**6. Solar photodecomposition of hormones**

The 17β-estradiol (E2) is the most natural estrogenic hormone occurring in sewagepolluted waters and also an intermediate key in the industrial synthesis of other estrogens. It is frequent in natural water environment with the high potential to hormonal disruption pathways in wildlife even in low nanogram concentrations. Recently, it was added to the watch list of priority substances in the EU Water Framework Directive. Many research projects use E2 as representative of emerging pollutant (EP) for water tertiary treatment study and photodecomposition improvement [8].

There are many studies of immobilized TiO2-based composites, TiO2- and iron-exchanged zeolite of ZSM5 type (TiO2-FeZ), or another semiconducting material (TiO2-SnS2) and active solar photocatalysts. The solar-driven photocatalytic parameters as pH values, H2O2 concentration, and composite formulation, on the effectiveness of E2 degradation, allow the calculation of the surface modeling. The solar/TiO2-FeZ/H2O2 process achieved E2 degradation by 78.1%; it was higher in comparison with the reference process of TiO2 P25 with 41.3% of remotions and

the solar/TiO2-SnS2 and solar/TiO2-SnS2/H2O2 processes with 51.0 and 34.4%, respectively. The E2 degradation by solar/TiO2<sup>−</sup>FeZ/H2O2 enhances in the presence of NOM, as real water constituents. On the other hand, the nitrates and carbonates presence show an inhibitory effect.

There are many studies using visible photodecomposition of the hormones such as estrone (E1), 17β-estradiol (E2), estriol (E3), and 17β-ethinylestradiol (EE2) with the concentration in the interval of 0.004–5.00 mg L<sup>−</sup><sup>1</sup> using TiO2 in porous sheets, microcrystalline glass plates, P25 suspension, UVC/H2O2, solar Fe II, and ozone 30 mg L<sup>−</sup><sup>1</sup> . The process usually includes UV and visible light from 280 to 400 nm and full spectrum from 200 nm to 30 μm, and LED lamp with the lines at 382 nm, 254 nm, and 254 high intensity. The kinetics of such process was from 550×10<sup>−</sup><sup>3</sup> min<sup>−</sup><sup>1</sup> (pH 5) to 3.4 min<sup>−</sup><sup>1</sup> (20°C) with and without H2O2 with solar light 86% in 60 min and 63.9% in 12 min. The hormones enter in the water environment mainly from the sewage discharge and the effluent of sewage treatment plants. The EE2 is the main composition of the oral contraceptives, and E1, E2, and E3 occur naturally. The estrogenicity order is EE2 > E2 > > E1>>>> > E3. Most of the hormones show photodegradation over immobilized TiO2 sheets under UV-LED irradiation or solar radiation following the first-order kinetics, faster at pH 4.

The most efficient hormone decomposition is the combination of the photodecomposition and ozonation using TiO2-coated glass with LED irradiation on λ = 382 nm. The application of such a dynamic process removes about 22 chemical priority substances and contaminants of emerging concern, including the resistant bacteria and genes after discharge in surface water resources. There was no compound with estrogen effect formed after the reaction; the process improves the removal efficiency of microbial loads.

The improvement of the EE2 degradation, clofibric acid, nonylphenol, and carbamazepine was slightly by the use of ultrasound combined with ozonation and photodecomposition. The removal percentage increases with pH, but at higher pH also showed an adverse decomposition effect.

The test in vitro can detect estrogen receptor agonists and antagonists. However, the estrogen-disrupting compounds do not only act on the estrogen receptor but also inhibit enzymatic catalysis reactions and the transport of hormones in the blood or the hormone production. Only in vivo analysis with a full spectrum of possible mechanisms can be identified in a whole organism.

