부산대학교 도서관

A fast and selective method for cadmium(II) removal from water by procaine hydrochloride (PQ+ Cl )immobilized polyurethane foam (PUFs) sorbent was developed. The method was based upon formationof [CdI4] 2aq in the test aqueous KI solution and subsequent extraction by PQ+ Cl treated PUFs. Thesorption of Cd2+ ions followed first order equation with an overall rate constant of 0.132 0.033 min 1. The values of DH and DS were 41.54 0.9 kJ mol 1 and 144.58 3.1 J mol 1 K 1, respectively with acorrelation factor of 0.998. The thermodynamic parameters (DH, DS and DG) suggest that the sorption wasspontaneous and exothermic process. The negative value of DS provides indication of moderate sorption of[CdI4]2 ion associate and ordering of the ionic charges without compensatory disordering of the sorbedspecies onto the sorbent. Cadmium(II) sorption is mainly dominated by absorption related to ‘‘solventextraction’’ and an added component for ‘‘surface adsorption’’. PQ+ Cl treated PUFs packed column was alsotested for preconcentration of trace concentrations of cadmium(II) species in various water samples. Theretained Cd species were successfully recovered with dilute HNO3 (1.0 mol L 1) and subsequently analyzedby ICP–OES. Thus, the proposed sorbent packed column provides efficient removal of traces of cadmium(II)ions from water samples. The method could be extended for preconcentrate of trace and ultra trace cadmiumspecies from large samples onto PUF packed column and subsequently analyzed. Indeed, the developedmethod could be satisfactorily applied to the determination of trace Cd ions in natural water.