Nanocompósitos na forma de fibras poliméricas à base de policaprolactona com hidrotalcita imobilizada para a adsorção de ácido clorogênico

Abstract

Water, vital for humanity, is widely used in coffee processing, resulting in effluents with a high organic load, including polyphenols that can be harmful to the environment. Adsorption is a simple and effective strategy to eliminate contaminants without generating unwanted byproducts. Developing adsorbent materials is crucial and incorporating them into polymeric matrices facilitates recovery and reuse. In this way, this work proposed obtaining composite membranes based on polycaprolactone (PCL) polymer to immobilize modified hydrotalcite, an adsorbent material, aiming to remove chlorogenic acid polyphenol through adsorption. The commercial hydrotalcite was thermally treated and modified with sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) to increase the affinity with the contaminant. The parameters of spinning pure polymer mats were experimentally optimized. Composite membranes were obtained by incorporating different concentrations of modified hydrotalcite into the polymeric solution for subsequent solution blow spinning. Hydrotalcite with surface modification and adsorption efficiency reaching 96% under established parameters was obtained; the higher the modifier percentage, the higher the percentage of adsorption, and the best removal results were presented by materials that underwent thermal treatment. Modification with SDS resulted in hydrophobic materials and with CTAB hydrophilic in character, which did not interfere with adsorption, leading to similar results. Increasing the polymer concentration in the solution resulted in more homogeneity but also increased the diameter of the fibers. Blends of PCL/polymethyl methacrylate (PMMA) and PCL/polystyrene (PS) were obtained with diameters ranging from 812 nm to 1542 nm and 417 nm to 659 nm, respectively. The mats of blends with a higher percentage of PCL demonstrated greater tensile strength when compared to other blends. The composite membrane containing 60% adsorbent material showed good efficiency in removing chlorogenic acid, achieving a removal rate of 55% of the contaminant under the tested conditions. Therefore, composite membranes demonstrated the ability to act as adsorbents for pollutants like chlorogenic acid, establishing the potential for environmental remediation applications.