Treatment of Indigo-Dyed Textile Wastewater Using Solar Photo-Fenton with Iron-Modified Clay and Copper-Modified Carbon

A heterogeneous photo-Fenton process was applied to treat aqueous solutions of indigo blue and textile wastewater using an iron-modified clay (Mt-Fe) and a copper-modified carbon (AC-Cu) as catalysts, the UV radiation source was the sunlight collected by a compound parabolic concentrator (CPC-2D). The treatments were conducted at pH 7.0 and 6.8 for the aqueous solutions and the textile wastewater, respectively, and different hydrogen peroxide concentrations and catalyst quantities were evaluated. The concentration of UV-A radiation collected by the CPC-2D was 54.29 +/- 0.71 W/m(2), with an applied energy of 97.36 kJ from the concentrator device. The indigo blue removal efficiencies for Mt-Fe and AC-Cu were 98% (3 h) and 99% (1.5 h), respectively, using 1.5 g of catalyst, 0.5 M of H2O2, and UV radiation. The color removal efficiency in the textile wastewater was 93% after 4 h of treatment using 1.5 g of AC-Cu, 0.5 M of H2O2, and UV radiation. The removal of dye and color was improved by using AC-Cu and UV radiation for both systems (the aqueous solutions and the textile wastewater), showing that Cu has an important catalytic activity. IR spectra showed a change after the oxidation of organic matter by heterogeneous photo-Fenton process, and the application of the UV radiation collected by CPC-2D played an important role in the heterogeneous photo-Fenton process.