Study On The Preparation, Photocatalytic Performance And Mechanism Of TiO₂/Montmorillonite Nanocomposites

The hydrated-titanium-oxide/mont mo rillonite nano compositestructure sa mples were prepared by using a hydrolysati on-intercalationcomposite method with TiOSO₄·2H₂O as a precursor of TiO₂nano-particles and mont morillonite as substrate. After calcinated atdifferent temperatures, TiO₂/mont morillonite samples were got. Theprocess conditions of pH value, TiOSO₄dosage, reaction time and endpH value have some effect on the properties of TiO₂/mont morillonitenanocomposite. The properties contains structure, phase, grain size,morphology and so on. The photocata lytic decolorization properties andantibacterial properties of the TiO₂/montmorillonite composite sa mple scalcinated at different temperatures were tested, and the mechanism ofphotocatalytic decolorization were revealed. Then a series of testingmethods were carried out to analysis the compound produced indifferent preparative stages of the TiO₂/montmorillonite, such as XRD、SEM、 EDS、 UV-vis and Raman.The results show that, the pH value of mont morillonite suspensionhas a significant influence on the hydrolyzation of TiOSO₄·2H₂O, sothe comp osite structure of hydrated-titanium-oxide/mo nt morillonitewas affected. When the pH value of mo nt morillonite suspension is0.5,the poly-titanium-ions are with the lower electrovalence and extent ofpolymerization and easily intercalate the interlayer space o fmont morillonite. Moreover the structural layers of mont morillonite areseparated best. Compared with pure TiO₂nano-particle and TiO₂-Montmorillonite composite samples, TiO₂/montmorillonite compositesa mple has a higher phase transition temperature from anatase phase torutile phase and s maller crystal size of TiO₂. Mont morillonite structur elayer has a significant blocking effect on TiO₂phase transformation andgrain growth. When the Ti/mont morillonite is12.5mmol/g, the relativecontent of anatase phase is highest, and the blocking effect on TiO₂phase transfor mation from mont morillonite structure layer reachesoptimal performance. Reaction ti me affect the composite structure and phase of the TiO₂/montmo rillonite nano composite less. During thereaction of TiOSO₄and montmorillonite suspension, morepoly-titanium-ions intercalated into the layers of mont morillonitewithin a relatively short time. As end pH value rise, the hydrolysis andpolymerization degree of the poly-titanium-ions intercalated into thelayers or distributed on the surface of mont morillonite increasedgradually, which destroyed the ordered structures of Montmorillonitelayer. Un der the influence of omprehensive factors,such as the contentof anatase phase, crystallinity, surface defect and forbidden band width,the TiO₂/montmor illonite nano composite calcinated at700℃⁹00℃have a strong ability of separating light-generatedelectron-holepairs,Sothat, the nano composite have a stronger photocatalytic decolorationproperties. The ceramic glaze added little TiO₂/mo nt morillonitecomposites have an obvious antibacterial performance.