Environmental problems are caused by means of water contamination are mainly by dyes from textile, paper printing, colour photography, agricultural research, leather-tanning industry and photo-electro-chemical cell industry [Gu Y. et al 2016; Malato S. et al 2016, Patil S. 2016]. Photo-dissociation of dyes and organic compounds has gained interest in order to overcome some of the environmental problems [Liu J. et al 2016]. TiO2 (Semiconductors) is the most popular system which shows good stability and excellent activity in degrading organic pollutant [Guan S.et al 2016, Ibhadon A.O. et al 2008, Konstantinou I.K. et al 2004, Lachhab H. et al 2002] and in hydrogen production from photodecomposition of water [Ni M. et al 2007, Zou Z. et al 2007]. There were two major problems with this system- low visible light response and difficult recovery which reduce its scope in some practical application [Yao Y. R. et al 2014]. BiWO6 [Fu H. et al 2014], ZnFe2O4 [Fu. Y et al 2011], InNbO4 [Zhang L.Z. et al 2007], Ca2BiO4 [Tang J. et al 2004], BiVO4 [Ng Y. H. et al 2010] and NaTaO3 [Kato H. et al 2003] are some photo-catalysts which show enhanced photo-catalysis in visible light. Due to high activity in visible light irradiation BiOBr is gaining great attention [Gondal M.A. et al 2011, Shen K. et al 2013, Shenaur-Khalil S. et al 2012, Fu J. et al 2012, Liuy Y. Y. 2011, Kang L. et al 2011, Ye L.Q. et al 2013]. However these visible-light photo catalyst have difficulty in recovering it from reaction mixture hence reducing their reusability. To overcome this recovery problem magnetic photo-catalysts are proven to be much better as they can be easily recovered by applying external magnetic field [Wang R. et al 2012]. Thus there is a need of the photo-catalysts which have high activity in visible light and magnetically separable such as Fe3O4 [Yao Y.R. et al 2014]. In TiO2 matrix Fe3O4 magnetic particles were incorporated to enhance the recovery and durability of the catalyst [Cheng W. et al 2010, Liu Z. et al 2011] along with this reduce the aggregation of the nano-particles and enhanced the surface area which in turn increased the photo-catalysis [Liu Z. et al 2011]. Semiconductor oxide phot-catalysts can also be modified by conducting polymers to improve their photo-catalytic activity. Many conducting polymers are being used for this purpose previously but the most promising is poly-pyrrole. Poly-pyrrole is most suitable because of its ease of preparation with high conductivity and good environmental stability. In presence of light, it acts as a good photosensitizer as it donate electrons and transport the holes easily. [Ketpang K. et al 2010, Mi H. et al 2010, Sun L. et al 2013,Luo Q. et al 2011].
Fly-ash cenosphere (FAC) is the solid waste obtained from coal thermal power plants is majorly composed of silicon oxide with some other metal oxides. They are hollow spheres of low density which intern makes it a suitable for different applications [Lu J. et al 2009, Niu J. et al 2007, Jin Z. et al 2014, Blissette R.S. et al 2012, Meng X.F. et al 2012]. These low density spheres acts as buoyant carriers which floats on the surface of the liquid and enhances the photo-catalyst’s activity by increasing the exposed surface area to light source [Blissette R.S. et al 2012, Wang B. et al 2011]. FAC, provides its porous surface to the substrate (photo catalyst) this will enhance the contact surface area between the pollutant and the photo-catalyst. Thus FAC increase the photo-degradation of the organic pollutant but without affecting the spectral response [Wang B. et al 2011, Zhang J. et al 2013].
In this manuscript, an effective method of synthesizing a novel ternary composites of PPY/Fe3O4/FAC is reported. Effect of varying the composition of Fe3O4 in the composite on photo-catalytic activity was studied. Fly ash-cenosphere (FAC) was used as a buoyant carrier for Fe3O4. The prime objective was to increase the photo-catalytic efficiency of Fe3O4. The prepared composites were analysed and elucidated by using SEM, TEM, XRD, XPS and FT-IR respectively. Photo-catalytic degradation was studied using UV-Vis Spectroscopy. FAC utilization solves the environmental and waste management problems of flyash to some extent, at the same time it can also increase the photo-catalytic activity and can further be used in sensors, LEDs etc.