1.6 Photocatalytic Reactors for Remediation of Organic
Pollutants
Photocatalytic reactor design is the major challenge in photocatalytic remediation of
organic pollutants in water. The important key in photocatalytic reactor design
consideration is that the large area of photocatalysts has to be illuminated efficiently.
In general, the photocatalytic reactor configuration for wastewater treatment can be
classified as two main groups, including fixed bed reactor and slurry type reactor
(Ibhadon and Fitzpatrick 2013). Apart from the conventional photocatalytic reactor,
the combination of photocatalysis with another treatment process has also been
developed to overcome the specific obstacles in each case, such as a photocatalytic
membrane reactor.
A wide variety of reactor configurations for removals of pharmaceuticals and
personal care products have been reported in the literature. For example, removal of
amoxicillin in water by a conventional slurry photocatalytic reactor under simulated
solar light irradiation was performed (Nguyen et al. 2019). The optimal conditions
for that study are an initial amoxicillin concentration of 1.0 μM, a photocatalyst
amount of 0.104 g/L, and a pH of 4 (Nguyen et al. 2019). The continuous fixed bed
photocatalytic reactor for the removal of paracetamol was developed (Borges et al.
2015). The reactor consists of TiO 2 -coated glass spheres placed in the glass tube.
The synthetic wastewater was recirculated along with the system by a peristaltic
pump during the irradiation of the simulated solar light. A submerged ceramic
membrane photocatalytic reactor for amoxicillin removal was designed and reported
(Li et al. 2019). The system is composed of two stainless steel rectangular tanks with
the ceramic membrane fixed inside the tanks. The air compressor was connected to
the top of the membrane for backwashing. The aeration pipe was installed at the
bottom of the tanks to prevent the accumulating of photocatalyst powder on the
membrane surface (Li et al. 2019).
A combination of conventional slurry or fixed bed photocatalytic reactors and
membrane filtration for remediation of persistent organic pollutants in water has
attracted considerable attention from researchers since the last decade. For example,
a slurry bed photocatalytic membrane reactor for the removal of 32 different persistent organic pollutants was developed. The system is composed of a pre-filter unit,
an irradiation unit with 32 UV lamps, and a photocatalyst recovery unit. A ceramic
microfiltration membrane was used to separate photocatalysts (Benotti et al. 2009).
For organic dyes, a number of reactors (apart from conventional slurry-type ones)
for remediation of organics dye in water have been created. A slurry-type reactor
combined with an air sparging unit for degradation of methylene blue in water was
reported (Abdellah et al. 2018). A fixed bed photocatalytic membrane reactor for
degradation of 4BS dye was designed. N-doped TiO 2 was immobilized on a ceramic
membrane, and then the membrane was installed between a reaction chamber and a
separation chamber. A xenon lamp was used as a light source. The dye-containing
aqueous solution was fed by a diaphragm pump (Wang et al. 2016). A photocatalytic
reactor consisted of a UVA or UVC light source installed on the top of a chamber
38
P. Kemacheevakul and S. Chuangchote
Pollutants
Photocatalytic reactor design is the major challenge in photocatalytic remediation of
organic pollutants in water. The important key in photocatalytic reactor design
consideration is that the large area of photocatalysts has to be illuminated efficiently.
In general, the photocatalytic reactor configuration for wastewater treatment can be
classified as two main groups, including fixed bed reactor and slurry type reactor
(Ibhadon and Fitzpatrick 2013). Apart from the conventional photocatalytic reactor,
the combination of photocatalysis with another treatment process has also been
developed to overcome the specific obstacles in each case, such as a photocatalytic
membrane reactor.
A wide variety of reactor configurations for removals of pharmaceuticals and
personal care products have been reported in the literature. For example, removal of
amoxicillin in water by a conventional slurry photocatalytic reactor under simulated
solar light irradiation was performed (Nguyen et al. 2019). The optimal conditions
for that study are an initial amoxicillin concentration of 1.0 μM, a photocatalyst
amount of 0.104 g/L, and a pH of 4 (Nguyen et al. 2019). The continuous fixed bed
photocatalytic reactor for the removal of paracetamol was developed (Borges et al.
2015). The reactor consists of TiO 2 -coated glass spheres placed in the glass tube.
The synthetic wastewater was recirculated along with the system by a peristaltic
pump during the irradiation of the simulated solar light. A submerged ceramic
membrane photocatalytic reactor for amoxicillin removal was designed and reported
(Li et al. 2019). The system is composed of two stainless steel rectangular tanks with
the ceramic membrane fixed inside the tanks. The air compressor was connected to
the top of the membrane for backwashing. The aeration pipe was installed at the
bottom of the tanks to prevent the accumulating of photocatalyst powder on the
membrane surface (Li et al. 2019).
A combination of conventional slurry or fixed bed photocatalytic reactors and
membrane filtration for remediation of persistent organic pollutants in water has
attracted considerable attention from researchers since the last decade. For example,
a slurry bed photocatalytic membrane reactor for the removal of 32 different persistent organic pollutants was developed. The system is composed of a pre-filter unit,
an irradiation unit with 32 UV lamps, and a photocatalyst recovery unit. A ceramic
microfiltration membrane was used to separate photocatalysts (Benotti et al. 2009).
For organic dyes, a number of reactors (apart from conventional slurry-type ones)
for remediation of organics dye in water have been created. A slurry-type reactor
combined with an air sparging unit for degradation of methylene blue in water was
reported (Abdellah et al. 2018). A fixed bed photocatalytic membrane reactor for
degradation of 4BS dye was designed. N-doped TiO 2 was immobilized on a ceramic
membrane, and then the membrane was installed between a reaction chamber and a
separation chamber. A xenon lamp was used as a light source. The dye-containing
aqueous solution was fed by a diaphragm pump (Wang et al. 2016). A photocatalytic
reactor consisted of a UVA or UVC light source installed on the top of a chamber
38
P. Kemacheevakul and S. Chuangchote