Characteristics of Heavy Metal Ion Adsorption by Silty Mudstones in Coal Mine Goafs

Table 2

Isothermal adsorption parameters.

	Metal ions
	Pb(II)	Cd(II)	Cr(III)	Mn(II)
Langmuir model
(mg/g)	6.3012	1.5701	1.2571	1.3729
(L/mg)	0.5964	0.9292	18.8061	0.322
	0.961	0.9941	0.9998	0.9738
Freundlich model
	2.4505	0.7787	1.1463	0.3394
	3.0331	3.252	17.0503	1.8292
	0.9954	0.9964	0.9364	0.9921
D–R model
(mg/g)	20.2089	5.2673	1.545	8.2101
(kJ/mol^2)	0.00233	0.00238	4.13-04	0.00449
(kJ/Mol)	-14.649	-14.4943	-34.8122	-14.7442
	0.9935	0.9904	0.9679	0.9694