Photocatalytic water disinfection of Cryptosporidium parvum and Giardia lamblia using a fibrous ceramic TiO2 photocatalyst

Abstract

Cryptosporidium parvum and Giardia lamblia are two of the most chlorine resistant microorganisms with notable adverse effects on humans. Our study shows that waters containing these two protozoa at low concentrations can be efficiently disinfected in continuous flow by using a commercial fibrous ceramic TiO(2) photocatalyst. The efficiency of the photocatalytic disinfection is largely enhanced by adding a small concentration of chlorine. In this way, the residence time on the photoreactor can be considerably shortened. In contrast, under the same conditions and radiance power, UV light without any photocatalyst is significantly less efficient, particularly for G. lamblia. These results exemplify the advantages of the photocatalytic process for safe and complete water disinfection.

TiO2‐Based Photocatalysis at the Interface with Biology and Biomedicine

“…García et al. demonstrated that water containing these two protozoans at low concentrations could be efficiently disinfected in continuous flow by using commercial fibrous ceramic TiO 2 photocatalysts . The efficiency of photocatalytic disinfection is largely enhanced by adding a small concentration of chlorine.…”

Mechanistic Modeling of Photocatalytic Water Disinfection

“…where ε m and ε s are the relative dielectric constants of the membrane and the solution respectively. Equations (32) and (33) can be solved numerically after applying the appropriate boundary conditions [117,119,120] to yield the electric potential profile across a cell membrane.…”

“…The electrostatic surface potential of the catalyst is defined by Equation (20). In like manner, the surface potential profile of the cells is defined by Equations (32) and (33). Under the pH conditions of interest (6 to 8, i.e., mostly neutral) and low electrolyte concentration, the TiO 2 surface is dominated by noncharged surface hydroxylated species, while the cell surface is mostly negative.…”

Photocatalysis of Titanium Dioxide for Water Disinfection: Challenges and Future Perspectives

“…Comparison should also be carried out with Legionella, Cryptosporidium, and Giardia lamblia, since previous studies found that these organisms are highly resistant to traditional disinfection practices [37]. Experimental work in this regard was in fact conducted in 2009 by Navalon et al and demonstrated that waters containing Cryptosporidium parvum and Giardia lamblia at low concentrations can be efficiently disinfected in continuous flow by using a commercial fibrous ceramic TiO 2 photocatalyst [38].…”