**5. The biocarbon: adsorbent uses**

compounds are responsible for their deactivation. There are several possible sites of the coordination for the metal ions on penicillin. The nitrogen and the double oxygen bonding are the

The amoxicillin and many antibiotics can act as a complex ligand with several possible sites for metal ions like Cu (II), Zn (II), and Cd(II) for coordination on penicillin. In the study, the kinetics and thermodynamics calculations are easy to find and how the neighboring group affects the probable complexation sites, of metals and the C=O of the antibiotic β-lactamic group and the NH amido penicillin group. The two most probable structures are shown in **Figure 7**. They are not excluding each other. For cephalexin and Cu2+, the interaction takes

The metal ligand binary constants at temperature 37°C and ionic strength for ampicillin and Co2+ are = 3.12, for Ni2+ = 3.66, for Cu2+ = 4.79 and for Zn2+ = 2.98. Usually, the complex constants

is steady, inexpensive photocatalyst, and widely applied for removal and decom-

remove high toxic contaminants from mixed solution, mostly in the presence of other pollutants [15, 16]. Some studies use tetracycline (TC) as a molecular template and the TiO2

ash cenospheres as a supporter, the synthesis of the molecularly imprinted photocatalyst (MIP). Such a material possesses the specific recognition ability toward tetracycline (TC) using surface-imprinting technology and the photo-induced method. The cenospheres hollow spherical structure has the diameter from 90 to 120 μm, and the degradation process of photocatalytic activity of MIP with 20 mgL−1 of TC under visible light radiation reached the photodegradation rate of 77%. Also, MIP showed the TC-selective recognition and promoted the photodegradation of TC in the ternary solutions containing TC, oxytetracycline (Oxy), and ciprofloxacin (CIP). The coefficients of selectivity of degradation from TC, Oxy, and CIP were 1.67 and 1.25, respectively. The photodegradation mechanism of TC analyzed by mass spectrum (MS) indicated the TC decomposition step by step, resulting in

A large number of antibiotics and their residues lead to the environmental emergence as a threat to indigenous microbial populations. The tetracycline (TC) ranks second in the global production and use. In spite of its consumption, environmental TC residues are very low (μgL−1 or nanogram L−1), but they are resilient, and the TC residues may cause a series of ecological environmental and human health effects, such as promoting the resistant bacteria. The photocatalytic with solar energy is green technology and capable of decomposing the organic

The molecular imprinting is a versatile and straightforward method for the preparation of robust materials which can recognize the specific target in secondary and tertiary systems. Then, stability, the ease of development, and low cost make the molecularly imprinted particularly

is not conducive to

fly

place through the side chain, the same as expected for ampicillin structure.

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

pose organic pollutants. However, the poor selectivity of the TiO2

most probable [13, 24, 26].

with Cooper are more stable [14, 23].

O, and other gases.

pollutant to a nontoxic compound.

The TiO2

CO2 , H2

**4. Binary and ternary antibiotics mixture**

Since the beginning, the powder biocarbon in Brazil was considered a worthless material, always related to airborne pollution, infant and slavery condition work, and work-related disease. Nowadays, a group of researchers is trying to restore the biocarbon industrial use as an essential additive for agroindustry on soil amendment with possibility of enhancing the organic matter and water content retention.

The biocarbon (biochar) has been used to increase the amount of organic matter in the agricultural soil. There are many benefits in this application, resulting in improved soil fertility, nutrient content, water retention, better physical structure, and improved microbial activity. Intense agricultural operation tends to reduce the amount of organic matter present in the soil.

The application of biocarbon can be decisive in the semi-arid region of the northeast region with low rainwater retention, and such water source is scarce and used in a short period of the year. Soon, the agriculturists of these areas will be able to produce the own bio-carbon utilizing the agriculture biomass.

