Direct yellow 50

This paper examined the possibility of applying ozone (O 3) and O 3 combined with ultraviolet (UV) to degrade the content of seawater containing Direct Yellow 50 dye. The Experimental parameters such as initial dye concentration and time of reaction were assessed in a batch reactor to achieve the optimum operating circumstances. The Results of this study showed that more than 88% color removal was obtained after 35 min of O 3 treatment (for 100 ppm dye concentration) and also partially removal of COD. These results also indicated that the application of O 3 is more effective than UV assisted Ozonation to reduce the reaction time. Also, Gas Chromatography Mass Spectrum analysis of treated synthetic dye solution was performed at the end of the pre-treatment time to the final degradation products of Direct Yellow 50 dye and showed no toxic compounds. 1. Introduction The existence of organic impurities such as dyes, surfactants, pesticides, etc. in the hydrosphere is of particular concern for the fresh water and marine environments because of their non-biodegradability and possible carcinogenic nature of most of these complexes [1-12]. The textile industry is considered one of the basic industries in Egypt with respect to the number of labor, the exports cost, and the local production cost. This industry has been revealed as an important supplier for the environmental pollution, and the streams, mainly the wet processes where risky chemicals are used. The Egyptian textile industry consist of 31 public sector companies and about 3000 private sector and joint venture facilities, [13,14]. Direct dye is still the most extensively used in dying printing process of the textile industry. Most of the printing process-textile plants belong to the small factory group (home-made textile products). Great volumes of synthetic dyes are used by numerous industries including textile dyeing (60%), plastic matter (10%) and paper (10%), [15-19]. Ozone reacts with wastewater compounds in two different techniques namely direct molecular and indirect radical type chain reactions [20-22]. Simplified reaction mechanisms of ozone at alkaline pH are given in below; 3O 3 + H 2 O → 2 ·OH + 4 O 2 (1) Photolysis of ozone in water in the existence of UV radiation in the range of 200-280 nm can lead to hydrogen peroxide creation. Hydroxyl radicals can be produced by this as given equations below: O 3 + hv + H 2 O → H 2 O 2 + O 2 (2) H 2 O 2 + hv → 2 ·OH (3)