Adsorption of Heavy Metals in Contaminated Water Using Zeolite Derived from Agro-Wastes and Clays: A Review

Table 9

Summary of adsorption isotherms on synthetic zeolites derived from agro-wastes and clay.

Zeolite	Raw materials	Metal ion	Langmuir model		Freundlich model		References
			(mg/g)	R ^2	(mg/g)	R ^2
Zeolite X	Ecuadorian clay	Pb^2+	131.6	0.994	31.33	0.977	[201]
Zeolite NaA	Bagasse ash	Ca^2+	555.54	0.987	2.24	0.9986	[237]
ZSM-5	Chlorite clay	As^5+	411.41	0.9907	74.63	0.9043	[238]
		Pb^2+	546.25	0.9921	653.15	0.7300
Zeolite X	Coal fly ash	Ni^2+	1.136	0.8348	0.22	0.5669	[239]
		Cd^2+	1.795	0.5600	0.23	0.8077
		Cu^2+	3.209	0.9890	1.65	0.9954
NaA zeolite	Oil shale ash	Cu^2+	156.74	0.998	87.07	0.979	[240]
		Ni^2+	53.02	0.996	27.42	0.984
		Pb^2+	224.72	0.978	91.34	0.938
		Cd^2+	118.34	0.993	62.91	0.768
Linde F (K) zeolite	Fly ash	Cu^2+	59.9	0.9763	66.8	0.0691	[241]
		Cd^2+	118.6	0.9567	1.42	0.7002
		Pb^2+	476.1	0.9864	248.5	0.8149
Zeolite 4A	Recycled coal fly ash	Co^2+	13.72	0.998	6.66	0.959	[242]
		Cr^3+	41.61	0.998	28.47	0.850
		Cu^2+	50.45	1.000	37.11	0.974
		Zn^2+	8.96	0.997	6.27	0.834
		Ni^2+	30.80	0.945	18.47	0.623