Ozonation of 1,2-dihydroxybenzene in the presence of activated carbon

Abstract

This work aims at obtaining experimental data on ozonation of 1,2-dihydroxybenzene (DHB) in the presence of activated carbon, with a view to assessing possible changes in its surface chemical structure and adsorption capacity. Experiments were conducted in a 0.5 L reactor, loaded with 2 g Filtrasorb 400 granular activated carbon, and 1-5 mM DHB aqueous solution at pH 2-8. Ozone gas was generated with an Ozocav generator, and fed into the reactor for a given exposure time, in the range 0.5-240 min, at 25 degrees C and 1 atm. After each run, liquid and activated carbon samples were taken for chemical assays. Soluble organic groups present on the active carbon surface were desorbed and analysed by GC-MS and HPLC. Activated carbon chemical surface properties were analysed using TPD, FT-IR, and XPS techniques. Reactions between ozone and adsorbed DHB were shown to be fast, leading to formation of C-6, C-4 and C-2 by-products. Oxygenated surface groups, particularly, COOH and C = O, increased as a result of ozonation.

Ozonation of benzothiazole saturated-activated carbons: Influence of carbon chemical surface properties

“…Indeed, activated carbon presents a large surface area where benzothiazoles could adsorb [7,8], while ozone readily destroys adsorbed aromatic molecules, helping to regenerate the activated carbon adsorption capacity [9]. In this combined treatment, activated surface groups may be responsible for catalytic effects found in ozonation of toxic organic contaminants in presence of activated carbon [10][11][12]. However, the mechanism of gaseous ozone regeneration of activated carbon adsorption column has not been fully elucidated nor the influence of chemical surface properties on the oxidation of adsorbed organic pollutants has been analysed.…”

AC/O3-BAC processes for removing refractory and hazardous pollutants in raw water

“…AC can initiate radical-type chain reactions that proceed in solution and accelerate the transformation of ozone into secondary oxidants, such as hydroxyl radical ( • OH) [8]. It was proved that ozonation of phenols [9], 1,2-dihydroxybenzene [10] and 1,3,6-naphthalene-trisulphonic acid [11] was enhanced in the presence of AC, probably due to catalytic effects provided by active surface groups. AC presents a large surface area where ozone and organic pollutants could be adsorbed and react.…”

Impacto del tratamiento con ozono sobre las propiedades superficiales del carbón activado

“…La utilización combinada de ozono y carbón activado en un mismo proceso de tratamiento ha sido identificada en los últimos años como una opción atractiva para destruir compuestos orgánicos tóxicos [6][7][8][9][10][11][12][13]. Se ha demostrado que la combinación del alto poder oxidante del ozono y la alta capacidad de adsorción del carbón activado permite una efectiva eliminación de los contaminantes orgánicos de alta toxicidad y baja biodegradabilidad [6][7][8][9][10][11][12][13].…”

“…Se ha demostrado que la combinación del alto poder oxidante del ozono y la alta capacidad de adsorción del carbón activado permite una efectiva eliminación de los contaminantes orgánicos de alta toxicidad y baja biodegradabilidad [6][7][8][9][10][11][12][13]. Además, se ha reportado que dicho proceso elimina la actividad mutagénica de compuestos orgánicos tóxicos [14][15].…”

“…En el proceso de tratamiento combinado ozonocarbón activado se ha constatado que el ozono modifica la composición química de los grupos superficiales del carbón activado [7]. Sin embargo, no se han identificado plenamente los mecanismos de las reacciones involucradas en este sistema heterogéneo.…”