Table 3.

Thermodynamic parameters for Pb²⁺ and Cr⁶⁺ adsorption onto L-Cyst-Fe₃O₄ NPs.

Adsorbate	ΔH° (kJ/mol)	ΔS° [kJ/(mol K)]	T (K)	K (L g−1)	ΔG° (kJ/mol)
Pb2+	83.7	0.31	298.15	3.448	−8.55
			308.15	4.360	−11.17
			318.15	5.571	−14.7
Cr6+	73.31	0.28	298.15	3.873	−9.60
			308.15	4.675	−11.98
			318.15	5.733	−15.16