Suite à la catastrophe nucléaire de Fukushima Dai-Ichi, des milliers de tonnes d’eau douce et d’eau de mer ont été utilisées pour le refroidissement des réacteurs ou contaminées du fait des infiltrations souterraines. La décontamination de ces eaux est rendue difficile par la présence d’autres cations (Na+, K+, Ca2+, Mg2+) présents naturellement dans ces eaux. Un procédé de décontamination en colonne garnie de deux types adsorbants minéraux, le TERMOXID 35 et le SORBMATECH® 202, a été étudié dans ce contexte. Le premier est un adsorbant commercial constitué du ferrocyanure mixte K/Ni imprégnés sur une matrice solide Zr(OH)4. Le second, synthétisé au CEA, est composé de ferrocyanure K/Cu imprégnés sur une matrice solide SiO2. Ces deux matériaux se sont révélés extrêmement efficaces pour décontaminer le Cs dans l’eau de mer avec des Kd,Cs de l’ordre de 105 mL/g.Les études menées en batch dans différentes solutions (eau pure, eau douce et eau de mer) ont permis de mettre en évidence les cinétiques de sorption ainsi que les mécanismes d’échange d’ions responsables de la sorption du Cs+ en tenant compte des effets compétitifs des cations des eaux naturelles. La modélisation des batchs a été menée avec le code géochimique CHESS en prenant en compte ces effets compétitifs selon le formalisme de Vanselow et les coefficients de sélectivité en constituant une base de données thermodynamiques spécifique. Les performances de ces matériaux ont ensuite été testées en colonne. Les paramètres opératoires tels que la vitesse de Darcy et le ratio H/D ont été étudiés pour définir les conditions de bon fonctionnement de ce procédé. Le T35 s’est révélé être moins performant du fait notamment de la diffusion lente du Cs dans les pores de ce matériau. Le S202 s’est révélé être un bon candidat pour l’application de forts débits de traitement. Les courbes de percée ainsi obtenues dans l’eau douce ont par ailleurs fait l’objet de modélisation avec les codes de transport réactif HYTEC et OPTIPUR couplés à la base CHESS de données thermodynamiques. Cette démarche permettra de mieux dimensionner les unités de décontamination définies par l’exploitant. / Following the nuclear disaster in Fukushima Dai-Ichi, thousands of tons of fresh water and seawater were used for cooling the reactors or contaminated as a result of groundwater seepage. Decontamination of these waters is complicated by the presence of other cations (Na+, K+, Ca2+, Mg2+) naturally present in these waters. Decontamination process in columns packed was studied in this context with two types of mineral adsorbents: the TERMOXID 35 and the SORBMATECH® 202. The first one is a commercial adsorbent and consists of mixed ferrocyanide K/Ni impregnated over a solid matrix Zr(OH)4. The second one was synthesized in CEA and is composed of ferrocyanide K/Cu impregnated over a solid matrix SiO2. Both materials have shown a high efficiency for Cs decontamination in seawater with Kd,Cs of about 105 mL/g.Batch studies conducted in different solutions (pure water, fresh water and seawater) allowed determining sorption kinetics and ion exchange mechanisms responsible for the sorption of Cs+, taking into account competitive effects of the natural water cations (Na+, K+, Ca2+, Mg2+). Modelling of batchs was performed with the geochemical code CHESS considering competitive effects according to the Vanselow formalism and selectivity coefficients, developing a specific thermodynamic database. The performances of these materials were then tested in column. The operating parameters such as Darcy’s velocity and the H/D ratio were studied for a proper functioning of this process. The T35 has proven to be less efficient mainly because of the slow diffusion of Cs in the pores of the material. The S202 has proven to be a good candidate for the application of high flow rates. The breakthrough curves obtained in fresh water have been modelled with the reactive transport codes HYTEC and OPTIPUR using the CHESS thermodynamic database. This approach will eventually help to support the design of a decontamination unit by the operator.

