Biosorption of Fe(II) and Mn(II) Ions from Aqueous Solution by Rice Husk Ash

Table 5

Comparison of maximum adsorption capacities of different adsorbents for Fe(II) and Mn(II) ions.

	Serial no.	Adsorbents	Adsorption capacity (mg/g)	Contact time (min)	Concentration range (mg/L)	pH	Temp. range (K)	References
Fe(II)	1	Coir fibres	2.84	120	73.50–83.9	5	308	[48]
	2	Modified coir fibres	7.49	120	73.50–83.9	5	308	[48]
	3	Activated carbon from coconut shells	81.89	90	20–100	6	298	[10]
	4	Chitosan/polyethylene glycol blend membrane	90.9	80	2–10	5	300	[49]
	5	Pine bark wastes	2.03	30	55.6–111.2	4	303–333	[50]
	6	Chitosan	57.5	40	3–9	5	—	[51]
	7	Cross-linked chitosan	64.1	60	3–9	5	—	[51]
	8	Rice husk ash	6.21	60	2–40	5	298	Present study
Mn(II)	9	Pithecellobium dulce carbon	7.0	50	5–25	7	—	[34]
	10	Crab shell particles	69.9	120	10–1000	6	296	[52]
	11	Bombax malabaricum	8.2	50	5–25	7	—	[35]
	12	Pithecellobium dulce	7.0	90	5–25	9	—	[35]
	13	Ipomea batatas	6.0	90	5–25	9	—	[35]
	14	Peltophorum ferrugineum	5.5	90	5–25	7	—	[35]
	15	Activated zeolite with NaCl	0.78	150	5–600	6	298	[30]
	16	Manganese oxide coated zeolite	1.1	150	25–600	6	298	[53]
	17	Chitosan/polyethylene glycol blend membrane	21.7	80	2–10	6	300	[48]
	18	Activated carbon from coconut shells	75.65	90	20–100	7	298	[10]
	19	Tannic acid immobilised activated carbon	1.13	60	1–10	7	298	[54]
	20	Rice husk ash	3.02	60	2–40	6	298	Present study