The photocatalytic degradation of 17α-ethynylestradiol (EE2) allows the identification of 12 intermediates. The decomposition efficiency of EE2 decreased at pH 3 and in the presence of methanol at pH 7. The study proposes three degradation pathways: (1) the transformation of the phenolic ring, (2) the photocatalytic degradation of the aliphatic carbon linked to the aromatic ring at pH 7, and (3) the isomerization of EE2 in the presence of methanol at pH 7. The EE2 photocatalytic degradation is pH-dependent and at pH of 3, 7, and 10 without methanol addition were 63, 72, and 99%, respectively. The pH increase facilitated the formation of hydroxyl or hydroperoxyl disubstituted intermediates. In aqueous solutions, aliphatic carboxylic acid decarboxylation is preferable to the corresponding reduced hydrocarbons; some published results indicate the favored pathway for dicarboxylic acid mineralization is the decarboxylation resulting from the photo-Kolbe reaction [Eq. (3)]. The responsible for the formation of intermediary compounds is the attack of the ˙OH and ˙OOH radicals:

$$\text{RCOO}^{-} + \text{h}^{\*} \rightarrow \text{R'} + \text{CO}\_{2} \text{ (photo-Kolbe)}\tag{3}$$

**75**

disadvantages.

*Green Water Treatment for Pharmaceutical Pollution DOI: http://dx.doi.org/10.5772/intechopen.85116*

oxidation.

and (5)]. Under acidic conditions, there is the inhibition of the radical methanol

solution, and the formation of EEO only occurred under neutral pH conditions:

h<sup>+</sup> + CH3OH → CH3O˙+H<sup>+</sup> (4)

The photodecomposition of methanol acts as an ˙OH scavenger and retards the photocatalytic degradation of EE2 reducing for only 8, 11, and 15% at pH of 3, 7, and 10, respectively, with methanol presence. Published researches indicate just the addition of a small amount of methanol or toluene inhibited the photocatalytic

The formation of the intermediate products was in low mineralization rate and low removal efficiencies, resulting in total organic carbon less than 20% with the

occurrence only of the phenolic ring transformation during the reaction.

plant and their effluents was in concentrations of 10 to 65 μg L<sup>−</sup><sup>1</sup>

quinone; both by-products are toxic of significant concern.

ments, allowing to reach surface water resources.

**7. Solar treatment for acetaminophen and antipyrine contamination**

The acetaminophen (ACE) is one of the most widely used analgesics and antipyretic drugs and is one of the top pharmaceuticals prescribed in the USA or England, being China the second ACE manufacturer. It is present in surface water bodies as a result of 60–70% of human excretion via urine after medicine consumption [9]. The ACE water detection in the USA and Europe on sewage treatment

such water pollution may lead to hepatic necrosis caused by its transformation to N-acetyl-benzoquinone imine upon oxidation, which can hydrolyze to 1,4-benzo-

The antipyrine (ANT) detection is common in sewage and polluted surface water. Such anti-inflammatory compound is a nonsteroidal and antipyretic drug which enters in the aquatic environment after use. Environmental accumulation causes adverse human health effects and affects aquatic life. The concentrations of emerging contaminants in the influent and effluent from wastewater treatment plants showed the concentration of ANT was relatively low (about 0.04 mg L<sup>−</sup><sup>1</sup>

and about 68.5% escaped from conventional activated sludge wastewater treat-

TiO2 is still the widest semiconductor used for ACE and ANT photodegradation due to its low cost, nontoxicity, and chemical stability. Nevertheless, the difficulty of TiO2 recovery after the reaction and the relatively limited adsorption capacity with low surface area and porosity are some of the technological

There is no acetaminophen degradation versus time under solar irradiation in the absence of photocatalyst after 6 h; the removal using different photocatalysts without light irradiation also can be considered negligible (lower than 6%). The sensitization of TiO2 by the carbon material titanium nanotubes and C-Ti showed a significantly higher activity than the non-modified Ti. However, the acetaminophen removal remained below 70% after 4 h of illumination. The lack of anatase crystal structure is responsible for the small photoactivity; the amorphous titanium is not active. The air calcination at above 300°C had a beneficial effect on C-Ti catalyst; the calcined samples at 400 and 500°C allowed the total acetaminophen conversion in only 1 h. The crystallization of TiO2 explains the effect into anatase (with a bandgap energy of 3.12 eV), which is the most active titanium phase for photocatalytic

existed in the

<sup>−</sup> (5)

. In population,

),

production. Alternatively, under alkaline condition, very little free h<sup>+</sup>

