Chemical Modifications of Cassava Peel as Adsorbent Material for Metals Ions from Wastewater

Table 9

Thermodynamic parameters for modified adsorbents from cassava peels in the removal of Cd(II), Pb(II), and Cr(III).

Adsorbents	Temp. °C	Cd(II)					Pb(II)					Cr(III)
		M. H2O2	15	6.4	3.0	15.5	43.6	0.93	11.8	−3.6	−59.5	−194.2	0.92	10.9	−1.4	−5.7	−15.1	0.93
25	6.1		2.6	10.7	−1.7				10.5	−1.2
35	7.8		2.1	10.0	0.3				10.7	−1.1
45	8.7		1.7	10.5	2.2				10.5	−0.9
55	9.0		1.3	10.7	4.1				10.1	−0.8
M. H2SO4	15	5.6	3.8	5.6	6.5	0.98	10.9	−1.0	−59.6	−203.9	0.80	10.1	−0.2	−9.9	−34.0	0.98
	25	6.0	3.7				7.7	1.1				8.6	0.2
	35	6.3	3.7				7.5	3.1				9.2	0.5
	45	6.2	3.6				8.6	5.2				9.6	0.8
	55	6.9	3.5				8.4	7.2				8.8	1.2
M. NaOH	15	12.5	−5.2	−29.7	−85.2	0.87	11.8	21.5	−0.26	−75.5	0.89	11.6	−3.2	18.1	74.1	0.87
	25	11.6	−4.3				11.7	22.2				11.7	−4.0
	35	11.5	−3.5				11.6	23.0				11.7	−4.7
	45	11.9	−2.6				11.5	23.8				11.9	−5.4
	55	11.2	−1.8				11.7	24.5				12.0	−6.2

(mg g⁻¹); (KJ mol⁻¹); (KJ mol⁻¹); (J mol⁻¹ K⁻¹).