Geochemical Association of Ni ²⁺ , Zn ²⁺ , Pb ²⁺ , Ag ⁺ , Cu ²⁺ , and Co ²⁺ Ions in Natural Pyrite

Table 3

Thermodynamic parameters for individual metal ion adsorption.

Metal ion	pH 4			pH 5			pH 6			pH 7			pH 8
	−Δ𝐺×10^2; J mol^−1	Δ𝑆×10^−2; J K^−1 mol^−1	−Δ𝐻×10^2; J mol^−1	−Δ𝐺×10^2; J mol^−1	Δ𝑆×10^−2; J K^−1 mol^−1	−Δ𝐻×10^2; J mol^−1	−Δ𝐺×10^2; J mol^−1	Δ𝑆×10^−2; J K^−1 mol^−1	−Δ𝐻×10^2; J mol^−1	−Δ𝐺×10^2; J mol^−1	Δ𝑆×10^−2; J K^−1 mol^−1	−Δ𝐻×10^2; J mol^−1	−Δ𝐺×10^2; J mol^−1	Δ𝑆×10^−2; J K^−1 mol^−1	−ΔH × 10^2; J mol^−1
Ni^2+	158.95	11.98	158.59	83.64	15.64	83.16	89.78	15.00	89.33	104.81	13.78	104.39	122.36	12.86	121.97
Zn^2+	67.19	17.69	66.66	69.25	17.51	68.72	67.93	17.71	67.40	84.02	15.60	83.55	ND	ND	ND
Pb^2+	133.87	12.47	133.49	127.99	12.64	127.61	155.60	12.02	155.24	ND	ND	ND	ND	ND	ND
Ag^+	88.39	15.13	87.93	95.04	14.52	94.60	138.19	12.36	137.82	ND	ND	ND	ND	ND	ND
Cu^2+	87.72	15.20	87.26	86.22	15.36	85.85	138.19	12.36	137.82	ND	ND	ND	ND	ND	ND
Co^2+	85.60	15.42	85.13	85.40	15.45	84.93	88.16	15.16	87.71	92.28	14.76	91.83	96.84	14.37	96.41

ND: not determinable.