Removal of Dyes from Industrial Wastewater using N/S Co-doped TiO2 Nanostructures

Abstract

With the development of mankind, society, science and technology, our sphere is approaching to a new horizon, but to meet the emerging stress in the current situation the cost level is going to be too high. Among these penalties of rapid growth, pollution in our ecosystem has become the major delinquent. In addition to all other requirements, the request for pure water has increased exponentially with agricultural, industrial and domestic sectors utilizing 70, 22 and 8% of the prevailing freshwater, respectively, hence resulted in the liberation of a significant amount of wastewater taking a number of toxic ‘pollutants’. Wastewater treatment now has become a major attention-seeking issue to researchers. In different manufacturing industries, commercial dyes are used in plastic, textiles, paper, leather, foodstuffs and pharmaceuticals. Synthetic dyestuffs that are extensively used in various industries, responsible for contamination of wastewater due to which approximately 10,000 synthetic dyes (e.g. triphenylmethane, anthraquinone, dichlorobenzidin and azo dyes) are increasing year after year. It is more or less investigated that the loss of reactive dyes (more than 10%) in textile processing resulted in the liberation of a significant amount of dye wastes that have a damaging effect on human health and environment. Thus the removal of hazardous dyes from wastes demands utmost attention because most of the dyes are not biodegradable easily. Adsorption has been recognized as a promising dye treatment technique due to its simplicity, substantial productivity, low cost and fast adsorbent/adsorbate interaction time. The removal efficiency of the adsorption process may reach up to 99.9%. The United States Environmental Protection Agency (USEPA) categorized adsorption as one of the most efficient wastewater treatment approaches. Titanium dioxide (TiO2) or Titania is known as an excellent adsorbent for environmental applications. Titania films possess high adsorption capacity for a large variety of dyes such as basic red 46, basic blue 41. TiO2 based nanocomposite materials have drawn the attention of investigators, due to the wide possibilities of properties modification in the field of material sciences. TiO2 doping with other materials is considered an effective strategy, in order to improve its adsorbent character and enhancing the efficiency to separate the dyes.