CH3O˙→ H2CO + H<sup>+</sup> + e

First was the oxidation of the EE2 and then the reduction to EEO in the presence of h<sup>+</sup> and electron, formed by the methanol radical as described in [Eqs. (4) *Green Chemistry Applications*

ozone 30 mg L<sup>−</sup><sup>1</sup>

min<sup>−</sup><sup>1</sup>

550×10<sup>−</sup><sup>3</sup>

presence show an inhibitory effect.

removal efficiency of microbial loads.

attack of the ˙OH and ˙OOH radicals:

also showed an adverse decomposition effect.

possible mechanisms can be identified in a whole organism.

the solar/TiO2-SnS2 and solar/TiO2-SnS2/H2O2 processes with 51.0 and 34.4%, respectively. The E2 degradation by solar/TiO2<sup>−</sup>FeZ/H2O2 enhances in the presence of NOM, as real water constituents. On the other hand, the nitrates and carbonates

with the concentration in the interval of 0.004–5.00 mg L<sup>−</sup><sup>1</sup>

(pH 5) to 3.4 min<sup>−</sup><sup>1</sup>

There are many studies using visible photodecomposition of the hormones such as estrone (E1), 17β-estradiol (E2), estriol (E3), and 17β-ethinylestradiol (EE2)

. The process usually includes UV and visible light from 280 to

(20°C) with and without H2O2 with solar light

sheets, microcrystalline glass plates, P25 suspension, UVC/H2O2, solar Fe II, and

400 nm and full spectrum from 200 nm to 30 μm, and LED lamp with the lines at 382 nm, 254 nm, and 254 high intensity. The kinetics of such process was from

86% in 60 min and 63.9% in 12 min. The hormones enter in the water environment mainly from the sewage discharge and the effluent of sewage treatment plants. The EE2 is the main composition of the oral contraceptives, and E1, E2, and E3 occur naturally. The estrogenicity order is EE2 > E2 > > E1>>>> > E3. Most of the hormones show photodegradation over immobilized TiO2 sheets under UV-LED irradiation or solar radiation following the first-order kinetics, faster at pH 4. The most efficient hormone decomposition is the combination of the photodecomposition and ozonation using TiO2-coated glass with LED irradiation on λ = 382 nm. The application of such a dynamic process removes about 22 chemical priority substances and contaminants of emerging concern, including the resistant bacteria and genes after discharge in surface water resources. There was no compound with estrogen effect formed after the reaction; the process improves the

The improvement of the EE2 degradation, clofibric acid, nonylphenol, and carbamazepine was slightly by the use of ultrasound combined with ozonation and photodecomposition. The removal percentage increases with pH, but at higher pH

The test in vitro can detect estrogen receptor agonists and antagonists. However, the estrogen-disrupting compounds do not only act on the estrogen receptor but also inhibit enzymatic catalysis reactions and the transport of hormones in the blood or the hormone production. Only in vivo analysis with a full spectrum of

The photocatalytic degradation of 17α-ethynylestradiol (EE2) allows the identification of 12 intermediates. The decomposition efficiency of EE2 decreased at pH 3 and in the presence of methanol at pH 7. The study proposes three degradation pathways: (1) the transformation of the phenolic ring, (2) the photocatalytic degradation of the aliphatic carbon linked to the aromatic ring at pH 7, and (3) the isomerization of EE2 in the presence of methanol at pH 7. The EE2 photocatalytic degradation is pH-dependent and at pH of 3, 7, and 10 without methanol addition were 63, 72, and 99%, respectively. The pH increase facilitated the formation of hydroxyl or hydroperoxyl disubstituted intermediates. In aqueous solutions, aliphatic carboxylic acid decarboxylation is preferable to the corresponding reduced hydrocarbons; some published results indicate the favored pathway for dicarboxylic acid mineralization is the decarboxylation resulting from the photo-Kolbe reaction [Eq. (3)]. The responsible for the formation of intermediary compounds is the

RCOO<sup>−</sup> + h<sup>+</sup> → R˙+CO2 (photo − Kolbe) (3)