The biocarbon organic matter composition allows its use as a slow-release fertilizer such as adsorbent properties promoting the addition, retaining and the release of nutrients. The addition of some plastic agents like stack gel and bentonite clay helps the nutrient releasing rate control during the pellets formation. The biocarbon is a renewable organic matter source and provides phosphate and nitrate from wastewater adsorption treatment with nutrient retention for further agriculture use as slow-release fertilizer.

Biocarbon produced in a high-temperature pyrolysis application on heavy metals retention such as cadmium and zinc is studied. In some cases, it has been used in the recovery of soils with different levels of cadmium, zinc, and leads contaminated by the mining industry, reducing the concentration of toxic metals in plants such as beans.

Biocarbon as an alternative adsorption matrix for water treatment and emerging pollutants removal has been confirmed. The biocarbon usually shows better environmental results in comparison with activated carbon, and also in many cases, it provides better potential energy supplied for lignocellulosic materials.

between biochar and SMZ [23, 26]. These studies confirmed that pH is the most crucial factor for

The integrated process of photodecomposition followed by adsorption study includes the adsorption isotherms, performing the calculations of Langmuir, Freundlich, and Redlich-Peterson (R-P) isotherms, Eqs. (7)–(9), respectively. The Langmuir isotherm adsorption assumes an ideal solid surface composed by a series of distinct sites capable of binding the adsorbate in a molecular coverage; the chemical reaction between the adsorbate molecule and the surface is a pseudo-second-order reaction. The Freundlich isotherm is empirical but widely used, and the value of n is a measure of the adsorption intensity higher than 1, where the adsorption processes are more favorable. The Redlich-Peterson (R-P) is more accurate than the Langmuir and Freundlich due the "g" value equal to 1. Usually, the R-P is by Langmuir and Freundlich isotherm equations; such observed behaviors were also studied. The error

logqe = logKf + 1/n logCe (8)

ln (Ce/qe) = g lnCe − lnKr (9)

where Ce = equilibrium concentration (mgL−1), qe = the amount adsorbed at equilibrium

rial, and b indicates the energy of adsorption. Kf and n are Freundlich constants. Kf indicates the adsorption capacity of the material and n indicates the efficiency of adsorption. Kr and g are Redlich-Peterson constants; Kr indicates the adsorption capacity and "g" is the exponent

The RL values were in the interval from 0 to 1, with favorable adsorption accordingly with Langmuir isotherm. The Freundlich isotherm constant n was also in the range of 2 < n < 10; the indication of the agreement with Freundlich model with equal adsorption heating and

The emerging pollutants are considered 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

, (7)

indicates the adsorption capacity of the mate-

EPs Antibiotics: Photodecomposition and Biocarbon Adsorption

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

93

biochar interactions with polar organic pollutants.

calculation will help to point out better isotherm adjustment

Ce/qe = 1/Q0 b + Ce/Q0

and b are Langmuir constants, Q<sup>0</sup>

Redlich-Peterson parameters were also promising.

(mg.g−1), Q0

between 0 and 1.

**6. Conclusion**

The biochar has various environmental applications like pollutant removal, carbon sequestration, and soil amendment. It has unique properties which makes it an efficient, cost-effective, and environmentally friendly material for contaminant removal. The different physical–chemical properties of the surface are microporosity and pH that can maximize its efficiency to various environmental applications. The research updates related to the pollutants interaction with surface functional groups of biochar and the effect of the parameters variability in biochar attribute to specific pollutants removal, involved mechanisms, and efficiency for these removals.

Emerging pollutants (EPs) include agrochemicals, antibiotics, polycyclic aromatic hydrocarbons (PAHS), polychlorinated biphenyls (PCBs), volatile organic compound (VOC), aromatic dyes, toxic metals, ammonia, nitrate, phosphate, sulfite from aqueous, gaseous, and solid phases. There is also the possibility of the biochar-tailoring properties to improve their removal efficiency for organic–inorganic contaminants [20]. The soil application not only remediates but improves soil properties as water-holding capacity, O2 content, and moisture level.

