A Comparative Study on Removal of Hazardous Anions from Water by Adsorption: A Review

Table 2

Adsorption isotherm for fluoride (F^-) removal.

Adsorbent	Adsorption capacity mg/g	Surface area m^2/g	Applicable isotherm; models	Initial fluoride conc. mg/L	References
Acidic alumina	8.4	144.27	Langmuir	15	[32]
Alkoxide origin alumina	2	100	Langmuir	5	[4]
Al(III) modified calcium hydroxyapatite	32.57	258.6	Langmuir	10	[146]
Bauxite	5.16	38	Langmuir	4–24	[147]
Ceramic	2.16	80.94	Freundlich and Langmuir	10	[40]
Chitosan-based mesoporous alumina	8.264	413.65	Langmuir	5	[66]
Granular red mud	0.851	10.2	Redlich–Peterson, Freundlich	15	[148]
Calcite	0.39	0.057	Freundlich	2.5 × 10^−5	[149]
Quartz	0.19	0.06	Freundlich	t0	[149]
Fluorspar	1.79	0.048	Freundlich	6.34 × 10^−2	[149]
Hydroxyapatite	4.54	0.052	Freundlich	—
Activated quartz	1.16	0.06	Freundlich	—	[149]
Nano alumina	14	151.7	Langmuir	—	[29]
Magnesia-amended activated alumina granules	10.12	193.5	Sips (S)	—	[150]
Manganese oxide-coated alumina	2.85	170.39	Langmuir	2–30	[151]
Mesoporous alumina (meso-Al-400)	39	361	Langmuir	10	[31]
Cerium-impregnated fibrous protein	17.5	3.65	Langmuir	—	[152]
Aluminium titanate (AT)	0.85	—	Freundlich, Langmuir	4	[153]
Bismuth aluminate (BA)	1.55	—	Freundlich, Langmuir	4	[153]
Alum-impregnated activated alumina (AIAA)	40.3	176	Bradley equation	—	[154]
Alumina/chitosan (AlCs) composite	3.809	55.23	Freundlich and Langmuir	—	[155]
Alumina cement granules	4.75 and 3.91	4.385	Langmuir	20; 8.65	[23]
Aluminum hydroxide-coated rice husk ash (AH-coated RHA)	15	50.4	Freundlich	10	[156]
Aluminum hydroxide, Al(OH)3	25	50.4	Freundlich	10	[156]
Activated alumina	2.41	—	Langmuir	—	[39]
Hydrated cement	2.6788	—	Freundlich, Langmuir	—	[157]
Waste mud	27.2	—	Langmuir	5.0 and 950	[64]
Sol-gel-derived activated alumina, CaO-AA	96.23	255.42	Langmuir	0.99	[135]
Sol-gel-derived activated alumina, MnO2-AA	0.99	218.0	Langmuir	432	[135]
Aluminum impregnation of activated carbon	2.549	—	Langmuir	—	[158]
Brushite	6.59	—	Langmuir and Freundlich	25	[159]
Ceramic	2.16	80.94	Freundlich and Langmuir isotherms	10	[40]
Granular ceramic	12.12	73.67	Freundlich	—	[40]
Ca650/C charcoal that contains calcium compounds	19.05	−	Langmuir	10	[160]
Titanium dioxide (TiO2)	0.27	56.	Temkin, Dubinin–Radushkevich (DR)	—	[68]
Magnetic-chitosan particle	20.96–23.98	—	Langmuir, Bradley’s	—	[161]
Mg–Al–Fe hydrotalcite-like compound	14	—	Langmuir	—	[65]
Mixed rare earth oxide	12.5	6.75	Langmuir	50	[162]
Plaster of Paris	0.366	—	Freundlich and Langmuir	2–10	[163]
Polypyrrole/Fe3O4 magnetic nanocomposite	17.6–22.3	—	Freundlich and Langmuir	—	[164]
Cross-linked chitosan particles	8.1	4.37	Freundlich and Langmuir	11.8 to 59.0	[165]
Carbon derived from Sargassum sp. by lanthanum	94.34		Langmuir		[166]
Hydroxyl aluminum oxalate	400		Langmuir		[133]
Hierarchical Ce–Fe bimetal oxides	60.97	164.9 m^2/g	Langmuir		[167]
Hydrous ferric oxide doped alginate beads	8.90	25.80	Langmuir		[168]
Al(III)–Zr(IV) binary oxide	114.54 mg/g		Langmuir		[169]
Hierarchical MgO microspheres	115.5 mg/g	33.7	Freundlich model		[143]
Micron-sized magnetic adsorbent (MMA)	41.8 mg/g		Langmuir	200 mg/L	[170]
Hydroxyapatite nanowires	40.65 mg/gat			200 mg/L	[171]
Aluminium fumarate	600	1156 m^2/g	Freundlich isotherm	1000	[134]