Essay On Photo Inactivation

Kinetic model of photo-inactivation
In order to understand the photo-disinfection, its kinetics and mechanism have significant importance for the designing, optimization and operation of large-scale photocatalytic water treatment processes. In this study, the linear relationship was inadequate to represent the three different regions of the photocatalytic inactivation curves in the N-TiO2 photocatalysis system. Three different regions were also observed by Marugán et al.27: (i) a shoulder region, (ii) a log-linear inactivation region, and (iii) a tail region. Shoulder region: This lag smooth decay, which occurs in the initial stage of photocatalytic inactivation, accounts for the undamaged and damaged cells. This initial delay may be caused

This can also be viewed in terms of the slow permeation rate of ROS species through the bacterial cell-wall, which were bounded by their short half-life before inducing an irreversible damage to the bacterial cells59. The tail characteristics, however, is not well-under-stood. Benabbou et al.8 proposed that the tail characteristics region can prolong the entire d is infection treatment process. This was caused by the competition between organic products released from constant cell lyses and the remaining intact cells. Others proposed that the tailing deviation from conventional log-linear bacterial survivor curves was due to the presence of variants in the bacterial population resistant to the disinfection method used 57. For the empirical models, a demand-free condition was assumed where the photocatalyst loadings during the irradiation period were considered to be constant. Marugán et al.27 found that bacteria by themselves had self-repair ability and can grow again after injured, therefore, the inactivation of bacteria requires a certain amount of cumulative damage, a process to prevent bacteria from growing or being killed. The damage cannot be completed in a short time, even though there are enough radicals produced by photocatalyst27,