Ypatingą pavojų aplinkai kelia beveik visi komerciniai halogeninti angliavandeniliai, ypač mažos molekulinės masės C1-C4 chlorinti alkanai ir alkenai, kurie plačiai vartojami kaip tirpikliai, riebalus šalinančios medžiagos. Todėl buvo domėtasi naujais vandens valymo būdais, kur chlorintiems organiniams dariniams šalinti naudojama metalinė geležis ir jos atliekos. Tyrimo metu paaiškėjo, kad ruošiant geležį reakcijoms, dalis geležies yra prarandama. Dalis išvalytos ir aktyvuotos geležies taip pat išsieikvoja reakcijų su chlororganinėmis medžiagomis metu. Trichlormetano ir 1,1,2 – trichloretileno skaidymui metaline geležimi svarbi yra jų vandeninių tirpalų terpės pH, kadangi 1,1,2 – trichloretilenas geriausiai redukavosi esant pH 3,5, o trichlormetanas – pH 4. Šių vandeninių tirpalų terpių pH po apdorojimu metaline geležimi nepasikeitė. H+ jonai arba nedalyvavo reakcijoje arba jų nedidelis kiekis buvo reikalingas nuolatos aktyvuoti Fe paviršių. Chloro atomus turintys organiniai junginiai geriau šalinami iš tirpalo atvirame inde, kuomet deguonis iš oro lengvai difunduoja į valomą tirpalą. Numanoma, tai vyksta todėl, kad fotocheminių procesų metu skiriasi vienas aktyviausių laisvųjų radikalų - OH∙ hidroksido radikalas. Jis skatina arba chlorintų organinių junginių skilima pagal Fentono reakcijos mechanizmą, arba šių junginių oligomerizaciją. Trichlormetano vandeninio tirpalo ChDSK2Cr2O7 reikšmė po 9 eksperimento valandų lygi 35 mg O2/l, o 1,1,2 – trichloretileno apdoroto geležimi... [toliau žr. visą tekstą] / A huge threat to the environment is done by almost all commercial halogen hydrocarbons, especially low mass C1-C4 alkans and alkens including chlorine atoms, which are widely used as solvents, agents eliminating fat. Due to this reason it was interested in new ways of water cleaning where metal iron was used to eliminate chlororganic compounds. Carrying out the research it was found out that preparing iron for the reactions a part of iron is lost. A part of cleaned and activated iron also wears out during the reactions with chlororganic substances. The pH environment of their hydrous solutions is important to dissociate threecholrmethan and 1,1,2–threechloroethylene with metal iron because 1,1,2-threecholrethylene revivified the most when pH was 3.5 and threechloromethan – pH 4. The pH environment of their hydrous solutions with metal iron didn’t change. Either H+ ions didn’t participate in the reaction or their small amount was necessary to constantly activate Fe surface. Organic compounds including chlorine atoms is better eliminated from the solution in an open dish when oxygen easily diffuse from the air into the cleaning solution. It is believed it happens so because during photochemical processes one of the most active free radicals – OH∙ hydroxide radical – dissolves. It stimulates either the fragmentation of chlororganic compounds according to Fenton’s mechanism of reaction or the oligomerisation of these compounds. The meaning of threechloromethan hydrous solution... [to full text]

Submitted by ALAN LIMA VIEIRA null (alan.vieira@hotmail.com) on 2016-03-23T00:12:16Z No. of bitstreams: 1 Dissertação ALAN LIMA VIEIRA.pdf: 3306402 bytes, checksum: bb2ced7b7ded44be46ee02b3cbf5db60 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-03-23T13:36:36Z (GMT) No. of bitstreams: 1 vieira_al_me_araiq.pdf: 3306402 bytes, checksum: bb2ced7b7ded44be46ee02b3cbf5db60 (MD5) / Made available in DSpace on 2016-03-23T13:36:36Z (GMT). No. of bitstreams: 1 vieira_al_me_araiq.pdf: 3306402 bytes, checksum: bb2ced7b7ded44be46ee02b3cbf5db60 (MD5) Previous issue date: 2016-03-04 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Estabelecer procedimentos simples, rápidos, eficientes e com preparo de amostras de baixo custo para determinar elementos em amostras de carne é um aspecto relevante para fins nutricionais e de saúde. Por esta razão, um sistema de digestão com aquecimento condutivo em frasco fechado (CHDS), foi avaliado recentemente para a decomposição de amostras “in natura” de músculo, fígado e rim (bovino, suíno e frango) visando a determinação de macronutrientes (Ca, Mg, Na, K, S e P), micronutrientes (Cu, Fe, Mn, Mo, Se e Zn) e contaminantes inorgânicos (As, Cd, Cr e Pb) por espectrometria de emissão óptica com plasma acoplado indutivamente (ICP OES) e espectrometria de massas com plasma acoplado indutivamente (ICP-MS). O aperfeiçoamento feito no CHDS foi planejado para melhorar a segurança, a praticidade e a robustez do sistema. Entre elas destaca-se a adaptação de um pistão a gás na tampa do gabinete de digestão; isolamento dos frascos no interior do gabinete de digestão; tampa de Teflon com sistema simples de alívio de pressão ao fim da decomposição sem manuseio do frasco. A precisão foi avaliada analisando três materiais de referência certificados digeridos pelo CHDS. As recuperações para Ca, Cu, Fe, Mg, Mn, Na, K, S, P e Zn determinados por ICP OES, variaram entre 85 a 106%. Para As, Cd, Cr, Mo, Pb e Se determinados por ICP-MS, foram obtidas recuperações entre 92 a 110%. A eficiência da digestão também foi avaliada pela determinação do teor de carbono residual, que variou de 10 a 12% m m-1. Quando as amostras de carne foram digeridas usando o CHDS, os resultados para Ca, Cu, Fe, Mg, Mn, Na, K, S, P e Zn determinados