Afin de traiter les effluents liquides radioactifs de faible et moyenne activités, le procédé utilisé à l'échelle industrielle est la coprécipitation. L'enjeu de cette thèse est d'optimiser le procédé continu de coprécipitation. Pour cela, un réacteur innovant est conçu et modélisé : le réacteur/décanteur continu. Deux systèmes modèles sont étudiés : la coprécipitation du strontium par le sulfate de baryum et la sorption du césium par le PPFeNi. Le milieu étudié est une solution contenant du nitrate de sodium afin de prendre en compte la force ionique élevée des effluents. Chaque système modèle est d'abord étudié de manière séparée, puis de manière simultanée. Les lois cinétiques de nucléation et de croissance cristalline du sulfate de baryum sont déterminées, puis intégrées au modèle de coprécipitation. Des études de cinétique et d'isotherme de sorption du césium par le PPFeNi sont aussi menées afin d'acquérir les données nécessaires à la modélisation du procédé. La modélisation permet de prédire finement la concentration résiduelle en strontium et en césium en fonction du type de procédé utilisé : cela constitue un outil précieux pour l'optimisation d'unités existantes ou le dimensionnement d'unités futures. Le réacteur/décanteur continu présente de très nombreux avantages par rapport au procédé continu classique : il permet d'améliorer sensiblement les performances de décontamination en strontium et en césium tout en réduisant le volume de boues générées par le procédé. Le réacteur/décanteur assure aussi une bonne séparation liquide/solide, et l'installation résultante se révèle nettement plus compacte. Ainsi, le réacteur/décanteur continu permet d'intensifier les procédés de traitement d'effluents liquides radioactifs, et constitue une technologie très prometteuse pour une application industrielle future / In order to decontaminate radioactive liquid wastes of low and intermediate levels, the coprecipitation is the process industrially used. The aim of this PhD work is to optimize the continuous process of coprecipitation. To do so, an innovative reactor is designed and modelled: the continuous reactor/classifier. Two model systems are studied: the coprecipitation of strontium by barium sulphate and the sorption of cesium by PPFeNi. The simulated effluent contains sodium nitrate in order to consider the high ionic strength of radioactive liquid wastes. First, each model system is studied on its own, and then a simultaneous treatment is performed. The kinetic laws of nucleation and crystal growth of barium sulphate are determined and incorporated into the coprecipitation model. Kinetic studies and sorption isotherms of cesium by PPFeNi are also performed in order to acquire the necessary data for process modelling. The modelling realised enables accurate prediction of the residual strontium and cesium concentrations according to the process used: it is a valuable tool for the optimization of existing units, but also the design of future units. The continuous reactor/classifier presents many advantages compared to the classical continuous process: the decontamination efficiency of strontium and cesium is highly improved while the volume of sludge generated by the process is reduced. A better liquid/solid separation is observed in the reactor/classifier and the global installation is significantly more compact. Thus, the radioactive liquid wastes treatment processes can be intensified by the continuous reactor/classifier, which represents a very promising technology for future industrial application

No description available.

