**3. Ozone applications in the textile industry**

There are two types of ozone application in the textile industry. They are:


For wet processes, aqueous ozone is more practical than gaseous ozone because working principle of finishing machines is suitable for solution. Use of gaseous ozone needs special airproof machines because of occupational health and comfort. Material of leakproof gasket has to resist gaseous ozone.

**Gas phase:** Half-life of gaseous ozone is more than that of aqueous ozone. So, it decomposes slowly [13]. Gaseous ozone is easily affected by the catalyst. Light, trace organic matter, nitrogen oxides, mercury vapor, and peroxides act as catalysts for homogeneous catalysis. Metals and metal oxides are catalysts for heterogeneous

**19**

*Use of Ozone in the Textile Industry*

porous solid substrates.

trace metals, H2O2/HO2

• temperature,

• gas dispersion,

• type of contactor [14].

**3.1 Use of ozone in denim washing**

• turbulence,

based on fiber types.

• pressure,

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

¯

• gaseous ozone concentration,

catalysis. If there is no any effect of the catalyst on the mixture, it will be stable. Porous solid substrates can adsorb gaseous ozone [14]. Textiles are the sample of

**Aqueous phase:** Solubility of ozone in water is better than the oxygen [27]. However, ozone dissolves moderately in water. It follows Henry's law [13]. The solubility of ozone depends on pressure, temperature, and ionic strength [14]. Efficient moving of ozone to solution needs dispersion of gaseous ozone into small bubbles. Positive-pressure ozone contractors, negative-pressure reactors (Venturi), and injectors achieve it [13]. At room temperature, decomposition of ozone in pure water is very slow. However, ozone decomposes with the catalysts like hydroxyl ion,

• solution composition (pH, ionic strength, reactive substances),

Recently, scientific studies about the use of ozone in textile manufacturing are very popular. But the use of ozone in textile manufacturing is not common in practice. It is only commercially common in denim and garment washing. Therefore, the use of ozone in denim washing is discussed in a special title. The other titles are

The denim garments are very popular, and they are preferred by people of all ages, classes, and genders. Depending on the desired effect, denim garments are treated with different substances [28, 29]. A lot of dry and wet processing techniques are used for desired effects [30]. Wet processes in denim washing are not environment friendly. High water and energy consumption, large amount of wastewater, and solid waste like pumice stones are generally environmental problem in denim washing [29, 30]. Sodium hypochlorite is a very common bleaching agent in denim washing. Especially AOXs (adsorbable halogenated organic compounds) are the most important environmental problem. Therefore, chlorine-free bleaching technologies are a good solution for AOX. Ozonation is an alternative bleaching method [28]. Ozonation is a simple and "green" process because it does not require steam and water. Therefore, it greatly reduces process time, water, chemical and energy consumption, and amount of wastewater [31, 32]. Ozone decomposes indigo and other dyes because of high oxidation potential. In addition to denim washing, it is generally applicable to treatment of other textiles like T-shirts, shirts, chinos, and casual wear. In ozonation, the ozone generated in the equipment can commercially provide bleaching effect. It is like washing machine without water for fading of color [31]. And ozone is generally applied to whole of the garment in this ozonation

, organic substances, heat, and UV light [14]. The parameters affecting the physical mass-transfer rate of ozone into water are:
