Abstract Water resource is the most precious resource for a human being that it is
necessary to make the water resource to be clean and also non-toxic. Recently, water
pollution becomes one of the most serious global issues, especially, water pollutions
that contaminate various types of organic compounds, including pharmaceuticals
and personal care products (PPCPs), persistent organic pollutants (POPs), and
organic dyes. Photocatalysis as one of the advanced oxidation processes using
reactive oxidative radicals or species to remediate the organic pollutants has drawn
much attention recently.
Photocatalysis is a process which a chemical reaction is accelerated in the
presence of a catalyst on exposure to light. The possibility to utilize solar energy
as a free energy from nature to solve the environmental problems is the key
significance of photocatalysis. Homogeneous photocatalysis has many advantages,
e.g., high oxidation properties. It is, however, not popular in various photocatalytic
applications, because it is difficult to separate the photocatalysts from the solution,
the photocatalysts have low potential to reuse, purification of products is necessary,
and almost homogeneous photocatalysts absorb narrowly light within the solar
spectrum. It has been proven that heterogeneous photocatalysis is one of the most
potential methods for treatment of organic pollutants in water. Anyhow, relatively
large band gap energy causes some limitations of metal oxide-based heterogeneous
photocatalysts. Modifications of the electronic band can be achieved by doping and
composites of semiconductors. Another modification technique in heterogeneous
photocatalysts is the utilization of electrical potential in photocatalysis. The coated
semiconductor photocatalysts are used as photoelectrodes in photo-electrocatalytic
applications. In addition, the photocatalytic reactor configuration for wastewater
treatment by heterogeneous photocatalysis can be classified as two main groups,
including fixed bed reactor and slurry type reactor. Apart from the conventional
photocatalytic reactors, 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.
Keywords Photocatalysis · Photocatalysts · Organic pollutants · Personal care
products · Persistent organic pollutants · Organic dyes · Remediation · Ozonation ·
Fenton · Metal oxide
1.1 Introduction
Water resource is the most precious resource for a human being that it is necessary to
make the water resource to be clean and also non-toxic. Anyway, due to urbanization, industrialization, and lack of people awareness to consider water as a crucial
commodity, people in many countries are now facing problems related to water
supply and security (Jayaswal et. al 2018; Meenakshisundaram 2019). Presently,
2
P. Kemacheevakul and S. Chuangchote
necessary to make the water resource to be clean and also non-toxic. Recently, water
pollution becomes one of the most serious global issues, especially, water pollutions
that contaminate various types of organic compounds, including pharmaceuticals
and personal care products (PPCPs), persistent organic pollutants (POPs), and
organic dyes. Photocatalysis as one of the advanced oxidation processes using
reactive oxidative radicals or species to remediate the organic pollutants has drawn
much attention recently.
Photocatalysis is a process which a chemical reaction is accelerated in the
presence of a catalyst on exposure to light. The possibility to utilize solar energy
as a free energy from nature to solve the environmental problems is the key
significance of photocatalysis. Homogeneous photocatalysis has many advantages,
e.g., high oxidation properties. It is, however, not popular in various photocatalytic
applications, because it is difficult to separate the photocatalysts from the solution,
the photocatalysts have low potential to reuse, purification of products is necessary,
and almost homogeneous photocatalysts absorb narrowly light within the solar
spectrum. It has been proven that heterogeneous photocatalysis is one of the most
potential methods for treatment of organic pollutants in water. Anyhow, relatively
large band gap energy causes some limitations of metal oxide-based heterogeneous
photocatalysts. Modifications of the electronic band can be achieved by doping and
composites of semiconductors. Another modification technique in heterogeneous
photocatalysts is the utilization of electrical potential in photocatalysis. The coated
semiconductor photocatalysts are used as photoelectrodes in photo-electrocatalytic
applications. In addition, the photocatalytic reactor configuration for wastewater
treatment by heterogeneous photocatalysis can be classified as two main groups,
including fixed bed reactor and slurry type reactor. Apart from the conventional
photocatalytic reactors, 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.
Keywords Photocatalysis · Photocatalysts · Organic pollutants · Personal care
products · Persistent organic pollutants · Organic dyes · Remediation · Ozonation ·
Fenton · Metal oxide
1.1 Introduction
Water resource is the most precious resource for a human being that it is necessary to
make the water resource to be clean and also non-toxic. Anyway, due to urbanization, industrialization, and lack of people awareness to consider water as a crucial
commodity, people in many countries are now facing problems related to water
supply and security (Jayaswal et. al 2018; Meenakshisundaram 2019). Presently,
2
P. Kemacheevakul and S. Chuangchote