Table 1.

Parameters of the isotherm models for the adsorption of the metal ions onto the pristine and aged DFMs.

DFMs	Metals	Parameters
		Freundlich model				Langmuir model
		KF ((µg·g−1)/(µg·L-1)1/n)	$n_{\mathrm{F}}$	Adj.R2	χ2	KL (L/µg)	Qm (μg/g)	Adj.R2	χ2
Pristine	Pb(Ⅱ)	0.165	1.57	0.990	28.9	2.90 × 10-5	265.63	0.994	17.1
	Cd(Ⅱ)	0.039	1.51	0.960	12.4	2.89 × 10-5	79.75	0.989	3.45
	Sr(Ⅱ)	0.016	1.42	0.966	4.71	2.30 × 10-5	58.54	0.990	1.36
Aged	Pb(Ⅱ)	0.209	1.54	0.988	71.2	2.76 × 10-5	384.16	0.993	42.5
	Cd(Ⅱ)	0.064	1.56	0.984	5.45	2.86 × 10-5	105.32	0.986	5.07
	Sr(Ⅱ)	0.062	1.65	0.982	3.86	3.65 × 10-5	64.34	0.992	1.83