γ-氧化铁/山梨酸/银-二氧化钛的制备及抗菌性能

Synthesis and antibacterial performance of γ-Fe_(2)O_(3)/sorbic acid/Ag-TiO_(2)

采用溶胶凝胶-水热法制备了γ-氧化铁/山梨酸/银-二氧化钛催化剂。以可见光驱动下对大肠埃希氏菌的对数去除率为评价指标,获得了催化剂的最佳制备参数:n(银)/n(钛)=0.03、n(山梨酸)/n(钛)=0.2、水热温度为160℃、水热时间为12 h。利用X射线衍射(XRD)、X射线光电子能谱(XPS)、BET法比表面积(BET)、高倍扫描电镜(FESEM)等表征方法对其结构、表面特性、光学性能和磁性性能进行分析。催化剂的物化性能优异:构成为纯锐钛矿二氧化钛、顺磁性γ-氧化铁和单质银,山梨酸以单齿方式与二氧化钛结合;外观为类球形构成的比表面积为125.726 m^(2)/g的介孔结构;可响应200~800 nm全波段光;是饱和磁化强度为10.478 A·m^(2)/kg的超顺磁材料。自由基淬灭试验确定活性氧(ROS)影响抗菌活性的顺序从大到小依次为·OH、O_(2)·^(-)、h^(+)。自由基、游离银离子和山梨酸构成协同抗菌体系,使催化剂在可见光和黑暗条件下均具有良好的抗菌活性,对数去除率分别为5.91和2.54。

Catalyst of γ-Fe_(2)O_(3)/SA/Ag-TiO_(2)was synthesized by the sol-gel hydrothermal method.The optimal preparation parameters ofγ-Fe_(2)O_(3)/SA/Ag-TiO_(2)were obtained,in which the log reduction of E.coli under visible light was adopted as the evaluation index.The results,such as n(Ag)/n(Ti),n(SA)/n(Ti),hydrothermal temperature,and hydrothermal time were determined as 0.03,0.2,160℃,and 12 h,respectively.XRD,XPS,BET,FESEM and other characterization methods were used to analyze the structure,surface properties,optical properties and magnetic properties.The catalyst had excellent physical and chemical properties.γ-Fe_(2)O_(3)/SA/Ag-TiO_(2)consisted of pure anatase,elemental silver,sorbic acid,and paramagnetic γ-Fe_(2)O_(3),among which sorbic acid was combined with TiO_(2)in a unidentate manner.The surface structure analysis indicated that the photocatalyst showed regular spherical,and constituted a mesoporous structure with a specific surface area of 125.726 m^(2)/g.It was proved that the photocatalyst could absorb the full wavelength light of 200~800 nm through optical performance analysis.The saturation magnetization of the material was 10.478 A·m^(2)/kg,which was paramagnetic material.The main ROS,affecting the antibacterial activity of γ-Fe_(2)O_(3)/SA/Ag-TiO_(2),were determined by the free radical trapping tests.The results were as following:·OH、O_(2)·^(-)、h^(+).Free radicals,free Ag^(+)and sorbic acid formed a synergistic antibacterial system,which made the photocatalyst exhibited strong antibacterial activity under visible light and dark conditions,with the logarithmic removal rates of 5.91 and 2.54,respectively.