首页|Comparison of E. coli inactivation by UV_(222)-ADPs and UV_(254)-ADPs in water
Comparison of E. coli inactivation by UV_(222)-ADPs and UV_(254)-ADPs in water
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NETL
NSTL
Higher Education Press
Pathogenic microorganisms pose a significant threat to water safety. Emerging disinfection processes that combine far-ultraviolet radiation with oxidants offer promising strategies for controlling these pathogens. This study investigated advanced disinfection processes (ADPs) that use 222 and 254 nm far-ultraviolet radiation in conjunction with hydrogen peroxide (H_2O_2), sodium percarbonate (SPC), and persulfate (PDS) to inactivate E. coli in water. The inactivation efficiencies of E. coli were measured as 6.50-log for UV_(222) alone and 2.50-log for UV_(254) alone at 0.0014 Einstein/L. When using UV_(222)-ADPs, the inactivation ranged from 5.20-log to 6.50-log, while UV_(254)-ADPs achieved inactivation levels of 2.55-log to 2.95-log. The inactivation occurred in the order of UV_(222) ≥ UV_(222)-ADPs > UV_(254)-ADPs > UV_(254), which was related to photon competition between E. coli and the oxidants, superiority of UV_(222) radiation compared with UV_(254) radiation, and the yields of radicals. When UV_(222) was combined with H_2O_2, SPC and PDS, the absorption fractions of 222 nm photons by E. coli reduced from 13.7% to 13.1%, 12.4%, and 12.2%, respectively, and the actual inactivation also decreased. This reduction was attributed to the light shielding effect of the oxidants. In addition, intracellular organic matter released from ruptured bacterial cell membranes during UV_(222)-ADPs could be further damaged by UV_(222) photons and radicals. The effectiveness of UV_(222)-ADPs was also demonstrated in real water samples. Moreover, it was shown that UV_(222)-ADPs are less susceptible to dissolved organic matter (DOM) than UV_(222) alone. This study provides novel insights into disinfection by UV_(222)-ADPs in water.
NETL
NSTL
Higher Education Press