First was the oxidation of the EE2 and then the reduction to EEO in the pres-

and electron, formed by the methanol radical as described in [Eqs. (4)

using TiO2 in porous

**74**

ence of h<sup>+</sup>

and (5)]. Under acidic conditions, there is the inhibition of the radical methanol production. Alternatively, under alkaline condition, very little free h<sup>+</sup> existed in the solution, and the formation of EEO only occurred under neutral pH conditions:

$$\text{h}^\* \star \text{CH}\_3\text{OH} \rightarrow \text{CH}\_3\text{O}^\* \star \text{H}^\* \tag{4}$$

$$\text{CH}\_3\text{O}^\cdot \rightarrow \text{H}\_2\text{CO} + \text{H}^+ + \text{e}^- \tag{5}$$

The photodecomposition of methanol acts as an ˙OH scavenger and retards the photocatalytic degradation of EE2 reducing for only 8, 11, and 15% at pH of 3, 7, and 10, respectively, with methanol presence. Published researches indicate just the addition of a small amount of methanol or toluene inhibited the photocatalytic oxidation.

The formation of the intermediate products was in low mineralization rate and low removal efficiencies, resulting in total organic carbon less than 20% with the occurrence only of the phenolic ring transformation during the reaction.

## **7. Solar treatment for acetaminophen and antipyrine contamination**

The acetaminophen (ACE) is one of the most widely used analgesics and antipyretic drugs and is one of the top pharmaceuticals prescribed in the USA or England, being China the second ACE manufacturer. It is present in surface water bodies as a result of 60–70% of human excretion via urine after medicine consumption [9]. The ACE water detection in the USA and Europe on sewage treatment plant and their effluents was in concentrations of 10 to 65 μg L<sup>−</sup><sup>1</sup> . In population, such water pollution may lead to hepatic necrosis caused by its transformation to N-acetyl-benzoquinone imine upon oxidation, which can hydrolyze to 1,4-benzoquinone; both by-products are toxic of significant concern.

The antipyrine (ANT) detection is common in sewage and polluted surface water. Such anti-inflammatory compound is a nonsteroidal and antipyretic drug which enters in the aquatic environment after use. Environmental accumulation causes adverse human health effects and affects aquatic life. The concentrations of emerging contaminants in the influent and effluent from wastewater treatment plants showed the concentration of ANT was relatively low (about 0.04 mg L<sup>−</sup><sup>1</sup> ), and about 68.5% escaped from conventional activated sludge wastewater treatments, allowing to reach surface water resources.

TiO2 is still the widest semiconductor used for ACE and ANT photodegradation due to its low cost, nontoxicity, and chemical stability. Nevertheless, the difficulty of TiO2 recovery after the reaction and the relatively limited adsorption capacity with low surface area and porosity are some of the technological disadvantages.

There is no acetaminophen degradation versus time under solar irradiation in the absence of photocatalyst after 6 h; the removal using different photocatalysts without light irradiation also can be considered negligible (lower than 6%). The sensitization of TiO2 by the carbon material titanium nanotubes and C-Ti showed a significantly higher activity than the non-modified Ti. However, the acetaminophen removal remained below 70% after 4 h of illumination. The lack of anatase crystal structure is responsible for the small photoactivity; the amorphous titanium is not active. The air calcination at above 300°C had a beneficial effect on C-Ti catalyst; the calcined samples at 400 and 500°C allowed the total acetaminophen conversion in only 1 h. The crystallization of TiO2 explains the effect into anatase (with a bandgap energy of 3.12 eV), which is the most active titanium phase for photocatalytic

applications; at the lowest calcination temperature tested (300°C), there is no significant crystallization of anatase.

Published results indicated the pseudo-first-order rates were 0.13, 0.19, and 0.38 h<sup>−</sup><sup>1</sup> for complete photodecomposition of antipyrine, acetaminophen, and ibuprofen, respectively. Regarding with the properties of the C-TiO2 semiconductor materials, the structured defects caused by the C incorporation (as substitutional anion or interstitial cation) are the responsible for the photocatalytic activity of these materials, acting as trap centers or the photogenerated charges.

The investigation of the role of the reactive oxygen species used selected scavengers as isopropanol, the OH radical scavenger; the addition reduced the degradation rate. The OH radicals are very reactive, and the reduction by the scavenger inhibited the degradation rate, an indication of the involvement of the OH radical production in acetaminophen photodegradation. Some references mentioned the O2 <sup>−</sup> radicals attack preferentially organic compounds with aromatic rings (as ACE aromatic ring).
