Equilibrium Isotherms, Kinetics, and Thermodynamic Mechanisms of a Novel Polyacrylamide-Strychnos potatorum Seed-Derived Activated Carbon Composite for Aqueous Hardness Removal

Table 2

Thermodynamic parameters of Ca, Mg, and hardness for PA-ACSPC adsorbent: (a) Gibbs free energy (∆G^o), (b) enthalpy (ΔH^o), and entropy (ΔS^o).

Temperature			Gibbs free energy (∆Go) (kJ)
			Ca	Mg	Hardness
20°C			−5.984	−2.414	−3.411
25°C			−7.354	−2.915	−4.019
30°C			−8.598	−3.497	−4.636
40°C			−10.092	−4.076	−5.259
ΔH^o (kJ/mol)			ΔS^o (J/mol/K)
Ca	Mg	Hardness	Ca	Mg	Hardness
62.730	25.401	0.928	234.765	96.032	3.381