Application of Calixarenes as Macrocyclic Ligands for Uranium(VI): A Review

Table 5

Solvent extraction of UO₂²⁺ in the presence of competing metal cations at 30°C and at pH 5.9.

Entry	Extraction agent	M^𝑛+	[M^𝑛+]/ [UO2^2+]	Ex%	Organic solvent	Reference
1	16	Mg^2+	5000^a	72	𝑜-Cl2C6H4^d	[57]
2	16/MTA^+Cl^− c	Mg^2+	5000^a	100	𝑜-Cl2C6H4^d	[57]
3	16	Mg^2+	1000^a	100	CHCl3	[58]
4	19	Mg^2+	1000^a	100	CHCl3	[58]
5	20	Mg^2+	943.4^b	92	CHCl3	[60]
6	16	Ni^2+	12.5^a	93	𝑜-Cl2C6H4^d	[57]
7	16/MTA^+Cl^− c	Ni^2+	12.5^a	100	𝑜-Cl2C6H4^d	[57]
8	16	Ni^2+	50^a	77	𝑜-Cl2C6H4^d	[57]
9	16/MTA^+Cl^−  c	Ni^2+	50^a	100	𝑜-Cl2C6H4^d	[57]
10	19	Ni^2+	10^a	77	CHCl3	[58]
11	15	Ni^2+	10^a	98	CHCl3	[58]
12	20	Ni^2+	2.4^b	98	CHCl3	[60]
13	20	Ni^2+	9.4^b	98	CHCl3	[60]
14	16	Zn^2+	36.5^a	63	𝑜-Cl2C6H4^d	[57]
15	16/MTA^+Cl^− c	Zn^2+	36.5^a	90	𝑜-Cl2C6H4^d	[57]
16	16	Zn^2+	60^a	51	𝑜-Cl2C6H4^d	[57]
17	16/MTA^+Cl^− c	Zn^2+	60^a	84	𝑜-Cl2C6H4^d	[57]
18	15	Zn^2+	12^a	51	CHCl3	[58]
19	19	Zn^2+	12^a	96	CHCl3	[58]
20	20	Zn^2+	6.9^b	98	CHCl3	[60]
21	19	Fe^3+	10^a	66	CHCl3	[58]
22	19	Fe^3+	1^a	100	CHCl3	[58]

^a[UO₂(CH₃CO₂)₂] = 0.020 mmol dm⁻³.
^b[K₄UO₂(CO₃)₃] = 0.106 mmol dm⁻³.
^cMTA⁺Cl⁻ methyltrioctylammonium chloride, [MTA⁺Cl⁻] = 1.0 mmol dm⁻³.
^d𝑜-dichlorobenzene.