Extraction and determination of Th(IV) from aqueous acidic solutions using natural cassitrite adsorbent

This work concerned with the extraction of Th(IV) from aqueous solutions using natural cassitrite adsorbent natural tin oxide mineral (SnO2). The achieved maximum Th(IV) adsorption efficiency (99.2%) depends mainly on some effective parameters such as pH value, contact time, dose of cassiterite, concentration of Th(IV) and temperature. The Langmuir and Freundlich models are used to simulate the sorption isotherms, respectively. On the other hand, not less than 99.6% of the uptaken Th(IV) was regenerated using 0.005 mol L-1 HCl solution by stirring for 25 min to yeild Th(IV) concentrated solution. The concentrations ofTh(IV) in all extraction process were spectrophotometric estimated using 1,4-di-hydroxy anthraquinone and Arsenazo(III) at lambda(max) 600 and 655 nm, respectively.