**2. Ozone**

Ozone is a strong oxidant agent, which can be produced synthetically, as well as is being naturally available in the atmosphere. Ozone layer behaves like a shield against ultraviolet radiation. Because it absorbs UVB and UVC light during the cycle (**Figure 1**) of formation and destruction of ozone in the atmosphere [6–8].

Christian Schönbein described "ozein" odor during electrolysis of water in 1839. Thomas Andrews found out that ozone was formed only by oxygen in 1856. In 1863, Soret defined the relationship between oxygen and ozone. He determined that 3 volumes of oxygen produce 2 volumes of ozone. Ozone is thermodynamically unstable and spontaneously reverts to oxygen (**Figure 2**). It dissolves very quickly in pure water and respects for Henry's law. Ozone immediately reacts with inorganic and organic substances dissolved in biological water generating a variety of free radicals [9, 10].

**Figure 1.** *Cycle of formation and destruction of ozone [8].*

**15**

• titrimetry,

*Use of Ozone in the Textile Industry*

**2.1 Generation of ozone**

*DOI: http://dx.doi.org/10.5772/intechopen.81774*

Ozone must be generated "in situ" because it is very reactive gas and cannot be stored and transported to anywhere. So, it has to be generated [3]. The basic

• **Photochemical ozone generation:** Oxygen atoms formed by the photodissociation of oxygen by short-wavelength UV radiation react with oxygen molecules to form ozone. The theoretical quantum yield of ozone by photochemical technique is 2%. Nevertheless, the actual yield is approximately 0.5% in practice. Because, the low-pressure mercury lamps produce not only the 185-nm radiation responsible for the production of ozone, but also the 254-nm radiations that destroy ozone. Medium-pressure UV produces higher levels of 185-nm radiation, and it generates more ozone. The low concentrations of ozone from UV generators limit their usage for water treatment to special applications. But

• **Electrolytic ozone generation:** An electrolytic cell is used for electrolytic ozone generation. Electrolysis involves converting oxygen in the water to ozone by passing the water through positively and negatively charged surfaces. Electrolysis of water can generate high concentrations of ozone. However, the output is low and the method is more expensive than the corona discharge process. Small electrolytic units can be used for treatment of ultrahigh purity waters in pharmaceuti-

• **Radiochemical ozone generation:** High-energy irradiation of gaseous or liquid oxygen by radioactive rays can help the formation of ozone. Energy efficiency of the method is greater than that of ozone produced by electric discharge. However, it has not yet been commercialized due to complex structure, problems associated with recovery of ozone, and separation of by-products and radioactive material.

• **Ozone generation by corona discharge (silent electrical discharge):** Ozone is generated by providing air or oxygen gas into the generator. And oxygen or air is converted into ozone by the electric discharge. Primary components in air are firstly separated into reactive atoms or radicals by effect of the intense electric field. Then, these reactive atoms can react among themselves. Ozone generation by corona discharge is especially the most widely used method for water treatment.

It is necessary to determine the concentration of ozone produced by an ozone generator because of efficiency of processes, costs, excessive ozone, and environmental drawback [14, 16]. Many analytical methods for the determination of ozone concentration have been described in the literature. However, most of them are not specific and often give incorrect results [17]. Analysis of ozone is difficult because of the instability of pure ozone, volatilization from solution, the rapid decomposition of ozone in water, and the reaction with trace contaminants in water, etc. [18].

Ozone can be analyzed by methods given below [15]:

• direct and colorimetric spectrometry,

methods for generating ozone artificially are below [5–7, 9, 12–15]:

it can be used in air treatment effectively.

cal and electronic industries.

**2.2 Measurement methods**

**Figure 2.** *Ozone molecule [6, 11].*