The synergistic effect of nitric oxide toward dephosphorylation reactions involving phosphate esters was the subject of investigation in this research. Sodium nitroprusside under UV irradiations at 254nm, 365nm and white light was utilized as nitric oxide donor in solutions. The effects of cobalt trimethylenediamine and nitroprusside towards dephosphorylation of nitrophenylphosphate and pyrophosphate which were modeled as organophosphate ester substrates were also investigated. The activated substrate models showed more rate enhancement than the unactivated models in all cases. The direct interaction of nitric oxide with the phosphorus centre is presumed to be the reason for enhanced hydrolysis. This study demonstrates the possible role of nitric oxide in decontamination reactions of poorly biodegradable phosphate esters in the biosphere. / Chemistry / M. Sc. (Chemistry)

La décontamination microbienne est sujet majeur de préoccupation du secteur agroalimentaire. Des nouvelles technologies physiques de décontamination, dites athermiques, sont d’un emploi croissant. La Lumière Pulsée, utilisée pour décontaminer les surfaces et les liquides clairs, en fait partie. Elle utilise des flashes de lumière blanche riches en UV, et délivrés en moins d'une milliseconde. La plupart des traitements par lumière pulsée sont définis dans la littérature par des paramètres spécifiques à l'équipement utilisé. Le but de cette étude a été dans un premier temps de caractériser le traitement par lumière pulsée par les grandeurs physiques appropriées (fluence, tension aux bornes de la lampe, etc…), en reliant une dose de lumière à niveau de décontamination microbienne. L'équipement pilote de la société CLARANOR a révélé des réduction logarithmiques allant jusqu'à plus de 5 unités sur des spores de B. subtilis, et de plusieurs autres espèces de bactéries sporulées, avec des fluences inférieures à 1,5 J/cm², appliquée en un seul flash La mise au point d'une méthode d'inoculation par spray à permis d'évaluer l'efficacité décontaminante de la lumière sur différentes surfaces, y compris des hydrophobes, par pulvérisation des microorganismes en couches formées d’une seule épaisseur de cellules. L'application de la technologie sur des surfaces inertes comme le polystyrène a montré une décontamination notamment sur des spores de B. subtilis, et d'A. niger, supérieures à 4 cycles logarithmiques en utilisant des fluences inférieures à 1 J/cm². L'influence des facteurs liés au système d'éclairage a montré une importance capitale des longueurs d'onde UV, mais ne permettent pas de réduire l'efficacité à la seule action de la dose UV-C. L'efficacité de la technologie a permis de réaliser une étude concernant la décontamination de sirop de sucre dans une optique d'application industrielle. Une réduction supérieure à 3 cycles logarithmiques de spores d'A. acidoterrestris dans du sirop de saccharose a été obtenue en flux continu, sur une épaisseur de 10 mm de liquide / Microbial decontamination is a major concern in the food industry. Non-thermal physical technologies are increasingly used. Pulsed Light used to decontaminate surfaces and clear liquids is one of these new technologies. Pulsed Light uses intense flashes of white light rich in UV, delivered in less than one millisecond. Most of treatments are characterised in the literature using parameters which are specific to the equipment. The aim of this study was firstly to characterise the PL treatment in expressing a log reduction as a function of the dose received by the microorganism. The pulsed light pilot of the CLARANOR company allowed a high decontamination of B. subtilis spores and other sporulating bacterial species, with more than 5 log reductions at fluences lower than 1.5 J/cm², obtained in only one flash. The development of a spray inoculation method was made to evaluate the decontamination efficiency on different surfaces, including hydrophobic surfaces, with a monolayer inoculation. The Pulsed light efficiency on inert surfaces such as polystyrene lead to high decontaminations including B. subtilis and A. niger spores, with more than 4 log reductions using fluences lower than 1 J/cm² in both cases. The influence of the physical factors of the light showed that UV wavelengths are essential for the decontamination, but the efficiency is not totally explained by the action of the UV-C dose. The efficiency of pulsed light allowed to study sugar syrup decontamination, in view of industrial application. Three log reductions of A. acidoterrestris spores were obtained in 10 mm thickness sugar syrup, using a flow-through system

