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

In this study, the catalytic performance of alpha-Fe2O3 nanoparticles (n alpha-Fe2O3) in the low-dose ferrate (Fe(VI)) system was systematically studied through the degradation of pentachlorophenol (PCP). Based on the established quadratic functions between n alpha-Fe2O3 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 n alpha-Fe2O3 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 n alpha-Fe2O3 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 n alpha-Fe2O3 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.

Automated summary

The catalytic performance of alpha-Fe2O3 nanoparticles in the low-dose ferrate system was studied for the degradation of pentachlorophenol. Quadratic functions were established to predict the optimal catalyst dosage and the maximum rate constant based on the correlation between alpha-Fe2O3 amount and observed rate constant. Characterization and cycling experiments showed the stability and recyclability of alpha-Fe2O3. The study proposed a catalytic mechanism involving the reaction between Fe(III) on the surface of alpha-Fe2O3 and Fe(VI) to enhance the generation of reactive Fe(IV)/Fe(V) species for the extraction of electrons from PCP molecules.