**2. EPs photodecomposition**

by-products (urban and industry), wood preservation, and industrial chemical manufacturing. Different types of EPs show different properties as the organic substances divided in PBT for persistent bioaccumulative and toxic substances as POPs and persistent organic compounds. The EPs with more polarity are the pesticides, pharmaceuticals, and industrial chemicals. The inorganic compounds as poisonous metals are also found in polluted waters and finally the

The EPs monitoring and control are a huge problem, and the solution represents a significant challenge in sampling procedures and analytical techniques. The monitoring procedures do not cover all EPs with a potential concern being the highly known hazardous controlled, and the newly discovered contaminants as nanomaterials and microplastics are virtually analytically nonexistent. In the study, the EPs presence and toxicity are studied using bioindication; the most common organism is the *Gammarus pulex* as a model invertebrate from water and sediment.

The properties such as absorption behaviors of pharmaceuticals, for example, can vary vastly in different soil types on ionized and nonionized form, affecting the interaction of soil. Little information is available about the EPs dynamics in the water column, sediments, and the accumulation in the aquatic food chain and the loads from the agro-environment through

The EPs decomposition products detection includes enantiomeric distribution of chiral compounds found in the environment, and their possible toxicological differences between enantiomers that are of concern. Such information for the risk assessment analysis is also considered [3].

Worldwide, the regulatory framework is under development to control the production and the discharge of the EPs into water resources, a complex set of regulations governing the production, commercialization, and emission to control the EPs presence in the environment and the drinking water (quality standards and monitoring specification). The European Union (EU) has a regulation plan to register, evaluate, authorize, and restrict the use of almost all

The agricultural activity is one of the most critical contributors to diffuse pollution in Europe, and such emissions are predicted to increase in the future. The agriculture activity is considered an essential business for regulating the chemical EPs use and emission discharge into the environment. Some research projects are under development, trying to treat, decompose, and

The emerging pollutants are considered the potentially toxic chemicals present in low concentrations and many environmental compartments. They include pesticides, biocides, pharmaceuticals, industrial chemicals, and personal care products. The common entrance of these compounds in surface water resources is via untreated sewage discharge, the effluents of wastewater treatment plants (WWTPs), and from agricultural, urban, and street runoff. The organic pollutant water inputs usually occur continuously in low dosages or as peaks trigged by emission or runoff events. Such a behavior is particularly harmful to antibiotics environmental contamination, providing the optimized conditions for microorganism adaptation

The concept of chemical activity helps to understand the EPs environmental fate, distribution, quantification, and prediction of the ecological partitioning theory of the chemicals in aquatic

newly developed particulate contaminants as nanoparticles and microplastics [2].

80 Emerging Pollutants - Some Strategies for the Quality Preservation of Our Environment

diffuse pollution or from urban and industrial areas [3, 4].

EPs substances manufactured or imported to EU.

remove those pollutants from the water resources.

and increase in resistance.

Two of the main topics of growing concern in analytical chemistry are the development of green water treatment. TiO2 has emerged as a promising photocatalyst for environmental cleanup applications; they have efficiently decomposed and removed a variety of pollutants promoting the generation of OH radicals using oxidation reactions with in situ active oxygen generated upon light irradiation. In water purification, photodegradation of contaminants in real water samples has become an important topic of research in the recent years.

There are some studies using electrocoagulation process to decompose EPs compounds. The process is an electrochemical introducing coagulants and removing suspended solids, colloidal material, and metals as well as other dissolved solids from water and wastewater eliminating pollutants, pesticides, and radionuclides. A direct current is applied, and one electrode is soluble into a solution which finally precipitates as oxides or hydroxides.

The environmental chemistry is the base for many treatment technologies of these pollutants, and the application of the adsorption process is one of the most used techniques. The results and comparison of different treatment technologies usually consider the initial concentration and the final concentration. The adsorbent materials are graphene oxide, clay mineral and biochar, nanocrystalline mineral, and arsenite using an enhanced coagulation process [6, 7]. The pharmaceuticals used iron chemical reduction reaction, and the advanced oxidation performed by ozone/UV also was used. The pharmaceuticals uses iron chemical reduction reaction, and the advanced oxidation performed by ozone /UV. The study of micropollutants biodegradation uses also a membrane.

The most common material used for EPs adsorption is the activated carbon (AC) with high porosity and surface area, and the use of AC shows the removal percentage higher than 90% for a wide variety of compounds bringing the residual concentration below the regulation limit. Other materials need more contact time for the same results. The advanced wastewater reclamation plant often uses the AC [5]. Many authors point out the high importance of the AC origin, depending on the initial crystalline structure of the biomass, the AC obtained from wood, vine, and olive waste, and coal showed the removal percentage always higher than 80% for antibiotics.

There are some adsorbents used for pharmaceutical removal as biochar, clay minerals, zeolites, Fe-Mn-binary oxide, graphene oxide, alumina, nanoscale iron, molecularly imprinted polymer, and carbon nanotubes [5, 8].

