Synthesis of Magnetic Sonophotocatalyst and its Enhanced Biodegradability of Organophosphate Pesticide

Abstract

A magnetic sonophotocatalyst Fe 3 O 4 @SiO 2 @TiO 2 is synthesized for the enhanced biodegradability of organophosphate pesticide. The as-prepared catalysts were characterized using different techniques, such as Xray diffraction (XRD) and transmission electron microscopy (TEM). The radial sonophotocatalytic activity of Fe 3 O 4 @SiO 2 @TiO 2 nanocomposite was investigated, in which commercial dichlorvos (DDVP) was chosen as an object. The degradation efficiency was evaluated in terms of chemical oxygen demand (COD) and enhancement of biodegradability. The effect of different factors, such as reaction time, pH, the added amount of catalyst on COD Cr removal efficiency were investigated. The average COD Cr removal efficiency reached 63.13% after 240 min in 12 L sonophotocatalytic reactor (catalyst 0.2 g L −1, pH 7.3). The synergistic effect occurs in the combined sonolysis and photocatalysis which is proved by the significant improvement in COD Cr removal efficiency compared with that of solo photocatalysis. Under this experimental condition, the BOD 5 / COD Cr ratio rose from 0.131 to 0.411, showing a remarkable improvement in biodegradability. These results showed that sonophotocatalysis may be applied as pre-treatment of pesticide wastewater, and then for biological treatment. The synthesized magnetic nanocomposite had good photocatalytic performance and stability, as when it was used for the fifth time, the COD Cr removal efficiency was still about 62.38%.

Sono‐photo‐assisted heterogeneous activation of peroxymonosulfate by Fe/CMK‐3 catalyst for the degradation of bisphenol A, optimization with response surface methodology

“…At ZPC > pH, the interaction between catalyst and the BPA is better and its oxidation increases due to the availability of catalyst surface. Similar results were reported by Lirong et al (2014) for the degradation of the organophosphate pesticide by the magnetic sonocatalyst process. The decrease in the efficiency at pH values higher than 8 can be explained by pK a of BPA.…”

Carrier separation and charge transport characteristics of reduced graphene oxide supported visible-light active photocatalysts

“…Thus, higher active sites can increase the reactive species generation on the surface of the photocatalysts. 58,59 As shown in Fig. 12(b), the XRD patterns of the rGO supported photocatalysts prepared in the presence of ultrasound shows more crystalline phases compare to that of the photocatalyst synthesized in the absence of ultrasound.…”

Recent Progress and Prospects in Catalytic Water Treatment

“…It may be used for the pretreatment of organophosphate pesticide wastewaters, increasing their biodegradability for a subsequent biological treatment. 1013 4.4.2.2. Sonophotocatalytic Degradation of Wastewaters with ZnO Photocatalysts.…”

“…The separation of the sono­photocatalyst nanoparticles from the aqueous phase can be improved using a magnetic core (Fe 3 O 4 @SiO 2 @TiO 2 ). It may be used for the pretreatment of organophosphate pesticide wastewaters, increasing their biodegradability for a subsequent biological treatment …”