ABSTRACT
Cellulose acetate is derived from cellulose and has the characteristics of biodegradability and reusability. So, it has been used for the elimination of toxic compounds capable of producing different diseases, such as cadmium, that result from human and industrial activity. For this reason, capsules functionalized with Cyanex 923 were prepared and characterized by FTIR spectroscopy, Energy Dispersive X-ray Spectroscopy (EDX), and SEM. The functionalized capsules were used for removing and recovering Cd(II) by modifying variables such as HCl concentration in the extraction medium and carrier content in the capsules, among others. The extraction of cadmium from battery leachates and the three isotherm models, Langmuir, Freundlich, and Dubinin Radushkevich, were also tested to model the cadmium removal process. The results showed a favorable physical sorption with a good capacity for extraction and the possibility of reusing the capsules for up to seven cycles without a decrease in the percentage of cadmium recovery.
ABSTRACT
The spiroarsoranes 5-phenyl-1,6-dioxa-4,9-diaza-5lambda(5)-arsaspiro[4.4]nonane (6), (3R,8R)-3,8-dimethyl-5-phenyl-1,6-dioxa-4,9-diaza-5lambda(5)-arsaspiro[4.4]nonane (7), (2S,7S)-2,7-dimethyl-5-phenyl-1,6-dioxa-4,9-diaza-5lambda(5)-arsaspiro[4.4]nonane (8), and (3S,8S)-3,8-dimethyl-(2R,7R)-2,5,7-triphenyl-1,6-dioxa-4,9-diaza-5lambda(5)-arsaspiro[4.4]nonane (9) were prepared by reaction of phenylarsonic acid and the correspondig amino alcohol. The presence of polytopal Delta left arrow over right arrow Lambda equilibrium in 6-9 was demonstrated by HPLC and NMR studies. NBO computations at the MP2/6-31+G(2d,2p) level indicate that methyl substitution in C2 or C3 of the oxazarsolane ring determines the predominance of Delta or Lambda stereoisomers. GIAO B3LYP/6-311++G(2d,2p) computations were used to assign experimental (1)H and (13)C NMR spectra.
