Ultrasound-assisted mineralization of organic contaminants using a recyclable LaFeO and Fe/persulfate Fenton-like system.

A recyclable heterogeneous catalyst has been successfully developed for application in a Fenton-type advanced oxidation process without adding external HO. LaFeO was prepared from Fe(NO)·9HO and La(NO)·6HO by a simple sol-gel method and its catalytic efficiency was evaluated for mineralization of 4-chlorophenol using a Fenton-like process. The mineralization process was carried out under ultrasonication in presence of heterogeneous LaFeO catalyst with HO that was produced during ultrasonication. The mineralization process was monitored through total organic carbon (TOC) analysis. Very importantly, utmost 5-fold synergism was evidenced by the ultrasound mediated LaFeO-catalyzed system. Besides, more than twofold synergism was observed by combining the ultrasound assisted LaFeO catalytic process and potassium persulfate (KPS) assisted advanced oxidation process. It is worth to mention that complete mineralization (∼96%) of 4-chlorophenol (initial concentration of 1.25×10M) was observed within 1h in the presence of LaFeO (0.5gL) and KPS (1.0mmol) under ultrasonication (40kHz). Even after four cycles, the activity of LaFeO remained intact which proved its recyclability. Extremely reusable heterogeneous LaFeO catalyst makes the system more interesting from both economic and environmental points of view.