas na superfície do eletrodo. O carvão ativado em conjunto com a corrente elétrica aplicada controlaram a contaminação da água em 20 UFC mL -1 . Este grupo de pesquisadores tem testado variações na utilização do processo eletrolítico para tratamento de água, variando o eletrodo, 5 quando utilizou eletrodo de nitreto de titânio ou, recentemente 6 com uso de "periodato" regenerado eletroquimicamente a partir da oxidação do iodato a periodato.Neste sentido, é tendência desta linha de pesquisa a busca por alternativas com menor ou nenhuma geração de cloro ou de substâncias oxidantes que possam causar prejuízo à saúde humana. 1,2O tratamento eletrolítico é um sistema constituído ...

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“…In studies evaluating the efficacy of electrochemical disinfection methods to prevent biofilm formation and biofouling, workers have used a potential of approximately 1.0 V (12,15,16). A potential of 0.74 V versus a saturated calomel electrode applied to Saccharomyces cerevisiae resulted in decreased respiratory activity and cell death (12).…”

mentioning

confidence: 99%

“…A potential of 0.74 V versus a saturated calomel electrode applied to Saccharomyces cerevisiae resulted in decreased respiratory activity and cell death (12). This method has been applied to disinfection of drinking water utilizing granular activated carbon (10), carbon-cloth sheets (11), activated carbon fibers (9,14), and titanium nitride mesh (13) as electrodes.…”

mentioning

confidence: 99%

Disinfection of Microorganisms by Use of Electrochemically Regenerated Periodate

Okochi

Yokokawa

Lim

et al. 2005

Appl Environ Microbiol

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A new method for disinfection of microorganisms by electrochemically regenerated periodate was developed. Oxidation of iodate to periodate was observed at 1.25 V versus a silver/silver chloride electrode in a cyclic voltammogram of potassium iodate. When 1.25 V was applied in 1.0 mM potassium iodate, approximately 4-log inactivation of Escherichia coli was observed in 30 min.Iodine-based disinfectant has been used for many years in the medical field and for potable water disinfection where municipal water treatment is not reliable. The mechanism of antimicrobial disinfection is based on the fact that iodine is a strong oxidant (1,6,7,17). Iodine-based disinfectants are more stable chemically and have a more acceptable taste than chlorine-based disinfectants, which makes them useful for disinfection in field work. Euthyroid individuals can be treated safely with iodine-containing solutions at a residual concentration less than 1.0 mg/liter, even for a long period of time (4, 5). However, excess iodine ingestion can be deleterious to human health. The major health effect of excess iodine ingestion is the development of thyroid diseases (2). Therefore, removal of excess iodine using activated carbon is required to ensure safe levels of iodine while efficient disinfection activity is maintained.In studies evaluating the efficacy of electrochemical disinfection methods to prevent biofilm formation and biofouling, workers have used a potential of approximately 1.0 V (12, 15, 16). A potential of 0.74 V versus a saturated calomel electrode applied to Saccharomyces cerevisiae resulted in decreased respiratory activity and cell death (12). This method has been FIG. 1. Time course of disinfection by potassium iodate and potassium periodate. Potassium iodate or potassium periodate (dissolved in 0.1 M phosphate buffer, pH 7.0) at concentrations of 0 mM (control), 0.1 mM, and 1.0 mM were incubated with an E. coli cell suspension (initial cell concentration; 1.0 ϫ 10 4 cells/ml).

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751—Electrochemical sterilization of microbial cells

Cited by 88 publications

References 8 publications

Protecting of Marble Stone Facades of Historic Buildings Using Multifunctional TiO2 Nanocoatings

Protecting of Marble Stone Facades of Historic Buildings Using Multifunctional TiO2 Nanocoatings

Avaliação em escala laboratorial da utilização do processo eletrolítico no tratamento de águas

Disinfection of Microorganisms by Use of Electrochemically Regenerated Periodate

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