Débora V. Franco

A screening method for detection of hexavalent chromium levels in soils

-1 was used throughout. For the different types of soils studied, more than 75% of the fortified soluble Cr(VI) were recovered for all levels of spike tested for both the proposed and standard methods. Recoveries of 83 and 99% were obtained for the proposed and the standard methods, respectively, taking into account the analysis of a heavily contaminated soil sample.

Decolorization, Degradation and Toxicity of Dye Solutions Containing Orange Cassafix ® CA-2R after UV/H2O2 Oxidation under Laminar Flow Conditions

Abstract Dye solutions containing Orange Cassafix® CA-2R were treated using the UV/H2O2 advanced oxidation process under laminar flow conditions characterized by Reynolds numbers in the range of 322-295 using an annular photochemical reactor. The initial dye concentration [dye]0 and the initial hydrogen peroxide concentration [H2O2]0 were shown to affect the percentage of decolorization (P.D.) as a function of the irradiation time (t). A maximum P.D. of 90% was achieved at t > 120 min, [H2O2]0 = 800 ppm and [dye]0 = 300 ppm. The total organic carbon (TOC) depends on [H2O2]0 and [dye]0, while a maximum TOC reduction of 45% was achieved when t > 100 min, [H2O2]0 = 800 ppm and [dye]0 = 200 ppm. The toxicity of the treated samples was changed from 38 to 79%, depending on the [H2O2]0/[dye]0 ratio. A minimum electric energy consumption of 0.383 kW h m-3 order-1 was obtained at the [dye]0/[H2O2]0 ratio of 0.25.