The Visible Light Induced Antibacterial Study And Self-Cleaning Solid-Phase Extraction Materials Based On The Photocatalysis Of Semiconductor

TiO2 and WO3 are two kinds of widely used semiconductor materials.Due to its wide band gap(3.20 eV),and TiO2 can be only used as antibacterial material under UV-light.Thus,it’s very urgent to prepare the nanocomposites based on TiO2,which show excellent photocatalytical active under visible light irradiation.Because the band gap of WO3 is 2.5～3.20 eV,it can response to the light from 410 to 500 nm.Thus,WO3 has good photocatalytical activity under the irradiation of Xe lamp irradiation,which can be applied in self-cleaning device.Furthermore,owing to the large surface area,strong adsorption capacity,high photocatalytic efficieny,good b ioco mp at ib il ity,nano tub ular and core-shell semiconductor nanostructures normally have promising applications in antibacterial study and protein separation.In the first chapter,we briefly described the classification,preparation method and applications of antibacterial and protein separation of the semiconductor nanocomposites.And then we introduced the concept,classify,and properties of the antibacterial material.In the end,the protein separation and enrichment method are described in detailIn the second chapter,we synthesized g-C3N4/TiNTs nanocomposites,explored their bactericidal activity under visible light irradiation,and investigated the mechanism of photocatalytic antibacteria.The photoresponse of TiNTs was broadened to visible-light region by the decoration of g-C3N4,which is known as a semiconductor with narrow band-gap.The result showed that the antibacterial efficiency of the g-C3N4/TiNTs was much higher than that of the TixNTs under visible light,and antibacterial efficiency could reach to 80%;the mechanism of photoinactived antibacterial effect was mainly originated from the super oxygen radicals which were generated by the reaction between electrons in conduction band and oxygen molecules.In the third chapter,the core-shell structured Fe3O4/WO3 nanocomposites were prepared,and their application in self-cleaning adsorbent for selective protein isolation was investigated.The core-shell Fe3O4/WO3 nanocomposites were synthesis by hydrothermal method,and their performances in selective separation and purification of protein,and the relevent mechanism is studied in detail.Fe3O4/WO3 nanocomposites showed specific adsorption for hemoglobin under pH 7,and the adsorption capacity of Fe3O4/WO3 reached to 612.61 mg/g,and the adsorptive separation of Hb was based on the hydrogen-bond interaction between the-NH2 groups of protein and the hydroxyl on Fe3O4/WO3 surface.Using the photocatalytical property of WO3,the surface of Fe3O4/WO3 can be further cleaned after separation and purification experiments by UV light irradiation.The result demonstrated that with self-cleaning the sample showed a higher adsorption and elution efficiency,the adsorption and elution efficiency didn’t show obviously decrease after several adsorption-elution cycles.In addition,circular dichroism(CD)spectra confirmed that the adsorption/desorption procedures didn’t influence the conformation and activity of Hb,suggesting the favorable biocompatibility of the Fe3O4/WO3.And Fe3O4/WO3 composites aslo was successfully applied in adsorptive separation of Hb in real whole blood.