The superior decomposition of 2,4-Dinitrophenol under ultrasound-assisted Fe₃O₄@TiO₂ magnetic nanocomposite: Process modeling and optimization, Effect of various oxidants and Degradation pathway studies

ABSTRACT

In the present study, the ultrasound-assisted Fe₃O₄@TiO₂ magnetic nanocomposite was employed to catalytic oxidation of 2,4-Dinitrophenol. The catalyst features were characterised by SEM, TEM, XRD, BET, FTIR, VSM, DLS and TGA techniques. The effect of operational parameters i.e. pH, catalyst amount, 2,4-Dinitrophenol concentration and ultrasound power on DNP removal was examined and optimised in terms of sono-catalytic degradation system using RSM-based CCD approach. Over 91.45% of DNP were removed by Fe₃O₄@TiO₂ /US system (FTU) under optimum conditions within 30 min and the mineralisation degree was found to be 73% and 64.2% based on COD and TOC, respectively. Quenching experiments confirmed that O^2•- is dominant radical species in degradation process. FTU system was more successful in activation of S₂O₈^2- than IO₄⁻ and H₂O₂. Based on GC-MS analyses, the possible decomposition pathway was proposed. AOS and COS analyses indicated that FTU system can improve the bioavailability of DNP. The effect of CO₃²⁻ on DNP degradation was more complicated than other anions. Fe₃O₄@TiO₂ could keep its performance to at least the 5^th cycle while Fe and Ti leaching was negligible. The performance of FTU system for DNP treatment under real conditions was tested and promising results were achieved.

KEYWORDS:

• Ultrasound-assisted magnetic degradation
• modelling and optimisation
• 2,4-dinitrophenol
• degradation pathway
• various oxidants effects

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No potential conflict of interest was reported by the author(s).

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Funding

This work was supported by the Iran University of Medical Sciences [1400-1-61-21259].