Cooperative Effects of Adsorption on Granular Activated Carbon and Hydroquinone-Driven Fenton Reaction in the Removal of Nonionic Surfactant from Aqueous Solution

Abstract

Abstract

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 97 mg g⁻¹ of hydroquinone adsorbed on GAC and concentrations of surfactant, H₂O₂, and iron (either Fe²⁺ or Fe³⁺) of, respectively, 1300, 450, and 9 mg L⁻¹. In the absence of carbon and hydroquinone, and with the same concentration of H₂O₂, conventional Fenton process required 300 mg 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.