Flavonoid extraction from Alpinia zerumbet (Pers.) Burtt et Smith leaves using different techniques and solvents

The current study aims to verify the best method for a rapid and efficient extraction of flavonoids from Alpinia zerumbet. Dried leaves were extracted using distillated water and ethanol 70% by extraction methods of shaking maceration, ultrasonic, microwave and stirring. By the application of TLC and reversed-phase HPLC techniques the rutin and kaempferol-3-O-glucuronide were detected. Ethanol 70% was more efficient for flavonoids extraction than water. No significant yielding variation was verified for ultrasonic, microwave and stirring methods using ethanol 70% (11 to 14%). The relative concentration of rutin and kaempferol-3-O-glucuronide, respectively, was higher by ultrasonic (1.5 and 5.62 mg g-1 dried leaves, respectively) and by microwave (1.0 and 6.64 mg g-1 dried leaves) methods using ethanol. Rapid and simplified extraction proceeding optimize phytochemical work and acquisition of secondary metabolites.

Flavonoids extraction from Alpinia zerumbet (Pers.) Burtt et Smith leaves using different procedures

The current study aims to verify the best method for a rapid and efficient extraction of flavonoids from Alpinia zerumbet. Dried leaves were extracted using distillated water and ethanol 70% by extraction methods of shaking maceration, ultrasonic, microwave and stirring. By the application of TLC and reversed-phase HPLC techniques the rutin and kaempferol-3-O-glucuronide were detected. Ethanol 70% was more efficient for flavonoids extraction than water. No significant yielding variation was verified for ultrasonic, microwave and stirring methods using ethanol 70% (11 to 14%). Relative concentration of rutin and kaempferol-3-O-glucuronide, respectively, was higher by ultrasonic (1.5 and 5.62 mg g-1 dried leaves) and by microwave (1.0 and 6.64 mg g-1 dried leaves) methods using 70% ethanol. Rapid and simplified extraction proceeding optimize phytochemical work and acquisition of secondary metabolites.

Composition of Hawthorn (Crataegus spp.) Fruits and Leaves and emblic Leafflower (Phyllanthus emblica) Fruits

