Research Article
Dissolution, Solubility, and Stability of the Basic Ferric Sulfate-Arsenates [Fe(SO4)x(AsO4)y(OH)z·nH2O] at 25–45°C and pH 2–10
Table 4
Experimental data and solubility determination for the basic ferric sulfate-arsenate FeSAsOH-3 [Fe(SO4)0.27(AsO4)0.72(OH)0.30·0.21H2O].
| Temp (°C) | Initial pH | Time (h) | Dissolution data (mmol/L) | log_IAP | Mean log_IAP | ΔGfo (kJ/mol) | Mean ΔGfo (kJ/mol) | pH | Fe | SO4 | AsO4 |
| 25a | 2 | 5760 | 1.97 | 0.144323 | 0.103381 | 0.059262 | −23.16 | −23.14 | −901.14 | −901.02 | 6480 | 1.98 | 0.145487 | 0.104004 | 0.059462 | −23.14 | ±0.02 | −900.99 | ±0.12 | 7200 | 1.98 | 0.145755 | 0.104160 | 0.059329 | −23.14 | | −900.99 | | 7920 | 1.98 | 0.145666 | 0.104472 | 0.059596 | −23.14 | | −900.98 | |
| 25 | 6 | 5760 | 3.91 | 0.000420 | 0.068764 | 0.010056 | −25.07 | −25.08 | −912.05 | −912.08 | 6480 | 3.90 | 0.000417 | 0.067517 | 0.009817 | −25.08 | ±0.01 | −912.11 | ±0.03 | 7200 | 3.90 | 0.000414 | 0.067049 | 0.010044 | −25.08 | | −912.09 | | 7920 | 3.90 | 0.000416 | 0.067829 | 0.010053 | −25.08 | | −912.07 | |
| 25 | 10 | 5760 | 4.22 | 0.000375 | 0.083110 | 0.012148 | −25.12 | −25.13 | −912.28 | −912.35 | 6480 | 4.21 | 0.000367 | 0.084045 | 0.011985 | −25.13 | ±0.01 | −912.34 | ±0.07 | 7200 | 4.21 | 0.000363 | 0.084825 | 0.011878 | −25.13 | | −912.38 | | 7920 | 4.21 | 0.000358 | 0.085293 | 0.011962 | −25.14 | | −912.40 | |
| 25b | 2 | 5760 | 1.97 | 0.143249 | 0.111801 | 0.057060 | −23.17 | −23.18 | −901.19 | −901.21 | 6480 | 1.97 | 0.145755 | 0.111489 | 0.055992 | −23.17 | ±0.01 | −901.19 | ±0.11 | 7200 | 1.96 | 0.144144 | 0.110163 | 0.056659 | −23.19 | | −901.32 | | 7920 | 1.97 | 0.145308 | 0.111333 | 0.056793 | −23.17 | | −901.16 | |
| 35 | 2 | 5760 | 1.95 | 0.213082 | 0.201304 | 0.041310 | −23.04 | −23.05 | | | 6480 | 1.95 | 0.216395 | 0.203642 | 0.039374 | −23.05 | ±0.01 | | | 7200 | 1.95 | 0.217290 | 0.201459 | 0.039641 | −23.04 | | | | 7920 | 1.95 | 0.217648 | 0.201771 | 0.039308 | −23.05 | | | |
| 45 | 2 | 5760 | 1.93 | 0.314430 | 0.285037 | 0.035971 | −22.90 | −22.89 | | | 6480 | 1.93 | 0.322936 | 0.287064 | 0.036238 | −22.89 | ±0.01 | | | 7200 | 1.93 | 0.322846 | 0.286596 | 0.036572 | −22.89 | | | | 7920 | 1.93 | 0.322936 | 0.288156 | 0.036638 | −22.89 | | | |
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a,bDissolution tests in duplicate.
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