The modification of minerals with metals can promote changes in their surface and, consequently, in their physicochemical properties. Minerals could have played an important role in the origin of life as they can protect molecules against degradation by radiation and hydrolysis, pre-concentrate molecules from dilute solutions and catalyse the formation of polymers. Thus, the current work studied the modification of montmorillonite with Cu2+ and Fe3+ ions. These modified montmorillonites were used to study the interaction with adenine dissolved in distilled water and artificial seawater 4.0 Gy (Gy = billion years ago). The most important result of this work is that the adsorption of adenine onto modified montmorillonites is a complex interaction among adenine, salts in seawater and Cu2+/Fe3+-montmorillonite (Cu2+/Fe3+-Mont) . The adsorption of Cu2+ and Fe3+ onto montmorillonite decreased its surface area and pore volume. The Sips isotherm model showed the best fit of the data and n values indicate that the adenine adsorption process was homogeneous. The highest adenine adsorption was obtained in artificial seawater 4.0 Gy onto Fe3+-Mont at 60°C and the lowest in distilled water or artificial seawater 4.0 Gy onto montmorillonite [montmorillonite washed with distilled water (Mont-STD)] at 60°C. Adenine adsorption onto Mont-STD/montmorillonite modified with 500 ml of 0.1 mol l−1 of CuCl2 and Fe3+-Mont was an exothermic process and an endothermic process, respectively. For all adsorptions ΔG was negative. The adsorption of adenine onto Fe3+-Mont was ruled out by entropy and the other samples by enthalpy and entropy, being a major contribution for Gibbs free energy from enthalpy. The Fourier transform-infrared data indicate that the interaction of adenine with minerals may occur through the NH2 functional group.

中文翻译：

---

腺嘌呤与 Cu2+ 和 Fe3+-蒙脱石的相互作用：益生元化学实验

用金属对矿物进行改性可以促进其表面的变化，从而促进其物理化学性质的变化。矿物质可能在生命起源中发挥了重要作用，因为它们可以保护分子免受辐射和水解的降解，从稀溶液中预浓缩分子并催化聚合物的形成。因此，目前的工作研究了Cu对蒙脱石的改性。2+和铁3+离子。这些改性蒙脱石用于研究与溶解在蒸馏水和人造海水 4.0 Gy（Gy = 十亿年前）中的腺嘌呤的相互作用。这项工作最重要的结果是腺嘌呤在改性蒙脱石上的吸附是腺嘌呤、海水中的盐类和铜之间的复杂相互作用。2+/铁3+-蒙脱石（Cu2+/铁3+-蒙特）。Cu的吸附2+和铁3+蒙脱石上的表面积和孔体积减小。Sips 等温线模型显示了数据的最佳拟合和n值表明腺嘌呤吸附过程是均匀的。在人工海水 4.0 Gy 中，Fe 上的腺嘌呤吸附量最高3+-蒙脱石在 60°C 和最低的蒸馏水或人造海水 4.0 Gy 到蒙脱石 [蒙脱石用蒸馏水洗涤 (Mont-STD)] 在 60°C。腺嘌呤吸附到用 500 ml 0.1 mol l 改性的 Mont-STD/蒙脱石上-1氯化铜2和铁3+-Mont 分别是一个放热过程和一个吸热过程。对于所有吸附 ΔG为阴性。腺嘌呤在 Fe 上的吸附3+-Mont 被熵排除，其他样本被焓和熵排除，这是 Gibbs 自由能来自焓的主要贡献。傅里叶变换红外数据表明，腺嘌呤与矿物质的相互作用可能通过 NH 发生。2功能小组。