Le procédé par coprécipitation est l’un des plus utilisé dans l’industrie nucléaire pour le traitement des effluents liquides radioactifs car il peut être appliqué à tous les effluents quelque soit leur composition. Ce procédé consiste à former in situ des particules solides par précipitation dans le but de capter sélectivement un ou plusieurs radioéléments. L’objectif de ce travail de thèse est de mettre en évidence les phénomènes impliqués lors de la coprécipitation d’un élément présent en faible concentration. Pour cela, cette étude propose une nouvelle modélisation des phénomènes de coprécipitation dont l’originalité tient dans la possibilité de simuler le phénomène hors équilibre thermodynamique et à l’échelle d’un réacteur chimique. Ce modèle, couplé avec la résolution du bilan de population, permet d’identifier l’influence des paramètres de procédés (débits, agitation…) sur la décontamination. Afin d’éprouver ce nouveau modèle, celui-ci est appliqué au traitement, dans les conditions industrielles, du strontium par le sulfate de baryum en réacteur continu et semi-fermé. A partir de ces simulations, des lois d’évolution de l’efficacité du traitement en fonction de différents paramètres de procédé (Temps de passage ou d’injection, agitation, concentration de BaSO4) ont été dégagées puis vérifiées expérimentalement. Cette étude permet de définir les meilleures conditions de traitement. Trois dispositifs (à recyclage, à lit fluidisé et réacteur/décanteur) permettant d’approcher ces meilleures conditions ont été testés avec succès. Ceux-ci ouvrent d’importantes perspectives pour la réduction de la quantité de boue produite. Deux brevets ont été déposés suite à ce travail / To decontaminate liquid nuclear wastes, the coprecipitation process is the most commonly used in nuclear field because it can be applied to any type of aqueous effluents whatever their composition may be. This process deals with the in situ precipitation of solid particles to selectively remove one or more radioelements. The aim of this PhD work is to investigate phenomena which take place during the coprecipitation of a trace component. To reach this objective, we have proposed a new modelling of the coprecipitation mechanism. The originality of this new approach lies in the possibility to simulate the phenomenon in non equilibrium conditions and at the reactor scale. This modelling combined with the resolution of the population balance, enable to identify the influence of process parameters (flowrates, stirring speed…) on crystal size and ultimately on decontamination. To test this new modelling, simulations of the coprecipitation of strontium ions with barium sulphate have been performed in continuous and semibatch reactors. Thanks to these simulations, laws of the treatment efficiency variation as a function of several process parameters (mean residence time, stirring speed, BaSO4 concentration) have been determined and experimentally verified. This study leads to the determination of optimal treatment conditions. Three apparatus (recycling apparatus, fluidised bed and reactor/settling tank) providing these optimal conditions have been successfully tested and offered significant outlooks for the reduction of the volume of sludge produced by the process. Two new processes are patent pending

Dans cette thèse, nous avons déterminé les mécanismes qui régissent l'efficacité des particules de fer zérovalent (ZVI) dans la dépollution des sols et des eaux souterraines. Dans les milieux contaminés par des polluants accepteurs d'électrons, le ZVI est injecté in situ sous forme de suspensions de particules micro et/ou nanométriques. La première étude a porté sur la caractérisation de poudres industrielles et de particules synthétisées au laboratoire à partir de thé vert. Afin de comparer la réactivité de l'ensemble des particules, un test en milieu fermé a été mis en oeuvre avec une solution de nitrate. Ce test a permis de différencier les particules en mettant en évidence des mécanismes réactionnels et des cinétiques de réduction qui dépendent du type de poudre utilisé. La seconde étude a porté sur la dégradation du chrome hexavalent (dans une matrice sol et eau) en combinant le ZVI à du thiosulfate de sodium. Les résultats ont été probants et ont mené au dimensionnement d'un pilote