Apparent energy of hydrated biomineral surface and apparent solubility constant: an investigation of hydrozincite.

摘要: Abstract The apparent solubility (Ksapp) of hydrozincite [Zn5(CO3)2(OH)6] was measured in samples different nature, including natural abiotic (“geologic”), synthetic (abiotic), and biominerals. A systematic variation is recorded from log Ksapp = 6.2 ± 0.1 geologic sample, log Ksapp between 7.0 ± 0.2 7.5 ± 0.2 analogues, 8.8 ± 0.2 9.1 ± 0.2 biomineral samples. Samples were thoroughly characterized by using SEM, TEM, synchrotron radiation X-rays powder diffraction (SR-XRPD), Zn K-edge absorption spectroscopy (EXAFS). Refining SR-XRPD data, it found a significant increase (up to 10%) the cell volume biologic hydrozincites with respect EXAFS analysis indicates small, but differences interatomic distances nature. Previous studies had shown that crystal size nanometer range for all samples, decreases going Combining these data structural obtained this study, effects on particle calculated classical thermodynamic equations. surface energy hydrated increases at least one order magnitude sample. effect deemed negligible, being same error measurements. Thus, investigated most likely ascribed energy. constants used build predominance diagrams; specifically biominerals, only use Ksapp derived study predicts fairly well seasonal biomineralization Naracauli, Sardinia.