Carbonized resin with Fe&Co bimetal for peroxymonosulfate activation to degrade atrazine

Abstract

Aiming at realizing heavy metal recycling and resource utilization, a carbon-based bimetallic material (Fe1Co2@C) was fabricated via calcining cationic resin exchanged with Fe and Co cations. It exhibited superior peroxymonosulfate (PMS) activation performance to degrade atrazine (ATZ) compared with the monometallic materials (Fe@C and Co@C). Fe1Co2@C/PMS performed high degradation of 5 mg/L ATZ with the reaction rate constant (kobs) of 0.0869 min−1 within 30 min of reaction time. The effects of catalyst loading, PMS dosage, initial pH, and the presence of inorganic ions (NO3−, SO42− Cl−, and HCO3−) and natural organic matters (NOMs) were also investigated in this work. According to the radical quenching experiments and electron paramagnetic resonance (EPR), hydroxyl radical (•OH) and sulfate radical (SO4•−) were identified to be the primary reactive oxygen species (ROS) responsible for the ATZ degradation, especially •OH. What’s more, reaction mechanism of Fe1Co2@C was demonstrated that −(C− SO3)x − Co(II) and the synergy between Fe and Co on the surface could both promote the heterogeneous redox cycles of Co(II)/Co(III) and Fe(II)/Fe(III) to activate PMS. Based on the detection results of intermediates by LC-MS, possible degradation pathways of ATZ included dealkylation, dichlorination, hydroxylation, and deamination-hydroxylation processes were proposed. This research not only provides new insights of PMS activation by carbon-based bimetallic catalyst for water treatment, but also proposes a new way for reusing the waste saturated cation resin waste with heavy metal.