sur un site de Soléo Services. Enfin, deux cas de remédiation de sites pollués aux solvants chlorés ont été étudiés. Des expériences de laboratoire ont été menées pour expliquer l'impact des conditions opératoires sur l'efficacité du traitement / This thesis aims at a better understanding of mechanisms governing the efficiency of zerovalent iron (ZVI) particles in soil and groundwater remediation. In these processes ZVI is injected in situ as micro and/or nanoparticles slurry in areas contaminated by electron acceptor pollutants. At first, we characterized industrial powders and particles synthetized with green tea in the laboratory. In order to compare the reactivity of all the particles, a batch test has been carried out with nitrate solution. Differences in pathways and kinetic reduction have been exhibited. Secondly, we combined ZVI with sodium thiosulfate to investigate hexavalent chromium degradation (soil and water matrices). The results are conclusive and were used to design a pilot on a Soléo Services site.Finally, remediation cases of sites contaminated by chlorinated solvents have been investigated. Lab experiments have been run to explain the influence of operating conditions on the treatment efficacy

O presente estudo analisou os efeitos da radiação gama na sobrevivência de fungos em plantas medicinais embaladas, adquiridas do comércio atacadista e varejista, em diferentes períodos (0 e 30 dias) após o tratamento por irradiação. Cinco tipos de plantas medicinais [Peumus boldus, Cameilia sinensis, Maytenus ilicifolia, Pauilinia cupana and Cássia angustifolia), foram coletadas de diferentes municípios do Estado de São Paulo e submetidas ao tratamento por irradiação, utilizando-se uma fonte 60Co (tipo Gammacell 220), com doses de 5,0 kGy e 10 kGy e taxa de dose de 3,0 kGy/h. Amostras não irradiadas (grupo controle) foram usadas na contagem de fungos e diluições seriadas de 10-1 a 10-6 das amostras foram semeadas em duplicata e plaqueadas usando o método de cultura em superfície, em ágar Dicloran Glicerol 18% (DG18) e contadas após cinco dias a 25°C. O grupo controle revelou a presença dos gêneros Aspergilius e Penicillium, os quais são conhecidos como fungos toxigênicos e poucas amostras do grupo controle estavam dentro dos limites seguros, estabelecidos pela Organização Mundial de Saúde (OMS, 1998) para plantas medicinais. Em resposta a resistência do tratamento por ionização, na dose de 5 kGy, foi obsen/ado que os gêneros Aspergilius, Piioma e Syncephalastrum foram radiorresistentes, após o processo (dia 0 e 30° dia). O tratamento por radiação gama foi efetivo na descontaminação de todas as amostras de plantas medicinais, após 30 dias, com a dose de 10 kGy e mantidas em condições de vedação. Não foram detectadas aflatoxinas nas amostras do grupo controle, ainda que estas amostras estivessem intensamente contaminadas com Aspergilius flavus. / This present study evaluated the effect of gamma radiation on the fungal survival in packed medicinal plants, purchased from wholesale and retail market, in different period (0 and 30 days) after the treatment. Five kind of medicinal plants (Peurnus boldus, Camellia sinensis, Maytenus ilicifolia, Pauilinia cupana and Cassia angustifolia), were collected from different cities of São Paulo State, and submitted to irradiation treatment using a 60Co source (type Gammacell 220) with doses of 5,0 kGy and 10 kGy and at dose rate of 3.0 kGy/h. Non-irradiated samples (control group) were used for fungal counts and serial dilutions from 10-1 to 10-6 of the samples were seeded in duplicates and plated using the surface culture method in Dichloran 18% Glycerol Agar (DG 18) and were counted after five days at 25°C. The control group revealed the presence of genera Aspergillus and Penicillium, which are known as toxigenic fungi and a few samples of control group were within the safety limits of World Health Organization (WHO, 1998) to medicinal plants. In response to resistance of ionizing treatment, in the dose of 5 kGy, it was obsen/ed that the genera Aspergillus, Phoma and Syncephalastrum were radio-resistant after the process (day 0 and 30° day). The treatment by gamma radiation was effective in decontamination of all irradiated samples of medicinal plants, after 30 days, with the dose of 10 kGy and kept of veiled conditions. It was not detected aflatoxins in samples of control group, even though these samples were heavily contaminated with Aspergillus flavus.

