Activation Of Persulfate By Novel Magnetic MnFe_xO_y For Removal Of PPCPS In Water

Pharmaceutical and personal care products(PPCPs),as an emerging contaminants in aquatic environment,have been paid increasing attentions to among eco-environmentalists due to their persistence,anti-biodegradation and potential risks to aquatic organisms and human beings.Butyl paraben(BuP),as one typical PPCPs,can be accumulated in human tissues,suppresses androgen expression and poses a health risks to organisms,thus causing great concerns of environmental researchers and highlighting the necessity of developing a cost-effective technique to treat BuP-containing wastewaters.Recently,heterogeneously activated persulfate-based advanced oxidation processes for removing aqueous emerging pollutants have become one of research hotspots.Aiming at the current limitations on how to develop an effective method of controlling the properties of magnetic Fe-based materials for persulfate activation to the removal of PPCPs in waters,this work prepared a series of synthetic conditions-regulated magnetic MnFexOy composites by the hydrothermal method,summarized the changes of their physicochemical characteristics and systematically studied the influences of synthetic conditions,experimental parameters and aquatic inorganic coexisted ions on their catalytic performance towards potassium peroxymonosulfate(PMS)activation by using BuP as a model pollutant,coupling with the assessment of their stability and reusability.The main contents and results of this study are summarized as follows:(1)The effects of synthetic conditions like the volume ratios of water/isopropanol,mole ratios of Fe/Mn,calcination parameters(temperature and time)on the crystal structures of MnFexOy were comparatively studied,followed by characterizing their surface morphologies,particle sizes,surface charges,spectral absorption features and valence states of elements.(2)Results showed that BuP removal can be mainly attributed to the formation of reactive radicals in MnFexOy/PMS reaction systems,which was largely dependent on the changes in the synthetic conditions of MnFexOy composites.The optimized synthetic conditions for MnFexOy composites were that the volume ratio of water/isopropanol.mole ratio of Fe/Mn,calcination temperature and time were 3:1,2:1,350℃and 4 h,respectively.(3)BuP removal by activated PMS using optimized MnFexOy increased with the increased MnFexOy dosages and solution temperature,while PMS concentrations had a slightly effect on BuP removal.The neutral and alkaline conditions were more favorable for BuP removal by MnFexOy/PMS than acid ones.Additionally,MnFexOy showed a good stability and reusability over BuP removal.(4)Results also showed that the presence of Mg2+ and Cl-ions enhanced BuP removal efficiency by MnFexOy/PMS system,while PO43-and SO42+ ions in solutions decreased the removal efficiency.However,HCO3-and NO3-ions were found to slight effect on BuP removal efficiency.In general,Ca2+ played no impact on BuP removal efficiency.