Precise determination of precipitation yield of uranyl nitrate with N-alkylated 2-pyrrolidone derivatives

Figures & data

Figure 1. Schematic structure of N-alkylated 2-pyrrolidone derivatives (NRPs, R = −C_nH_2n+1, cycloalkyl).

Figure 2. Simulated species distribution diagram in aqueous solution containing [UO₂]²⁺ (50 mM) and [SO₄]²⁻ (0.76 M) at 1 M ionic strength [10,11].

Table 1. Summary of NBP system (C^U_ini = 1.56 M, C^H_ini = 3.11 M).

C^NBP/C^Uini	$C_{sup}^{\mathrm{H}}$ (M)	$C_{sup}^{\mathrm{U}}$ (M)	Vsup/Vini	y′ (%)	y (%)	Δy (%)	E (%)	$C_{sup}^{\mathrm{NBP}}$ (M)^a	V^UNM (L mol^−1)
0.927	3.15	0.901	0.987	42.4	43.1	0.7	92.9	0.104	–
1.19	3.25	0.691	0.957	55.8	57.7	1.9	97.0	0.059	–
1.30	3.33	0.580	0.934	62.9	65.4	2.4	100.9	–	6.5 × 10^−2
1.48	3.33	0.435	0.934	72.2	74.0	1.8	99.7	0.007	5.7 × 10^−2
1.68	3.35	0.261	0.929	83.3	84.5	1.2	100.6	–	5.4 × 10^−2
1.83	3.33	0.148	0.934	90.5	91.2	0.6	99.9	0.004	4.6 × 10^−2

^a$C_{sup}^{\mathrm{NBP}}$ denotes the concentration of NBP remaining in the supernatant, and is equal to C^NBP(1 − E)/(V_sup/V_ini).

Figure 3. Yield of UO₂(NO₃)₂(NRP)₂ precipitate (y, left axis, open symbols) and efficiency of NRP to form the precipitate (E, right axis, solid symbols) as a function of C^NRP/C^U_ini. NRP = NBP (circle), NProP (square).

Table 2. Summary of NProP system (C^U_ini = 1.51 M, C^H_ini = 3.09 M).

C^NProP/C^Uini	$C_{sup}^{\mathrm{H}}$ (M)	$C_{sup}^{\mathrm{U}}$ (M)	Vsup/Vini	y′ (%)	y (%)	Δy (%)	E (%)	C^NProP(M)^a
1.02	3.24	0.849	0.954	43.7	46.2	2.6	91.0	0.144
1.21	3.25	0.688	0.951	54.3	56.5	2.2	93.8	0.119
1.39	3.33	0.536	0.928	64.4	66.9	2.6	96.0	0.091
1.58	3.37	0.410	0.918	72.8	75.0	2.2	94.8	0.134
1.81	3.34	0.236	0.924	84.3	85.5	1.2	94.6	0.160
2.02	3.32	0.126	0.931	91.6	92.2	0.6	91.8	0.266

^aC^NProP_sup denotes the concentration of NProP remaining in the supernatant, and is equal to C^NProP(1 − E)/(V_sup/V_ini).