The phase extraction uses organic phase to remove organic contaminants, and the use of membrane technology is for pharmaceuticals removal from polluted waters. The bases of the membrane technology are the hydrostatic pressure to remove suspended solids, and solutes with a high molecular weight also classified as ultrafiltration, nanofiltration, microfiltration, forward osmosis, and reverse osmosis. The high removal percentages are obtained for forward and reverse osmosis with the removal percentages usually more than 95%.

The biological processes in conventional activated sludge decompose only the natural pharmaceutical compounds like caffeine, dichlorofenac, and trimethoprim. The advanced oxidation processes provide higher removal percentages associated with the hydroxyl radical production with removal percentages always higher than 96% including the sonochemical decomposition. The solar photo Fenton process obtains the removal percentage of 95–97.5% in just 20 min of reaction.

Many published results indicate that the degradation of EPs using a single treatment is not likely the best approach to treat and remove EPs from water, and the use of a combined technology can overcome deficiencies of individual technologies and be able to ply in complex mixtures of contaminants. The advanced oxidation processes are at present the most efficient degradation processed for EPs contamination.

The results of the kinetics studies of photodecomposition and biocarbon sorption provide valuable insights about the kinetics models: pseudo-first-order (Eq. (1)), pseudo-secondorder (Eq. (2)), and intraparticle (Eq. (3)) with the determination of photodecomposition and adsorption rates on pseudo-first-order equation [9, 10].

$$
\log(\mathbf{q}\_\circ - \mathbf{q}\_\circ) = \log(\mathbf{q}\_\circ) - \frac{\mathbf{K}\_\circ}{2.303} \mathbf{t} \tag{1}
$$

and the reaction time; larger K<sup>1</sup>

tion with pseudo-first-order, sometimes just one K<sup>1</sup>

spondence with the pseudo-second order.

complete the reaction; the R2

where the slope value is K<sup>2</sup>

slow step of the adsorption reaction.

adsorbent-reduced surface area, TiO2

TiO2

low cost.

The use of integrated processes as solar/TiO2

**3. The antibiotics photodecomposition products**

indicates a fast reactant consumption and small time to

EPs Antibiotics: Photodecomposition and Biocarbon Adsorption

value; all results showed a better corre-

http://dx.doi.org/10.5772/intechopen.76893

83

photodecomposition followed by adsorption

oxidation surface, and solid low stability due to long-

values obtained for the pseudo-first equation indicate a lower

. The pseudo-second order showed better correspondence with

correspondence between the results and the theory. Some published results show the solar photodecomposition processes with goethite as pseudo-first-order kinetics with K = 0.26 × 10−2 min−1. Usually, the photodecomposition experimental results indicated a lower correla-

Considering the pseudo-second-order reaction, the sum of the exponents in the equation rate is equal to two for the plotted reactant concentrations with time. The pseudo-second-order response depends on the initial content, of the two different reactants A and B combining in a single elementary step. Before the rate, where A decreases, they can be expressed using the differential equation, and the linear equation can be rearranged, integrated, and followed

the experimental results corroborating with many published results for biocarbon adsorption and amoxicillin (AMX) removal treatments. The interparticle reaction usually points out the

has many advantages as an excellent potential for photocatalysis with the application of solar treatment chambers and possible self-cleaning surfaces. However, the practical applications and continuous use demand solutions to kinetics problems, and they may rise as the

term use and the potential oxide mass production. The amoxicillin degradation with solar/

The electrospray ionization mass spectrometry (ESI-MS) analytical technique measures the EPs methylene blue (MB) photodecomposition. Before the photodecomposition reaction, the methylene blue compound was m/z 284 (**Figure 1(a)**), and after 1 day of photodecomposition, there are several peaks (**Figure 1(b)**). Those peaks were MB fragment degradation compounds with m/z values of 109, 129, and 165. Those peaks have the relative intensity of 37.3,

The EPs dye photosensitization process involves the dye initial electronic excitation D to D\* induced by hν incident radiation energy which ejects one electron in the semiconductor (SC) conduction band [8, 16, 17]. The emitted electron reacts with the environment oxygen oxidiz-

44.2, and 40.5% considering the original MB peak of 100% with m/z 284 (**Figure 1(a)**).

ing the radial D\*o, and the total process results in colorless products, Eq. (6).

 anatase proceeds about three times faster than with ultraviolet (UV) lamp [14, 15]. The explanation of the disproportional improvement oxidation rates is the difference between the small spectrum irradiance of UV band and the broad spectrum of visible solar light. The intensity of radiation spectrum grows with an increasing wavelength from 300 to 500 nm. The combination of solar photodecomposition and the adsorption process is efficient and

where K<sup>1</sup> is the pseudo-first-order rate (min−1) and qe (mgg−1) refers to the experimental adsorbed mass at equilibrium. The plotting of the calculated values of ln (qe-qt) for t (time) and the calculation of K<sup>1</sup> were used the slope values of the line equation.

Pseudo-second order equation:

$$\frac{\mathbf{t}}{\mathbf{q}\_1} = \frac{1}{\mathbf{K}\_2} + \frac{1}{\mathbf{q}\_o}\mathbf{t} \tag{2}$$

where K<sup>2</sup> (g.mg−1.min−1) is the kinetics adsorption rate, plotting the t/qt for t (min), and the calculation predicted the adsorption capacity qe (mg g−1) and the integrated adsorption rate K2 with the slope and the intercept of the line equation, respectively.

