Ultrasonic Destruction of Acid Orange 7: Effect of Humic Acid, Surfactants and Complex Matrices

Abstract

The ultrasonic degradation at 600 kHz of an azo dye, acid orange 7 (AO7), in the presence of various dissolved natural organic matters (humic acid and surfactants) and in environmentally relevant matrices (natural water and seawater) was investigated. Additionally, the dependence of AO7 degradation on several operating parameters was clarified. The obtained results showed that ultrasound completely destroyed AO7 in 90 min of treatment but only 10% of TOC was removed after a long irradiation time. Investigations using the radical scavengers tert-butyl alcohol and KI revealed that AO7 degradation proceeds through radical reactions occurring at the bubble-liquid interface. AO7 conversion was strongly affected by the operating conditions. While the degradation of the dye was not affected by the presence of humic acid, it was impacted negatively by the presence of surfactants. Replacing deionized water by natural water and seawater as real environmental matrices did not affect the degradation of the dye.

Removal of persistent textile dyes from wastewater by Fe(ii)/H2O2/H3NOH+ integrated system: process performance and limitations

“…Therefore, both processes are affected similarly by the presence of NOM. These outcomes, which are relatively well known regarding the impact of NOM on the performance of numerous ˙OH-based AOPs, 3,35,40,55 are ascribed to the quenching of hydroxyl radicals by NOM, in addition to the consumption of H 2 O 2 reagent by NOM. The rate constant of the ˙OH-NOM reaction is 2.5 × 10 4 M −1 s −1 .…”

“…Because of the ubiquitous presence of mineral salts and natural organic matter (NOM) in surface water and real wastewater effluents, [53][54][55] we decided to test the impact of NaCl, Na 2 SO 4 , NaNO 2 and NaNO 3 (as sources of chloride, sulfate, nitrate and nitrite ions) and humic acids, as the main constituents of NOM, 55 on the performance of the Fe(II)/H 2 O 2 /NaH 3 OH + ternary system toward the breakdown of BF (20 mM) at pH 3 using [Fe(II)] 0 ¼ 0.05 mM and [H 2 O 2 ] 0 ¼ [H 3 NOH + ] 0 ¼ 0.5 mM. Fig.…”

Protonated Hydroxylamine‐Assisted Iron Catalytic Activation of Persulfate for the Rapid Removal of Persistent Organics from Wastewater

“…[56][57][58] Their effect is investigated herein by using NaCl, Na 2 SO 4 , NaNO 2 , and NaNO 3 (as sources of chloride, sulfate, nitrate, and nitrite ions) and humic acids as principal constituents of NOM. [58] Figure 6 shows the effect of 1 to 10 × 10 −3 m of each salt, whereas Figure 7 shows the influence of 5 to 20 mg L −1 of NOM on the degradation of pararosaniline in the presence and absence of hydroxylamine. As seen from Figure 6, excepting the case of 10 × 10 −3 m of sulfate (Figure 6b), the degradation efficiency of pararosaniline in the presence of H 3 NOH + is clearly unaffected by the existence of mineral anions, even though Cl − , NO 2 − , and NO 3 − are known as radical scavengers (see Table 3).…”

Characterization and application of a 1700-kHz acoustic cavitation field for water decontamination: a case study with toluidine blue

“…However, due to the rapid occurrence of bubble-collapse event (~ 0.17 µs at 1700 kHz and 15 W), • OH diffusion from the acoustic bubble could not be completely suppressed, and this why FA addition at 1 g/L did not yield further reduction as compared to 0.5 g/L. Indeed, an early analysis of acid orange 7 (AO7) degradation in the presence of high concentrations of interfacial agents, i.e., Triton X-100 and Tween 20 surfactants, confirmed the existence of an optimum dose for these additives above which no further reduction in the degradation rate of AO7 was observed (Hamdaoui and Merouani 2017). The optimum reductive dose of surfactants on the production rate of H 2 O 2 was also reported (Yim et al 2002).…”