Degradation of azo dye Acid black 1 using low concentration iron of Fenton process facilitated by ultrasonic irradiation

A combination of ultrasonic and low concentration iron (<3 mgL ^‑1) of Fenton process (US/Fenton) has been used to treat wastewater containing Acid black 1 (AB1). The results show that the oxidation power of low concentration iron of Fenton could be significantly enhanced by ultrasonic irradiation. The degradation of AB1 in aqueous solution by US/Fenton can receive better results compared with either Fenton oxidation or ultrasonic alone. Many operational parameters, such as ultrasonic power density, the pH value, the Fe ²⁺ dosage, the H ₂O ₂ dosage, AB1 concentration and the temperature, affecting the degradation efficiency were investigated. Also, the effects of various inorganic anions (such as Cl ^‑, NO 3 - , CO 3 2 - , etc.) on the oxidation efficiency of US/Fenton were studied. Under the given test conditions, 98.83% degradation efficiency was achieved after 30 min reaction by US/Fenton. The effect of various inorganic anions was in the following decreasing order: SO 3 2 - > CH 3 COO - > Cl - > CO 3 2 - > HCO 3 - > SO 4 2 - > NO 3 - . The results show that the US/Fenton can be an effective technology for the treatment of organic dyes in wastewater.