Photodegradation of Dichlorvos using in situ generated TiO2 over zeolitic supports as reusable catalysts

SILVINA GÓMEZ; CANDELARIA L. MARCHENA; MARÍA S. RENZINI; LUIS PIZZIO

APPLIED CATALYSIS B-ENVIRONMENTAL

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 162 p. 167 - 173

0926-3373

Materials based on titania supported on zeolitic matrices (HBETA, HY and HZSM5) were synthesized byin situ generation of TiO2. The supported catalysts characterized by XRD indicate the presence of theanatase phase alone. The materials were also characterized by FTIR, SBET, and UV-VIS DRS. A high TiO2content produced lower degradation, due to the presence of TiO2particle aggregates of greater size onthe zeolite matrix surface, as evidenced by the calculated crystal size. TiO2/HBETA(20%) presented moreactivity than TiO2supported on the other matrices due to higher adsorption of dichlorvos on HBETA. Ithas more surface area and a lower band gap value too, which makes it more effective. The mineralizationdegree is lower than the degradation percentage due to the formation of organophosphorous interme-diates that are less toxic than the starting material. The complete degradation and mineralization of thepollutant was obtained in 360 and 540 min of reaction with TiO2/HBETA(20%), respectively. This catalystresulted in degradation percentages close to that of commercial TiO2P25. The main advantage of sup-ported catalysts is their easy separation and reuse, in this case resulting in a very low activity loss duringeight cycles. These materials present suitable properties to be used as catalysts in the photocatalytictreatment of wastewater that contains pesticide dichlorvos in water.