纳米TiO_2的制备及其在处理含DNBA废水中的应用研究

在室温条件下,以钛酸四丁酯水解制备了无定形Ti(OH)4胶体,然后在酸性条件下,加入分散剂,搅拌、老化16h,加入甲苯,用油水分离器除去水和大部分甲苯,60℃真空干燥,得到纳米TiO2粉末。在400℃煅烧3h即得到锐钛矿晶型TiO2;500℃煅烧3h即有部分锐钛矿晶型TiO2转化为金红石晶型TiO2;700℃煅烧3h主要以金红石晶型存在;在800℃煅烧3h完全转化为金红石晶型,粒径20～50nm。室温条件下,金红石晶型的纳米TiO2粒子,能够使3,5 二硝基苯甲酸(DNBA)发生光催化降解反应,DNBA经光催化反应160min后,其浓度由原来的2×10-4mol/L降为9 7×10-6mol/L。表明金红石晶型的纳米TiO2粒子对DNBA具有很高的光催化活性。H2O2能显著提高DNBA的光催化降解速率。

Preparation of Nanosize TiO2 and Its Use in Treatment of Wastewater Containing DNBA

Titanium tetrabutoxide was hydrolyzed at room temperature to form amorphous titanium hydroxide,which was aged for 16 h under acidic conditions in the presence of dispersant hydroxypropyl cellulose.Then toluene was added to the mixture,and all of the water and part of toluene were distilled out through an oil-water separator.The nanosize TiO_2 powder was obtained by drying at 60 ℃ in vacuum and then calcinated at 400,500,700 or 800 ℃ for 3 h.The rutile titania with particle size of 20～50 nm was formed by calcinating at 800 ℃ for 3 h.At room temperature,3,5-dinitrobenzoic acid(DNBA) was degraded under ultraviolet light in the presence of rutile titania obtained above,with the concentration drop of DNBA from 2×10~(-4) to 9.7×10~(-6) mol/L after 160 min.This shows that the nanosize rutile titania powder possesses high catalytic activity to degrade DNBA.The photodegradation efficiency increases markedly with addition of hydrogen peroxide.