onto hydroxyl radicals that oxidize CECs. Alteration of dimethyl amino groups
and aniline of antimicrobials by ozonation leads to the deactivation of the
bactericidal functions of these compounds (Gogoi et al. 2018). Efficiency higher
than 90% was obtained when using ozonation onto non-aromatic alkenes, aromatic compounds that are abundant in electrons (sulfamethoxazoles—SMXs),
and aromatic compounds with deprotonated amine groups (trimethoprim—TMP)
(Gogoi et al. 2018). The combination of ozone and UV irradiation has been
studied to remove pesticides (Adeleye et al. 2016; Ikehata et al. 2006; Lafi and
Al-Qodah 2006), pharmaceuticals (Gebhardt and Schröder 2007), and antibiotics
(Akmehmet Balcioğlu and Ötker 2004) from wastewater. Photocatalysis is
another promising AOP that has been found to be highly effective in removing
CECs and their derivatives through the formation of free hydroxyl radicals in the
presence of a metal oxide semiconductor such as TiO 2 and a light source (Fast
et al. 2017). Removal efficiencies greater that 90% have been reported in some
studies presented in Fast et al. (2017) and Rodriguez-Narvaez et al. (2017). The
dosage of photocatalyst to be used is of huge importance as under- or overdosing
loads may result in slower degradation rates of CECs. The fouling of TiO 2
catalyst or UV lamps can occur, resulting in loss of CECs degradation efficiencies
(Fast et al. 2017). In recent years, hexavalent state of tetraoxy iron [Fe(VI)O 4
2À ],
also known as ferrate, has been used as a strong oxidant to remove pollutants
from municipal and hospital wastewater including pharmaceuticals, personal care
products, endocrine disrupting chemicals, and cyanotoxins (Jiang 2013; Jiang
et al. 2014; Li 2017; Sharma et al. 2005; Sharma et al. 2015). According to
several studies, ferrates showed satisfactory disinfectant properties, inactivating a
wide variety of microorganisms even at low Fe(VI) concentrations (Sharma et al.
2005). Ferric ions produced from Fe(VI) represent a powerful coagulant that is
suitable for the removal of humic acids, radionuclides, and metals from wastewater (Sharma et al. 2005). Sharma et al. (2015) reported that complete degradation of two antibiotics, sulfamethoxazole and trimethoprim, was observed when
using Fe(VI) with molar ratio of SMX:Fe(VI) or TMP:Fe(VI) between 4:1 and
5:1. Moreover, the authors observed that by-products with no residual antibiotic
activity were produced during the oxidation of TMP using Fe(VI). The degradation of fluoroquinolone antibiotics (FQAs) from synthetic and natural waters was
studied at pH 7 using Fe(VI). The results highlighted that, except for flumequine,
all FQAs were degraded within 2 min at molar ratio Fe(VI):FQA lower than 20:1.
The authors mentioned that both multivalent cations (e.g., Ca
2+ , Mg
2+ , Cu
2+ , and
Fe
3+ ) and humic acid decreased the degradation of fluoroquinolone (Feng et al.
2016). Yang et al. (2012) investigated ferrate performance to degrade 68 endocrine disrupting chemicals and personal care products from spiked wastewater. Li
(2017) showed that 44% of mefenamic acid (C 0 ¼ 1 mg/L), a pharmaceutical, can
be removed using 2 mg/L of ferrate.
Previous studies on mine water with AOPs aimed at cyanides and derivatives
(including NH 3 -N), sulfur, sulfides and thiosalts, and metal removal using ferrates
[Fe(VI)] (Gonzalez-Merchan et al. 2016; Sharma 2011) and ozone microbubbles
29 Future Prospects for Treating Contaminants of Emerging Concern in. . .
597
and aniline of antimicrobials by ozonation leads to the deactivation of the
bactericidal functions of these compounds (Gogoi et al. 2018). Efficiency higher
than 90% was obtained when using ozonation onto non-aromatic alkenes, aromatic compounds that are abundant in electrons (sulfamethoxazoles—SMXs),
and aromatic compounds with deprotonated amine groups (trimethoprim—TMP)
(Gogoi et al. 2018). The combination of ozone and UV irradiation has been
studied to remove pesticides (Adeleye et al. 2016; Ikehata et al. 2006; Lafi and
Al-Qodah 2006), pharmaceuticals (Gebhardt and Schröder 2007), and antibiotics
(Akmehmet Balcioğlu and Ötker 2004) from wastewater. Photocatalysis is
another promising AOP that has been found to be highly effective in removing
CECs and their derivatives through the formation of free hydroxyl radicals in the
presence of a metal oxide semiconductor such as TiO 2 and a light source (Fast
et al. 2017). Removal efficiencies greater that 90% have been reported in some
studies presented in Fast et al. (2017) and Rodriguez-Narvaez et al. (2017). The
dosage of photocatalyst to be used is of huge importance as under- or overdosing
loads may result in slower degradation rates of CECs. The fouling of TiO 2
catalyst or UV lamps can occur, resulting in loss of CECs degradation efficiencies
(Fast et al. 2017). In recent years, hexavalent state of tetraoxy iron [Fe(VI)O 4
2À ],
also known as ferrate, has been used as a strong oxidant to remove pollutants
from municipal and hospital wastewater including pharmaceuticals, personal care
products, endocrine disrupting chemicals, and cyanotoxins (Jiang 2013; Jiang
et al. 2014; Li 2017; Sharma et al. 2005; Sharma et al. 2015). According to
several studies, ferrates showed satisfactory disinfectant properties, inactivating a
wide variety of microorganisms even at low Fe(VI) concentrations (Sharma et al.
2005). Ferric ions produced from Fe(VI) represent a powerful coagulant that is
suitable for the removal of humic acids, radionuclides, and metals from wastewater (Sharma et al. 2005). Sharma et al. (2015) reported that complete degradation of two antibiotics, sulfamethoxazole and trimethoprim, was observed when
using Fe(VI) with molar ratio of SMX:Fe(VI) or TMP:Fe(VI) between 4:1 and
5:1. Moreover, the authors observed that by-products with no residual antibiotic
activity were produced during the oxidation of TMP using Fe(VI). The degradation of fluoroquinolone antibiotics (FQAs) from synthetic and natural waters was
studied at pH 7 using Fe(VI). The results highlighted that, except for flumequine,
all FQAs were degraded within 2 min at molar ratio Fe(VI):FQA lower than 20:1.
The authors mentioned that both multivalent cations (e.g., Ca
2+ , Mg
2+ , Cu
2+ , and
Fe
3+ ) and humic acid decreased the degradation of fluoroquinolone (Feng et al.
2016). Yang et al. (2012) investigated ferrate performance to degrade 68 endocrine disrupting chemicals and personal care products from spiked wastewater. Li
(2017) showed that 44% of mefenamic acid (C 0 ¼ 1 mg/L), a pharmaceutical, can
be removed using 2 mg/L of ferrate.
Previous studies on mine water with AOPs aimed at cyanides and derivatives
(including NH 3 -N), sulfur, sulfides and thiosalts, and metal removal using ferrates
[Fe(VI)] (Gonzalez-Merchan et al. 2016; Sharma 2011) and ozone microbubbles
29 Future Prospects for Treating Contaminants of Emerging Concern in. . .
597