1
|
Woignier T, Fernandes P, Soler A, Clostre F, Carles C, Rangon L, Lesueur-Jannoyer M. Soil microstructure and organic matter: keys for chlordecone sequestration. J Hazard Mater 2013; 262:357-364. [PMID: 24056248 DOI: 10.1016/j.jhazmat.2013.08.070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 08/22/2013] [Accepted: 08/26/2013] [Indexed: 06/02/2023]
Abstract
Past applications of chlordecone, a persistent organochlorine pesticide, have resulted in diffuse pollution of agricultural soils, and these have become sources of contamination of cultivated crops as well as terrestrial and marine ecosystems. Chlordecone is a very stable and recalcitrant molecule, mainly present in the solid phase, and has a strong affinity for organic matter. To prevent consumer and ecosystem exposure, factors that influence chlordecone migration in the environment need to be evaluated. In this study, we measured the impact of incorporating compost on chlordecone sequestration in andosols as a possible way to reduce plant contamination. We first characterized the transfer of chlordecone from soil to plants (radish, cucumber, and lettuce). Two months after incorporation of the compost, soil-plant transfers were reduced by a factor of 1.9-15 depending on the crop. Our results showed that adding compost modified the fractal microstructure of allophane clays thus favoring chlordecone retention in andosols. The complex structure of allophane and the associated low accessibility are important characteristics governing the fate of chlordecone. These results support our proposal for an alternative strategy that is quite the opposite of total soil decontamination: chlordecone sequestration.
Collapse
Affiliation(s)
- T Woignier
- IRD UMR 237 Institut Méditerranéen de Biodiversité et d'Ecologie Marine et Continentale PRAM B.P. 214 Petit Morne, 97232, Le Lamentin, Martinique; CNRS 7263 - Institut Méditerranéen de Biodiversité et d'Ecologie Marine et Continentale PRAM B.P. 214 Petit Morne, 97232, Le Lamentin, Martinique.
| | | | | | | | | | | | | |
Collapse
|
2
|
Abstract
ABSTRACTThe mechanical properties of silica gels (alcogels and aerogels) are measured by three point bending. The elastic moduli (E,G) and the fracture strength (σ) are investigated as functions of the concentration of silicon precursor, the catalysing conditions, and the aging time.Elastic moduli and strength follow scaling laws as a function of the bulk density of the solid. The scaling exponents are discussed in terms of percolation theory.The evolution of the mechanical properties is also followed during the steps of the gel to glass transformation:- hypercritical drying- oxidation of the organic groups-densification heat treatmentAt each step of the process the increases of the elastic moduli and σ are related to the gel structure. During the hypercritical drying flexible “dead ends” in the network can condense and form new links. The connectivity is also enhanced by the removal of the organic groups creating siloxane bonds. Finally densification leads to a material having mechanical properties identical to those of conventional vitreous silica.
Collapse
|
3
|
Abstract
ABSTRACTThe Young's modulus of silica aerogels is measured using the three points flexural technique. Various parameters have been investigated such as the catalyting conditions used to elaborate the initial alcogel and the heat treatment performed to density the material. In a given sample porosity the elastic behaviour of aerogels depends on the conditions of gel preparation. This different elastic behaviour is related to the different spatial arrangement of the particles pointed out by fractal features.