Intraparticle equation:

$$
\log \text{(q)}\_{\text{l}} = \log \text{(K}\_{\text{ul}}) + \text{alog}(\text{t}) \tag{3}
$$

The use of the experimental results allows performing the kinetics calculations [11–13], using Eqs. (1)–(3). The pseudo-first-order equation represents a logarithm of the reactant species and the reaction time; larger K<sup>1</sup> indicates a fast reactant consumption and small time to complete the reaction; the R2 values obtained for the pseudo-first equation indicate a lower correspondence between the results and the theory. Some published results show the solar photodecomposition processes with goethite as pseudo-first-order kinetics with K = 0.26 × 10−2 min−1. Usually, the photodecomposition experimental results indicated a lower correlation with pseudo-first-order, sometimes just one K<sup>1</sup> value; all results showed a better correspondence with the pseudo-second order.

The phase extraction uses organic phase to remove organic contaminants, and the use of membrane technology is for pharmaceuticals removal from polluted waters. The bases of the membrane technology are the hydrostatic pressure to remove suspended solids, and solutes with a high molecular weight also classified as ultrafiltration, nanofiltration, microfiltration, forward osmosis, and reverse osmosis. The high removal percentages are obtained for for-

The biological processes in conventional activated sludge decompose only the natural pharmaceutical compounds like caffeine, dichlorofenac, and trimethoprim. The advanced oxidation processes provide higher removal percentages associated with the hydroxyl radical production with removal percentages always higher than 96% including the sonochemical decomposition. The solar photo Fenton process obtains the removal percentage of 95–97.5%

Many published results indicate that the degradation of EPs using a single treatment is not likely the best approach to treat and remove EPs from water, and the use of a combined technology can overcome deficiencies of individual technologies and be able to ply in complex mixtures of contaminants. The advanced oxidation processes are at present the most efficient

The results of the kinetics studies of photodecomposition and biocarbon sorption provide valuable insights about the kinetics models: pseudo-first-order (Eq. (1)), pseudo-secondorder (Eq. (2)), and intraparticle (Eq. (3)) with the determination of photodecomposition and

adsorbed mass at equilibrium. The plotting of the calculated values of ln (qe-qt) for t (time)

calculation predicted the adsorption capacity qe (mg g−1) and the integrated adsorption rate

log(qt) = log(Kid) + alog(t) (3)

The use of the experimental results allows performing the kinetics calculations [11–13], using Eqs. (1)–(3). The pseudo-first-order equation represents a logarithm of the reactant species

qt = \_\_\_1 K2 + \_\_1 qe

with the slope and the intercept of the line equation, respectively.

were used the slope values of the line equation.

is the pseudo-first-order rate (min−1) and qe (mgg−1) refers to the experimental

(g.mg−1.min−1) is the kinetics adsorption rate, plotting the t/qt for t (min), and the

2.303 t (1)

t (2)

ward and reverse osmosis with the removal percentages usually more than 95%.

82 Emerging Pollutants - Some Strategies for the Quality Preservation of Our Environment

in just 20 min of reaction.

where K<sup>1</sup>

where K<sup>2</sup>

K2

and the calculation of K<sup>1</sup>

Intraparticle equation:

Pseudo-second order equation:

\_\_t

degradation processed for EPs contamination.

adsorption rates on pseudo-first-order equation [9, 10].

log(qe <sup>−</sup> qt) <sup>=</sup> log(qe) <sup>−</sup> \_\_\_\_\_ <sup>K</sup><sup>1</sup>

Considering the pseudo-second-order reaction, the sum of the exponents in the equation rate is equal to two for the plotted reactant concentrations with time. The pseudo-second-order response depends on the initial content, of the two different reactants A and B combining in a single elementary step. Before the rate, where A decreases, they can be expressed using the differential equation, and the linear equation can be rearranged, integrated, and followed where the slope value is K<sup>2</sup> . The pseudo-second order showed better correspondence with the experimental results corroborating with many published results for biocarbon adsorption and amoxicillin (AMX) removal treatments. The interparticle reaction usually points out the slow step of the adsorption reaction.

The use of integrated processes as solar/TiO2 photodecomposition followed by adsorption has many advantages as an excellent potential for photocatalysis with the application of solar treatment chambers and possible self-cleaning surfaces. However, the practical applications and continuous use demand solutions to kinetics problems, and they may rise as the adsorbent-reduced surface area, TiO2 oxidation surface, and solid low stability due to longterm use and the potential oxide mass production. The amoxicillin degradation with solar/ TiO2 anatase proceeds about three times faster than with ultraviolet (UV) lamp [14, 15]. The explanation of the disproportional improvement oxidation rates is the difference between the small spectrum irradiance of UV band and the broad spectrum of visible solar light. The intensity of radiation spectrum grows with an increasing wavelength from 300 to 500 nm. The combination of solar photodecomposition and the adsorption process is efficient and low cost.
