Smart design for CBRN protection by coupling adsorption and photocatalysis: Regeneration adsorbent efficiency – CWAs’ continuous purification

Abstract

This investigation and optimization of the adsorption and photocatalysis coupling process for treating chemical warfare agents (CWAs) were performed with a compact cartridge based on activated carbon felt (AF) and TiO2 photocatalyst deposited on luminous textiles. The target pollutants were simulants of the chemical warfare agent (yperite), methyl salicylate, diethyl sulfur (a simulant of sulfur mustard gas), and cyclohexane, which is the benchmark for type A gas filtration tests. To take better advantage of this new configuration, an optimization of the photocatalytic process was highlighted with an improvement of the regeneration process by implementing the integrated compactness of desorption by the Joule effect (in situ). In the case of methyl salicylate treatment, the recovery of the adsorption capacity of the AF were about 95% and a working time of 85% compared to initial adsorbent performance. For the second cycle regeneration, the recovered adsorption capacity was about 88% compared to initial capacity. We note also that the working time decrease by 15% for each regeneration step. The evaluation of the new coupling configuration aimed at highlighting the influence of a sulfur compound was encouraging, with a regeneration rate of the adsorbent of about 80%. Compared to MS, the regeneration seems to be more difficult. This is due to by-products (SO2, MSH) formation which is highlighted by the degradation pathway proposed. The removal efficiency of the coupling system (UV-LED/AF) under continuous process, was equal to 36%. This leads an increase in filter working time of 50 min over that of a conventional adsorption process. Special attention was paid to validating the coupling system performance in real conditions. The system was placed on a humanlike seated thermal manikin used to simulate an occupant of a chamber of 30 m3 with the realistic condition of applying chemical, biological, radiological, and nuclear (CBRN) agent protection. The time protection was 60 and 30 min for respective concentrations of about 150 and 300 mg.m−3.This global investigation addressed how to overcome the scientific barriers to designing a compact, self-contained filtration cartridge for personal protection in CBRN emergency response and management in accordance with the United Nations Sustainable Development Goals (SDGs).