Table 2. Non-linear isotherm data for heavy metals adsorption on DPAC.

Temperature (K)	Non-linear isotherm models
	Langmuir				Freundlich
	qm (mg/g)	b (L/mg)	RL	R2	Kf (mg/g)(L/mg)1/n	n	R2
Pb(II)
298	133.49	0.2233	0.0147	0.9703	38.84	3.76	0.8091
308	77.93	0.1524	0.0214	0.9813	25.71	4.64	0.9662
328	72.14	0.1327	0.0245	0.9954	24.48	5.42	0.9759
Cd(II)
298	212.10	0.1605	0.0203	0.9852	50.27	3.03	0.9490
308	144.62	0.0799	0.0400	0.9424	26.81	2.97	0.9411
328	150.23	0.0194	0.1466	0.9890	14.22	2.44	0.9553
Cu(II)
298	194.45	0.0180	0.2358	0.9516	17.42	2.39	0.9821
308	144.85	0.0169	0.1647	0.9261	13.74	2.54	0.9844
328	134.43	0.0133	0.2004	0.9349	12.76	2.58	0.9483
Zn(II)
298	111	0.0303	0.0991	0.9228	19.36	3.28	0.9798
308	105.69	0.0113	0.2278	0.8782	18.80	2.41	0/9785
328	88.96	0.0041	0.4484	0.5920	1.15	1.32	0.9716