Development of Advanced Photocatalytic Materials for Degradation of Pesticides Herbicides from Aqueous Streams

Abstract

Many ruinous pollutants are omnipresent in the environment and among them; pesticides are xenobiotic and pose to be a bio-recalcitrance. Their detrimental ecological and environmental impacts attract attention of environmental excerpts and the surge of stringent regulations have endows the need of a technically feasible treatments. The presented work discusses the practiced remedial strategies and in particular, the advanced oxidation processes utilizing the photo-catalytic properties of nano-composites for pesticide degradation. Conductive polymer based materials were employed in surface modification of the support material; titanium dioxide (TiO2). The present study used three conductive polymers such as polyaniline (PANI), polypyrrole (PP) and polythiophene (pTh) in the fabrication of three distinct nanocomposites which were designated as Pt-TiO2, PPT-TiO2 and pTH-TiO2. The synthesized materials were thoroughly characterized for their morphological and functional features using ultraviolet-visible (UV-Vis) spectrophotometry, Tauc s plot, scanning electron microscope (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopic analyses. The fabricated nanocomposites were used in removing selected pesticides through adsorption-photocatalysis. The outcome reveal that adsorption is followed by photocatalytic breakdown of three detrimental pesticides; 2,4-dichlorophenoxyacetic acid (2,4-D), triclopyr acid (TCP) and 4-chlorophenoxyacetic acid (4-CPA). Adsorption equilibrium attainment was observed within 30 min and photocatalytic breakdown required 120 min, thus the overall retention time is 150 min. Results reveal that 0.5 g/L PT-TiO2 was sufficient in removing 90.72% and 99.91% of 10 mg/L pesticides (2,4-D and TCP) at pH 5 and pH 4 respectively. newline