ABSTRACT Organic compounds present on industrial wastes are mostly resistant to conventional biological and chemical treatments. Textile industry has presented several environmental problems mainly related to the use and management of water resources. It has a high consumption of potable and underground water in its processes. These wastewaters are one of the most polluting of the industrial area. The Advanced Oxidation Process AOPs allow to decompose organic matter in a non-selectively way by the attack of •OH radicals. This work presents the characterization and application of several catalysts for real textile effluent treatment (from an industry dedicated to dyeing and finishing clothes; in Buenos Aires province).Three different iron catalysts are used: 1º) Synthesized in a laboratory, 2º) Waste from metallurgic industry and 3º) commercial steel wool. These are characterized using SEM/EDX. The effluent is characterized before and after treatment, where the degradation is following by measure of % COD, pH and Fe2+ content in solution by condition different of treatment. The effect of catalysts on the applied treatment is studied, which consists of an oxidation of organic matter by action of Fe species and H2O2 in solution, assuming a Fenton process a pH neutral. The results show that the three catalysts are efficient for use in the process of degradation of the real textile effluent. In all cases, the COD final values are suitable for discharge into a sewer system.

RESUMEN Los compuestos orgánicos presentes en efluentes industriales son en su mayoría resistentes a los tratamientos biológicos y químicos convencionales. La industria textil ha presentado notables problemas medioambientales vinculados principalmente al uso y la gestión del recurso hídrico, tiene un alto consumo de agua potable y subterránea en sus procesos. Sus aguas residuales son las más contaminantes de los sectores industriales. Las Procesos Avanzados de Oxidación (PAOs) permiten degradar dichos compuestos de forma no selectiva mediante el ataque de radicales •OH. En este trabajo se presenta la caracterización y aplicación de diferentes catalizadores para el tratamiento de un efluente textil real (proveniente de una empresa dedicada al teñido y acabado de prendas; ubicada en la provincia de Buenos Aires). Se utilizan tres catalizadores de Fe diferentes: 1°) Sintetizado en el laboratorio, 2°) Residuo proveniente de la industria metalúrgica y 3°) Lana de acero comercial. Los mismos se caracterizan por medio de SEM/EDX. El efluente es caracterizado antes y después del tratamiento, donde el seguimiento de la degradación se mide mediante el % DQO, pH y contenido de Fe2+en solución para diferentes condiciones de tratamiento. Se estudia el efecto de catalizadores en el tratamiento aplicado, el cual consiste en una oxidación de la materia orgánica por acción de las especies de Fe en solución y H2O2, dando un proceso Fenton a pH cercano a la neutralidad. Los resultados muestran que los tres tipos de catalizadores son eficientes para el proceso de degradación de un efluente textil reales, alcanzando valores de DQO finales aptos para la descarga en una colectora cloacal.

The characterization by mass spectrometry and the kinetic study of the thermal decomposition reaction of deuterated acetone diperoxide (dACDP) was studied in ethanol in the 140-165 ºC temperature range. The comparison with the non deuterated species (ACDP) was also made. The kinetic behavior observed for both compounds follows a pseudo first order kinetic law up to at least 86 % peroxide conversions. It could be observed that under the established experimental conditions, the dACDP decomposes ca. 1.2 times faster than the ACDP. The activation parameters were calculated for both peroxides and allowed to postulate a single process initial step, the unimolecular thermal decomposition through the O-O bond cleavage to form an intermediate biradical. The products of the acetone derived peroxides thermal decomposition support a radical-based decomposition mechanism. The changes in kinetic parameters between dACDP and ACDP were justified attending to differences in ring substituents sizes. A secondary inverse kinetic isotope effect is observed (kH/kD <1).

The thermal decomposition reaction of trans-3,6-dimethyl-3,6-diphenyl-1,2,4,5-tetraoxacyclohexane (acetophenone cyclic diperoxide, DPAF), in different solvents (methanol, 1,4-dioxane, acetonitrile and 2-propanol/benzene mixtures) in the initial concentration and temperature ranges of (4.2-10.5) x 10-3 M and 140.0 to 185.0 ºC, respectively, follows a pseudo first order kinetic law up to at least 70% DPAF conversion. An important solvent effect on the rate constant values, activation parameters (DH# and DS#) and reaction products obtained in different solvents is detected, showing that the reaction is accelerated in alcohols.

The thermal decomposition reaction of pinacolone diperoxide (DPP; 0.02 mol kg-1) in 2-methoxyethanol solution studied in the temperature range of 110.0-150.0 °C, follows a first-order kinetic law up to at least 50% DPP conversion. The organic products observed were pinacolone, methane and tert-butane. A stepwise mechanism of decomposition was proposed where the first step is the homolytic unimolecular rupture of the O-O bond. The activation enthalpy and activation entropy for DPP in 2-methoxyethanol were calculated (deltaH# = 43.8 ± 1.0 kcal mol-1 and deltaS# = 31.9 ± 2.6 cal mol-1K-1) and compared with those obtained in other solvents to evaluate the solvent effect.