Hawthorn (Crataegus sp.) is widely distributed in the northern hemisphere (Asia, Europe and North America). It has been used as a medicinal material and food for hundreds of years both in Europe and in China. Clinical investigations and other research suggest that extracts of hawthorn fruits and leaves have multiple health effects including hypolipidaemic, anti-atherosclerotic, hypotensive, cardioprotective and blood vessel relaxing activities. Hawthorn fruit extracts have also displayed antioxidant and radical scavenging activities. Emblic leafflower fruit (Phyllanthus emblica) is widely used in Chinese and Indian traditional medicine. It has been found to have anti-cancer, hypoglycaemic and hypolipidaemic activities as well as cardioprotective effects and antioxidant activity. The fruit is currently used as a functional food targeted at obese people in China. Phenolic compounds, procyanidins (PCs), flavonols and C-glycosyl flavones in hawthorn and hydrolysable tannins in emblic leafflower fruits are considered among the major bioactive compounds in these berries. Moreover, hawthorn and emblic leafflower fruits are rich in vitamin C, triterpenoids, fruit acids, sugar alcohols and some other components with beneficial effects on the health of human beings. The aim of the thesis work was to characterise the major phenolic compounds in hawthorn fruits and leaves and emblic leafflower fruits as well as other components contributing to the nutritional profile and sensory properties of hawthorn fruits. Differences in the content and compositional profile of the major phenolic compounds, sugars, acids and sugar alcohols within various origins and species of hawthorn were also investigated. Acids, sugars and sugar alcohols in the fruits of different origins/cultivars belonging to three species (C. pinnatifida, C. brettschneideri and C. scabrifolia) of hawthorn were analysed by gas chromatography (GC-FID) and mass spectrometry (Publication I). Citric acid, quinic acid, malic acid, fructose, glucose, sorbitol and myo-inositol were found in all the subspecies. Sucrose was present only in C. scabrifolia and three cultivars of C. pinnatifida var. major. Forty-two phenolic compounds were identified/tentatively identified in fruits of C. pinnatifida var. major by polyamide column chromatography combined with high-performance liquid chromatograph-electrospray ionisation mass spectrometry (HPLC-ESI-MS) (Publication II). Ideain, chlorogenic acid, procyanidin (PC) B2, (-)-epicatechin, hyperoside and isoquercitrin were the major phenolic components identified. In addition, 35 phenolic compounds were tentatively identified based on UV and mass spectra. Eleven major phenolic compounds (hyperoside, isoquercitrin, chlorogenic acid, ideain, (-)-epicatechin, two PC dimers, three PC trimers and a PC dimer-hexoside) were quantified in the fruits of 22 cultivars/origins of three species of Chinese hawthorn by HPLC-ESI-MS with single ion recording function (SIR) (Publication III). The fruits of the hawthorn cultivars/origins investigated fell into two groups, one rich in sugars and flavonols, the other rich in acids and procyanidins. Based on the compositional features, different biological activities and sensory properties may be expected between cultivars/origins of the two groups. The results suggest that the contents of phenolic compounds, acids, sugars and sugar alcohols may be used as chemotaxonomic information distinguishing the hawthorn species from each other. Phenolic compounds in fruits and leaves of C. grayana and their changes during fruit ripening/harvesting were investigated using HPLC-UV-ESI-MS (Publication IV). (-)-Epicatechin, PC B2 and C1, hyperoside and a quercetin-pentoside were the major phenolic compounds in both fruits and leaves. Three C-glycosyl flavones (a luteolin-C-hexoside, a methyl luteolin-C-hexoside and an apigenin-C-hexoside) were present in leaves in abundance, but only at trace levels in fruits. Ideain and 5-O-caffeoylquinic acid were found in fruits only. Additionally, eleven phenolic compounds were identified/tentatively identified in both leaves and fruits (three B-type PC trimers, two B-type PC tetramers, a quercetin-rhamnosylhexoside, a quercetin-pentoside, a methoxykaempferol-methylpentosylhexoside, a quercetin-hexoside acetate, a methoxykaempferol-pentoside, chlorogenic acid and an unknown hydroxycinnamic acid derivative). The total content of phenolic compounds reached the highest level by the end of August in fruits and by the end of September in leaves. The compositional profiles of phenolic compounds in fruits and leaves of C. grayana were different from those of C. pinnatifida, C. brettschneideri, C. scabrifolia, C. pinnatifida. var. major, C. monogyna, C. laevigata and C. pentagyna. Phenolic compounds in emblic leafflower fruits were characterised by Sephadex LH-20 column chromatography combined with HPLC-ESI-MS (Publication V). A mucic acid gallate, three isomers of mucic acid lactone gallate, a galloylglucose, gallic acid, a digalloylglucose, putranjivain A, a galloyl-HHDP-glucose, elaeocarpusin and chebulagic acid represented the major phenolic compounds in fruits of emblic leafflower. In conclusion, results of this study significantly increase the current knowledge on the key bioactive and nutritional components of hawthorn and emblic leafflower fruits. These results provide important information for research on the mechanism responsible for the health benefits of these fruits.

