Nano Titanium Dioxide And Titanium Mesoporous Silica Molecular Sieves Synthesis, Characterization, And Photocatalytic And Study Of Electrochemical Sensor

Photo-catalytic degradation became the hot topic due to its highcatalytic activity, rapid degradation, no secondary pollution etc. Today,many different kinds of photocatalyst are used, includingsemiconductors, supramolecular materials, and mesoporous materialsetc.Titanium dioxide （TiO₂） is well known as its low cost, good chemicaldurability, non-toxic etc.Mesoporous titanosilicate material is a material which combinesthe features and advantages of mesoporous and titanium dioxide.Because of high specific surface area, titanium dioxide whichdeposited in the SBA-15not only increases its photocatalytic activity butalso be helpful for adsorption of organic molecules. Mesoporoustitanosilicate material is beneficial to disperse the HRP, therefore theadsorption capacity of the enzyme on the electrode surface has alsobeen greatly improved. And the biosensor had good biological stability,reproducibility and high sensitivity. The research about the titaniumdioxide which has photocatalytic activity is embedded in theamorphous carrier and the molecular sieve amorphous is verymeaningful.Cyclodextrins （CDs） are composed of hydrophobic internal cavityand hydrophilic external surface. So this kind of special molecularstructure allows organic molecular to form host/guest inclusion complexto accelerate the rate of photo-degradation.The contents of the thesis are as follows:（1） The photocatalytic degradation of RhB using nano titaniumdioxide:5mg of TiO₂was added to the50ml system of RhB of the initialconcentration2ppm, under the100W UV light irradiation, RhB had thebest photo-degradation effect; the degradation of RhB meet first-order dynamics equation of the reaction. The degradation process was ethylremoved first, then the-OH attacked the benzene ring so that the ringwas fractured and oxidized to H₂O and CO₂.（2） Mesoporous titanosilicate materials were prepared by differenttitanium source as the precursor for titanium source respectively bydirect approach. The synthesized materials were characterized by XRD,SEM, BET, UV-vis, FT-IR and the photocatalytic activity of mesoporousmaterials with Rhodamine B was researched. The photocatalytic effectof P25under100W UV irradiation is greater than the mesoporoustitanosilicate, in addition the photocatalytic effect of the mesoporoustitanosilicate materials under sunlight irradiation is greater than P25.（3） Mesoporous titanosilicate material was explored on glassycarbon electrode and Nafion/HRP/Ti-SBA-15/GCE biosensor wasprepared. The special structure of mesoporous titanosilicate material isbeneficial to the adsorption of the enzyme, and it can maintain thebiological activity of HRP. The cyclic votammetric results indicated thatthe embedded HRP can transfer electron directly and theelectrochemical behaviors were also improved. Excellent biocatalyticactivity of HRP in the modified system was confirmed by the reductionof hydrogen peroxide. The linear calibration was obtained in the rangefrom1.07×10-7to2.18×10-6mmol.L-1with a detection limit of1.0×10-7mmol.L-1（at the ratio of signal to noise, S/N=3）. The apparentMichaelis-Meten constant （） was estimated to be0.0219mmol.L-1.（4） Diclofenac in aqueous solution was measured by HPLC. Theresults indicated that:300W UV and the initial concentration5mg/L isthe best catalytic condition. the formation of an inclusion complexbetween diclofenac and CDs was studied and the enhancedphotodegradation behavior of diclofenac in the presence of β-CDswas investigated under different light irradiation and1:2is the optimummole ratio of diclofenac to β-CDs.