Natural and Modified Clays for Removal of Organic Pollutants from Water

Abstract

Nowadays there is a continuously increasing worldwide concern for organicmicro pollutants such as antibiotics, personal care products, plasticizers, surfactants, herbicides, etc., because they generate significant environmental problems. Unfortunately, conventional waste water treatment techniques can not completely remove all residues of these emerging contaminants. In this context, the development of nanotechnology in the sector of Advance oxidation process (AOP) Photocatalysis creates opportunities for environmental cleanup at relatively lower costs. In this study metal vanadate based nanostructures namely; bismuth vanadate (BiVO4), ferric vanadate (FeVO4), zinc vanadate Zn3(VO4)2, bismuth vanadate/ferric vanadate (BiVO4/FeVO4) and zinc vanadate/bismuth vanadate (Zn3(VO4)2/BiVO4) were fabricated by using facile hydrothermal route. The possible reaction processes of the as-synthesized nanomaterials were discussed briefly. Optimizations of the growth and/or synthesis conditions were performed to obtainhigh quality metal vanadate nanostructures (nanoparticles, nano plates, nanorods and nano-flowers). Parameters which affect the activity of the photo catalysts, namely, the amount of molar ratio, catalyst loading, pH, heating time and reaction temperature were also studied extensively. Characterization of the nanostructures were performed by powder X-ray diffraction (XRD), Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), X-rays photoelectron microscopy (XPS), UV (ultraviolet) spectrophotometer, Fourier transform infrared spectroscopy (FTIR),Transmission electron microscopy (TEM), Raman Spectroscopy, Brunauer– Emmett–Teller (BET) surface area analyzer, photoluminance (PL), electron paramagnetic resonance (EPR) spectrophotometer. For catalytic response the as prepared samples were used to degrade the different pollutants organic dyes (crystal violet (CV), methylene blue (MB), congo red (CR), Rhodamine-B (RhB)) and industrial waste water, electrochemical response of (BiVO4/FeVO4) and (Zn3(VO4)2/ BiVO4) over ascorbic acid (A.A) and hydrogen peroxide (H2O2) was evaluated by using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques. The as-prepared metal vanadate nanomaterials exhibited excellent photocatalytic response for dye solutions, industrial waste water and sensors.