Reaaliaikaisen esikäsittelyn kehittäminen hemiselluloosa-analytiikalle

Tämän työn tavoitteena oli kehittää esikäsittelymenetelmä, jolla voidaan reaaliaikaisesti vähentää hydrolysaatin ligniinipitoisuutta ja näin vähentää fluoresenssia hemiselluloosan analysoimisessa. Työn kirjallisuusosassa käsitellään hemiselluloosien rakennetta sekä niiden erottamista puusta, sekä käydään läpi hemiselluloosien käyttömahdollisuuksia ja niiden reaaliaikaiseen analysointiin soveltuvia tekniikoita. Kokeellisessa osassa tutkittiin ultrasuodatusta sekä adsorptiohartsikäsittelyä hydrolysaatin esikäsittelynä ennen Raman-analyysiä. Esikäsittelyn tavoitteena oli vähentää Raman-analyysia häiritsevää ligniinistä johtuvaa fluoresenssia. Suodatukset tehtiin Amicon-suodatuslaitteistolla käyttäen viittä eri suodatuskalvoa. Hartsikäsittelyissä käytettiin Amberliten XAD16 ja XAD7HP adsorbtiohartseja. Hartsisuhteina käytettiin 1/80, 1/40, 1/19 ja 1/13. Käytetyt ultrauodatuskalvot osoittautuivat suodatusnäytteistä tehtyjen HPLC-analyysien perusteella cut-off-luvultaan liian pieniksi, sillä hemiselluloosien ja ligniinin erotus ei onnistunut, vaan molemmat väkevöityivät konsentraattiin. Hartsikäsittelyillä saatiin ligniiniä poistettua aiheuttamatta hemiselluloosahäviöitä. Parhaimmillaan ligniinin poistumista kuvaava UV-absorbanssi pieneni hartsilla XAD16 37 % ja hartsilla XAD7 25 %. Vaikka ligniinipitoisuus aleni, näytteet fluoresoivat edelleen voimakkaasti Raman-mittauksessa. Tulosten perusteella näyttäisi siltä, että hartsikäsittelyä optimoimalla analyysiä häiritsevää fluoresenssia olisi edelleen mahdollista vähentää.

Marcadores séricos de estresse oxidativo e resultados dos procedimentos de reprodução assistida em pacientes inférteis com síndrome dos ovários policísticos e controles

OBJETIVO: comparar os níveis séricos de cinco marcadores de estresse oxidativo e os resultados de reprodução assistida (RA), entre pacientes com infertilidade por fator tubário e/ou masculino e portadoras de síndrome dos ovários policísticos (SOP). MÉTODOS: foram inclusos 70 pacientes, sendo 58 com infertilidade por fator tubário e/ou masculino e 12 com SOP, que foram submetidas à estimulação ovariana controlada para realização de injeção intracitoplasmática de espermatozoide (ICSI). A coleta de sangue foi realizada entre o terceiro e o quinto dia do ciclo menstrual, no mês anterior à realização da estimulação ovariana. Foram analisados os níveis de malondialdeído, hidroperóxidos, produtos de oxidação proteica, glutationa e vitamina E, pela leitura da absorbância em espectrofotômetro e por cromatografia líquida de alta eficiência (HPLC). Para a análise estatística, utilizou-se o teste t de Student e o teste exato de Fisher. RESULTADOS: entre as pacientes com SOP, foi constatado maior índice de massa corporal, volume ovariano e número de folículos antrais e uma menor dose total utilizada de hormônio folículo estimulante. Não observamos diferença em relação à resposta à estimulação ovariana, aos resultados de RA e aos níveis séricos de malondialdeído, hidroperóxidos, produtos de oxidação proteica, glutationa e vitamina E entre os grupos. CONCLUSÕES: no estudo não evidenciamos diferença entre os níveis séricos de marcadores de estresse oxidativo, nem nos resultados de RA, comparando pacientes inférteis não-obesas com SOP e controles. Estes dados sugerem que, neste subgrupo específico de portadoras de SOP, os resultados de RA não estejam comprometidos. Todavia, as interpretações acerca da ação do estresse oxidativo sobre os resultados de RA ainda não estão claras e as implicações reprodutivas do estresse oxidativo precisam ser mais bem avaliadas.

Technological development of 40mg furosemide tablets: equivalence and bioavaibility study in dogs

Furosemide (40mg) was administered to 20 street dogs, 10 males and 10 females, in two different pharmaceutical forms: (1) compressed furosemide 40mg formulated at the Federal University of Pernambuco (UFPE-tablet), and (2) a commercial formulation with equal bioequivalence produced by the Laboratory for Pharmaceutical Technology of Pernambuco State (LAFEPE), the LAFEPE-furosemide. The study aimed to evaluate the kinetics of dissolution of the UFPE-tablet in order to analyze the behavior of bioavailability of the best formulation for veterinary use. The plasmatic concentrations of furosemide for the determination of parameters of pharmacological kinetics were analyzed by high-performance liquid chromatographic method (HPLC). The in vitro study accomplished through physiochemical analyses demonstrated that the formulas of the furosemide tablets attained the pharmaceutical requirements in agreement with USP 23 and the Brazilian Pharmacopoeia. The evaluation accomplished in dogs with UFPE-tablets given in only dose demonstrated uniformity in blood levels indicating stability in maintenance of the pharmaceutical formulation and efficiency in absorption of the active compound. These values are not significantly different in relation to the 5% confidence limit. Regarding maximum concentration (Tmax) time and global bioavaibility assessed by AUC means, there were no considerable differences as well. UFPE-furosemide displayed 743.492µg/mL.h as AUC average value whereas LAFEPE-furosemide had an average of 537.284µg/mL.h.

