Synthesis of Magnetically Responsive Photocatalytic Composite for Degradation of Dyes in Aqueous Medium

Abstract

The environmental pollution is increasing exponentially, inviting the attention of researchers around the world, for evolving solutions, in respect of specific problems. In the field of textile industries, one of the major problems encountered in practice is the disposal of wastewater effluent containing residues of dyes, used in a major process of imparting colour to the fabrics. The dyes contain organic and inorganic ingredients. Some of them contain toxic and poisonous materials, a few of them being harmful to aquatic life, apart from being carcinogenic. newlineMost of the residues of organic dyes remain in wastewater, even after giving treatment. Therefore, a tertiary treatment must be given to the textile wastewater effluent, after carrying out the conventional biological treatment, such as Activated Sludge Process (ASP), Trickling Filter, etc. For the purpose of incorporating in a suitable tertiary treatment system, numerous strategies were developed, which can be categorized as advanced wastewater treatment techniques, such as Reverse Osmosis (R.O), Coagulation and Electrochemical Oxidation (CEO) etc. newlineIn a recent analysis, photocatalytic degradation has been prompted, to get rid of the organic dyes and pollutants from wastewater. In this system, the treatment is attempted, with metal oxides like Titanium dioxide (TiO2). Among the semiconductors in nano regime, the unique features of TiO2 are claimed to be inexpensive, non-toxic, exhibiting chemical stability in respect of photostability, etc. It is easily available. These are the considerations making it to be an effective photocatalyst, used for the degradation of various organic pollutants like textile dyes. Although, TiO2 is very effective in removing organic contaminants, it also causes difficulties during the separation of TiO2 particles from the effluent, due to the small particle size. Therefore, one approach is to develop a stable photocatalyst for easy recovery by applying external magnetic field. Thus, the aim of the present study is to explore the synthesis of magnetically active photocatalytic composite (Fe-AC/TiO2), (by including Ferrous and Activated Carbon in the content), versus Ordinary photocatalytic composites (Fe/TiO2 and AC/TiO2).The characterization of synthesized photocatalytic composites were performed by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS). Free radical scavenging activities of the photocatalytic composites were analyzed by 2, 2-diphenyl-1-picryl-hydrazyl-hydrate assay. The toxicological nature of photocatalytic composites were analyzed by (3 [4,5dimethylthiazol 2yl] 2,5 diphenyltetrazolium bromide assay (MTT Assay). The efficiency of photocatalytic composites in degradation of organic dyes in aqueous medium, real textile dyeing industry wastewater and its photokinetic mechanisms were analyzed. newlineThe results of the present study clearly indicate that the photocatalytic activities of synthesized composites were very effective in degradation of textile dyes and real textile dyeing industry wastewater. newline newline newline