Preparation,Characterization And Its Properties Of Bi-containing Magnetic Nanocomposites

Dye wastewater has high chrominance and hydrocarbon content and is non-biodegradable and resistant to conventional wastewater treatments.If wastewater is not dealing with any technologies,discharging will seriously endanger human health and ecological environment.The triphenylmethane dyes have considerable yield.Rhodamine B?RhB?is one of the most extensively used as a dyeing agent and cosmetic industry.But International Agency for Research on Cancer?IARC?on chemical carcinogenic risk assessment reports that the ingestion and contact with RhB is a potential carcinogenic hazard to human beings.If it is used for a long time,it may cause damage to the nervous system to the human beings.RhB has been classified as a class C carcinogenic by the Environmental Protection Agency.The removal of RhB wastewater is imminent.In this work,Fe₃O₄/BiPO₄ magnetic nanocomposite was prepared by a facile co-precipitation and a simple glycerin-assisted hydrothermal method.Fe₃O₄/BiPO₄ was characterized by XRD,SEM-EDS,UV-Vis DRS and FTIR.Fe₃O₄ was spherical with 20-30nm particle size and BiPO₄ is triangular prism structure,respectively.And E_g of Fe₃O₄,BiPO₄and Fe₃O₄/BiPO₄ were 0.91,3.98 and 3.51 eV,respectively.Moreover,the degradation rate of5 mg/L 250 mL RhB with 0.25 g/L Fe₃O₄/BiPO₄ nano-photocatalyst was 92%.The mineralization rate was 91%.There was no significant loss of the photocatalytic activity of Fe₃O₄/BiPO₄ after five successive runs,about 86%.Fe₃O₄/BiPO₄ magnetic nano-photocatalyst with strong magnetism had high reusability and excellent photocatalyst activity.·O₂^-and h⁺were the main oxidative species in UV photocatalytic reaction.The acute toxicity was increased first and then decreased during the degradation of RhB.Fe₃O₄/BiPO₄ nanocomposite was introduced into CGDE for the degradation of RhB.The degradation rate of RhB solution?15 mg/L,250 mL?was up to 94%with 0.50 g/L Fe₃O₄/BiPO₄ catalyst after 40 min CGDE treatment,whereas only 40%was achieved in the absence of the catalyst.The degradation rate of RhB in CGDE+Fe₃O₄/BiPO₄ system is much higher than that of heterogeneous Fenton reaction H₂O₂+Fe₃O₄/BiPO₄ and CGDE+Fe²⁺/Fe³⁺.Fe₃O₄/BiPO₄ catalyst showed the better reusability and the degradation rates achieved 55%after 5 runs.·OH is the main active species in the reaction.It was determined that the overall acute toxicity was much higher than the initial acute toxicity in degradation of RhB by CGDE+Fe₃O₄/BiPO₄.In order to prevent metal ions Fe²⁺/Fe³⁺dissolved from catalyst,SiO₂ is wrapped on the outside of Fe₃O₄ by hydrolysis.Fe₃O₄@SiO₂@BiO_1.8·0.04H₂O/Ag₃PO₄?FSBAP?magnetic nanocomposite was prepared via the reverse precipitation and ion exchange method.Fe₃O₄and Ag₃PO₄ were spherical with 21 nm and 200 nm,respectively.Fe₃O₄@SiO₂ was magnetic core shell structure and BiO_1.8·0.04H₂O was nanosheet structure.The E_g value of FSBAP was2.15 eV and had eminent photocatalytic activity.With 1.00 g/L FSBAP,the degradation rate of RhB solution?10 mg/L,250 mL?was 93%under visible light irradiation for 2 h.The degradation rates were 93%,86%,83%,80%and 79%after 1,2,3,4 and 5 runs,which demonstrated its better reusability.The trapping experiment demonstrated that h⁺played an essential role in photocatalytic reaction but·O₂^-and·OH were not neglected.In general,the acute toxicity was increased in photocatalytic degradation of RhB by FSBAP photocatalyst.In summary,Fe₃O₄/BiPO₄ and FSBAP catalysts have good catalytic activity for the simulated pollutant RhB solution,and the catalysts can be recycled by permanent magnet,which avoids secondary pollution to the environment.