Interaction of Nd(iii) and Cm(iii) with borate in dilute to concentrated alkaline NaCl, MgCl₂and CaCl₂solutions: solubility and TRLFS studies

Abstract

Interaction of Ln(iii) and An(iii) with borate impacts radionuclide solubility and speciation in saline aqueous solutions.

Interaction of Np(v) with borate in alkaline, dilute-to-concentrated, NaCl and MgCl2solutions

“…We note that similar observations were reported for Nd(III) in the presence of comparable borate concentrations and pH m . 13 A comparable decrease in the solubility of NpO 2 OH(am) accompanied by a change in the colour of the solid phase from greenish to white-greyish occurs in dilute MgCl 2 systems at pH m < 9 and [B] tot = 0.16 M (dark blue symbols in Fig. 1c).…”

“…8,9 Only a very limited number of experimental studies available in the literature deal with the impact of borate on the solution chemistry of actinides. [10][11][12][13][14][15] Most of these studies focus on Nd(III), Eu(III) and Cm(III) as analogues of the trivalent actinides Am(III) and Pu(III). [10][11][12][13] Spectroscopic and solubility data indicated the formation of relatively weak Cm(III)borate(aq) and Ln(III)-borate(aq) complexes in mildly alkaline aqueous solutions.…”

“…[10][11][12][13][14][15] Most of these studies focus on Nd(III), Eu(III) and Cm(III) as analogues of the trivalent actinides Am(III) and Pu(III). [10][11][12][13] Spectroscopic and solubility data indicated the formation of relatively weak Cm(III)borate(aq) and Ln(III)-borate(aq) complexes in mildly alkaline aqueous solutions. [10][11][12][13] On the other hand, the most distinct feature observed in was the formation of a previously unreported Nd(III)-borate(s) amorphous solid phase that defined solubility limits well below the solubility of Nd(OH) 3 (s) in weakly alkaline solutions.…”

“…[10][11][12][13] Spectroscopic and solubility data indicated the formation of relatively weak Cm(III)borate(aq) and Ln(III)-borate(aq) complexes in mildly alkaline aqueous solutions. [10][11][12][13] On the other hand, the most distinct feature observed in was the formation of a previously unreported Nd(III)-borate(s) amorphous solid phase that defined solubility limits well below the solubility of Nd(OH) 3 (s) in weakly alkaline solutions. 13 In her PhD thesis, Hinz revealed also no (or very minor) impact of borate on the solubility of Th(IV), very likely as a result of the strong An(IV) hydrolysis that cannot be outcompeted by borate complexation.…”

“…[10][11][12][13] On the other hand, the most distinct feature observed in was the formation of a previously unreported Nd(III)-borate(s) amorphous solid phase that defined solubility limits well below the solubility of Nd(OH) 3 (s) in weakly alkaline solutions. 13 In her PhD thesis, Hinz revealed also no (or very minor) impact of borate on the solubility of Th(IV), very likely as a result of the strong An(IV) hydrolysis that cannot be outcompeted by borate complexation. 14 The formation of An(VI)-borate(aq) aqueous complexes was confirmed in solubility (for U(VI) 14 ) and spectroscopic (for Pu(VI) 15 ) studies.…”