Sheep poisoning by Panicum dichotomiflorum in northeastern Brazil

Different species of Panicum, including P. dichotomiflorum,have been reported as a cause of photosensitization in sheep, horses, cattle and goats. An outbreak of hepatogenous photosensitization occurred in 3 flocks of hair sheep in the Brazilian semiarid region. Eighty one out of 365 sheep were affected and 39 died. The main affected animals were nursing lambs and sheep younger than one year old. Donkeys, goats and cattle grazing in the same pasture were not affected. Clinical signs were edema of the head, followed by dermatitis, mainly in the face, ears, and croup, ocular discharge, corneal opacity with blindness, and redness of the coronary band and hoof. At necropsy of one affected lamb the liver was yellowish. Upon histologic examination scattered necrotic hepatocytes were observed in the liver and focal areas of necrosis of myocytes appeared in the heart. Samples of P. dicotomiflorum were analyzed by TLC and those containing saponins were isolated by HPLC using RP-C18 column and eluted with a mixture of MeOH and H2O. The isolated compounds were submitted to ¹H and 13C NMR spectroscopy. Reactions were positive to furostanol saponins with the same Rf of the standard protodioscin (0.21) and methylprotodioscin (0.32). The spectroscopic results indicated a mixture of (25R)- and (25S)-protodioscin isomers in a proportion of 3:1, and methylprotodioscin.

Analytical methods for analyzing organic peroxides

Työn tarkoituksena oli kehittää analyyttinen erotusmenetelmä eräässä valmistusprosessissa käytettävän hapettavan aineen ja liuottimen välillä syntyvien reaktiotuotteiden tutkimiseen ja analysoimiseen. Lisäksi tarkoituksena oli tutkia prosessiolosuhteiden turvallisuutta. Kirjallisuusosassa käsitellään erilaisia orgaanisia peroksideja, niiden käyttötarkoituksia ja niiden käyttöön liittyviä huomioitavia asioita. Lisäksi tarkastellaan yleisimpiä analyysimenetelmiä, joita on käytetty erilaisten peroksidien analysoinnissa. Näitä analyysimenetelmiä on useimmiten käytetty nestemäisten näytteiden tutkimuksissa. Harvemmin on analysoitu kaasu- ja kiintoainenäytteitä. Kokeellisessa osassa kehitettiin kirjallisuuden perusteella peroksidiyhdisteille identifiointimenetelmä ja tutkittiin prosessin näytteet. Analyysimenetelmiksi valittiin iodometrinen titraus ja HPLC-UV-MS-menetelmä. Lisäksi käytettiin peroksidimittaukseen soveltuvia testiliuskoja. Tutkimus osoitti, että iodometrisen titrauksen ja testiliuskojen perusteella näytteissä oli vähäisiä määriä peroksideja viikon jälkeen peroksidilisäyksestä. HPLC-UV-MS-analyysien perusteella näytteiden analysointia häiritsi selluloosa, jota löytyi jokaisesta näytteestä.

Pulsed corona discharge as an advanced oxidation process for degradation of organic