por ICP OES e para As, Cd, Cr, Mo, Pb e Se determinados por ICP-MS foram concordantes com aqueles obtidos após digestão ácida assistida por radiação micro-ondas em frasco fechado (MW-AD). Ao utilizar o CHDS, os limites de quantificação foram similares aos obtidos com a MW-AD para todos os analitos. O CHDS é capaz de digerir 800 mg de amostra de carne “in natura” utilizando 2 mL de HNO3 e 1 mL H2O2. O procedimento proposto foi capaz de atender a Instrução Normativa da Secretária de Defesa Agropecuária (SDA) nº 13 que trata do monitoramento de resíduos e contaminantes em carnes para As, Cd e Pb. Os resultados obtidos neste estudo estendem as aplicações do CHDS para amostras com maior teor de gordura, tais como músculo, fígado e rim. Este sistema de digestão simples e de baixo custo pode ser utilizado para preparar amostras para determinação subsequente de um grande número de elementos por espectrometria de ICP, incluindo espécies voláteis, tais como, As, Cd e Se. / Establishing simple, fast, efficient and low-cost sample preparation procedures to determine elements in meat samples is a relevant aspect for nutritional and health purposes. For this reason, the recently proposed closed-vessel conductivelyheated digestion system (CHDS) was evaluated for the decomposition of muscle, liver and kidney (cattle, pigs and chickens) samples fresh aiming for the determination of macronutrients (Ca, Mg, Na, K, S and P), micronutrients (Cu, Fe, Mn, Mo, Se and Zn) and inorganic contaminants (As, Cd, Cr and Pb) by inductively coupled plasma optical emission spectrometry (ICP OES) and inductively coupled plasma mass spectrometry (ICP-MS). The optimization of the CHDS was planned to improve safety, practicality and robustness such as adaptation of a gas piston in the digestion cabinet cover, isolation of vessels inside the digestion cabinet and a Teflon cap with a simple pressure relief system in the end of the decomposition without handling the vessel. The accuracy was evaluated by analyzing three certified reference materials digested by the CHDS. Recoveries for Ca, Cu, Fe, Mg, Mn, Na, K, S, P and Zn determinations by ICP OES varied from 85 to 106%. For As, Cd, Cr, Mo, Pb and Se determinations by ICP-MS, recoveries within the 92-110% were obtained. The digestion efficiency was also evaluated by determining the residual carbon content, which varied from 10 to 12% m m-1. When fresh meat samples were digested using the CHDS, results for Ca, Cu, Fe, Mg, Mn, Na, K, S, P and Zn determinations by ICP OES and for As, Cd, Cr, Mo, Pb and Se determinations by ICP-MS were in agreement with those obtained after closed-vessel microwave-acid digestion (MW-AD). When using the CHDS, limits of quantification were similar to those obtained with the MW-AD for all analytes. The CHDS enabled the digestion of 800 mg of fresh meat with 2 mL of HNO3 and 1 ml of H2O2. The proposed procedure was able to attend the normative instruction of agricultural defense secretary SDA N°. 13 for As, Cd and Pb. The results obtained in this study extend the applications of the CHDS to samples with higher contents of fat such as muscle, liver and kidney. This simple and low-cost digestion system can be used to prepare samples for subsequent determination of a large number of elements by ICP spectrometry, including volatile species such as As, Cd and Se.

Šiame darbe yra aprašomi lengvai biologiškai skaidomų organinių teršalų koncentracijos Palangos miesto nuotekose atskirais metų laikotarpiais bei Visagino miesto nuotekose tyrimai. Tyrimams nuotekos buvo imamos prieš biologinį valymą, o veiklusis dumblas – iš veikliojo dumblo reaktoriaus pabaigos. Tyrimai atlikti VGTU Vandentvarkos katedros ir UAB „Palangos vandenys“ laboratorijose. Siekiant įvertinti teršalų bei technologinių parametrų kitimą bei jų įtaką nuotekų išvalymo rodikliams, buvo surinkti ir statistiškai apdoroti Palangos ir Visagino nuotekų tyrimų rodikliai. Analizuota nuotekų parametrų priklausomybė, teršalų koncentracijų kaita, nuotekų valymo efektyvumas ir jų įtaka biologiniam fosforo šalinimui. Ištirtos lengvai biologiškai skaidomų organinių teršalų koncentracijos. Gauti rezultatai palyginti su anksčiau VGTU Vandentvarkos katedroje atliktų magistrantų nuotekų tyrimų rezultatais. / It is the investigations for determination of concentration of easily biodegradable organic matter in wastewater of Palanga and Visaginas towns. Wastewater for investigations have been taken before biological treatment, and active sludge - from the end of active sludge reactor. The investigations were carried out at Water Management Department of Vilnius Gediminas Technical University and UAB "Palangos vandenys" laboratories. The indicators of investigations of Palanga and Visaginas wastewater were collected and statistically processed in order to evaluate alteration of technological parameters and their influence to indicators of wastewater cleaning. It was analysed the relationship between various parameters in order to find out their influence for the efficiency of biological phosphorus removal. It was studied easily biodegradable organic pollutant concentrations too. The results are compared with previously results of investigations, made by postgraduates of Water Management Department of Vilnius Gediminas Technical University.