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R. Kumar et al.
studies with silica, mesoporous alumina, biomass obtained from cork, etc., have been
done for the removal of ofloxacin (OFL) (Goyne et al. 2005; Crespo-Alonso et al.
2013).
Yet another technique is the photolysis, in which chemical contaminants are lysed
or decomposed with the help of light. When applied in water treatment, indirect
photolysis is enhanced by H 2 O 2 , O 3 or persulfates. Another method, electrochemical oxidation, generates hydroxyl ions in situ at ambient temperature and pressure,
without any addition of chemicals. Moreover, electrochemical oxidation is the most
promising process to eliminate the toxicity. Antibiotics mineralization is poor when
an electrochemical process is employed alone (Guo et al. 2016). Furthermore, ozone
splits into hydroxyl radicals in water, which by their very nature are even more strong
oxidizing agents. Specific pollutants are targeted to be oxidized directly in the presence of ozone or indirectly by hydroxyl radicals. However, there is difference in their
oxidizing mechanism. Ozone oxidation is more specific and at a higher rate, while
hydroxyl radicals oxidize indiscriminately. Henry John Horstman Fenton in 1894
discovered the Fenton’s reaction, a special type of oxidation process which involved
the exploitation of properties of certain metals that can transfer oxygen thereby creating hydroxyl radicals with strong reactivity. These entities were generated via free
radical chain reaction and had immense catalytic power. The breakdown of hydrogen peroxide into
• OH radicals via an Fe-salt-based decomposition process can be
utilized for degradation of antibiotic compounds. Implementation of ultrasonic technique to treat wastewater is also in trend, and a couple of recent publications have
reported antibiotic treatment via ultrasonication.
To address the issue of carbon sequestration, energy and economic factor, as
well as waste material recycle, biochar is considered as a propitious substitute for
the treatment of wastewater. Biochar is reported to be efficacious for alleviating
diverse number of antibiotics (Yao et al. 2012; Wu et al. 2013a, b). Adsorption of
sulfapyridine (Xie et al. 2014; Inyang et al. 2015), sulfamethazine (SMT) (Vithanage
et al. 2014; Peng et al. 2016), sulfamethoxazole (SMX) (Jung et al. 2013; Zheng et al.
2013; Calisto et al. 2015) and sulfadiazine (SDZ) (Peng et al. 2016) with the help
of biochar and/or activated/functionalized biochar have been studied. Additionally,
biochar was investigated to decompose H 2 O 2 or SO
•−
4 to form highly reactive species
that were capable of removing the organic pollutants (Fang et al. 2015). Lately,
metal-organic frameworks (MOFs), e.g., zirconium-based MOF(PCN-128Y), MIL101(Cr)–SO 3 H, etc., consisting of an inorganic part developed from metal subunits
and the other part organic ligands, gained extensive research focus through modifying
the functional groups and also the structure of MOFs their utility capacity in many
areas, viz., separation techniques, catalysis of reactions and adsorption (Lee et al.
2009; Sumida et al. 2012; Huang et al. 2015a, b). In contrast, graphene derived
and carbon nanotubes are largely restricted at the laboratory scale and are seldom
applied to treat antibiotic containing wastewater. Biochar was promulgated to be
meagerly efficacious in terms of adsorptive removal capacity than activated carbon
from aqueous media due to lesser surface area and various other abiotic and/or biotic
phenomena influence on its properties (Anderson et al. 2013). Therefore, biochar
conglomerations obtained by inculcating biochar with certain substances that further
R. Kumar et al.
studies with silica, mesoporous alumina, biomass obtained from cork, etc., have been
done for the removal of ofloxacin (OFL) (Goyne et al. 2005; Crespo-Alonso et al.
2013).
Yet another technique is the photolysis, in which chemical contaminants are lysed
or decomposed with the help of light. When applied in water treatment, indirect
photolysis is enhanced by H 2 O 2 , O 3 or persulfates. Another method, electrochemical oxidation, generates hydroxyl ions in situ at ambient temperature and pressure,
without any addition of chemicals. Moreover, electrochemical oxidation is the most
promising process to eliminate the toxicity. Antibiotics mineralization is poor when
an electrochemical process is employed alone (Guo et al. 2016). Furthermore, ozone
splits into hydroxyl radicals in water, which by their very nature are even more strong
oxidizing agents. Specific pollutants are targeted to be oxidized directly in the presence of ozone or indirectly by hydroxyl radicals. However, there is difference in their
oxidizing mechanism. Ozone oxidation is more specific and at a higher rate, while
hydroxyl radicals oxidize indiscriminately. Henry John Horstman Fenton in 1894
discovered the Fenton’s reaction, a special type of oxidation process which involved
the exploitation of properties of certain metals that can transfer oxygen thereby creating hydroxyl radicals with strong reactivity. These entities were generated via free
radical chain reaction and had immense catalytic power. The breakdown of hydrogen peroxide into
• OH radicals via an Fe-salt-based decomposition process can be
utilized for degradation of antibiotic compounds. Implementation of ultrasonic technique to treat wastewater is also in trend, and a couple of recent publications have
reported antibiotic treatment via ultrasonication.
To address the issue of carbon sequestration, energy and economic factor, as
well as waste material recycle, biochar is considered as a propitious substitute for
the treatment of wastewater. Biochar is reported to be efficacious for alleviating
diverse number of antibiotics (Yao et al. 2012; Wu et al. 2013a, b). Adsorption of
sulfapyridine (Xie et al. 2014; Inyang et al. 2015), sulfamethazine (SMT) (Vithanage
et al. 2014; Peng et al. 2016), sulfamethoxazole (SMX) (Jung et al. 2013; Zheng et al.
2013; Calisto et al. 2015) and sulfadiazine (SDZ) (Peng et al. 2016) with the help
of biochar and/or activated/functionalized biochar have been studied. Additionally,
biochar was investigated to decompose H 2 O 2 or SO
•−
4 to form highly reactive species
that were capable of removing the organic pollutants (Fang et al. 2015). Lately,
metal-organic frameworks (MOFs), e.g., zirconium-based MOF(PCN-128Y), MIL101(Cr)–SO 3 H, etc., consisting of an inorganic part developed from metal subunits
and the other part organic ligands, gained extensive research focus through modifying
the functional groups and also the structure of MOFs their utility capacity in many
areas, viz., separation techniques, catalysis of reactions and adsorption (Lee et al.
2009; Sumida et al. 2012; Huang et al. 2015a, b). In contrast, graphene derived
and carbon nanotubes are largely restricted at the laboratory scale and are seldom
applied to treat antibiotic containing wastewater. Biochar was promulgated to be
meagerly efficacious in terms of adsorptive removal capacity than activated carbon
from aqueous media due to lesser surface area and various other abiotic and/or biotic
phenomena influence on its properties (Anderson et al. 2013). Therefore, biochar
conglomerations obtained by inculcating biochar with certain substances that further