Advanced oxidation processes (AOPs) have been studied and developed to suffice the effective removal of refractory and toxic compounds in polluted water. The quality and cost of wastewater treatment need improvements, and electric discharge technology has a potential to make a significant difference compared to other established AOPs based on energy efficiency. The generation of active oxidant species such as ozone and hydroxyl radicals by high voltage discharge is a relatively new technology for water treatment. Gas-phase pulsed corona discharge (PCD), where a treated aqueous solution is dispersed between corona-producing electrodes free of the dielectric barriers, was developed as an alternative approach to the problem. The short living radicals and ozone formed in the gas phase and at the gas-liquid interface react with dissolved impurities. PCD equipment has a relatively simple configuration, and with the reactor in an enclosed compartment, it is insensitive towards gas humidity and does not need the gas transport. In this thesis, PCD was used to study and evaluate the energy efficiency for degrading various organic compounds, as well as the chemistry of the oxidation products formed. The experiments investigate the aqueous oxidation of phenol, humic substances, pharmaceutical compounds (paracetamol, ibuprofen, indomethacin, salicylic acids, -estradiol), as well as lignin degradation and transformation to aldehydes. The study aims to establish the influence of initial concentration of the target pollutant, the pulsed discharge parameters, gas phase composition and the pH on the oxidation kinetics and the efficiency. Analytical methods to measure the concentrations of the target compounds and their by-products include HPLC, spectrophotometry, TOC and capillary electrophoresis. The results of the research included in this summary are presented in the attached publications and manuscripts accepted for publication. Pulsed corona discharge proved to be highly effective in oxidizing each of the target compounds, surpassing the closest competitor, conventional ozonation. The increase in oxidation efficiencies for some compounds in oxygen media and at lower pulse repetition frequencies shows a significant role of ozone. The role of the ·OH radicals was established in the surface reactions. The main oxidation products, formation of nitrates, and the lignin transformation were quantified. A compound specific approach is suggested for optimization of the PCD parameters that have the most significant impact on the oxidation energy efficiency because of the different characteristics and responses of the target compound to the oxidants, as well as different admixtures that are present in the wastewater. Further studies in the method’s safety (nitration and nitrosation of organic compounds, nitrite and nitrate formation enhancement) are needed for promoting the method.

Hartsin likaantuminen ja kestävyys mustalipeän fraktioinnissa kokoekskluusiokromatografialla

Sellunkeiton sivutuotteena syntyvä mustalipeä sisältää arvokkaita orgaanisia yhdisteitä, kuten hydroksihappoja. Toistaiseksi hydroksihapot on käytetty muun mustalipeän tavoin sellutehtaan lämmöntuotantoon. Hydroksihappojen merkitys lämmöntuotannon kannalta on kuitenkin pieni verrattuna mustalipeän sisältämään ligniiniin. Viime vuosina kiinnostus hydroksihappoja kohtaan on kasvanut sillä ne voisivat toimia lähtöaineena monille kemikaaleille, joiden valmistukseen käytetään perinteisesti fossiilisia polttoaineita. Hydroksihappoja voidaan erottaa mustalipeästä useilla eri menetelmillä. Erotukseen soveltuvia menetelmiä ovat esimerkiksi ioniekskluusiokromatografia, kalvosuodatus ja kiteytys sekä kokoekskluusiokromatografia. Kromatografisissa menetelmissä käytetyt hartsit ja kalvosuodatuksessa käytettävät kalvot ovat kuitenkin alttiita eri yhdisteiden aiheuttamalle likaantumiselle. Tämän työn kirjallisuusosassa käsitellään mustalipeän koostumusta sekä mustalipeän sisältämiä hydroksihappoja ja niiden käyttökohteita. Lisäksi kirjallisessa osassa on kuvattu aikaisemmin tutkittuja menetelmiä hydroksihappojen erottamiseksi mustalipeästä. Viimeisin menetelmä mustalipeän fraktioimiseksi on kokoekskluusiokromatografia. Työssä on kuvattu kokoeksluusiokromatografian periaate ja selvitetty menetelmän soveltuvuutta mustalipeän fraktiointiin. Lisäksi on käsitelty kromatografisissa menetelmissä käytettyjen hartsien likaantumista, likaantumisen vaikutusta erotustehokkuuteen ja likaantumisen ehkäisyä. Kokeellisessa osassa käsitellään hydroksihappojen erotusta mustalipeästä kokoekskluusiokromatografialla sekä kokoekskluusiokromatografiassa käytettävän hartsin likaantumista ja kestävyyttä. Työssä selvitettiin toistokokein likaantumisen vaikutusta hartsin erotuskykyyn käsitellyn mustalipeän määrän kasvaessa. Malliaineena käytettiin ultrasuodatettua soodakeitettyä mustalipeää. Tulosten perusteella hartsin likaantuminen ei vaikuttanut hydroksihappojen erotukseen mustalipeästä. Kestävyyskokeissa hartsin vesiretentiossa ei havaittu mittausten perusteella johdonmukaista muutosta. HPLC-analyysien perusteella huomattiin liuoksista kuitenkin mahdollisia hartsin hajoamistuotteita, joita ei kuitenkaan pystytty tunnistamaan.

