Fast and almost 100 % of roxarsone conversion to As(V) on CoFe₂O₄/peracetic acid system

The increased discharge of organoarsenic to natural waters, brings significant risks to ecosystems and human health. It is curial to rapidly transform organoarsenic to harmless arsenate (As(V)) before conventional coagulation-sedimentation treatment. In this study, the roxarsone (ROX) was destroyed to form As(V) with almost 100 % transformation rate and reaction rate of 0.43 min⁻¹ via the CoFe₂O₄/peracetic acid (PAA) system. Specifically, PAA was primarily activated to form singlet oxygen (¹O₂) and organic radicals (R-O·) by Co(II)/Co(III) redox cycle existed on the CoFe₂O₄ surface, the presence of iron (Fe) in the CoFe₂O₄ facilitated the transformation of Co(III) to Co(II), and then that reactive oxygen species (ROS) was employed to mineralize ROX. The presence of common anions, and natural organic matters (NOM) hardly inhibit the degradation of ROX. Furthermore, the catalytic efficiency of CoFe₂O₄/PAA system remained above 94 % after five cycles. These findings suggest that the CoFe₂O₄/PAA system is a promising technique for enhanced arsenic decontamination.