A colonização bacteriana no sulco periimplantar ocorre muito precocemente, logo após a cirurgia de instalação dos implantes. Com este intuito, o projeto foi proposto a fim de avaliar o efeito da terapia fotodinâmica (PDT) na manutenção da crista óssea alveolar. Em um estudo de boca dividida, 20 pacientes foram reabilitados com implantes Standard Plus (Straumann®), divididos em dois grupos: um grupo controle (GC) e um grupo submetido à terapia fotodinâmica (GPDT), cujo protocolo foi: densidade de energia 120J/cm2, potência de 40mW, associada ao corante azul de metileno a 0,005%. As aplicações foram realizadas no dia da instalação do implante, após 15, 30 e 45 dias. As coletas microbiológicas foram efetuadas no período inicial e 6ª semana, nos dois grupos, utilizando cones de papel estéril. No GPDT, outras duas coletas foram realizadas após aplicação da terapia: no dia da cirurgia e após 45 dias. As unidades formadoras de colônias totais (UFCt) e pigmentadas de preto (UFCpig) foram contadas. Dados clínicos (Índice de Placa- IP e Sangramento a Sondagem- SS modificados por Mombelli) foram obtidos na 6a semana, 6 meses e 1 ano. Análise radiográfica, com radiografias periapicais, foram efetuadas utilizando a técnica da subtração radiográfica. As películas foram digitalizadas com o escaner SprintScan 35 Plus - Polaroid. Com softwares de manipulação de imagens (Adobe Photoshop CS2®- Califórnia, EUA e ImageJ- National Institutes of Health) foram medidas as distâncias do ombro do implante ao primeiro contato implante-osso, nas seguintes fases: inicial; 6a semana; instalação da prótese, 6 meses e 1 ano após instalação protética. Os testes estatísticos aplicados foram Friedman, Wilcoxon e MannWhitney. Quanto à eficiência da PDT, os resultados mostraram que houve uma redução, estatisticamente significante, tanto para UFCt como UFCpig nos dois momentos aplicados. O número de UFCt e UFCpig do pós-cirúrgico até a 6ª semana apresentou aumento, estatisticamente significante, nos dois grupos. No comparativo entre grupos não houve diferença, estatisticamente significante, entre a diferença do número de UFCt e UFCpig do período inicial ate a 6ª semana. O IP e SS foram similares entre os dois grupos. A avaliação radiográfica mostrou que houve uma perda da crista óssea crescente do período inicial até a instalação da prótese, que se manteve mantém estável após um ano de função para os dois grupos. A média da perda óssea, do período inicial até a instalação da prótese, foi de 0,73mm para o GC e de 0,84mm para o GPDT. Durante o período de função protética as médias de perda óssea foram, respectivamente, 0,27mm e 0,19mm para os GC e GPDT, sem diferença estatisticamente significante entre os grupos. Concluiu-se que: a PDT é eficiente para a redução das UFCt e UFCpig, presentes no sulco periimplantar, durante a osteointegração; a PDT não impede a recolonização, nem o crescimento bacteriano ao longo do tempo, exceto as UFCpig do GPDT, onde a quantidade de bactérias durante a osteointegração manteve-se estatisticamente estável; e com relação à manutenção da crista óssea periimplantar, os GC e GPDT tiveram resultados similares, sem diferença estatisticamente significante. / Bacterial colonization of the peri-implant sulcus occurs very early, right after the implant placement surgery. To this purpose, the project was proposed to evaluate the effect of photodynamic therapy (PDT) in the maintenance of {the} alveolar bone crest. In a split-mouth study, 20 patients were rehabilitated with Standard Plus implants (Straumann®) and they were divided into two groups: a control group (CG) and a group submitted to photodynamic therapy (GPDT), whose protocol was: energy density of 120J/cm2 at power of 40 mW, combined with 0,005% methylene blue. The applications were performed on the day of implant placement, after 15, 30 and 45 days. Microbiological samples were collected in the initial period and after 6 weeks on both groups, using sterile paper cones. In GPDT, two other collections were made after the application of the therapy: on the day of surgery and after 45 days. The total colony forming units (UFCt) and pigmented black units (UFCpig) were counted. Clinical data (Plaque Index-IP and Sulcus bleeding index- SS modified by Mombelli) were obtained at the 6th week, 6 months and 1 year. Radiographic analysis with periapical radiographs were made using the radiographic subtraction technique. The films were digitalized with the scanner SprintScan 35 Plus- Polaroid. Using image