נגישות
menu      
חיפוש מתקדם
תחביר
חפש...
הספר "אוצר וולקני"
אודות
תנאי שימוש
ניהול
קהילה:
אסיף מאגר המחקר החקלאי
פותח על ידי קלירמאש פתרונות בע"מ -
Sorption and detoxification of toxic compounds by a bifunctional organoclay
Year:
2004
Source of publication :
Journal of Environmental Quality
Authors :
גרסטל, זאב
;
.
מינגלגרין, אורי
;
.
Volume :
33
Co-Authors:
Groisman, L., Research Laboratory of Water Quality, Ministry of Health, P.O. Box 8255, Tel-Aviv 61080, Israel
Rav-Acha, C., Research Laboratory of Water Quality, Ministry of Health, P.O. Box 8255, Tel-Aviv 61080, Israel
Gerstl, Z., Inst. of Soil, Water/Environ. Sci., Volcani Center, ARO, P.O. Box 6, Bet Dagan, 50250, Israel
Mingelgrin, U., Inst. of Soil, Water/Environ. Sci., Volcani Center, ARO, P.O. Box 6, Bet Dagan, 50250, Israel
Facilitators :
From page:
1930
To page:
1936
(
Total pages:
7
)
Abstract:
Organoclays are excellent sorbents for nonionic contaminants and therefore may have many environmental applications. A major limitation on the use of organoclays is that the contaminant merely changes its location from one environmental compartment to another while still remaining intact. In this study, a new type of organoclay, termed a bifunctional organoclay, has been prepared. It is able not only to sorb organophosphate pesticides, but also to catalyze their hydrolysis, and thereby detoxify them. The bifunctional organoclay prepared in this study is based on sodium montmorillonite, in which the inorganic counter ions are replaced by N-decyl-N,N-dimethy-N-(2-aminoethyl) ammonium (DDMAEA). The detoxifying capacity of this organoclay for two organophosphate pesticides, methyl parathion [0, O-dimethyl O-(p-nitrophenyl) thionophosphate] and tetrachlorvinphos [2-chloro-1-(2,4,5-trichlorophenyl) ethenyl dimethyl phosphate], was demonstrated. It was shown that although the sorption of these pesticides on the bifunctional organoclay is very similar to that on N-decyl-N,N,N-trimethyl ammonium (DTMA) organoclay (the corresponding nonbifunctional organoclay), the hydrolysis of these pesticides is substantially enhanced only by the bifunctional organoclay. The half-life for the hydrolysis of the investigated pesticides in the presence of the bifunctional organoclay is about 12 times less than for their spontaneous hydrolysis, and the enhancement is even more pronounced relative to the hydrolysis of these pesticides in the presence of the DTMA organoclay (which actually inhibits their hydrolysis). Based on kinetic measurements, the pKa of the ethylamino group of the bifunctional organoclay was estimated to be around 9.0. It is postulated that the catalytic effect of the bifunctional organoclay can be attributed to a nucleophilic attack of the unprotonated ethylamino group of the organoclay on the organophosphate ester.
Note:
Related Files :
Adsorption
amine
ammonium derivative
Catalytic effects
insecticides
parathion methyl
pesticides
עוד תגיות
תוכן קשור
More details
DOI :
Article number:
Affiliations:
Database:
סקופוס
Publication Type:
מאמר
;
.
Language:
אנגלית
Editors' remarks:
ID:
23066
Last updated date:
02/03/2022 17:27
Creation date:
16/04/2018 23:56
Scientific Publication
Sorption and detoxification of toxic compounds by a bifunctional organoclay
33
Groisman, L., Research Laboratory of Water Quality, Ministry of Health, P.O. Box 8255, Tel-Aviv 61080, Israel
Rav-Acha, C., Research Laboratory of Water Quality, Ministry of Health, P.O. Box 8255, Tel-Aviv 61080, Israel
Gerstl, Z., Inst. of Soil, Water/Environ. Sci., Volcani Center, ARO, P.O. Box 6, Bet Dagan, 50250, Israel
Mingelgrin, U., Inst. of Soil, Water/Environ. Sci., Volcani Center, ARO, P.O. Box 6, Bet Dagan, 50250, Israel
Sorption and detoxification of toxic compounds by a bifunctional organoclay
Organoclays are excellent sorbents for nonionic contaminants and therefore may have many environmental applications. A major limitation on the use of organoclays is that the contaminant merely changes its location from one environmental compartment to another while still remaining intact. In this study, a new type of organoclay, termed a bifunctional organoclay, has been prepared. It is able not only to sorb organophosphate pesticides, but also to catalyze their hydrolysis, and thereby detoxify them. The bifunctional organoclay prepared in this study is based on sodium montmorillonite, in which the inorganic counter ions are replaced by N-decyl-N,N-dimethy-N-(2-aminoethyl) ammonium (DDMAEA). The detoxifying capacity of this organoclay for two organophosphate pesticides, methyl parathion [0, O-dimethyl O-(p-nitrophenyl) thionophosphate] and tetrachlorvinphos [2-chloro-1-(2,4,5-trichlorophenyl) ethenyl dimethyl phosphate], was demonstrated. It was shown that although the sorption of these pesticides on the bifunctional organoclay is very similar to that on N-decyl-N,N,N-trimethyl ammonium (DTMA) organoclay (the corresponding nonbifunctional organoclay), the hydrolysis of these pesticides is substantially enhanced only by the bifunctional organoclay. The half-life for the hydrolysis of the investigated pesticides in the presence of the bifunctional organoclay is about 12 times less than for their spontaneous hydrolysis, and the enhancement is even more pronounced relative to the hydrolysis of these pesticides in the presence of the DTMA organoclay (which actually inhibits their hydrolysis). Based on kinetic measurements, the pKa of the ethylamino group of the bifunctional organoclay was estimated to be around 9.0. It is postulated that the catalytic effect of the bifunctional organoclay can be attributed to a nucleophilic attack of the unprotonated ethylamino group of the organoclay on the organophosphate ester.
Scientific Publication
You may also be interested in