Recent advancements in photocatalyst-based platforms for the destruction of gaseous benzene: Performance evaluation of different modes of photocatalytic operations and against adsorption techniques

The photocatalytic technique is a promising alternative option for the treatment of volatile organic compounds (VOCs) to replace conventional methods. The primary feature of photocatalysis is the generation of environmentally benign end products (water and carbon dioxide). Titanium dioxide (TiO2) has been the most frequently used photocatalyst, and the advent of TiO2-based composites and other novel materials has expanded the photocatalytic domain in terms of efficiency and visible-light operation. This review assesses the performance of recently developed photocatalysts in removal of gaseous benzene (as a model VOC). The applied photocatalytic systems were classified by mode of operation, i.e., a continuous or batch system. The results of diverse studies were compared and evaluated in terms of key performance metrics (e.g., space-time and quantum yield values) to learn more about the influence of inherent properties (e.g., surface chemistry, functionalities, and structure) and operational conditions (e.g., humidity and processing time) on the destruction of VOCs. Further, attempts are made to compare the performance of continuous-mode photocatalytic systems against an adsorption system in terms of space velocity. In addition, photothermal catalysis was discussed as a hybrid technology for future applications. The article also highlights the present obstacles and possible opportunities for the application of photocatalytic systems toward air quality management. (C) 2019 Elsevier B.V. All rights reserved.