manipulation softwares (Adobe Photoshop® CS2- California and ImageJ-National Institutes of Health) distances from the implant shoulder to the first bone-implant contact were measured in phases: initial; 6th week; installation of the prosthesis, 6 months and 1 year after prosthetic installation placement. Friedman, Wilcoxon and Mann-Whitney were the statistical tests applied. Concerning the PDT efficacy, the results presented a statistically significant reduction for both UFCt and UFCpig in the two performed moments. The number of UFCt and UFCpig of the immediate postoperative to 6 weeks indicated a statistically significant increase in both groups. Comparing both the two groups, there was no statistically significant difference between the number of UFCt and UFCpig of the initial period to the 6th week. The IP and SS were similar in both groups. Radiographic evaluation indicated that there was an increasing loss of bone crest during the initial period and the installation of the prosthesis, which remained stable after a year of function for both groups. The bone loss average from the initial period until the installation of the prosthesis was 0,73mm for the GC and 0,84mm for the GPDT. During the prosthetic function the bone loss averages were, respectively, 0,27mm and 0,19mm for the GC and for the GPDT, with no statistically significant difference for both groups. The data led to the conclusion that: PDT is effective in reducing UFCt and UFCpig present in the peri-implant groove during the osseointegration; the PDT does not avoid the re-colonization or bacterial growth over time, except for the UFCpig of GPDT, wherein the amount of bacteria during the osseointegration remained statistically stable; and regarding to the maintenance of the peri-implant bone crest, the GC and GPDT obtained had similar results, with no statistically significant difference.

A qualidade, eficácia e segurança no emprego de drogas vegetais dependem, entre outras questões, de sua qualidade sanitária. Sua origem e manuseio, em condições no geral inadequadas, propiciam biocarga elevada e abrangente, o que implica riscos para saúde. O presente trabalho objetivou conhecimento da microbiota das plantas estudadas e o desenvolvimento de estudos de sua descontaminação por plasma, tendo-se analisado os parâmetros físicos que influenciaram este processo. O projeto possibilitou a descontaminação de drogas vegetais com alta carga microbiana. Estudou-se a alcachofra (Cynara scolymus L.), camomila (Chamomilla recutita (L.) Rauschert.), ginco (Ginkgo biloba L.) e guaraná (Paullinia cupana Kunth), adotando parâmetros de processo que alegadamente permitem a integridade dos princípios ativos termossensíveis. Para isso, foi empregado reator disponível no Laboratório de Sistemas Integráveis, pertecente à Escola Politécnica da Universidade de São Paulo, em sistema com acoplamento capacitivo modo RIE (Reactive Ion Etching). Neste sistema, trabalhou-se com oxigênio adicionado de peróxido de hidrogênio. Todos os processos de descontaminação foram desenvolvidos a temperatura ambiente, sob diferentes parâmetros físicos complementares. A eficácia do processo foi investigada, empregando-se contagem de microrganismos heterotróficos, assim como pesquisa de indicadores de patogênicos (Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella spp, Escherichia coli). As avaliações microbiológicas, quantitativas e qualitativas, assim como os estudos decorrentes dos dados obtidos, foram desenvolvidos no Laboratório de Controle Biológico da Faculdade de Ciências Farmacêuticas - USP. Os resultados obtidos após a descontaminação por plasma de oxigênio (100%), a potência de 150 W, evidenciaram redução de até 4 ciclos de aeróbicos totais. No processo por plasma peróxido de hidrogênio (20%) e oxigênio (80%), a uma potência de 150 W, observou-se a redução de até 4 ciclos log de aeróbios totais para as drogas vegetais deste estudo. A presença de substâncias químicas complexas da camomila, que contêm óleo volátil, flavonóides, aminoácidos, ácidos graxos, sais minerais, cumarinas, mucilagens e ácidos orgânicos, interferem no processo por plasma provavelmente em decorrência de a mucilagem formar um filme protetor, impedindo a difusão gasosa em ambos os processos por plasma. Assim, não só a camomila mas também o guaraná, com biocargas iniciais respectivamente de 6,6x106 UFC/g e 2,7x106 UFC/g, mantiveram-se com níveis de contaminação da mesma ordem de grandeza, após os desafios com plasma. A contagem bacteriana