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Activated carbon as catalyst for microwave-assisted wet peroxide oxidation of aromatic hydrocarbons

Garcia-Costa, Alicia L., Lopez-Perela, Lucia, Xu, Xiyan, Zazo, Juan A., Rodriguez, Juan J., Casas, Jose A.
Environmental science and pollution research international 2018 v.25 no.28 pp. 27748-27755
activated carbon, adsorption, benzene, catalysts, hydrogen peroxide, hydroxylation, microwave treatment, naphthalene, oxidation, pollutants, toluene, toxic substances, wastewater, xylene
This paper addresses the removal of four aromatic hydrocarbons typically found in petrochemical wastewater: benzene (B), toluene (T), o-xylene (X), and naphthalene (N), by microwave-assisted catalytic wet peroxide oxidation (MW-CWPO) using activated carbon (AC) as catalyst. Under the studied conditions, complete pollutant elimination (B, 1.28 mM; T, 1.09 mM; X, 0.94 mM; and N, 0.78 mM) was achieved, with more than 90% TOC removal after only 15-min reaction time, working at 120 °C, pH₀ = 3, AC at 1 g L⁻¹, and H₂O₂ at the stoichiometric dose. Furthermore, in the case of toluene, naphthalene, and xylene, the hydroxylation and breakdown of the ring is very rapid and toxic intermediates were not detected. The process follows two steps: (i) pollutant adsorption onto AC followed by (ii) adsorbed compounds oxidation. Thus, MW-CWPO with AC as catalyst appears a promising way for a fast and effective process for B, T, X, and N removal in aqueous phase.