Photocatalytic And Antibacterial Properties And Mechanism Of SnSO₄ Modified TiO₂ Nanomaterials

In the 21st century,with the rapid economic development,environmental pollution and energy crises are increasing,people are paying more and more attention to the protection of the environment and the development of clean energy.People’s closely related water pollution problems and microbial pathogens are becoming more and more serious.Traditional treatment technologies have been difficult to purify sewage and mineralize microbial pathogens.As a result,photocatalysis has been rapidly developed as a simple and efficient organic matter catalytic oxidation technology with antibacterial effects.As we all know,TiO₂has become the most used material among many photocatalysts due to its stable chemical properties,excellent photocatalytic properties,low toxicity,low price,and long-lasting antibacterial properties.In this paper,a sol-gel method was used to successfully prepare xSnSO₄-TiO₂nanomaterials with excellent photocatalytic degradation of pollutants and antibacterial properties.This nanomaterial has excellent photodegradation properties for the photocatalytic degradation of methyl orange（MO）and has excellent antibacterial activity toward the E.coli and S.aureus.The basic morphology,crystal structure,chemical composition,optical properties and surface acidity of SnSO₄-modified TiO₂nanomaterials were characterized by SEM,XRD,BET,TEM,Raman,XPS,UV-vis and Py-IR.It is obvious that after being modified with SnSO_4,the crystallite size decreased or became smaller,the specific surface areas increased,the optical respond range blu e shifts and the surface acidity increased.As same time,the XPS analysis showed that Sn had the valence state of+4 and existed as SnO₂;and S existed on the surface as sulfate.Furthermore,the surface sulfate play a significantly important role for the photodegradation properties and antibacterial activity.The photocatalytic degradation of MO solution experiments showed that SnSO₄modified TiO₂ changed the absorption peak of MO,that is,the structure of methyl orange gradually changed from azo structure to quinone structure.When MO was converted to quinone structure,it was easier to be photodegradation.The photocatalytic performance of the SnSO₄-TiO₂ nanomaterials prepared when the addition amount of SnSO₄ is 5%is the best.The photodegradation rate of methyl orange solution is close to 100%under the UV light irradiation for 3 h,and the photodegradation rate of MO solution reached 91.3%and under the condition of visible light irradiation for 14 h.At the same time,the reasons for the structural change of MO and the mechanism of photodegradation are discussed.The results show that the sulfate substance on the surface of the material is the main reason for the structural change of MO.The·O₂^-produced by the material is the most active reactive oxygen species photodegradation of MO solution,and the possible mechanism of MO degradation is proposed based on the experimental data of the photodegradation experiment.The test results of antibacterial performance showed that compared with pure TiO₂,SnSO₄ modified TiO₂ has better antibacterial activity.The antibacterial activity of the SnSO₄-TiO₂ nanomaterials prepared when the addition amount of SnSO₄ is 5%is the best.The antibacterial rate 93.6%for E.coli and antibacterial rate of 85%for S.aureus under visible light irradiation,the antibacterial rate 80.4%for E.coli and antibacterial rate of 72.5%for S.aureus under dark conditions.At the same time,the antibacterial mechanism of the material was discussed,and the results showed that the sulfate on the surface of the material caused changes in the living environment of the bacteria,and the growth environment gradually shifted to acidic conditions with the increase of SnSO₄ addition,causing the bacterial activity to decrease,and the material produced at the same time The ROS causes bacteria to produce oxidative stress,which eventually leads to the death of bacteria.And the antibacterial experiments of ROS scavengers show that OH is the most active ROS species that promotes the death of bacteria.