Preparation And Application Of Gold Nanoparticle Loaded Magnetic Carbon Microsphere

Organic pollutants were mostly toxic,highly stable and difficult to degrade.How to solve water pollution was the main problem to improve water environment.Carbon materials removed dye pollutants with excellent characteristics.Au nanoparticles had high catalytic activity,and magnetic nanoparticles possess superparamagnetic properties.Therefore,the gold loaded magnetic carbon materials were prepared,which combined the two characteristics of Au nanoparticles and magnetic nanoparticles.Such a combination preserved high catalytic performance and avoided the problem of difficult separation of catalyst.It had remarkable effect in solving water environmental pollution.P-nitrophenol?4-NP?and methylene blue?MB?were selected as research objects,and the catalytic effects of gold loaded magnetic carbon materials on pollutants were studied.The main contents of this paper are as follows:?1?The Au particles were loaded onto the material Fe₃O₄@PDA by self-polymerization of dopamine?DA?to the Fe₃O₄ surface,and then the magnetic carbon materials of the load gold((Fe₃O₄@C_?D?@Au)were obtained by carbonization.The catalytic behavior of Fe₃O₄@C_?D?@Au for p-nitrophenol was investigated.The experimental results showed that the particle size of Au loaded on Fe₃O₄@C_?D?@Au was about 20 nm,and the catalytic activity of Fe₃O₄@C_?D?@Au with Au 5%was good.At25?,the dosage of Fe₃O₄@C_?D?@Au is 0.12 g·L^-1,the molar ratio of NaBH₄ to 4-NP is 80:1,and the initial concentration of 4-NP was 110mg·L^-1.The reduction rate of the solution was up to 100%,the 4-NP could be completely reduced within 7 min.In addition,after 8 cycles,Fe₃O₄@C_?D?@Au could still reduce 4-NP completely.Therefore,Fe₃O₄@C_?D?@Au was a catalyst with great potential.?2?The tannic acid?TA?was used as carbon sources.Fe₃O₄@TA@PA@Cys materials was prepared by copolymerization of tannic acid?TA?and formaldehyde?PA?.Cysteine?Cys?was applied to immobilize Au particles to Fe₃O₄@TA@PA@Cys materials coated.And then,under the protection of argon,the magnetic carbon materials loaded gold(Fe₃O₄@C_?T?@Au)were obtained by carbonization.4-NP was used to test its catalytic reduction performance.The experimental results showed that the amount of NaBH₄,the addition of Fe₃O₄@C_?T?@Au and the initial concentration of 4-NP solution would affect the reduction performance of 4-NP.Considering the economy and effect,there was a better value.Through repeated experiments,it was proved that the gold loaded magnetic carbon Fe₃O₄@C_?T?@Au prepared had excellent stability.?3?The gold-loaded magnetic carbon(Fe₃O₄@C_?T?@Au based on tannic acid was used as catalyst to degrade MB and its catalytic conditions were investigated in H₂O₂system.At pH=7,the concentration of catalyst was 0.5 g·L^-1,the H₂O₂ concentration was 1.8%,the MB solution concentration was 20 mg·L^-1,the degradation rate of MB solution could reach 100%.and the possible mechanism is discussed by fluorescence spectroscopy,the results showed that the catalyst accelerated the decomposition of hydrogen peroxide?H₂O₂?to form·OH radicals.It was the main driving force for the degradation of MB solutions.Tert-butanol was a strong scavenger of hydroxyl,which further validates the effect of the degradation of MB solution by Fe₃O₄@C_?T?@Au.