Insights into oxidation of pentachlorophenol (PCP) by low-dose ferrate(VI) catalyzed with α-Fe2O3 nanoparticles

In this study, the catalytic performance of α-Fe 2 O 3 nanoparticles (nα-Fe 2 O 3 ) in the low-dose ferrate (Fe(VI)) system was systematically studied through the degradation of pentachlorophenol (PCP). Based on the established quadratic functions between nα-Fe 2 O 3 amount and observed pseudo first-order rate constant ( k obs ), two linear correlation equations were offered to predict the optimum catalyst dosage and the maximum k obs at an applied Fe(VI) amount. Moreover, characterization and cycling experiments showed that nα-Fe 2 O 3 has good stability and recyclability . According to the results of reactive species identification and quenching experiment and galvanic oxidation process , the catalytic mechanism was proposed that Fe(III) on the surface of nα-Fe 2 O 3 may react with Fe(VI) to enhance the generation of highly reactive Fe(IV)/Fe(V) species, which rapidly extracted a single electron from PCP molecule for its further reaction. Besides, two possible PCP degradation pathways, i.e., single oxygen transfer mediated hydroxylation and single electron transfer initiated polymerization were proposed. The formation of coupling products that are prone to precipition and separation was largely improved. This study proved that nα-Fe 2 O 3 can effectively catalyze PCP removal at low-dose Fe(VI), which provides some support for the application of Fe(VI) oxidation technology in water treatment in the context of low-carbon emissions.