Curva de dissipação de imazapyr em água de drenos de irrigação, após aplicação para controle da taboa

O herbicida sistêmico imazapyr foi usado no controle da taboa (Typha subulata Crespo & Peres-Moreau f.) em drenos de irrigação, como alternativa ao controle mecânico. O resíduo do princípio ativo do herbicida na água foi analisado por cromatografia líquida de alta performance (HPLC). A curva de dissipação de imazapyr mostrou que o herbicida pode ser usado para o controle de taboa em drenos de irrigação, sem causar danos a culturas vizinhas, desde que a água seja usada, no mínimo, depois de 1,6 a 3,7 dias da aplicação das doses de 500 a 1500 g ha-1, respectivamente.

Efeito residual dos herbicidas imazaquin e imazethapyr, aplicados na soja, sobre o milho safrinha

Com o objetivo de se avaliar os efeitos da persistência dos herbicidas imazaquin e imazethapyr na cultura do milho safrinha em sucessão à da soja, tratada com estes produtos, foi instalado um ensaio na Fazenda Escola da Universidade Estadual de Londrina, solo argiloso (75% de argila), na safra agrícola 1995/96. O delineamento experimental adotado foi o de blocos ao acaso, com parcelas subdivididas em faixas. Os tratamentos principais foram constituídos pelos herbicidas: 1.Testemunha; 2.Imazaquin PPI -120 g.i.a./ha; 3.Imazaquin PPI - 240 g.i.a./ha; 4.Imazethapyr PRE - 80 g.i.a./ha e 5.Imazethapyr PRE - 160 g.i.a./ha. Os tratamentos secundários foram constituídos pelas épocas de semeadura do milho: 0 (zero), 30, 60, 90, 120 e 150 dias após a aplicação - DAA. As avaliações, tanto de fitotoxicidade visual como de biomassa seca das plantas e produtividade do milho, revelaram uma maior sensibilidade da cultura ao imazaquin do que ao imazethapyr, embora a quantidade (ppb) de imazethapyr encontrada nas análises cromatográficas das amostras de solo (HPLC) tenha sido maior que a de imazaquin. Nos primeiros plantios, o imazaquin causou dano praticamente total às plantas, enquanto o imazethapyr proporcionou uma injúria de 30-40% na dose normal(80 g.i.a./ha). Nos plantios após 120 DAA esses sintomas foram diminuindo gradativamente até desaparecerem. A curva de regressão dos dados de colheita revelou intervalos de 87 e 112 dias para imazethapyr e imazaquin, respectivamente, para que não mais houvesse diminuição na produtividade do milho semeado após a aplicação da dose normal destes produtos. Correlacionando-se os parâmetros avaliados, observou-se que, mesmo havendo fitotoxicidade no início do desenvolvimento das plantas de milho, essas se recuperaram, tendo produtividade normal após os referidos intervalos. Dos parâmetros avaliados no bioensaio com pepino (Cucumis sativus), a biomassa seca das plantas confirmou a maior sensibilidade do pepino em relação ao milho, sendo prejudicada pela ação residual dos herbicidas no solo até o intervalo mínimo de 127 e 135 DAA para imazethapyr - 80 g.i.a./ha e imazaquin - 120 g.i.a./ha, respectivamente.

