A 40 μm cylindrical microporous titanium plate, which was planted at the bottom
of the reactor, played a crucial role in generating ozone macrobubbles (with a mean
bubble diameter of approximately 1 mm). Moreover, an ozone generator (CF-YG5,
Shanmei Shuimei Co. Beijing) was attached with the reactor, which produced ozone
gas at the rate of 5 g O 3 /h by using dehumidified air as gas source (flow rate of air of
0.5 L/min). The reaction process began by injecting acrylic fiber manufacturing
wastewater (3 L) with a peristaltic pump. The wastewater persistently circulated
between the microbubble generator and the reactor. The ozone gas that came out
from the reactor was absorbed with 2% KCl solution. At preselected regular time
intervals, the samples were withdrawn and instantly purged by N 2 gas in order to
eliminate the residual ozone. Throughout the experiment, the reaction temperature
was maintained at 20
C.
10.3.3 Photo-Fenton Reactor
The photo-assisted Fenton process adds UV radiation to the system resulting in the
formation of more hydroxyl free radicals. Recently, studies have been carried out to
compare the Fenton and photo-assisted Fenton process. In general, various reactor
geometries have been used among which cylindrical reactor with UV lamps placed
in the center has gained the highest popularity. For the testing of photodegradation of
organic pollutants, a glass reactor with an external loop, which had a capacity of
1.6 L, was utilized and operated in batch mode as shown in Fig. 10.11 (Bañuelos
et al. 2014). A medium-pressure Hg lamp (type EQ 1023 Z4) surrounded by a
cooling pipe made of quartz glass was located in the center. In this photo-Fenton
reactor, jet-loop reactor and UV reactor were connected by a polyvinyl chloride
(PVC) tube. The obtained results showed that the degradation efficiency of pollutants got improved with continuous aeration.
10.3.4 Photocatalytic Reactor
A vertical circulating photocatalytic reactor was designed by Shahrezaei and colleagues for the photocatalytic degradation of aniline using TiO 2 NPs. A 400 W
mercury UV lamp of 22 cm body length and 16 cm arc length was used as a UV
source and placed inside a quartz tube which is totally immersed in the reactor
(Fig. 10.12) (Shahrezaei et al. 2012).
In order to attain homogeneity of the nanocomposites along the quartz tube, a
pump was used to provide a tunable circulating stream and fed wastewater from the
top of the reactor. In this process, continuous airflow was delivered to the reactor at a
constant flow rate (3 L/min) with the aid of a lab-scale air compressor. It was not
anticipated that through the short reactor a single pass of polluted water would give
sufficient degradation.
10 Photo-oxidation Technologies for Advanced Water Treatment
243
of the reactor, played a crucial role in generating ozone macrobubbles (with a mean
bubble diameter of approximately 1 mm). Moreover, an ozone generator (CF-YG5,
Shanmei Shuimei Co. Beijing) was attached with the reactor, which produced ozone
gas at the rate of 5 g O 3 /h by using dehumidified air as gas source (flow rate of air of
0.5 L/min). The reaction process began by injecting acrylic fiber manufacturing
wastewater (3 L) with a peristaltic pump. The wastewater persistently circulated
between the microbubble generator and the reactor. The ozone gas that came out
from the reactor was absorbed with 2% KCl solution. At preselected regular time
intervals, the samples were withdrawn and instantly purged by N 2 gas in order to
eliminate the residual ozone. Throughout the experiment, the reaction temperature
was maintained at 20
C.
10.3.3 Photo-Fenton Reactor
The photo-assisted Fenton process adds UV radiation to the system resulting in the
formation of more hydroxyl free radicals. Recently, studies have been carried out to
compare the Fenton and photo-assisted Fenton process. In general, various reactor
geometries have been used among which cylindrical reactor with UV lamps placed
in the center has gained the highest popularity. For the testing of photodegradation of
organic pollutants, a glass reactor with an external loop, which had a capacity of
1.6 L, was utilized and operated in batch mode as shown in Fig. 10.11 (Bañuelos
et al. 2014). A medium-pressure Hg lamp (type EQ 1023 Z4) surrounded by a
cooling pipe made of quartz glass was located in the center. In this photo-Fenton
reactor, jet-loop reactor and UV reactor were connected by a polyvinyl chloride
(PVC) tube. The obtained results showed that the degradation efficiency of pollutants got improved with continuous aeration.
10.3.4 Photocatalytic Reactor
A vertical circulating photocatalytic reactor was designed by Shahrezaei and colleagues for the photocatalytic degradation of aniline using TiO 2 NPs. A 400 W
mercury UV lamp of 22 cm body length and 16 cm arc length was used as a UV
source and placed inside a quartz tube which is totally immersed in the reactor
(Fig. 10.12) (Shahrezaei et al. 2012).
In order to attain homogeneity of the nanocomposites along the quartz tube, a
pump was used to provide a tunable circulating stream and fed wastewater from the
top of the reactor. In this process, continuous airflow was delivered to the reactor at a
constant flow rate (3 L/min) with the aid of a lab-scale air compressor. It was not
anticipated that through the short reactor a single pass of polluted water would give
sufficient degradation.
10 Photo-oxidation Technologies for Advanced Water Treatment
243