Effects of operating parameters on sonochemical decomposition of phenol

Sonochemical destruction of nonylphenol: Effects of pH and hydroxyl radical scavengers

“…It was found that the reaction was extremely slow in the control (pH 6), 2.2 times faster at pH 3.0 and 4 times faster at pH 10.8. Acceleration by acidification must be due to enriched hydrophobicity of the molecule by protonation of the phenolic moiety [23]. Further acceleration by alkalinization, however, is a more complex phenomenon that may be related to structural properties of the compound and more cautiously to its potential hydrolysis, which occurs frequently during its metabolic and enzymatic cleavage by wheat cells and by some aquatic organisms [24,25].…”

Ultrasonic degradation of Rhodamine B in aqueous solution: Influence of operational parameters

“…Hence, the efficient treatment of organic water contaminants with molecular structure like RB with ultrasonic technique should be performed in acidic medium. Decreasing of decolorization rate by increase of pH is due to dissociation of RB at -COOH sites, so that retards it to diffuse into the reactive zone (bubble-liquid interface), where uncombined • OH concentration is maximum [9].…”

“…The hydroxyl radicals are short-lived and highly reactive chemical species which react non-selectively with organic matter present in wastewater. Among many ways of producing hydroxyl radicals in AOPs, ultrasound is a novel method [9]. In recent years considerable interest has been shown on the application of ultrasonic degradation for the removal of hazardous contaminants from water [9][10][11].…”

“…Among many ways of producing hydroxyl radicals in AOPs, ultrasound is a novel method [9]. In recent years considerable interest has been shown on the application of ultrasonic degradation for the removal of hazardous contaminants from water [9][10][11]. Sonochemical degradation methods are relatively new and involve exposing aqueous solutions containing the organic pollutant to ultrasound and the effect of different operational * Corresponding author.…”

Catalysis of advanced oxidation reactions by ultrasound: A case study with phenol

“…During sonication, however, maximum rate of phenol removal was accomplished at highly acidic pH due to the fact phenol exists mainly in molecular form at this condition, which has a much higher liability to approach the cavity bubbles (or the interfacial area), where OH radical concentration is very high, than the disassociation product-phenolate ion that forms at alkaline pH [10].…”