研究目的
To study the degradation of malachite green on chitosan films containing heterojunctions of melon/TiO2 absorbing visible-light in solid-gas interfaces.
研究成果
TiO2 nanoparticles modified with urea showed visible light absorption possibly due to formation of condensed urea thermolysis byproducts such as melon. All QS/UTiO2 films exhibited high malachite green photobleaching activity upon different wavelengths. When UV-A was present, classic photocatalytic processes involving VB holes or ?OH radicals would be responsible for dye photobleaching events. Upon visible light irradiation, especially blue light (400-500 nm), a photocatalytic process, where melon light absorption would play the key role, could produce both ?OH radicals and singlet oxygen as the main oxidative species leading to the malachite green photobleaching. Participation of dye excited states could also be responsible for photo-fading of dye but under light irradiation at λ>600 nm. Moreover, 70QS/30UTiO2-10 films exhibited good dye photo-bleaching after 18 h of continuous UV-A+visible light irradiation. However, some surface modification of polymer was observed. This could be due to an oxidative attack of photo-induced reactive oxygen species such as OH and 1O2 on the polymer structure.
研究不足
The study is limited to the photobleaching of malachite green stains on chitosan films under specific wavelengths. The potential for optimization in the synthesis and application of the films is noted.
