Environmental Engineering Reference
In-Depth Information
25.9 TiO
2
for Pesticide Degradation ....................................................................................... 493
25.9.1 Photodegradation of Methyl Parathion Using Suspended and
Immobilized TiO
2
Systems under UV Light .................................................. 493
25.9.2 Photodegradation of Lindane Using Suspended and Immobilized
TiO
2
Systems under UV Light .......................................................................... 494
25.9.3 Photodegradation of Dichlorvos Using Suspended and Immobilized
TiO
2
Systems under UV Light .......................................................................... 496
25.9.4 Degradation of Dichlorvos, Methyl Parathion, and Lindane under
Visible and Solar Light ...................................................................................... 496
25.10 Nitrogen-Doped TiO
2
for Pesticide Removal ............................................................... 498
25.11 TiO
2
for Disinfection ........................................................................................................ 502
25.11.1 Mechanism of Bacterial Degradation Using TiO
2
......................................... 503
25.12 Photocatalytic Degradation of
E. coli
Using Nitrogen-Doped Titanium Dioxide .... 504
References ..................................................................................................................................... 507
25.1 Introduction
Scarcity of resources and pollution of existing water resources are major problems faced
nowadays. Anthropogenic activities and climate change have deteriorated the quality and
quantity of available water. Population growth also signiicantly increased the demand for
water. There is a severe water crisis in sub-Saharan Africa and South Asia. According to
a United Nations Children's Fund/World Health Organization report, 2012, only 63% of
the world population has improved sanitation facilities and 89% of the people have access
to improved drinking water resources. India also faces water scarcity. Most of the people
in India lack access to treated drinking water. The problem is severe since >700 million
people reside in rural areas. It is estimated that around 40 million people are affected by
waterborne diseases annually.
Various pollutants are found in the water bodies because of the discharge of industrial
efluents, municipal sewage, and agricultural runoff. Open defecation also contaminates
the nearby water body. Pollutants present in water can be pesticides, solvents, organic mat-
ter, or pathogens. With the use of more sophisticated instruments and new technologies,
more and more pollutants are detected in water bodies. These include pharmaceuticals,
personal care products (PCPs), pesticides, and solvents. These compounds are catego-
rized as “emerging contaminants” since their presence has been identiied in water only
recently. These compounds can have adverse effects on humans at very low concentra-
tions, and hence it is important to remove these pollutants from water. There is a class of
pollutants known as endocrine disruptors, which cause abnormalities in the endocrine
system by mimicking the hormones in the body.
25.2 Emerging Contaminants
Emerging contaminants include pollutants whose presence has been identiied in water
recently. These compounds can cause serious health effects to the ecosystem. The removal
