Degradation of Acid Orange 7 by persulfate activated with zero valent iron in the presence of ultrasonic irradiation

• Published in: Separation and purification technology 2014-02, Vol.122, p.41-46
• Main Authors: Wang, Xue, Wang, Liguo, Li, Jiangbo, Qiu, Juanjuan, Cai, Chun, Zhang, Hui
• Format: Article
• Language: English
• Subjects: Acid Orange 7; Decolorization; Heterogeneous activation; Sulfate radicals; Ultrasound; Zero valent iron
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2013.10.037

•The combination of ultrasound with zero valent iron activated persulfate process was proposed.•Decolorization of Acid Orange 7 under different systems was carried out.•The effect of operating parameters on the decolorization by US/Fe0/PS process was investigated.•The changes of UV–vis spectra and TOC during the treatment were monitored. The removal of Acid Orange 7 by zero-valent iron (Fe0) activated sodium persulfate (Na2S2O8, PS) in the presence of ultrasonic irradiation (US) was performed in this study. The effects of persulfate concentration, zero valent iron addition, ultrasonic power and initial pH on the decolorization rate of Acid Orange 7 were investigated. The results showed that the decolorization rate increased with an increase in persulfate concentration from 0.1 to 0.5g/L, an increase in zero valent iron amount from 0.1 to 0.5g/L, and an increase in ultrasonic power from 40 to 60W. But further increase in persulfate concentration, zero valent iron addition and ultrasonic power would result in an unpronounced increase of decolorization rate. The optimal initial pH for decolorization was found as 5.8. The maximum decolorization efficiency of 96.4% was achieved within 20min with persulfate concentration of 0.3g/L, zero valent iron concentration of 0.5g/L, initial pH value of 5.8 and ultrasonic power of 60W.