**2.1 Ozone production**

The ozone was obtained from dry air, using a corona type discharge generator (Peak Corporation). For the analysis by FTIR spectroscopy, ozone was obtained using the same generator, fed with pure oxygen (99.5%, Infra). The ozone concentration was analyzed at the output of the generator with a BMT201 (BMT Messtechnik).

**39**

*Chemical and Tinctorial Aspects Related to the Reuse of Effluents Treated by Ozonation…*

The ozonation experiments were carried out in a semicontinuous glass reactor of 500 mL capacity. The reactor has an entrance in the lower part where the O2/O3 gaseous mixture is injected; this mixture ascends passing through a porous silica plate diffuser that evenly distributes the ozone bubbles in the liquid phase, ensuring that these are as small as possible to achieve a better mass transfer [10]. The reactor also has an outlet at the top for the ozone that does not participate in the reaction. Also, the reactor has a side key in the lower part to sample the ozone solution.

Initially, a model solution of 50 mg/L concentration was prepared for each dye. This concentration is within the range of concentrations regularly found in the effluents of the textile industry [5]. Subsequently, concentrations of 100 and 150 mg/L were used to study the effect of the concentration on the kinetics of the reaction, and solutions of 5 g/L, to carry out a preliminary analysis by FTIR.

The ozonation experiments were carried out on 400 mL of each model solution in the 500 mL reactor, with 2 mg/L of initial ozone concentration and a gaseous mixture flow (O3/O2) of 500 mL/min, at room temperature (20–25°C). The maximum ozonation time was 120 min. Samples were taken every 10 min and, in some

Preparation cycles of the model solution and ozonation were made for 10 min, up to five times, with 50 mg/L solutions under the described conditions. That is, the sample solution of dye was prepared at 50 mg/L, and the ozone treatment was applied for 10 min; after this, the same sample was reconstituted with a concentration of 50 mg/L of textile dye, and it was treated again with ozone for 10 min. This cycle of contamination-discoloration was repeated up to five times with each textile dye, so that at the end there was a series of five samples of 400 mL, for each dye. The first sample had been subjected to a single cycle, the second sample to two cycles, the third sample to three, and so on until completing the five cycles. The purpose of this part of the work was to represent the recirculation of water within the process. These samples were used for dyeing tests of textile material with reactive dyes and direct dyes. For the dyeing with reactive dyes, Reactive Black 5 (RB5), Reactive Yellow 84 (RY84), and Reactive Red (RR141) were used, while for dyes with direct dyes, a trichromy composed of Direct Yellow 50 (DY50), Direct Blue 80 (DB80), and Direct Red 23 (DR23) was selected. The dyes were carried out in a closed machine with infrared heating (Mathis). The DY50 corresponds to group A of the SDC classification of direct dyes (self-regulating); DB80, group B (controllable by means of salt); and DR23, group C (controllable by means of salt and temperature). The color difference was measured with respect to control samples, dyed with

A second series of samples was prepared in the manner described in the previous paragraph, adding from the first cycle the equivalent to 50 mg/L of sodium ion. This was carried out in order to verify their presence throughout the ozonation

The variation of the pH during the ozonation was measured with a Jenway pH meter model 3310 equipment. Likewise, the variation of conductivity was

distilled water by reflectance spectrophotocolorimetry.

cycles, using atomic absorption spectroscopy.

*2.4.1 pH and conductivity measurement*

**2.4 Analytic methods**

*DOI: http://dx.doi.org/10.5772/intechopen.81468*

**2.2 Ozone reactor**

**2.3 Experimental procedure**

cases, every 5 min.

*Chemical and Tinctorial Aspects Related to the Reuse of Effluents Treated by Ozonation… DOI: http://dx.doi.org/10.5772/intechopen.81468*

### **2.2 Ozone reactor**

*Textile Industry and Environment*

**38**

Messtechnik).

**2. Methodology**

*Chemical structure of Reactive Red 141 (RR141).*

*Chemical structure of Reactive Blue 160 (RB160).*

**2.1 Ozone production**

market.

**Figure 2.**

**Figure 1.**

The dyes were studied individually, varying their initial concentration and varying inorganic chemical auxiliaries to simulate a dyeing effluent. Industrial samples of the three dyes were used, without any further purification. The supplier was Sinochem Ningbo, which is one of the largest presences in the Mexican

The ozone was obtained from dry air, using a corona type discharge generator (Peak Corporation). For the analysis by FTIR spectroscopy, ozone was obtained using the same generator, fed with pure oxygen (99.5%, Infra). The ozone concentration was analyzed at the output of the generator with a BMT201 (BMT

The ozonation experiments were carried out in a semicontinuous glass reactor of 500 mL capacity. The reactor has an entrance in the lower part where the O2/O3 gaseous mixture is injected; this mixture ascends passing through a porous silica plate diffuser that evenly distributes the ozone bubbles in the liquid phase, ensuring that these are as small as possible to achieve a better mass transfer [10]. The reactor also has an outlet at the top for the ozone that does not participate in the reaction. Also, the reactor has a side key in the lower part to sample the ozone solution.
