The role of hydroxyl radicals for the decomposition of p-hydroxy phenylacetic acid in aqueous solutions

Degradation of the antibiotic sulfamonomethoxine sodium in aqueous solution by photo-Fenton oxidation

“…For example, degradation of SMMS declined from 98.5% to 92.2% when the concentration of H 2 O 2 was increased from 0.49 to 1.92 mmol/L in the photo-Fenton process. This phenomenon has been widely reported by many researchers [20,22,27,29]. This could be explained by a critical concentration of H 2 O 2 in the Fenton oxidation process.…”

“…In addition, H + could act as an OH scavenger. At high pH, ferric oxyhydroxides would precipitate and stop the reaction of Fe 3+ with H 2 O 2 to regenerate Fe 2+ , which would reduce the amount of ·OH [20,29]. Therefore, pH 4.0 was optimum for the photo-Fenton process, and resulted in a maximum degradation of SMMS of 98.5%.…”

“…In recent years, advanced oxidation processes (AOPs) have been identified as an attractive option for wastewater treatment, particularly in the case of contaminants that are difficult to remove or eliminate by conventional biological or physicochemical technologies [20][21][22][23]. AOPs are based on the generation of highly reactive and nonselective oxidant hydroxyl radicals (OH), which can oxidize a broad range of organic pollutants to CO 2 and H 2 O.…”

Mineralization of an azo dye Acid Red 14 by photoelectro-Fenton process using an activated carbon fiber cathode

“…Many studies have revealed that the solution pH can dramatically influence the Fenton degradation of organic compounds and at higher rates in the region 2.5-4, with an optimum at pH 3 [39]. At too high pH, the decomposition rate decreases because of the decrease of the free iron species in the solution, due to the formation of Fe(II) complexes and the precipitation of ferric oxyhydroxides [40]. When the pH is too low and the concentration of hydrogen ions is too high, it will slow down the formation of FeOOH 2+ , which consecutively causes the production rates of ferrous ions and hydroxyl radicals to decrease as well [41].…”

Degradation of dyes in aqueous solutions by the Fenton process

“…However, sludge generation and adsorbent regeneration are the principal weakness of these processes (Slokar and Majcen Le Marechal, 1998). The Fenton process that uses Fe 2+ to react with H 2 O 2 to generate OH with powerful oxidizing ability, one of the advanced oxidation processes (AOPs), has been proposed for the degradation of organic pollutants (Chen and Pignatello, 1997;Benitez et al, 2001;Huang et al, 2002), including some dye pollutants (Kang et al, 2002;Feng et al, 2003;Swaminathan et al, 2003).…”