Photocatalytic degradation of chlorpyrifos and methylene blue using α-Bi2O3 nanoparticles fabricated by sol–gel method

Abstract

Organic dyes and pesticides, i.e. methylene blue and chlorpyrifos are the most frequently used in the various fields in everyday life for the different purpose. The presence of organic dyes and pesticides within the aquatic environment causes serious problems to the both types ecosystems. The aim of this study, to evaluate the photocatalytic degradation of methylene blue and chlorpyrifos in aqueous solution using α-Bi2O3 nanoparticles (NPs). The α-Bi2O3 NPs were successfully synthesized by sol–gel method and characterized by XRD, SEM, TEM, EDX and FTIR techniques. Moreover, the photocatalytic degradation of methylene blue and chlorpyrifos was investigated by optimizing the various parameters like pH, an initial concentration of the solution, irradiation time and photocatalyst dose, etc. The photocatalytic efficiency of α-Bi2O3 NPs was measured using a UV–visible double beam spectrophotometer. The results show that the α-Bi2O3 NPs have an average crystallite size of 32.47 nm with a highly rough and porous surface area. The optimized condition for the photocatalytic degradation was obtained at pH = 2 and pH = 5, the initial concentration of solution 10 mg/L and irradiation time 90 min for methylene blue and chlorpyrifos respectively. Besides this, the kinetics of photocatalytic degradation were investigated and the results indicate that the photocatalytic degradation of methylene blue and chlorpyrifos follows the pseudo-first order kinetics.