The most crucial role played by minerals was in the preconcentration of biomolecules or precursors of biomolecules in prebiotic seas. If this step had not occurred, molecular evolution would not have occurred. Thiocyanate is an important molecule in the formation of biomolecules as well as a catalyst for prebiotic reactions. The adsorption of thiocyanate onto ferrihydrite was carried out under pH and ion composition conditions in seawater that resembled those of prebiotic Earth. The seawater used in this work had high Mg2+, Ca2+ and SO42- concentrations. The most important result of this work was that ferrihydrite adsorbed thiocyanateata pH value (7.2 ± 0.2) that usually does not adsorb thiocyanate. The high adsorptivity of Mg2+, Ca2+ and SO42-onto ferrihydrite showed that seawater ions can act as carriers of thiocyanate to the ferrihydrite surface, creating a huge outer-sphere complex. Kinetic adsorption and isotherm experiments showed the best fit for the pseudo-second-order model and an activation energy of 23.8 kJ mol-1forthe Langmuir-Freundlich model, respectively. Thermodynamic data showed positive ΔG values, which apparently contradict the adsorption isotherm data and kinetic data that was obtained. The adsorption of thiocyanate onto ferrihydrite could be explained by coupling with the exergonic SO42- adsorption onto ferrihydrite. The FTIR spectra showed no difference between the C≡N stretching peaks of adsorbed thiocyanate and free thiocyanate, corroborating the formation of an outer-sphere complex. All the results demonstrated the importance of the artificial seawater composition for the adsorption of thiocyanate and for understanding prebiotic chemistry.

中文翻译：

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在益生元化学条件下意外的硫氰酸盐吸附到三水铝石上。

矿物质发挥的最关键作用是在益生元海洋中对生物分子或生物分子的前体进行预浓缩。如果没有发生此步骤，则不会发生分子进化。硫氰酸盐是生物分子形成中的重要分子，也是益生元反应的催化剂。硫氰酸盐在亚铁酸盐上的吸附是在类似于益生元地球的海水中在pH和离子组成条件下进行的。在这项工作中使用的海水中Mg2 +，Ca2 +和SO42-的浓度很高。这项工作的最重要结果是，水铁矿吸附的硫氰酸盐的pH值（7.2±0.2）通常不吸附硫氰酸盐。Mg2 +的高吸附性 Ca 2+和SO 4 2-上的亚铁水合物表明，海水离子可作为硫氰酸盐的载体带入亚铁水合物表面，从而形成巨大的外层复合物。动力学吸附和等温线实验显示最适合拟二阶模型，Langmuir-Freundlich模型的活化能分别为23.8 kJ mol-1。热力学数据显示出正ΔG值，这显然与吸附等温线数据和所获得的动力学数据相矛盾。硫氰酸盐在亚铁酸盐上的吸附可以通过将能态SO42-吸附到亚铁酸盐上来解释。FTIR光谱表明，吸附的硫氰酸盐和游离硫氰酸盐的C≡N拉伸峰之间没有差异，从而证实了外层络合物的形成。