Synergetic degradation of reactive dye Acid Red 1 by cobalt-doped lignite fly ash

Abstract

Degradation studies on a reactive dye Acid Red 1 are carried out by lignite fly ash (LFA) and cobalt-doped over LFA under UV-C radiation. In India, disposal of fly ash is a major problem. As fly ash is an inert material containing small quantities of photoreactive, inorganic oxides like TiO2, CaO and Fe2O3, this paper makes an effort to use it to overcome the degradation of dye and disposal of the fly ash problem. The chemical composition of LFA is analysed by X-ray fluorescence. Scanning electron microscopy with energy dispersive X-ray spectroscopy and X-ray diffraction are carried out to characterise the physical and photophysical properties of the catalyst. The optimum parameters affecting the dye degradation are found for LFA and cobalt-doped LFA under UV-C light. The kinetic coefficients for both catalysts are also determined. Cobalt-doped LFA proved the most effective, followed by LFA, and the corresponding efficiencies are 99 and 95%, respectively, at the end of 60 min. The reuse of cobalt-doped fly ash and fly ash are also tested, and it is found that the efficiency for the first reuse is 93 and 88%, respectively, at the end of 60 min.