Extraction of cadmium chloride by 18-crown-6 ether into various diluents: A comparative study with bromide and picrate extraction systems

Pb(II) Extraction with Benzo-18-Crown-6 Ether into Benzene under the Co-Presence of Cd(II) Nitrate in Water

“…Here, the constants K ex and K ex± have been generally defined as [ [7][8][9]. The symbols M z+ , A − , and the subscript "org" denote a metal ion with the formal charge of z+, a univalent pairing anion, and an organic phase, respectively.…”

“…The symbols M z+ , A − , and the subscript "org" denote a metal ion with the formal charge of z+, a univalent pairing anion, and an organic phase, respectively. For evaluating the ability and selectivity of L for its extraction, many studies have been present [1][2][3][4][5][6][7][8][9], but those for clarifying ionic strength (I) dependences of the equilibrium constants seemed to be few [10,11]. Recently, one of the authors reported the I and I DCE (with HNO 3 as an I conditioner) dependences of the K ex and K ex± values in the silver picrate (AgPic) extraction with benzo-18-crown-6 ether (B18C6) into 1,2-dichloroethane (DCE), where I DCE refers to the I value for the DCE phase [12].…”

“…Recently, one of the authors reported the I and I DCE (with HNO 3 as an I conditioner) dependences of the K ex and K ex± values in the silver picrate (AgPic) extraction with benzo-18-crown-6 ether (B18C6) into 1,2-dichloroethane (DCE), where I DCE refers to the I value for the DCE phase [12]. At the same time, conditional distribution constants (K D,A = [A − ] org /[A − ]) of the picrate ion Pic − (=A − ) into the DCE (=org) phases have been determined [12] and thereby distribution equilibrium potential-differences (dep; ∆ϕ eq as a symbol in an equation) have been evaluated [7,8,12]. In the present paper, to expand such characterization [12] for the AgPic extraction system to that for an M II Pic 2 extraction one, we determined at 298 K the K ex , K ex± , and K D,Pic values for PbPic 2 extraction with B18C6 into benzene (Bz) under a co-presence of Cd(NO 3 ) 2 in a water phase.…”

“…Then, I and I Bz dependences of these equilibrium constants were mainly examined [12]. Similar examinations were performed for other overall or component equilibrium-constants, such as K Pb/PbL , K ex,ip , and K 1,Bz (see Equations (6)- (8) for their definitions), derived from the above equilibrium constants. This study is expected to be useful for comparisons between the K ex and K ex± values, because magnitudes of their comparable values depend on I [10,11] or I Bz in general.…”

“…Additionally, Bz was selected because a lot of data for the extraction of these M(II) ions with B18C6 or 18-crown-6 ether (18C6) is available [1, 3,6,8,[18][19][20].…”