. Author manuscript; available in PMC: 2023 Sep 22.

Published in final edited form as: Environ Sci Technol. 2020 Aug 4;54(16):9769–9790. doi: 10.1021/acs.est.0c01666

Table 6.

Adsorbents selective for the removal of target oxo-anions

Target Oxo-anion	Technology Type		Observed Selectivity	Selectivity Metric(s)	Mechanism(s) of Selectivity	References
H₂AsO₄⁻	PLE	Cu(II)-PLE	As(V) ~ P > C > S	$\propto$	Electrostatic, HSAB	^{24,79,117,179}
		Zr(VI)-PLE	As(V) ~ P > C ~ S	%R	Electrostatic, HSAB	^16,99
		ZV-PLE	As(V) > S > N > P	%R	Hydrophobicity, sterics	¹⁸⁰
		Cu(II)-chitosan	As(V) > P	$\propto$ , %R	Electrostatic, HSAB	^11,133,181
	AE	WB-AE	S > As(V) > N	%I	Electrostatic, HSAB	²⁵
		WB-AE	P > As(V) > S > N	%I	Electrostatic, hydrophobicity	⁵⁷
	MOF	Fe(III)-MOF	As(V) > S ~ N > C	%R	Sterics	¹⁷⁵
		SM-Zr(VI)-MOF	P ~ As(V) > Si > S > N	TL	Electrostatic	¹⁸²
	LDH	Mg-Al LDH	P > As(V) > C ~ S > N	%I	Electrostatic, sterics	^173,174
H₃AsO₃	MIP	MIP	As(III) > P > S > N	K_d, $β$	Electrostatic, sterics	¹²⁶
		MIP	S > As(III) > Si ~ P > N	K_d, $β$	Electrostatic, sterics	¹⁸³
HSeO₃⁻	PLE	Cu(II)-PLE	Se(IV) > S	$\propto$	Electrostatic, HSAB	¹¹⁷
		Cu(II)-chitosan	Se(IV) > P	$\propto$ , %R	Electrostatics, sterics	¹¹
	MMSi	MMSi	Se(IV) > S ~ N > P	%R	Electrostatics	¹⁸⁴
SeO₄^2-	HBC	Mg(II)-HBC	S > Se(VI) > C	$Δ G^{\circ}$	Hydrophobicity, sterics, electrostatic	⁹⁸
HCrO₄⁻	PLE	ZVE-PLE	Cr(VI) > S > N > P	%R	Hydrophobicity, sterics	¹⁸⁰
	AE	SB-AE	Cr(VI) > S > N	$\propto$	Hydrophobicity, sterics, electrostatic	¹¹⁰
	MOF	Zr(VI)-MOF	Cr(VI) > S > N	K _d , %R	Electrostatic, HSAB, sterics	^112,122
		Co(II)-MOF	Cr(VI) > S ~ N	K _d	Electrostatic, sterics	¹⁷⁷
		Zn(II)-MOF	Cr(VI) > S ~ N	K _d	Electrostatic, sterics	¹⁷⁷
		Cd(II)-MOF	Cr(VI) > S > N	%R	Electrostatic, sterics	¹⁷⁸
		Ag(I)-MOF	Cr(VI) > N > C	%R	Electrostatic, sterics	¹⁷⁶
	SM-clay	SM-clay	Cr(VI) > N > S ⁻	qr	Sterics	¹⁷²
	MIP	MIP	Cr(VI) > S ~ N	K_d, $β$	Sterics	¹²⁷
		MIP	Cr(VI) > S > N	K_d, $β$	Sterics	¹⁸⁵
		MIP	Cr(VI) > S > P > N	K_d, $β$	Sterics	^186,187
		NMO-MIP	Cr(VI) > N > S > P	TL	Electrostatic, sterics	¹⁸⁸
	SM-MCWNT	SM-MCWNT	Cr(VI) > C ~ P ~ N	%R	Electrostatic	¹⁸⁹
	SM-activated C	SM-activated C	Cr(VI) > P > S > N	%I	Sterics	¹⁹⁰

Note: PLE is polymeric ligand exchanger, HSAB is hard-soft acid base principle, ZV is zero valent iron, SB-AE is a strong base anion exchanger, WB-AE is weak base anion exchanger, MOF is metal organic framework, LDH is layered double hydroxide, SM is surfactant modified, and MIP is molecularly imprinted polymer, MMSi is modified mesoporous silica, HBC is hydrogen bonding capsule, MCWNT is multi-walled carbon nanotube. $\propto$ is binary separation factor, %R is % removal, %I is % interference, TL is tolerance limit, K_d is distribution coefficient, $β$ is the selectivity coefficient, $Δ G^{°}$ is energy of crystallization, qr is ratio of q the adsorption capacity.