**Abstract**

In this chapter, we report previous results about advances of an electrolysis process developed for breakdown of endocrine disrupting drugs in aqueous media. The objective is to achieve the breakdown of two drugs: trimethoprim and a mixture of clavulanic acid-amoxicillin (1:7) with an electrolytic cell by means of oxidization-reduction reactions. The evaluation of the process was carried out using spectrometry techniques UV-Vis, thin layer chromatography (TLC), chemical oxygen demand (COD), and total organic carbon (TOC). Handcrafted mineral carbon electrodes doped with titanium dioxide were designed, platinum and copper wires were placed, and a potassium hydroxide solution was used as electrolyte. The electrolyte, being an alkaline salt, allows the transport of charges from one side to the other, and electrode doped with titanium dioxide is used in order to help the electronic transfer, and the mineral carbon, having a strong affinity for organic and non-polar compounds, performs an adsorption process. Results from several performed assays showed that after 1 hour of treatment, it can be seen the breakdown of the drugs present in a synthetic wastewater solution.

**Keywords:** electrolysis, oxidation, reduction, drug, depuration, breakdown, absorbance, concentration, electrode

### **1. Introduction**

Unregulated emerging pollutants enter aquatic systems through wastewater treatment plants after consumption and use by humans and animals [1].

This poses a significant risk to aquatic organisms and to public health. Among the main effects described to date are the appearance of changes in fish reproduction due to the presence of hormones and inhibition of photosynthesis in algae

by the presence of these [2]. We know that the presence of antibiotics in the environment can make bacteria in wastewater relatively more resistant to them and resistant microorganisms develop.

wavelength of 283–350 nm [11], and it is mentioned that in visible light, it is still

For the preparation of synthetic wastewater (SWW) contaminated by trimethoprim and clavulanic acid-amoxicillin, three samples with 500 mL of clean water (0.1 mS/cm) were added with different drug concentrations (trimethoprim 0.1%, trimethoprim 0.2%, and clavulanic acid-amoxicillin 0.2%). Type curves for each drug were prepared with 2 g/L (0.2%) as the highest concentration and 0.1 g/L

The drugs supplied by Merck | Sigma-Aldrich were white powders, and the

For the construction of the electrodes, two glass tubes were used, each one of 6.1 cm length and 0.7 cm width, containing the following elements: an electrode connected to the negative pole (cathode) was handcrafted with mineral carbon introducing a copper wire (0.3 mm Ø) and the electrode connected to the positive pole (anode) was also handcrafted with mineral carbon doped with TiO2 and it was used a platinum wire (0.1 mm Ø). In the cathode, the reduction processes take place and oxidation occurs in the anode, where both are connected to a power supply

Platinum is an inert metal that does not participate in the redox reaction but only exchanges electrons [14] since it has a low reactivity with oxygen and with water [15]. Copper is a metal with great ductility and high electrical conductivity [16], which leads to the conclusion that both metal wires are good conductors and will show little corrosion. Furthermore, platinum has catalytic activity and low reactivity. Due to these characteristics, the platinum and copper wires were selected for the electrodes. Doping carbon with TiO2 aids a better oxidation process at the anode, in addition to having photocatalytic properties that can improve the dissoci-

solutions prepared were kept in refrigeration (6°C) until needed.

amoxicillin-clavulanic acid mixture, the spectra recorded are in a wavelength range of 200–380 nm [13]. Therefore, the results on the UV-Vis spectrum were analyzed

*Electrolytic Cell Applied for the Breakdown of Endocrine Disrupting Drugs in Aqueous Tributaries*

observed at a wavelength between 400 and 600 nm [12]. In the case of

within these intervals.

**2. Methodology and materials**

*DOI: http://dx.doi.org/10.5772/intechopen.93018*

**2.1 Preparing the model pollutant**

(0.01%) as the lowest concentration.

with a 5 V electrical potential (**Figure 1**).

ation reaction in the electrolytic cell.

**Figure 1.**

**47**

*TiO2-doped electrodes and coal.*

**2.2 Electrode construction**

To make clear how these molecules act as endocrine disruptors, we must indicate that they interfere with the body's homeostasis, usually by mimicking the natural hormones that lead to the activation or blocking of their receptors [3].

Trimethoprim in Mexico is one of the most used drugs for treating urinary tract infections, and it is commonly used in the foreign tourism for attending the traveler's diarrhea [4]. Trimethoprim is incompletely metabolized by humans during the therapeutic process and approximately 80% is excreted in the pharmacologically active form, which can promote the development of bacterial resistance to this compound's form promoting it as an emerging contaminant [5].

Clavulanic acid-amoxicillin is a mixture of two drugs in typical commercial compositions of 185/125 and 500/125 mg and commercially known in México as Augmentin and Clamoxin or Gimaclav, respectively. It is indicated for the treatment of acute and chronic infections of the upper and lower respiratory tracts, meningitis and genitourinary, skin, soft tissue, gastrointestinal and biliary infections, and in general for the treatment of infections caused by pathogens sensitive to this mixture of drugs [6].

Both drugs have been studied by our research group as emerging pollutants with an effect of endocrine disruptors due to their high presence in wastewater of domestic and hospital effluents in México (work in process of being published) and their consequent impact on all types of aquifers, which could act as final receiving bodies. However, in our research group, different advanced oxidation processes have been used and improved for the removal of these kinds of contaminants, these processes include cavitation, photo-catalytic oxidation, or Fenton chemistry, but they have high costs. New expectations were found when it has been applied an electrochemical process.

Electrochemical oxidation is based on the application of an electric current or a potential difference between two electrodes (anode and cathode), wherewith hydroxyl radicals or other oxidizing species can be generated, depending on the anode material used and the type of electrolyte support used [7].

In this chapter, the use of electrolysis for the removal of pharmaceutical-type pollutants is based on the chemical reactions that are carried out between the electrodes submerged in electrolytic solutions by effect of the passage of the electric current, being the function of the electrolyte to serve as a means of transporting electrical loads and provoke the reactions of oxidation-reduction for the degradation of compounds in order to transform them into less hazardous compounds for the environment. The electrolyte being of the family of salts allows the anions to carry negative loads toward the anode and the cations transport the positive loads to the cathode [8]; the effectiveness of several visible light-activated TiO2 photocatalysts has been proven for the treatment of emerging contaminants. Doping or co-doping of titanium dioxide using nitrogen, nitrogen-silver, sulfur, carbon, and copper and incorporating graphene nano-leaves increases its effectiveness. The use of titanium dioxide is to improve photocatalytic activity [9]. Considering all the above backgrounds, the experiments reported hereby were performed in order to establish if the proposed system could breakdown or transform the pollutants (drugs) into simpler molecules.

Based on different references, it is known that the trimethoprim can be determined with an absorbance at 237.6 nm [10] or that it can be displayed at a *Electrolytic Cell Applied for the Breakdown of Endocrine Disrupting Drugs in Aqueous Tributaries DOI: http://dx.doi.org/10.5772/intechopen.93018*

wavelength of 283–350 nm [11], and it is mentioned that in visible light, it is still observed at a wavelength between 400 and 600 nm [12]. In the case of amoxicillin-clavulanic acid mixture, the spectra recorded are in a wavelength range of 200–380 nm [13]. Therefore, the results on the UV-Vis spectrum were analyzed within these intervals.
