Substrates of magnetite-based adsorbents for the removal of radionuclides.

Adsorbent	Method	Substrates	Functional group	Target	Temp	pH	Q max (mg g−1)	Solution condition	Time	Mechanism	References
CB[6]/GO/Fe3O4	Co-precipitation	GO	CB[6]	U(vi)	298	5	122.5	DI	2.5 h	Complexation with functional groups of CB[6]/GO/Fe3O4	82
Fe3O4/GO	Co-precipitation	GO		U(vi)	293	5.5	69.5	0.01 M KNO3	>4 h	At high pH: precipitation and inner sphere surface complexation	79
AOMGO	Co-precipitation	GO	Amidoxime	U(vi)	298	5	284.9	0.01 M NaClO4	2 h	Inner sphere surface complexation	123
MnO2–Fe3O4–rGO	Hydrothermal	rGO	MnO2	U(vi)	328	6	108.7	n.a	6 h	Surface complexation, cation exchange and electrostatic interaction	124
AMGO	Hydrothermal	GO	Amino	U(vi)	298	5.9	141.2	DI	100 min	Interaction with nitrogen- and oxygen containing functional groups	125
Fe3O4/GO	Hydrothermal	GO		U(vi)	298	5.9	283.2	0.01 M NaNO3	5 h		126
Fe3O4/GO	Co-precipitation	GO		Cs(i) Sr(ii)	293	5	15.8 38.4	0.01 M NaCl	24 h	H+/Na+ exchange	127
MGO	Co-precipitation	GO		Eu(iii)				NaClO4 and N2	5 h	Inner-sphere surface complexation	128
Magnetic GOs	Co-precipitation	GO		Eu(iii)	293	4.5	70.2	0.01 M NaClO4	24 h	Inner-sphere surface complexation	129
M/GO	Co-precipitation	GO		Sr(ii)	303	8.5	9.8	0.01 M NaClO4	2 h	Inner-sphere surface complexation	130
Magnetic graphene oxides	Co-precipitation	GO		Sr(ii) Cs(i)	293	4	14.7 9.3	0.01 M NaClO4	24 h	Cation exchange and inner-sphere surface complexation	131
PB/Fe3O4/GO	Co-precipitation	GO	PB	Cs(i)	298	7	55.6	DI	24 h	H+ exchange and/or ion trapping	80
PFGM	Co-precipitation	GO/calcium alginate	PB	Cs(i)	298	7	43.5	DI	24 h	K+/H+ exchange and or ion trapping	132
Fe3O4@C@Ni–Al LDH	Co-precipitation	Carbon	Ni–Al LDH	U(vi)	298	6	174	n.a	3 h	Surface adsorption and intercalation	133
MMWCNTs	Co-precipitation	CNTs		Th(iv)	298	4.1	0.232	n.a	40 h	Surface complexation	134
Fe3O4/AC	Co-precipitation	AC		Sr(ii)	303	5	42.3	0.01 M NaCl	4 h		135
PAF magnetic adsorbent	Co-precipitation	AC	Polyethylenimine	U(vi)	293	5	115.3	n.a	1 h		136
CD/HNT/iron oxide	Co-precipitation	HNT	CD	U(vi)	298	5.5	107.6	0.01 M NaNO3	4 h	At high pH: inner-sphere surface complexation, at low pH electrostatic or outer sphere complexation	85
HNTs–Fe3O4	Co-precipitation	Halloysite nanotubes		U(vi)		5.5	88.3	0.01 M NaCl	12 h	Ion exchange and surface complexation	137
MZC	Co-precipitation	Zeolite		Sr(ii) Cs(i)	298	8	83.7207.4	n.a	>2 h	Ion exchange	138
MZNC	Co-precipitation	Zeolite		Sr(ii) Cs(i)	298	8	89, 229	n.a	>30 min	Ion exchange	139
Magnetic 4A zeolite	Hydrothermal	Zeolite		Cs(i)	298		106.6	n.a	48 h		140
Attapulgite-iron oxide	Co-precipitation	Attapulgite		Eu(iii)	293	5	117	0.01 M NaClO4	24 h	At low pH: outer sphere surface complex, ion exchange, at high pH: inner sphere surface complex, surface precipitation	86
Magnetic citrate Mg–Al LDH	Co-precipitation	Mg–Al LDH	Citrate	U(vi)	298	6	180	n.a	4 h	Formation of chelate complex	88
CMLH	Co-precipitation	LDH/hydroxyapatite		U(vi)	298	6	208	n.a	1 h	Surface adsorption or complexation	141
CS-g-MB	Solvothermal	Bentonite	Chitosan	Cs(i)		7.61	149	Seawater	24 h	Ion exchange with chitosan functional groups such as OH groups	89
Silicate-based multifunctional nanostructured materials with magnetite and prussian blue	Co-precipitation	Sepiolite	PB	Cs(i)	295		102	n.a	3 h		87
MMT/Fe3O4	Co-precipitation	Ammonium-pillared montmorillonite		Cs(i)	298	6.7	27.5	n.a	1 h	NH4+ ion exchange and surface hydroxyl group coordination	142