Photochemical Treatment of Blue-Indigo using TiO2-Sunligth System in Heterogeneous Conditions.†

Abstract

: Ecuador is one of the countries in the Latin American region with a high textile production. However, chemical treatment strategies in the Ambato, Tungurahua and Quito areas are inefficient and not systematically applied, and the volumes of dyes and pigment-type contaminants generate serious environmental problems. The treatments of indigo textile wastewater and related indigo derivatives are very complex. Taking these into consideration, a simple photochemical protocol in heterogeneous conditions was developed, for degrading “blue-indigo” (Ambato textile group) in solution, using TiO 2 (Degussa P25, with a purity of ≈ 99% and BET surface area 50 ± 15 m 2 /g) and solar light at lab scale. The photocatalytic oxidation of “blue-indigo” in aqueous solution was assessed by solar irradiation, in the presence of TiO 2 particles. The effect of indigo concentrations, pH and TiO 2 loading for maximum degree of degradation were evaluated. The mineralization of “blue-indigo” was reported by measuring COD-i and COD-f of the solution that was irradiated with sunlight under optimized conditions. The results enable the re-designing of strategies for controlling contamination in textile wastewaters in eco-sustainable conditions for Ecuador.