da alcachofra (fornecedor B), que foi submetida ao processo de descontaminação através do plasma O2 (100%), (potência de 150 W, pressão de 100 mTorr e vazão de 200 sccm), sofreu redução de dez vezes, independentemente do tempo do processo. Possivelmente este resultado, que aparenta inconsistência, decorre da ação apenas superficial do plasma. A descontaminação por processo de plasma de oxigênio e de peróxido de hidrogênio para a alcachofra (fornecedor B) não foi eficaz, devido à predominância de elementos lignificados. As amostras de alcachofra (fornecedor C), com baixa percentagem de vasos de xilema lignificados e fibras lignificadas evidenciaram a maior eficácia do processo por plasma, pois possibilitou grande difusão gasosa sobre as amostras. O estudo permitiu ainda concluir que à aplicabilidade do plasma na descontaminação de drogas vegetais depende da resistência dos microrganismos, mas igualmente das características da planta, sejam aquelas de natureza morfoanatômica, enzimática ou química. Estudos específicos devem ser desenvolvidos para cada situação. / The quality, effectiveness and safety of vegetal drugs usage depend, among others issues, on their sanitary quality. Their origin and handling, usually under inadequate conditions, propitiate high bioburden, what presents risks to health. This project aimed at the evaluation of the microbiota of the plants studied and the development of studies concerning their decontamination by plasma, after the analysis of the physical parameters that influence this process. This project made the vegetal drugs decontamination with high microbiana load possible. Artichoke (Cynara scolymus L.), chamomile (Chamomilla recufifa (L.) Rauschert), ginco (Ginkgo biloba L.) and guaraná (Paullinia cupana Kunth) were studied through parameters that allowed the integrity of thermal sensible active principies. The achievement of our purpose depended on the use of a reactor with RIE (Reactive Ion Etching) capacitive coupled systems, available in the Laboratory of Integrating Systems from Escola Politécnica, University of São Paulo. In this system we worked whith oxygen, whith hydrogen peroxide addition. All decontamination processes were developed at room temperature, under different complementary physical parameters. The process effectiveness was investigated using counting of heterotropic microorganisms, aswell as pathogenic register research (Sfaphylococcus aureus, Pseudomonas aeruginosa, Salmonella spp, Escherichia coll). The microbiological, quantitative and qualitative evaluations, as well as the studies of the data obtained were developed in the Laboratory of Biological Control of Pharmaceutical Sciences Faculty - USP. The results obtained after decontamination by plasma , oxygen (100%) at 150 W potency, evidenced reduction of up to 4 cycles of total aerobics. In the process by plasma hydrogen peroxide (20%) and oxygen (80%) at 150 W potency, a reduction of up to 4 cycles of total aerobics was observed in vegetal drugs. The presence of chamomile chemical complex substances, which contain volatile oil, flavonoids, aminoacids, fatty acids, mineral salts, coumarins, mucilages and organic acids, interfere in the process by plasma, probably due to the fact that the muclilage forms a protective film, preventing the gaseous diffusion in both processes by plasma. Thus no only chamomile but also guaraná, whith initial bioburden of respectively 6,6x106 UFC/g and 2,7x106 UFC/g, kept similar contamination levels after the challenges whith plasma. The bacterial count of artichoke (supolier B), which was sumitted to decontamination process by plasma 02 (100%), (150 W potency, 100mTorr pressure and 200sccm) was reduced ten times, independently of the time of process. This apparently inconsistent result is possibly a consequence of a superficid plasma action. The decontamination by Oxygen and Hydrogen Peroxide plasma process for artichoke (supplier B) was not efficient due to the predominance of lignitic elements. The samples of artichoke from supplier C, whith low percentage of liginitic xylem vessels and fibres evidenced higer efficacy of the process by plasma, what eased great gaseous diffusion over thesamples of artichoke leaves (supplier C). Thus the study of plasma aplicability in vegetal drug decontamination depends not only of microorganisms resistence but also of the plant characteristics, either the morphopanatomic, enzymatic, or chemical ones. A specific study must then be developed for each situation.