In this study, preliminary tests were conducted aiming to validate the use of ceramic porous cup for collecting soil water samples and monitoring pesticides contents, as usually made for nitrates. Interactions between porous cup and pesticides were examined under different experimental conditions for three herbicides (atrazine, isoproturon, 2,4-D) and one insecticide (carbofuran).
The results showed that ceramic was not inert for pesticides : as much as 80% of the applied pesticide could be retained during the flowing of the first tenth milliliters of solution. Interactions were attributed to sorption and “screening” of molecules by the porous walls and were related to the ionic character of pesticides. However, retention was not irreversible, since pesticides were quickly released by rinsing with distilled water.
After these tests, porous ceramic cups could be considered as suitable samplers for pesticide determinations in soil solution, contingent on gaining further informations about soil - porous cup - pesticide interactions. 相似文献
Monoclinic BiVO4 with multiple morphologies and/or porous structures were fabricated using the hydrothermal strategy. The materials were characterized by means of the XRD, Raman, TGA/DSC, SEM, XPS, and UV-Vis techniques. The photocatalytic activities of the BiVO4 materials were evaluated for the degradation of Methyl Orange under visible-light irradiation. It is observed that pH value and surfactant exerted a great effect on the morphology and pore structure of the BiVO4 product. Spherical BiVO4 with porous structures, flower-cluster-like BiVO4, and flower-bundle-like BiVO4 were generated hydrothermally at 100℃ with poly(vinyl pyrrolidone) (PVP) and urea (pH = 2) and at 160℃ with NaHCO3 (pH = 7 and 8), respectively. The PVP-derived BiVO4 showed much higher surface areas (5.0-8.4 m2/g) and narrower bandgap energies (2.45-2.49 eV). The best photocatalytic performance of the spherical BiVO4 material with a surface area of 8.4 m2/g was associated with its higher surface area, narrower bandgap energy, higher surface oxygen vacancy density, and unique porous architecture. 相似文献
Porous S-doped bismuth vanadate with an olive-like morphology and its supported iron oxide (y wt.% FeOx/BiVO4-δS0.08, y = 0.06, 0.76, and 1.40) photocatalysts were fabricated using the dodecylamine-assisted alcohol-hydrothermal and incipient wetness impregnation methods, respectively. It is shown that the y wt.% FeOx/BiVO4-δS0.08 photocatalysts contained a monoclinic scheetlite BiVO4 phase with a porous olive-like morphology, a surface area of 8.8-9.2 m^2/g, and a bandgap energy of 2.38-2.42 eV. There was co-presence of surface Bi^5+, Bi^3+, V^5+, V^3+, Fe^3+, and Fe^2+ species in y wt.% FeOx/BiVO4-δS0.08. The 1.40 wt.% FeOx/BiVO4-δS0.08 sample performed the best for Methylene Blue degradation under visible-light illumination. The photocatalytic mechanism was also discussed. We believe that the sulfur and FeOx co-doping, higher oxygen adspecies concentration, and lower baudgap energy were responsible for the excellent visible-light-driven catalytic activity of 1.40 wt.% FeOx/BiVO4-δS0.08. 相似文献