Towards Scaling-up Photocatalytic Process for Multiphase Environmental Applications: A Review

Abstract

Recently, we have witnessed a booming development of composites and multi-dopant metal oxides to be employed as novel photocatalysts. Yet the practical application of photocatalysis for environmental purposes is still elusive. Concerns about the unknown fate and toxicity of nanoparticles, unsatisfactory performance in real conditions, mass transfer limitations and durability issues have so far discouraged investments in full-scale applications of photocatalysis. Herein, we provide a critical overview of the main challenges that are limiting large-scale application of photocatalysis in air and water/wastewater purification. We then discuss the main approaches reported in the literature to tackle these shortcomings, such as the design of photocatalytic reactors that retain the photocatalyst, the study of degradation of micropollutants in different water matrices, and the development of gas-phase reactors with optimized contact time and irradiation. Furthermore, we provide a critical analysis of research-practice gaps such as treatment of real water and air samples, degradation of pollutants with actual environmental concentrations, photocatalyst deactivation, and cost and environmental life-cycle assessment.

SWOT analysis of photocatalytic materials towards large scale environmental remediation

“…Certainly, many research groups are struggling to overcome the common technological shortcomings of photocatalytic technology by emphasizing the engineering of photocatalytic materials or/and photoreactors [29] ••. If we wipe up the literature, we can find on the top of the list that the combination of photocatalytic technology with other technologies (e.g., AOPs, adsorption, electrochemical and chemical) may solve many technological problems and synergistically speed up the overall process.…”