Title: Pre-treatment of refinery spent caustic by Fenton's reaction

Authors: M.T. Orta de Velásquez; A.G. Martínez; H.A.F. Matamoros; I. Yañez-Noguez; I. Monje-Ramirez

Addresses: Instituto de Ingeniería, Universidad Nacional Autónoma de México (UNAM), 70-472 Ciudad Universitaria, 04315, México, D.F, México ' Comisión Federal para la Protección contra Riesgos Sanitarios (COFEPRIS), Perlillar 110, Col. Progreso Nacional 07600 México, D.F, México ' Instituto Mexicano del Petróleo (IMP), 152 Eje central Lázaro Cárdenas, 07730, México, D.F., México ' Instituto de Ingeniería, Universidad Nacional Autónoma de México (UNAM), 70-472 Ciudad Universitaria, 04315, México, D.F., México ' Instituto de Ingeniería, Universidad Nacional Autónoma de México (UNAM), 70-472 Ciudad Universitaria, 04315, México, D.F., México

Abstract: Experimental results for applying Fenton oxidation as a pre-treatment method for spent caustic are presented. A combination of dilution and Fenton's reaction is proposed as a method for reduction of total COD and total phenols in spent caustics. This approach was used to obtain a decrease in total phenols from 5,200 mg/L to less than 130 mg/L. The greatest removal occurred within a pH range of 2.7-6, with a (Fe³⁺/H₂O₂) mass ratio of 1 : 3, Fe³⁺ concentration of 2.85 g/L and a stoichiometric w/w H₂O₂/COD ratio of 0.3. Under these conditions, and over 30 min reaction time, 99.5% of total phenols and 95.5% of COD were removed, while sulphides and mercaptans decreased to <0.1 mg/L.

Keywords: chemical oxidation; Fenton oxidation; spent caustic; coagulation; refinery waste; pre-treatment; total COD; chemical oxygen demand; total phenols; sludge; wastewater treatment.

DOI: 10.1504/IJEE.2012.050806

International Journal of Environmental Engineering, 2012 Vol.4 No.3/4, pp.383 - 393

Published online: 31 Dec 2014 *

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