Sorption of²²⁶Ra from waste effluents using Syrian bentonite

Abstract

In view of environmental concern, sorption of radium on natural bentonite mineral (Aleppo, Syria) was investigated using a batch-type method. Data were expressed in terms of distribution coefficients. An attempt to increase the selectivity of bentonite for radium was made by preparing M-derivatives. Loss of mineral crystallinity in acidic media and the formation of a new phase, such as BaCO3, in Ba-derivative were evidenced by XRD characterizations. Of the cationic forms, Na-bentonite showed the highest affinity. Mechanisms of radium uptake were studied using M-derivatives and simulated radium solutions. The obtained results indicated that surface sorption/surface ion exchange were the predominant processes. The distinct sorption behaviour observed with the Ba-form was, possibly, a reflection of radium coprecipitation with barium carbonate. The competing order of macro components, likely present in waste streams, was investigated by studying different concentrations of the corresponding salt media. Sodium was found to be the weakest inhibitor. The performance of natural bentonite and the most selective forms, i.e. Ba- and Na-derivatives, to sorb radium from actual oil co-produced waters, collected form Der Ezzor Petroleum Company (DEZPC), was studied. This showed the influential effect ofpH compared with other parameters.

A Study on Sorption of 226Ra on Different Clay Matrices

“…The adsorption ratio was constant at about 75 % from 300 to 12,000 min. Differences in 226 Ra adsorption equilibrium time between illite and bentonite may be due to the fact that illite has a more complex structure than bentonite, which enhances the 226 Ra adsorption (Al-Attar et al, 2010). Illite contains different complexing compounds and high specific surfaces differences (very fine particles) (Delle Site, 2001).…”