Authors : Fella Assassi and Christophe Renac
Abstract: Reliability of hydrogen isotopes analyses have been discussed by some authors. Using highly depleted water all agree that the hydroxyl group in 10 Å halloysite can exchange hydrogen by 30% in minutes with interlayer water and therefore exchange is fast enough to occur during clay separation in the laboratory with ambient water. Even if most halloysite 10 Å samples were exchangeable there has not been many experiments done on collapsed 7Å halloysite (metahalloysite) because of it�s re-expandable capacity. Since little information is known about halloysite-hydrogen exchange, exchange experiments were designed between laboratory water of D-66 and -184� V-SMOW and clay minerals ( pure metahalloysite ) from two size fractions of <0.5 and 2-5 �m for 2 years at room temperature with ratio 15 mg water for 1 mg of clay were designed to prove the validity of D.These experiments attest that metahalloysite does not allow hydrogen exchange in laboratory conditions. Therefore D values are reliable, increases with smaller size fraction and the difference between metahalloysite and kaolinite are either related to temperature variation from 15 to 25�C or exchanges.
Fella Assassi and Christophe Renac , 2006. Hydrogen-Deuterium Exchange Experiments Between Laboratory Water and Clays (Pure Metahalloysite). Asian Journal of Information Technology, 5: 1023-1027.