Cooperative effects of adsorption on granular activated carbon and hydroquinone-driven fenton reaction in the removal of nonionic surfactant from aqueous solution

Fenton oxidation of the nonionic surfactant Brij 35 was enhanced by the effect of 1,4-hydroquinone adsorbed on granular activated carbon (GAC). The procedure allowed 90%-94% surfactant removal after 24 h at pH= 2.7-3.0, using 97mg g- 1 of hydroquinone adsorbed on GAC and concentrations of surfactant, H2O2, and iron (either Fe2 + or Fe3 + ) of, respectively, 1300, 450, and 9mg L- 1. In the absence of carbon and hydroquinone, and with the same concentration of H2O2, conventional Fenton process required 300mg L- 1 of Fe(II) to obtain 85% removal of Brij 35. Quinone-loaded carbon was effectively recycled until surfactant removal decreased to 50%-60%. Only 3% of hydroquinone was desorbed from GAC to the aqueous solution, and about 40% of the dissolved fraction was degraded to low-molecular-weight organic acids. This is the first description of a Fenton process performing the recycling of a redox-active organic compound adsorbed on GAC, with the aim of decreasing the amount of iron salt utilized in the conventional Fenton reaction.