Faculty of Engineering, Professional School of Environmental Engineering, Universidad Nacional Intercultural de la Selva Central Juan Santos Atahualpa (UNISCJSA), La Merced, Chanchamayo, 1285, Peru.
Faculty of Engineering, Universidad Continental (UC), Huancayo, 12004, Peru.
Environ Sci Pollut Res Int. 2024 Oct;31(50):59700-59711. doi: 10.1007/s11356-024-34971-7. Epub 2024 Oct 4.
This paper reports a comprehensive study of Theobroma cacao pericarp (TCP) residues, which has been prepared, characterized, and tested as an inexpensive and efficient biosorbent of Cr(VI) from aqueous solutions. The maximum adsorption capacity of TCP obtained at optimal conditions (pH = 2, dose = 0.5 g L, C = 100 mg L) was q = 48.5 mg g, which is one of the highest values reported by the literature. Structural and morphological characterization has been performed by FTIR, SEM/EDX, and pH measurements. FTIR analysis revealed the presence of O-H, -NH, -NH, C = H, C = O, C = C, C-O, and C-C functional groups that would be involved in the Cr(VI) biosorption processes. The experimental equilibrium data of biosorption process were successfully fitted to non-linear Langmuir (R = 0.95, χ = 11.0), Freundlich (R = 0.93, χ = 14.8), and Temkin (R = 0.93, χ = 14.7) isotherm models. Kinetics experimental data were well adjustment to non-linear pseudo-2nd (R = 0.99, χ = 2.08)- and pseudo-1st-order kinetic models (R = 0.98, χ = 2.25) and also to intra-particle Weber-Morris (R = 0.98) and liquid film diffusion (R = 0.99) models. These results indicate that Cr(VI) biosorption on heterogeneous surfaces as well as on monolayers of TCP would be a complex process controlled by chemisorption and physisorption mechanisms. The thermodynamic results indicate that the Cr(VI) biosorption on TCP is a feasible, spontaneous, and endothermic process. TCP can be regenerated with NaOH and reused up to 3 times.
本文全面研究了可可果皮（TCP）残渣，将其制备、表征并测试为从水溶液中提取六价铬（Cr(VI)）的廉价高效生物吸附剂。在最佳条件（pH=2，剂量=0.5 g/L，C=100 mg/L）下，TCP 的最大吸附容量为 q=48.5 mg/g，这是文献报道的最高值之一。通过傅里叶变换红外光谱（FTIR）、扫描电子显微镜/能谱（SEM/EDX）和 pH 值测量对其结构和形态进行了表征。FTIR 分析表明，参与 Cr(VI)生物吸附过程的官能团有 O-H、-NH、-NH、C=H、C=O、C=C、C-O 和 C-C。生物吸附过程的实验平衡数据成功拟合到非线性朗缪尔（R=0.95，χ=11.0）、弗伦德利希（R=0.93，χ=14.8）和特姆金（R=0.93，χ=14.7）等温线模型。动力学实验数据很好地符合非线性拟二级（R=0.99，χ=2.08）和拟一级动力学模型（R=0.98，χ=2.25）以及内扩散韦布尔-莫里斯（R=0.98）和液膜扩散（R=0.99）模型。这些结果表明，Cr(VI)在异质表面以及 TCP 单层上的吸附是一个复杂的过程，受化学吸附和物理吸附机制的控制。热力学结果表明，Cr(VI)在 TCP 上的吸附是一个可行的、自发的和吸热过程。TCP 可以用 NaOH 再生，并重复使用 3 次。
