amount, agglomeration between catalyst particles reduces the available surface area,
so becoming unfavorable to the system (Rachna et al. 2019).
5.7.3 pH
In the degradation of polycyclic aromatic hydrocarbons, pH of the reaction mixture
can affect the various phenomena occurring in between the system. Some of the
studies have shown that under acidic pH, highest degradation of polycyclic aromatic
hydrocarbons was obtained, while some showed it to be at basic or neutral pH
(Rachna and Shanker 2018, 2019b; Dong et al. 2019a, b). It was suggested that
under low pH, generation of SO 4
–• radicals was facilitated in soil. Since in soilthe
chemical oxidation is based upon both the sulfate and hydroxyl radicals (Matzek and
Carter 2016). In a soil degradation study of polycyclic aromatic hydrocarbons by
Fe 3 O 4 À CM/PS, SO 4
–• radicals were found as the chief dynamic species formed
though the activation of PS, and it had greater tendency of oxidizing than bare •OH
radicals (Peluffo et al. 2018). On the other hand, under basic conditions, magnetite
showed its property and catalytic stabilities (Li et al. 2019a, b). Under neutral
condition, zinc hexacyanoferrate@zinc oxide was able to degrade some five ringmembered polycyclic aromatic hydrocarbons owing to their stability in these conditions. The π-electron cloud of the polycyclic aromatic hydrocarbons formed
complexes (“cation-π”) with the nanocatalyst through surface interaction (Rachna
and Shanker 2019b).
5.7.4 Time
Time is another factor playing critical role in degradation of polycyclic aromatic
hydrocarbons. Increase in irradiation time enhances the degradation of polycyclic
aromatic hydrocarbons mainly in water. In real samples there are other contaminants
present along with the polycyclic aromatic hydrocarbons, and those are difficult to
degrade due to competitiveness between them. Moreover, concentration also inhibits
the catalytic activity of the catalysts. Hence, much time is needed to achieve
reasonable degradation of polycyclic aromatic hydrocarbons in wastewater (Khan
et al. 2015).
5.7.5 Temperature
Various studies have suggested that the removal tendency of functionalized
nanocatalysts is affected by the temperature of reaction mixture (Shahrezaei et al.
2012). As the temperature increases up to 45
C, the degradation is generally
5 Degradation of Polycyclic Aromatic Hydrocarbons by Functionalized Nanomaterials
157
so becoming unfavorable to the system (Rachna et al. 2019).
5.7.3 pH
In the degradation of polycyclic aromatic hydrocarbons, pH of the reaction mixture
can affect the various phenomena occurring in between the system. Some of the
studies have shown that under acidic pH, highest degradation of polycyclic aromatic
hydrocarbons was obtained, while some showed it to be at basic or neutral pH
(Rachna and Shanker 2018, 2019b; Dong et al. 2019a, b). It was suggested that
under low pH, generation of SO 4
–• radicals was facilitated in soil. Since in soilthe
chemical oxidation is based upon both the sulfate and hydroxyl radicals (Matzek and
Carter 2016). In a soil degradation study of polycyclic aromatic hydrocarbons by
Fe 3 O 4 À CM/PS, SO 4
–• radicals were found as the chief dynamic species formed
though the activation of PS, and it had greater tendency of oxidizing than bare •OH
radicals (Peluffo et al. 2018). On the other hand, under basic conditions, magnetite
showed its property and catalytic stabilities (Li et al. 2019a, b). Under neutral
condition, zinc hexacyanoferrate@zinc oxide was able to degrade some five ringmembered polycyclic aromatic hydrocarbons owing to their stability in these conditions. The π-electron cloud of the polycyclic aromatic hydrocarbons formed
complexes (“cation-π”) with the nanocatalyst through surface interaction (Rachna
and Shanker 2019b).
5.7.4 Time
Time is another factor playing critical role in degradation of polycyclic aromatic
hydrocarbons. Increase in irradiation time enhances the degradation of polycyclic
aromatic hydrocarbons mainly in water. In real samples there are other contaminants
present along with the polycyclic aromatic hydrocarbons, and those are difficult to
degrade due to competitiveness between them. Moreover, concentration also inhibits
the catalytic activity of the catalysts. Hence, much time is needed to achieve
reasonable degradation of polycyclic aromatic hydrocarbons in wastewater (Khan
et al. 2015).
5.7.5 Temperature
Various studies have suggested that the removal tendency of functionalized
nanocatalysts is affected by the temperature of reaction mixture (Shahrezaei et al.
2012). As the temperature increases up to 45
C, the degradation is generally
5 Degradation of Polycyclic Aromatic Hydrocarbons by Functionalized Nanomaterials
157