Using photoactivated acetone for the degradation of Chlorazol Black in aqueous solutions: Impact of mineral and organic additives

Highlights: • Acetone-assisted UV-irradiation accelerated drastically the removal of Chlorazol Black (CB). • Methyl radical implication in the CB removal was confirmed by specific-radical scavengers. • The beneficial effect of acetone may be unaffected, decreased or suppressed by selected salts. • Ascorbic acid, as free radicals scavenger, completely quenched the positive effect of acetone. • Sucrose, glucose and humic acid slightly reduced the CB degradation rate. -- Abstract: This study examined the effect of different mineral and organic additives on the degradation of Chlorazol Black (CB, 25.5 μM) in aqueous media by UV/acetone process. Initially, it was found that acetone (50 mM)-assisted UV irradiation accelerated the CB removal within 30 min to 98% against 34% for the sole UV, presumably due to the implication of methyl radicals in the degradation process as confirmed by O₂ saturation and nitrite addition (as CH₃-specific scavengers). While NaCl and Na₂SO₄ have no impact on the degradation kinetics of CB upon UV/acetone process, NaHCO₃ and Na₂CO₃ slightly inhibited it and a relatively more inhibition was observed with NaNO₃ and KBr. The degradation performance was somewhat decreased in natural mineral water. On the other hand, ascorbic acid, as free radicals scavenger, at low concentration (0.1 mM) completely quenched the positive effect of acetone confirming the free radical mechanism on CB degradation. Besides, the implication of OH was excluded by adding 2‑propanol (up to 50 mM). Furthermore, the slight decrease in CB removal in the presence of sucrose, glucose and humic acid is a clear indication that UV/acetone process is a promising technique for removing organic dyes from environmental samples.