Dégradation d’un polluant organique par un système ternaire Fe(II)/Persulfate de potassium/Hydroxylamine

Abstract

Abstract Advanced oxidation processes (AOPs), which involve the activation of oxidant precursors (e.g. hydrogen peroxide, persulphate, chlorine) as well as the generation of reactive radical species, have emerged as promising alternatives for the treatment of organic pollutants. The current work was conducted to estimate the efficiency of the Fe(II)/KPS/HA ternary system in the removal of the dye Chlorzol Black (CB). Furthermore, a comparison between the Fe(II)/KPS system and the HA- intensified system was examined. Fe(II) can activate persulphate to generate sulfate radicals (SO4•− ) and hydroxyl radicals (HO•) in the presence of HA. Radical generation was clearly enhanced by hydroxylamine in solution, as a result of the efficiency of the Fe(III)/Fe(II) reaction promoted by HA. The study of the effects of treatment conditions, such as pH, initial concentration of CB, KPS, Fe(II) and HA was examined to estimate the performance of CB removal by Fe(II)/KPS/HA (T =25°C; [CB]=10μM; [Fe(II)] =0.05mM; [KPS]=1mM; [HA]=1mM); pH=3.) (SO4•−) and (HO•) radicals contributed comparably to CB degradation, as confirmed by radical scavenging tests. Moreover, the addition of inorganic salts in large amounts, such as NaCl and NaNO₂, leads to a decreased efficiency of the Fe(II)/KPS/HA process. On the other hand, NaNO₃ significantly accelerates the CB degradation rate. Finally, humic acids presence reduced the degradation performance. The removal of Chlorazol Black was monitored by UV/Vis spectrophotometry and its mineralization is evaluated by measuring total organic carbon (TOC). The findings indicate that the best oxidation system used is Fe(II)/KPS/HA.