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Previous issue date: 2014 === Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (Capes) === Funda??o de Amparo ? Pesquisa do estado de Minas Gerais (FAPEMIG) === A oxida??o de efluentes sint?ticos contendo os f?rmacos paracetamol (PCT) e dipirona (DPN), ambos analg?sicos largamente utilizados por humanos e animais foi conduzida pelos processos O3, O3/UV, H2O2/UV e H2O2/UV/O3 via rea??o direta (oz?nio molecular), indireta (radical hidroxila) e mista (O3/HO?) manipulando-se o pH do meio reacional. Essas subst?ncias tem grande resist?ncia aos processos convencionais de tratamento de efluentes e, assim buscam-se ferramentas mais eficientes para a degrada??o desses f?rmacos. A remo??o dos f?rmacos PCT e DPN nas amostras tratadas com os diferentes POA foi monitorada utilizando a t?cnica cromatografia l?quida de alta efici?ncia (HPLC). A quantidade total de compostos arom?ticos e o grau de mineraliza??o da mat?ria org?nica dissolvida foram avaliados por meio dos par?metros UV (254 nm), Demanda Qu?mica de Oxig?nio (DQO) e de Carbono Org?nico Total (COT). Al?m disso, a susceptibilidade a biodegradabilidade foi avaliada por meio da raz?o da DQO/COT. Os resultados experimentais mostraram que o tempo gasto para a degrada??o depende da natureza do f?rmaco, bem como do pH e do tipo de processo oxidativo. Verificou-se uma elevada percentagem de remo??o (95%) e um percentual moderado de mineraliza??o (35%) para os estudos utilizando os processos O3 (pH 12) e O3/UV. De um modo geral, verificou-se um aumento da biodegradabilidade das amostras tratadas para os diferentes tratamentos oxidativos. No caso dos processos H2O2/UV e H2O2/UV/O3 a remo??o dos f?rmacos foi alta, especialmente no caso do processo H2O2/ UV/O3 onde ap?s 45 min e dose de 200 ppm de per?xido obteve-se ?88% de remo??o dos f?rmacos. No caso do processo H2O2(800ppm)/O3/UV e para o f?rmaco PCT, verificou-se percentagens de remo??o de DQO e COT de 77% e 42%, respectivamente. J? para o f?rmaco DPN, os valores correspondentes obtidos foram de 70% e 68%, respectivamente. Analisando os resultados observou-se que a remo??o da DQO e do COT foi maior para os processos processo H2O2/UV/O3. Por outro lado, a maior remo??o das subst?ncias parentais (PCT e DPN) foi obtida utilizando o processo O3 (pH 12). A partir dos valores das constantes de velocidade em fun??o do pH estimou-se a contribui??o dos processos de oxida??o por via direta e indireta. De um modo geral, o estudo revelou que o uso dos presentes POA e/ou ozoniza??o pode constituir um processo de tratamento alternativo vi?vel para a remo??o/degrada??o dos f?rmacos PCT e DPN presente em ?guas contaminadas. === Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Qu?mica, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2014. === ABSTRACT
The oxidation of synthetic wastewaters containing the drugs Acetaminophen (PCT) and Dipyrone (DPN), which are analgesics of widespread use by the human being and animals, was carried out by means of the O3, O3/UV, H2O2/UV e H2O2/UV/O3 oxidative processes. The ?direct? oxidation process was promoted by action of the O3 (acidic solutions) while in the case of the ?indirect? processes the application of the Advanced Oxidation Processes (AOPs) has permitted the use of the hydroxyl radical (HO?) as the major oxidant. These substances are recalcitrant towards the conventional wastewater treatments and, therefore, the search for an efficient treatment for these effluents is of current interest. The removal of PCT and DPN in the treated samples using the different AOPs was monitored using the high performance liquid chromatography (HPLC) technique. The total amount of aromatics and the degree of mineralization of the dissolved organic matter were evaluated by means of the UV(254 nm) technique and the Chemical Oxygen Demand (COD) and Total Organic Carbon (COT) methods, respectively. In addition, biodegradability susceptibility was evaluated by means of the COD/TOC ratio. The experimental findings showed that the time spent for degradation depends on the nature of the drug, as well as on the pH and the type of the oxidative process. It was verified for the studies using the O3(pH 12) and O3/UV processes a high percentage of removal (95%) and a moderate percentage of mineralization (35%). On the whole, it was verified an increase in the biodegradability of the treated samples for the different oxidative treatments. In the case of the H2O2/UV and H2O2/UV/O3 processes the removal of PCT and DPN was high, especially in the case of the H2O2/UV/O3 where after 45 min and by using a peroxide dosage of 200 ppm a percentage of removal of ?88% was obtained. In the case of the H2O2(800ppm)/UV/O3 process and for PCT, it was verified percentages of removal for COD and COT of 77% and 42%, respectively. Accordingly, the corresponding values obtained for DPN were 70% and 68%, respectively. As a rule, the removal of COD and COT was higher for the H2O2/UV/O3 process. On the contrary, a higher removal (e.g., HPLC) of the parental substances (PCT and DPN) was obtained using the O3 (pH 12) process. In the case of the ozonation the contribution of the direct and indirect oxidation processes was evaluated from the values of the pseudo first-order rate constants obtained in the acidic and alkaline conditions. On the whole, the current study has revealed that the use of the present AOPs and/or ozonation can constitute a viable alternative treatment process for the removal/degradation of the PCT and DPN drugs present in contaminated waters.
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