Chlorine dioxide gas generation using rotating packed bed for air disinfection in a hospital

Chlorine dioxide (ClO2) has proven its efficiency as a fumigant toward bacteria and viruses. However, it still has challenges on its portability and simplicity of ClO2 generation to meet the demand for disinfection in public and medical sectors. In this study, ClO2 stripping process via a rotating packed bed (RPB) from the commercial ClO2 solution was developed to a non-chemical-reaction ClO2 generation for air sterilization in a hospital. The ClO2 stripping efficiency (η) and the volumetric liquid mass-transfer coefficient (KLa) were examined under various operating variables, such as initial liquid concentration (CLi), rotational speed (ω), gas-to-liquid flow rate ratio (QG/QL), and liquid flow rate (QL). The results indicated that the gaseous ClO2 can be rapidly and continuously generated via stripping using RPB with η varied above 97% in the certain range of CLi (100–2000 mg/L) and QL (0.04–0.250 L/min). The overall KLa depends on the change of QL and ω, varied from 0.009 s−1 to 0.027 s−1. The output concentration of gaseous ClO2 (CG) can be adjusted from around 10 ppm to over 1000 ppm based on the established prediction model and controlling CLi, QL, QG, and ω. The results of the on-site disinfection test in the Mycobacterium Tuberculosis Laboratory in a hospital have shown effective elimination of all sites of E. coli and 2 of 5 sites of G. stearothermophilus with a CT value at the gas monitoring point of 642 ppm-h and humidity of 81%.