Díaz Enzo, Gutiérrez Leopoldo, Elgueta Elizabeth, Núñez Dariela, Carrillo-Varela Isabel, Hernández Vicente A
Facultad de Ciencias Químicas, Universidad de Concepción, Edmundo Larenas 129, Concepción 4070371, Chile.
Departamento de Ingeniería Metalúrgica, Universidad de Concepción, Edmundo Larenas 219, Concepción 4070371, Chile.
Polymers (Basel). 2025 Jul 17;17(14):1958. doi: 10.3390/polym17141958.
In this study, a methacrylic derivative of xylan (XYLMA) was synthesized through transesterification reactions, with the aim of evaluating its physicochemical behavior and its interaction with kaolinite particles. Structural characterization by FT-IR and NMR spectroscopy confirmed the incorporation of methacrylic groups into the xylan (XYL) structure, with a degree of substitution of 0.67. Thermal analyses (TGA and DSC) showed a decrease in melting temperature and enthalpy in XYLMA compared to XYL, attributed to a loss of structural rigidity. Thermal analyses (TGA and DSC) revealed a decrease in the melting temperature and enthalpy of XYLMA compared to XYL, which is attributed to a loss of structural rigidity and a reduction in the crystalline order of the biopolymer. Aggregation tests in solution revealed that XYLMA exhibits amphiphilic behavior, forming micellar structures at a critical aggregation concentration (CAC) of 62 mg L. In adsorption studies on kaolinite, XYL showed greater affinity than XYLMA, especially at acidic pH, due to reduced electrostatic forces and a greater number of hydroxyl groups capable of forming hydrogen bonds with the mineral surface. In contrast, modification with methacrylic groups in XYLMA reduced its adsorption capacity, probably due to the formation of supramolecular aggregates. These results suggest that interactions between xylan and kaolinite clay are key to understanding the role that hemicelluloses play in increasing copper recovery when added to flotation cells during the processing of copper sulfide ores with high clay content.
在本研究中，通过酯交换反应合成了木聚糖的甲基丙烯酸衍生物（XYLMA），旨在评估其物理化学行为及其与高岭土颗粒的相互作用。傅里叶变换红外光谱（FT-IR）和核磁共振光谱（NMR）进行的结构表征证实了甲基丙烯酸基团已并入木聚糖（XYL）结构中，取代度为0.67。热分析（TGA和DSC）表明，与XYL相比，XYLMA的熔点和焓降低，这归因于结构刚性的丧失。热分析（TGA和DSC）显示，与XYL相比，XYLMA的熔点和焓降低，这归因于结构刚性的丧失以及生物聚合物结晶度的降低。溶液中的聚集测试表明，XYLMA表现出两亲行为，在临界聚集浓度（CAC）为62 mg/L时形成胶束结构。在对高岭土的吸附研究中，XYL表现出比XYLMA更大的亲和力，尤其是在酸性pH值下，这是由于静电力减弱以及能够与矿物表面形成氢键的羟基数量增加。相比之下，XYLMA中甲基丙烯酸基团的改性降低了其吸附能力，这可能是由于超分子聚集体的形成。这些结果表明，木聚糖与高岭土粘土之间的相互作用是理解半纤维素在处理高粘土含量的硫化铜矿石时添加到浮选槽中对提高铜回收率所起作用的关键。
