玻璃固载TiO2/纳米纤维素复合薄膜的制备及其光催化性能

将微晶纤维素溶解于NaOH-尿素的低温溶液中形成纤维素溶液, 在水浴中再生形成纳米纤维素溶液。然后将纳米纤维素溶液与TiO₂(P25)混合, 并添加少量的钛酸正丁酯作为交联剂形成复合溶液。将制备得到的复合溶液通过流延法固载到玻璃片表面形成玻璃固载的TiO₂/纳米纤维素复合膜。通过SEM、XRD表征了复合膜的形貌与结构。将玻璃固载的TiO₂/纳米纤维素复合膜在紫外光下进行光催化降解甲基橙(MO)以评估复合膜的光催化性能, 研究了纳米TiO₂含量对复合膜光催化性能的影响, 复合膜的重复使用性能以及光降解的动力学过程。结果表明: 复合膜对MO的光催化降解能力可达90%以上, 与纯TiO₂粉末相当, 并重复使用3次光催化性能基本保持不变。复合膜对甲基橙的降解动力学符合一级动力学特征。当纳米TiO₂相对于纤维素的质量分数为33.3%时, 光催化活性最高, 动力学速率常数为0.035 min^-1。

Preparation and photocatalytic activity of TiO2/nanocrystalline cellulose composite films coating on glass

TiO₂/nanocrystalline cellulose composite solution was prepared via blending nano TiO₂ powder and nanocrystalline cellulose solution, which was produced by dissolving microcrystalline cellulose(MCC) in low temperature NaOH-ureal aqueous solution, and then regeneration in water bath. The composite solution was coated on glass to form TiO₂/nanocrystalline cellulose composite film by adding a little tetrabutyl orthotitanate as cross-linking agent. The morphology and structure of the composite films were characterized by using SEM and XRD. The photocatalytic activitives of the composite films were evaluated by decomposition of the methyl orange under UV-light irradiation. The mass fraction of the TiO₂ in the film, and the repeatability of photocatalytic activity of the films were discussed, and also the degradation kinetics was analyzed. The results show that photocatalytic activity of the films is comparable to the pure TiO₂ powder, up to 90%.When the films are repeated three times, it still keeps the same photocatalytic activity. The dynamic kinetics of the photodegradation is first order process. When the mass fraction of TiO₂ is up to 33.3%, the film possesses the better photocatalytic activity and higher dynamic rate constant with 0.035 min^-1.