This research explored the efficiency of snail shells powder (SSP) for Cu(II) removal from aqueous solutions and the production of valuable compounds from the residual product. To confirm its chemical and mineral components, the material was characterized by different instrumental techniques. The effects of experimental parameters such as the pH of the solution, the effect of SSP dose, particle size, and initial concentration of Cu(II) on the removal process were studied. The removal of Cu(II) was reasonably fast to be completed within a time frame of 90 min. The kinetics following the pseudo-second-order model (R² = 0.979) were better compared to the pseudo-first-order model (R² = 0.896). The increase in pH values leads to an increase in the amount of Cu(II) adsorbed. Afterward, the adsorption capacity reaches stability at pH near 7. The maximum Cu(II) removal occurred with a mass of 8 g·L⁻¹ and a particle size of 300 μm. This particle size presents approximately 44.5% of SSP particles, which is the largest proportion of the sample as shown by particle size analysis. The adsorption isotherm was well described by Langmuir and Freundlich equations. The thermodynamic parameters values showed that the Cu(II) adsorption was a spontaneous and exothermic process. Furthermore, with the presence of CaCO₃, the precipitation of Cu(II) in the form of posnjakite occurred with a high Cu(II) removal rate close to 99%. The residual SSP was used for the production of valuable compounds through the thermal decomposition process at various temperatures.

中文翻译：

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用于从水溶液中去除铜和生产有价值化合物的蜗牛壳吸附剂

该研究探讨了蜗牛壳粉 (SSP) 从水溶液中去除 Cu(II) 的效率以及从残留产品中生产有价值的化合物。为了确认其化学和矿物成分，该材料通过不同的仪器技术进行了表征。研究了溶液的 pH 值、SSP 剂量、粒径和 Cu(II) 初始浓度等实验参数对去除过程的影响。Cu(II) 的去除相当快，可在 90 分钟的时间范围内完成。伪二阶模型（以下动力学- [R ²  = 0.979）的更好相比伪一阶模型（- [R ² = 0.896）。pH 值的增加导致吸附的 Cu(II) 量增加。之后，吸附容量在 pH 值接近 7 时达到稳定。最大的 Cu(II) 去除发生在质量为 8 g·L ^-1和粒径为 300  μ m 的情况下。这种粒径占 SSP 颗粒的大约 44.5%，这是样品的最大比例，如粒径分析所示。Langmuir 和 Freundlich 方程很好地描述了吸附等温线。热力学参数值表明Cu(II)吸附是自发放热过程。此外，随着 CaCO ₃的存在，Cu(II) 以 posnjakite 的形式沉淀发生，Cu(II) 去除率接近 99%。残留的 SSP 用于通过不同温度下的热分解过程生产有价值的化合物。