Persistent Organic Pollutants
Persistent organic pollutants are a group of toxic organic chemicals with long halflives and persistence in the environment. Persistent organic pollutants have been
mentioned to toxic and harmful to human health and the environment. The commonly encountered persistent organic pollutants are organochlorine pesticides from
agricultural discharge such as DDT, industrial chemicals such as polychlorinated
biphenyls (PCBs), and industrial by-products, especially polychlorinated
dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) as known as
dioxins. These pollutants are classified into three categories based on Stockholm
Convention (Stockholm Convention 2019) as shown in Table 1.5.
Nowadays, the scientists, governments, and non-governmental organizations
(NGOs) are very concerned about these pollutants because of their long persistence
in the environment, long range transportability, high toxicity even at a low level of
concentration, and accumulation in fatty tissues due to their high lipophilicity.
Persistent organic pollutants are widely contaminated in air, water, soil, and migratory species which move across international regions. Moreover, persistent organic
pollutants are found in even non-chemical areas such as the arctic regions (Teran
et al. 2012). The resistance property of persistent organic pollutants under biological
degradation is the main reason, causing bioaccumulation into animal bodies through
food chains. The exposure of persistent organic pollutants creates various serious
health problems such as cancer, allergies and hypersensitivity, hormone disruption,
cardiovascular diseases, reproductive disorders, learning disabilities, and disruption
of the immune system.
Therefore, it is very important to develop methods for mitigation and elimination
of persistent organic pollutants. The existing remediation techniques include
coagulation–flocculation–sedimentation, adsorption, membrane filtration, ozonation, and advanced oxidation processes (Kumari et al. 2020). Photocatalytic process
is one solution to reduce these pollutants in the environment because of the high
efficiency and fast degradation. However, a challenge of the elimination of persistent
organic pollutants by-products should be concerned.
Organic Dyes
The industries in this century, whether they are the textile, paper, rubber, printing,
plastics, cosmetics, dye intermediates, and so forth. All industries used dye as a
component in the production to the desired color product. Nowadays, the organic
dyes could be classified by two types which are natural and synthetic dyes. Firstly,
the natural organic dyes are dyes extracted from organic compounds (contain
carbon) which form the animal, minerals, and vegetable resources such as annatto
(yellow to orange colors), henna plant (brown color), and tomatoes (orange or
reddish colors). All of these dyes occur by natural which means they have no side
effect from dyes and also can degrade by itself. Notwithstanding, natural dyes are not
1 Photocatalytic Remediation of Organic Pollutants in Water
19
Persistent organic pollutants are a group of toxic organic chemicals with long halflives and persistence in the environment. Persistent organic pollutants have been
mentioned to toxic and harmful to human health and the environment. The commonly encountered persistent organic pollutants are organochlorine pesticides from
agricultural discharge such as DDT, industrial chemicals such as polychlorinated
biphenyls (PCBs), and industrial by-products, especially polychlorinated
dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) as known as
dioxins. These pollutants are classified into three categories based on Stockholm
Convention (Stockholm Convention 2019) as shown in Table 1.5.
Nowadays, the scientists, governments, and non-governmental organizations
(NGOs) are very concerned about these pollutants because of their long persistence
in the environment, long range transportability, high toxicity even at a low level of
concentration, and accumulation in fatty tissues due to their high lipophilicity.
Persistent organic pollutants are widely contaminated in air, water, soil, and migratory species which move across international regions. Moreover, persistent organic
pollutants are found in even non-chemical areas such as the arctic regions (Teran
et al. 2012). The resistance property of persistent organic pollutants under biological
degradation is the main reason, causing bioaccumulation into animal bodies through
food chains. The exposure of persistent organic pollutants creates various serious
health problems such as cancer, allergies and hypersensitivity, hormone disruption,
cardiovascular diseases, reproductive disorders, learning disabilities, and disruption
of the immune system.
Therefore, it is very important to develop methods for mitigation and elimination
of persistent organic pollutants. The existing remediation techniques include
coagulation–flocculation–sedimentation, adsorption, membrane filtration, ozonation, and advanced oxidation processes (Kumari et al. 2020). Photocatalytic process
is one solution to reduce these pollutants in the environment because of the high
efficiency and fast degradation. However, a challenge of the elimination of persistent
organic pollutants by-products should be concerned.
Organic Dyes
The industries in this century, whether they are the textile, paper, rubber, printing,
plastics, cosmetics, dye intermediates, and so forth. All industries used dye as a
component in the production to the desired color product. Nowadays, the organic
dyes could be classified by two types which are natural and synthetic dyes. Firstly,
the natural organic dyes are dyes extracted from organic compounds (contain
carbon) which form the animal, minerals, and vegetable resources such as annatto
(yellow to orange colors), henna plant (brown color), and tomatoes (orange or
reddish colors). All of these dyes occur by natural which means they have no side
effect from dyes and also can degrade by itself. Notwithstanding, natural dyes are not
1 Photocatalytic Remediation of Organic Pollutants in Water
19