Lixiviação do glyphosate e do imazapyr em solos com diferentes texturas e composição química: II. método analítico

Em razão das poucas de informações existente na literatura, sobre a mobilidade do glyphosate e do imazapyr, em solos de baixa atividade, comum em países tropicais, foi conduzido, em laboratório, um estudo sobre a mobilidade vertical desses herbicida s em dois solos com diferente s composições químicas e fisicas. Para estudar essa mobilidade, foram utilizadas colunas de solo com diferentes alturas, as quais, após aplicação dos produtos na dose comerc ial de 4 L ha-1, foram submetida s a um regime hídrico de 40 mm h-1, por um período de 4 h. As análises dos resíduos nas diferentes profundidades foram feitas utilizando-se os métodos voltamétrico (polarografia) e HPLC, para o glyphosate e imazapyr, respectivame nte. Com base nos resultados, foi possível concluir que: a) os métodos voltamétrico, para o glyphosate, e HPLC, para o imazapyr, são adequados para os estudos de identificação e quantificação de resíduos em água e solo; b) os limites de quantificação dos resíduos foram de 0,4 μg mL-1 e 5 μg L-1 para o glyphosate e o imazapyr, respectivamente; c) a taxa de recuperação do glyphosate, nas amostr as de solo (76 e 78% para os solos de Viçosa e Sabará, respectivamente) foi menor que na amostra de água (83%); d) a taxa de recuperação do imazapyr, em água e solo, foi próxima de 100%; e) a lixiviação do glyphosate nos solos foi muito baixa; e f) o imazapyr apresentou alta lix iviação, porém dif ere nciada entre os solos estudados, sendo essa maior no solo de tex tura franco -are nosa de Viçosa que no de argila de Sabará.

Wet oxidation of biomass for chemical production

Tämän kandidaatintyön tarkoituksena oli tutkia märkähapetusprosessia jätevesien käsittely-menetelmänä ja mahdollisena menetelmänä kemikaalien tuottamiseksi jätevesistä. Erityishuomio on kiinnitetty paperiteollisuudessa syntyviin jätevesiin. Teoriaosassa käsitellään vesikiertoja paperitehtaassa, paperitehtaalla syntyvän jäteveden ominaisuuksia sekä itse märkähapetusprosessia. Märkähapetusprosessissa perehdytään tavalliseen happea käyttävään märkähapetukseen sekä vetyperoksidia käyttävään menetelmään sekä näissä prosesseissa syntyviin väli- ja lopputuotteisiin. Märkähapetus (WO) on terminen hapetusmenetelmä, jolla voidaan käsitellä jätevesiä, jotka ovat liian konsentroituja biologisiin käsittelyihin tai jotka ovat huonosti biohajoavia. Märkähapetuksen tarkoituksena on parantaa molekulaarisen hapen ja orgaanisen aineen välistä kontaktia, jolloin orgaaninen aines pilkkoutuu muodostaen pääasiassa karboksyylihappoja, aldehydejä, hiilidioksidia ja vettä. Märkähapetuksessa hapettavana kaasuna voidaan käyttää joko puhdasta happea tai ilmaa. Vetyperoksidia käyttävässä märkähapetuksessa (WPO) hapettava kaasu on korvattu nestemäisellä vetyperoksidilla. Kokeellisessa osassa tutkittiin orgaanisen aineksen hapetusta käyttäen Fentonin reagenssia, jolloin katalyyttina reaktiossa toimii rautaionit (Fe2+ ja Fe3+) ja hapettimena vetyperoksidi. Hapetettavana jätevetenä käytettiin paperitehtaan hiomolta saatua kiertovettä, TMP-vettä. Hapetuskokeita tehtiin eri vetyperoksidin annoksilla ja katalyytin määrillä eri lämpötiloissa. Hapetuksen jälkeen näytteistä mitattiin kemiallinen hapenkulutus (COD), orgaanisen hiilen kokonaismäärä (TOC) sekä pH. Lisäksi näytteistä määritettiin nestekromatografilla (HPLC) tyypillisten välituotteiden, kuten oksaalihapon, muurahaishapon ja etikkahapon, määrät. Tehdyissä kokeissa COD-arvoja saatiin pienennettyä 50-88 % siten, että suodatetuissa näytteissä muutos oli suurempi kuin suodattamattomissa näytteissä. Lisäksi TOC-arvot laskivat 28-58 %. Tehdyissä kokeissa saatiin myös tuotettua välituotteina karboksyylihappoja, joista etikkahappoa ja oksaalihappoa tuotettiin suurimmat määrät. Myös muurahaishappoa ja meripihkahappoa saatiin tuotettua.