1,721,049 research outputs found
CATALYTIC HYDROLYSIS OF DICLOFOP-METHYL ON CA-MONTMORILLONITES, NA-MONTMORILLONITES AND K-MONTMORILLONITES
No full textDirect and indirect photolysis of two quinolinecarboxylic herbicides in aqueous systems
No full textThe photodegradation of two quinolinecarboxylic herbicides, 7-chloro-3-methylquinoline-8-carboxylic
acid (QMe) and 3,7-dichloroquinoline-8-carboxylic acid (QCl), was studied in aqueous solution at different
irradiation wavelengths. The effect of sunlight irradiation was investigated also in the presence of
titanium dioxide (TiO2). UV irradiation degraded rapidly QMe affording 7-chloro-3-methylquinoline
(MeQ) through a decarboxylation reaction. The reaction rate was lower in the presence of dissolved
organic carbon (DOC) because of the adsorption of the herbicide on the organic components. Instead,
QCl was stable under both UV light and sunlight irradiation. The irradiation of QMe or QCl solutions with
simulated sunlight in the presence of TiO2 produced the complete mineralization of the two herbicides
HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC DETERMINATION OF THE HERBICIDE IMAZAPYR RESIDUES IN WATER AND SOIL
No full textA rapid method for determining residues of the herbicide imazapyr in water and soil is described. The soil samples were extracted with aqueous methanol and, after concentrating, the residue was estimated by HPLC with UV detection at 250 nm. Imazapyr dissolved in water was quantified by injecting the samples without any previous treatments. Analyses were performed without clean-up of soil and water samples. The pre-concentration of samples was required only at very low herbicide amounts. The maximum recovery was achieved by methanol/water (3:2 v/v) with both soils after three extraction procedures. The detection limits were 0.01 mg/l and 0.05 mg/kg in water and soil, respectively
INTERACTION OF THE HERBICIDE ACIFLUORFEN WITH MONTMORILLONITE - FORMATION OF INSOLUBLE FE3+, AL3+, CU2+, AND CA2+ COMPLEXES
No full textAnalytical, spectroscopic, and X-ray powder diffraction techniques were used to investigate the adsorption of the herbicide sodium acifluorfen (acifluorfen = 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid) from aqueous solution onto Cu2+-, Al3+-, Fe3+-, and Ca2+-saturated montmorillonite. As indicated by infrared and electron spin resonance spectra, which are coincident with those of the corresponding solid metal complexes, and by the basal spacings, which are the same for all the samples, acifluorfen extracted the exchangeable ions from the clay interlayer and precipitated them on external surfaces. The process involved the replacement of sodium as the saturating ion and was due to the formation of insoluble complexes between the herbicide and polyvalent metal ions
- …
