| An easy,high efficient synthesis approach was investigated in this paper,m-GO-MFO?m=0, 2, 5, 10? hybrids were synthesized by co-precipitation technique. 5-rGO-MFO-n?n=200, 300, 500? hybrids with superior catalytic ozonation for DBP removal in water were obtained after being calcined by various temperature under N2 atmosphere. Di-n-butyl Phthalate ?DBP? removal under multiple water qualities were studied. Mechanism of ·OH formation in various catalytic ozonation processes were discussed.Multiple techniques were used to character morphology, crystal structure, element composition, valence state and surface groups of catalysts. GO with the function as supporter of nanoparticles ?NPs? limit the MFO NPs to agglomerate. Pore structure transition from slit-pore to vase-shaped pore was observed by N2 adsorption-desorption techniques of 5-GO-MFO and 5-rGO-MFO-200. High calcination temperature destroyed typical pore structure resulting sharp decrease of BET surface area and pore volume. The XRD peak of ?31 1? was decreased by the increasing GO content. Organic groups including -OH, -COO, -O-were observed by FT-IR. The O 1s XPS results of 5-GO-MFO prove the following. Surface abundant oxygen-containing groups could absorb Mn?II? and Fe?III? at first, then the absorbed Mn?II? and Fe?III? was in situ converted into MFO NPs in combition with NaOH.For catalytic ozonation for DBP degradation, as-prepared 5-rGO-MFO-200 catalyst resulted in great enhancements in reaction rate and DBP removal compared to that of ozone alone system or 5-GO-MFO/O3 system. Typically, 1000 mL DBP solution (0.5 mg·L-1) could be 78% DBP removal and 62% mineralized with 5-rGO-MFO-200 dosage of 0.01 g·L-1,initial pH7. There was little influence on DBP removal with addition of Mg2+, K+, Na+, Ca2+,N03-. Negligible metal leakage of catalysts and visible light could not influence DBP removal as well. There was a negative effect of DBP removal with addition of Cl-,Br-,F- , SO4-.However, addition of HCO3- increase DBP removal. Magnetic, stable 5-rGO-MFO-200 catalyst performed great reproducibility in DBP removal after 5 successive runs. Catalytic H2O2 or PMS by 5-rGO-MFO-200 show much lower DBP removal than catalytic ozonation.Surface hydroxyl sites concentration ?SHSC? plays a significant role in reaction. There was a linear correlation between SHSC and pseudo first order reaction rate constant ?k?.Linear correlation between k and DBP removal rate ?E? or average ozone utilization ?R? were also observed. This indicated that catalytic ozonation was mainly depended on SHSC. Lower activation energy of MFO (10.5 kJ·mol-1) indicated that the reaction was controlled by diffusion. However, the higher activation energy of 5-rGO-MFO-200 (26.8 kJ·mol-1) implied that this process was dominated by intrinsic chemical reactions rather than the rate of mass transfer. Cyclic voltammetry curve ?CV? showed different catalysts redox ability which corresponded to catalytic ozonation performance. A specific catalytic ozonation mechanism was discussed here by analysis of radicals quenching experiments and XPS data. |
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