The removal of aromatic dyes, for example, rhodamine, methyl violet, and methyl blue by anionic biochar, is mainly involved in electrostatic attraction/repulsion interactions [17, 18, 25]. In these sorption mechanisms, highly polar biochar pyrolyzed at = <400°C contained aromatic Pi-configuration and electron donor and acceptor functional groups [20]. These π electronrich biochar functional groups (-Ve) have electron donor-acceptor interactions with π electron-deficient (+Ve) organic dyes. Hence, these interactions have resulted in an electrostatic repulsion and promoted pollutant adsorption via H-bonding between biochar and apolar dyes [26].

Crop residues as peanut, canola, soybean straw, rice hull, and so on derived biochar at a temperature of <400°C contained more O- and H-bearing functional groups. Thus, such a material exhibited a higher sorption capacity for apolar methyl violet and methylene blue due to pH change through biochar amendment [17, 24]. At higher pH, the net negative charge on biochar surface (due to dissociation of phenolic OH groups) increased the electrostatic interactions with methyl violet, whereas at lower pH, the π-π electron donor-acceptor interactions increased, thus improving the H-bonding for methylene blue sorption.

At zero point charge (ZPC), biochar does not have any surface charge, and it develops surface charge dependent on pH. The pH below the biochar ZPC (8.17, 8.52 and 8.79) comprised positive charge and sorbs less methylene blue. Whereas the pH higher of the biochars ZPC comprise negative surface charge increasing the methylene blue adsorption due high electrostatic attractions.

Likewise, the sorption of polar antibiotics sulfamethazine (SMZ) by hardwood/softwoodderived biochars (produced at 300–700°C has pH-dependent interactions. At higher pH, H bonding occurs between anionic SMZ and COOH or OH group biochar. At lower and neutral pH, the π-π electron donor-acceptor interactions and cation exchange are dominant mechanisms between biochar and SMZ [23, 26]. These studies confirmed that pH is the most crucial factor for biochar interactions with polar organic pollutants.

The integrated process of photodecomposition followed by adsorption study includes the adsorption isotherms, performing the calculations of Langmuir, Freundlich, and Redlich-Peterson (R-P) isotherms, Eqs. (7)–(9), respectively. The Langmuir isotherm adsorption assumes an ideal solid surface composed by a series of distinct sites capable of binding the adsorbate in a molecular coverage; the chemical reaction between the adsorbate molecule and the surface is a pseudo-second-order reaction. The Freundlich isotherm is empirical but widely used, and the value of n is a measure of the adsorption intensity higher than 1, where the adsorption processes are more favorable. The Redlich-Peterson (R-P) is more accurate than the Langmuir and Freundlich due the "g" value equal to 1. Usually, the R-P is by Langmuir and Freundlich isotherm equations; such observed behaviors were also studied. The error calculation will help to point out better isotherm adjustment

$$\text{Ce/qe} = 1/\text{Q}\_0 \text{b} + \text{Ce/Q}\_{0'} \tag{7}$$

$$\text{log}\text{qe = } \log \text{Kf} + 1/\text{n} \log \text{Ce} \tag{8}$$

$$
\ln\left(\text{Ce/qe}\right) = \text{g}\ln\text{Ce} - \ln\text{Kr} \tag{9}
$$

where Ce = equilibrium concentration (mgL−1), qe = the amount adsorbed at equilibrium (mg.g−1), Q0 and b are Langmuir constants, Q<sup>0</sup> indicates the adsorption capacity of the material, and b indicates the energy of adsorption. Kf and n are Freundlich constants. Kf indicates the adsorption capacity of the material and n indicates the efficiency of adsorption. Kr and g are Redlich-Peterson constants; Kr indicates the adsorption capacity and "g" is the exponent between 0 and 1.

The RL values were in the interval from 0 to 1, with favorable adsorption accordingly with Langmuir isotherm. The Freundlich isotherm constant n was also in the range of 2 < n < 10; the indication of the agreement with Freundlich model with equal adsorption heating and Redlich-Peterson parameters were also promising.
