Improved waste water treatment by bio-synthesized Graphene Sand Composite

The photocatalytic and antibacterial properties of graphene biosynthesized from sugar and anchored on sand particles has been focused here. The morphology and composition of the synthesized Graphene Sand Composite (GSC) was investigated by means of X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDAX), Fourier Transform Infra-red Spectroscopy (FTIR) and UV-Visible spectroscopy. SEM images show wrinkly edges. This is characteristic of graphenic morphology. Three types of waste water samples namely, textile waste (TW), sugarcane industrial waste water (SW) and domestic waste water from a local purification center at Kodaikanal (KWW) were collected and treated. Adsorption experiments showed effective removal of impurities at 0.2 g of GSC. Photocatalytic activity was analyzed under visible and ultraviolet irradiation. The rate constant for TW increased to 0.0032/min for visible light irradiation from 0.0029/min under UV irradiation. SW showed similar improved activity with rate constant as 0.0023/min in visible irradiation compared to 0.0016/min under UV irradiation. For MAW enhanced activity was seen only in visible light irradiation with rate constant 0.0025/min. GSC showed an inhibition zone of 20 mm against the bacterium Escherichia coil. Results suggest development of economic and effective waste water management systems. (C) 2015 Elsevier Ltd. All rights reserved.