Collapse
|
4
|
Cicognani G, Dianoux AJ, Fontana A, Rossi F, Montagna M, Scopigno T, Pelous J, Terki F, Pilliez JN, Woignier T. Low frequency dynamics of silica xerogel porous system. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/13642819908223098] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- G. Cicognani
- a Institut Laue Langevin , BP 156, F-38042 , Grenoble , Cedex , 9 , France
- e Istituto Nazionale per la Fisica delia Materia , Italy
| | - A. J. Dianoux
- b Institut Laue Langevin , BP 156, F-38042 , Grenoble , Cedex , 9 , France
| | - A. Fontana
- c Dipartimento di Fisica and Istituto Nazionale di Fisica della Materia , Universita di Trento , 1-38050, Povo , Trento , Italy
| | - F. Rossi
- c Dipartimento di Fisica and Istituto Nazionale di Fisica della Materia , Universita di Trento , 1-38050, Povo , Trento , Italy
| | - M. Montagna
- c Dipartimento di Fisica and Istituto Nazionale di Fisica della Materia , Universita di Trento , 1-38050, Povo , Trento , Italy
| | - T. Scopigno
- c Dipartimento di Fisica and Istituto Nazionale di Fisica della Materia , Universita di Trento , 1-38050, Povo , Trento , Italy
| | - J. Pelous
- d Laboratoire des Verres, UMR5587 , Universite Montpellier II , Place Eugene Bataillon, case 069, 34095 , Montpellier , Cedex , France
| | - F. Terki
- d Laboratoire des Verres, UMR5587 , Universite Montpellier II , Place Eugene Bataillon, case 069, 34095 , Montpellier , Cedex , France
| | - J. N. Pilliez
- d Laboratoire des Verres, UMR5587 , Universite Montpellier II , Place Eugene Bataillon, case 069, 34095 , Montpellier , Cedex , France
| | - T. Woignier
- d Laboratoire des Verres, UMR5587 , Universite Montpellier II , Place Eugene Bataillon, case 069, 34095 , Montpellier , Cedex , France
| |
Collapse
|
5
|
Affiliation(s)
- J. Pelous
- a Laboratoire de Science des Matériaux Vitreux (associé au CNRS 1119) , Université des Sciences et Techniques du Languedoc , F-34060 , Montpellier Cedex , France
| | - R. Vacher
- a Laboratoire de Science des Matériaux Vitreux (associé au CNRS 1119) , Université des Sciences et Techniques du Languedoc , F-34060 , Montpellier Cedex , France
| | - T. Woignier
- a Laboratoire de Science des Matériaux Vitreux (associé au CNRS 1119) , Université des Sciences et Techniques du Languedoc , F-34060 , Montpellier Cedex , France
| | - J. L. Sauvajol
- b Groupe de Dynamique des Phases Condensées (associé au CNRS 233) , Université des Sciences et Techniques du Languedoc , F-34060 , Montpellier Cedex , France
| | - E. Courtens
- c IBM Research Division, Zurich Research Laboratory , 8803 , Riischlikon , Switzerland
| |
Collapse
|
6
|
Fehr C, Dieudonné P, Primera J, Woignier T, Sauvajol JL, Anglaret E. Solid state polymorphism of liquid crystals in confined geometries. Eur Phys J E Soft Matter 2003; 12 Suppl 1:S13-S16. [PMID: 15011006 DOI: 10.1140/epjed/e2003-01-004-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2003] [Indexed: 05/24/2023]
Abstract
Solid polymorphism of 4-alkyl-4'-cyanobiphenyl (nCB) was studied so far as a function of thermal history. In this paper we show that metastable solid phases of 4-octyl-4'-cyanobiphenyl (8CB) are also formed when the mesogens are confined in porous silica matrices and we study their structure by neutron diffraction and by Raman spectroscopy. Three metastable solid states are identified: one crystalline phase K', two frozen-in smectic-like phases K(s) and K'(s). We discuss the relation between the structure of the metastable solid phases and that of the mesomorph phases.
Collapse
Affiliation(s)
- C Fehr
- Groupe de Dynamique des Phases Condensées, UMR, CNRS 5581 Université de Montpellier II, Montpellier, France
| | | | | | | | | | | |
Collapse
|
7
|
Dieudonné P, Calas S, Fehr C, Primera J, Woignier T, Delord P, Phalippou J. Monolithic porous glasses with controlled mesopore size. ACTA ACUST UNITED AC 2000. [DOI: 10.1051/jp4:2000713] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
|
8
|
Sempéré R, Bourret D, Woignier T, Phalippou J, Jullien R. Scaling approach to sintering of fractal matter. Phys Rev Lett 1993; 71:3307-3310. [PMID: 10054940 DOI: 10.1103/physrevlett.71.3307] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
10
|
Vacher R, Courtens E, Coddens G, Pelous J, Woignier T. Neutron-spectroscopy measurement of a fracton density of states. Phys Rev B Condens Matter 1989; 39:7384-7387. [PMID: 9947417 DOI: 10.1103/physrevb.39.7384] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
11
|
Vacher R, Woignier T, Pelous J, Courtens E. Structure and self-similarity of silica aerogels. Phys Rev B Condens Matter 1988; 37:6500-6503. [PMID: 9943900 DOI: 10.1103/physrevb.37.6500] [Citation(s) in RCA: 224] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
|
12
|
|
13
|
Courtens E, Pelous J, Phalippou J, Vacher R, Woignier T. Brillouin-scattering measurements of phonon-fracton crossover in silica aerogels. Phys Rev Lett 1987; 58:128-131. [PMID: 10034610 DOI: 10.1103/physrevlett.58.128] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|