Oxygen Content in the Water
The adsorption of bacteria on the surface of a photocatalytic material can also be
affected by the content of oxygen in the media. Deng et al. (2017) investigated the
generation of reactive species from the photocatalytic material with the intracellular
respiration. They showed that bacteria were profoundly affected by the absence of
oxygen. Low oxygen levels not only hindered the generation of reactive oxygen
species, but the microorganism respiration was also affected (Deng et al. 2017).
Ionic Strength in Water
Another aspect that affects the performance of the photocatalytic disinfection process is the existence of anions, such as SO 4
2À , NO 3
À
, and Cl
À , in the water solution.
Liang et al. (2017) proposed to disinfect bacterial cells using Bi 2 MoO 6 -AgI as
photocatalytic materials. They showed that the bacterial inactivation was significantly affected by the existence of common ions in the solution. This increases the
repulsion forces between the anions of the nanomaterials with bacterial cell walls
leading to a decrease in the disinfection process (Liang et al. 2017). Hu et al. (2003)
showed that the existence of anions in the solution enhanced the generation of
reactive species inactivating the bacterial cells. However, in another study, Liang
et al. (2017) investigated the resistance of phosphate ions in a solution and showed a
decline in the rate of disinfection when compared to chloride ion, which can act as an
electron donor to generate reactive species. Marugán et al. (2010) also reported the
same result. Having a small concentration of phosphate ions in the photocatalyst
materials led to a decrease in the disinfection process (Marugán et al. 2010).
In general, to have effective disinfection of bacterial cells, a full understanding of
the effect of the chemical characteristics of the water matrix is needed. However,
there is a massive difference in the water matrix characteristics and performance
efficiency and generation of reactive species so that more research must be carried
out shortly. Optimizing the chemical characteristics of the water matrix can increase
the generation of reactive species and the bacterial disinfection on the surface of
nanomaterial to apply on a large scale.
7.6 Supported Catalysts for Water/Wastewater
Disinfection
Currently, our world faces problems related to the removal of hazardous substances
and disinfection of pathogens from wastewater and remediation of pollutants in the
groundwater and surface water to prevent the expansion of waterborne diseases that
affect public health. Hence, to solve this problem, different oxidation processes such
as biological, chemical, and physical methods are applied. However, the presence of
7 Photocatalytic Nanomaterials for Bacterial Disinfection
229
The adsorption of bacteria on the surface of a photocatalytic material can also be
affected by the content of oxygen in the media. Deng et al. (2017) investigated the
generation of reactive species from the photocatalytic material with the intracellular
respiration. They showed that bacteria were profoundly affected by the absence of
oxygen. Low oxygen levels not only hindered the generation of reactive oxygen
species, but the microorganism respiration was also affected (Deng et al. 2017).
Ionic Strength in Water
Another aspect that affects the performance of the photocatalytic disinfection process is the existence of anions, such as SO 4
2À , NO 3
À
, and Cl
À , in the water solution.
Liang et al. (2017) proposed to disinfect bacterial cells using Bi 2 MoO 6 -AgI as
photocatalytic materials. They showed that the bacterial inactivation was significantly affected by the existence of common ions in the solution. This increases the
repulsion forces between the anions of the nanomaterials with bacterial cell walls
leading to a decrease in the disinfection process (Liang et al. 2017). Hu et al. (2003)
showed that the existence of anions in the solution enhanced the generation of
reactive species inactivating the bacterial cells. However, in another study, Liang
et al. (2017) investigated the resistance of phosphate ions in a solution and showed a
decline in the rate of disinfection when compared to chloride ion, which can act as an
electron donor to generate reactive species. Marugán et al. (2010) also reported the
same result. Having a small concentration of phosphate ions in the photocatalyst
materials led to a decrease in the disinfection process (Marugán et al. 2010).
In general, to have effective disinfection of bacterial cells, a full understanding of
the effect of the chemical characteristics of the water matrix is needed. However,
there is a massive difference in the water matrix characteristics and performance
efficiency and generation of reactive species so that more research must be carried
out shortly. Optimizing the chemical characteristics of the water matrix can increase
the generation of reactive species and the bacterial disinfection on the surface of
nanomaterial to apply on a large scale.
7.6 Supported Catalysts for Water/Wastewater
Disinfection
Currently, our world faces problems related to the removal of hazardous substances
and disinfection of pathogens from wastewater and remediation of pollutants in the
groundwater and surface water to prevent the expansion of waterborne diseases that
affect public health. Hence, to solve this problem, different oxidation processes such
as biological, chemical, and physical methods are applied. However, the presence of
7 Photocatalytic Nanomaterials for Bacterial Disinfection
229