| 1. |
|
|
| 2. |
- Jonsson, Caroline, 1977, et al.
(författare)
-
Adsorption of glyphosate on goethite (alpha-FeOOH): Surface complexation modeling combining spectroscopic and adsorption data
- 2008
-
Ingår i: Environmental Science & Technology. - 0013-936X. ; 42:7, s. 2464-2469
-
Tidskriftsartikel (refereegranskat)abstract
- N-(phosphonomethyl)glycine (glyphosate, PMG) is the most widely used herbicide, and its adsorption onto soil minerals plays a significant role in its mobility and rate of degradation. In this work, we present the results of the first serious effort to find a realistic surface complexation model that fits both adsorption and total proton concentration data for PMG on the common soil mineral, goethite. Special attention was focused on making sure that the final model was in good semiquantitative agreement with previously reported X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopic measurements. Electrostatic effects were accounted for using the Basic Stern model, and the charges of the PMG-containing surface complexes were assumed to be distributed across the O- and beta-planes. The reactions for the protonation of the goethite surface were described using the 1 pK model, We optimized on the intrinsic formation constants and the charge distributions of the complexes, as well as the initial total proton concentration (l = 0.1 M Na(NO3), 25.0 degrees C), and the following model was obtained. FeOH0.5- + H3L reversible arrow FeHL1.5- +H++H2O Log10 beta = 4.70 +/- 0.08, Q(0) = -0.18 +/- 0.02 FeOH0.5- + H3L reversible arrow FeL2.5- + 2H(+) + H2O Log(10) beta = -3.9 +/- 0. 1, Q(0) = -0.7 +/- 0.1 Here, beta is the intrinsic formation constant, Q(0) is the charge at the 0-plane, and the errors are reported as one standard deviation. The charge distributions of the complexes are rationalized by considering intramolecular hydrogen bonding between the protons of the amine group and both the phosphonate and carboxylate groups.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
- Hartman, J, et al.
(författare)
-
Hemicellulose films obtained from softwood process water
- 2005
-
Ingår i: Abstracts of Papers of the American Chemical Society. - Royal Inst Technol, Dept Fibre & Polymer Technol, SE-10044 Stockholm, Sweden. : AMER CHEMICAL SOC. - 0065-7727. ; 229, s. U39-U39
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Purgel, M., et al.
(författare)
-
Glyphosate complexation to aluminium(III). An equilibrium and structural study in solution using potentiometry, multinuclear NMR, ATR-FTIR, ESI-MS and DFT calculations
- 2009
-
Ingår i: Journal of Inorganic Biochemistry. - 0162-0134. ; 103:11, s. 1426-1438
-
Tidskriftsartikel (refereegranskat)abstract
- The stoichiometries and stability constants of a series of Al3+-N-phosponomethyl glycine (PMG/H3L) complexes have been determined in acidic aqueous solution using a combination of precise potentiometric titration data, quantitative Al-27 and P-31 NMR spectra, ATR-FTIR spectrum and ESI-MS measurements (0.6 M NaCl, 25 degrees C). Besides the mononuclear AlH2L2+, Al(H2L)(HL), Al(HL)(2)(-) and Al(HL)L2-, dimeric Al-2(HL)L+ and trinuclear Al3H5L42+ complexes have been postulated. H-1 and P-31 NMR data show that different isomers co-exist in solution and the isomerization reactions are slow on the P-31 NMR time scale. The geometries of monomeric and dimeric complexes likely double hydroxo bridged and double phosphonate bridged isomers have been optimized using DFT ab initio calculations starting from rational structural proposals. Energy calculations using the PCM solvation method also support the co-existence of isomers in solutions. (C) 2009 Elsevier Inc. All rights reserved.
|
|
| 10. |
|
|
| 11. |
|
|
| 12. |
|
|
| 13. |
- Straat, K, et al.
(författare)
-
Activation of telomerase by human cytomegalovirus
- 2009
-
Ingår i: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 1460-2105 .- 0027-8874. ; 101:7, s. 488-497
-
Tidskriftsartikel (refereegranskat)
|
|
| 14. |
|
|
| 15. |
|
|
