Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua do Dr. Roberto Frias, 4200-465, Porto, Portugal; CAPES Foundation, Ministry of Education of Brazil, Brasília, DF 70040-020, Brazil.
Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua do Dr. Roberto Frias, 4200-465, Porto, Portugal.
J Environ Manage. 2018 Jul 1;217:555-564. doi: 10.1016/j.jenvman.2018.04.003. Epub 2018 Apr 7.
The current work presents different approaches to overcome mass and photon transfer limitations in heterogeneous photocatalytic processes applied to the reduction of hexavalent chromium to its trivalent form in the presence of a sacrificial agent. Two reactor designs were tested, a monolithic tubular photoreactor (MTP) and a micro-meso-structured photoreactor (NETmix), both presenting a high catalyst surface area per reaction liquid volume. In order to reduce photon transfer limitations, the tubular photoreactor was packed with transparent cellulose acetate monolithic structures (CAM) coated with the catalyst by a dip-coating method. For the NETmix reactor, a thin film of photocatalyst was uniformly deposited on the front glass slab (GS) or on the network of channels and chambers imprinted in the back stainless steel slab (SSS) using a spray system. The reaction rate for the NETmix photoreactor was evaluated for two illumination sources, solar light or UVA-LEDs, using the NETmix with the front glass slab or/and back stainless steel slab coated with TiO-P25. The reusability of the photocatalytic films on the NETmix walls was also evaluated for three consecutive cycles using fresh Cr(VI) solutions. The catalyst reactivity in combination with the NETmix-SSS photoreactor is almost 70 times superior to one obtained with the MTP.
目前的工作提出了不同的方法来克服多相光催化过程中的质量和光子传递限制，该过程应用于在牺牲剂存在下将六价铬还原为其三价形式。测试了两种反应器设计，即整体式管状光反应器（MTP）和微介孔结构光反应器（NETmix），两者均具有每反应液体积的高催化剂表面积。为了减少光子传递限制，将管状光反应器用涂覆有催化剂的透明醋酸纤维素整体结构（CAM）填充。对于 NETmix 反应器，使用喷涂系统将光催化剂的薄膜均匀地沉积在前玻璃平板（GS）或印在背面不锈钢平板（SSS）上的通道和腔室网络上。使用涂覆有 TiO-P25 的 NETmix 与前玻璃平板和/或背面不锈钢平板评估了 NETmix 光反应器对于两种光源，即太阳光或 UVA-LED 的反应速率。还使用新鲜的 Cr(VI)溶液评估了 NETmix 壁上光催化膜的三次连续循环的可重复使用性。催化剂的反应性与 NETmix-SSS 光反应器结合使用时，其活性几乎比使用 MTP 时高 70 倍。
