Fenton-like Degradation Of Acetaminophen With Nano-Fe₃O₄ And Nano-Fe⁰ Particles

Pharmaceuticals and personal care products?PPCPs?with the properities of a wide distribution and potential toxicity has attracted broad attention from scholars.As a common analgesic,acetaminophen?ACTP?was adopted as a kind of typical PPCPs in this paper.Nano-Fe₃O₄ and Nano-Fe⁰ Fenton-like process was taken respectively to treat with the simulated wastewater of ACTP.And the TOC degradation process was further studied.The Nano-Fe₃O₄ and Nano-Fe⁰ used in the study were prepared in the lab and its XRD,SEM,BET test results showed the high purity of the Nano-Fe₃O₄ and Nano-Fe⁰.Nano-Fe₃O₄ was cubic and flake,particle size²2.4nm,BET specific surface area 98.45m²/g,while Nano-Fe⁰ was cubic,spherical,particle size 10¹00nm,BET specific surface area 25.09 m²/g.A preliminary study of the effects of the two different kinds of Fenton-like methods on ACTP mineralization rates was done.In the experiments,the TOC removal rate of ACTP simulated wastewater increased with the decreasing pH and increasing temperature,decreased with the increment of the initial pollutant concentrations.With the increase of hydrogen peroxide and the dosage of magnetic nanoparticles,the TOC removal rate increased at first but decreased when they were overdose.In the case of 35?,the initial ACTP concentration 0.2mM,the optimum case in the Nano-Fe₃O₄ Fenton-like process was at pH=3.0,Nano-Fe₃O₄ dosage 1.0g/L,H₂O₂ dosage 8.4mM in 120min,the TOC removal rate reached 76.6%;under 35?,Nano-Fe⁰ Fenton-like showed its superiority under neutral conditions,pH=6.0,Nano-Fe⁰ dosage0.75g/L,H₂O₂ dose 4.2mM,the TOC removal rate reached 58.1%in120min.It is not difficult to find that the process of both Nano-Fe₃O₄Fenton-like system and Nano-Fe⁰ Fenton-like system can be divided to two processes:First,slow degradation stage;the second is the rapid oxidation.The two stages followed pseudo first-order kinetics,respectively.By eliminating free radicals,the mechanism of the reaction can be further defined.At p H=3.0,Nano-Fe₃O₄ Fenton-like system is mainly dominated by the hydroxyl radicals,especially those in the solution;Nano-Fe⁰ Fenton-like system at pH=6.0 was mainly ascribed to theactionof Fe?IV?andhydroxylradicals,especiallythe surface-bounded ones.