Comparative study of copper sulfide hydrophobictextile treatment: hierarchical structures versusnanostructures

Abstract

This study compares membranes coated with hierarchical structures and copper sulfide nanostructures for water and oilseparation. Copper was synthesized by a REDOX reaction, followed by sulfidation by a solid vapor method to producecopper sulfide hierarchical structures. A high-energy mechanical milling process was then applied to obtain copper sulfidenanostructures. Both types of copper sulfide structures were applied to cotton textiles by a dip coating method withvarying copper sulfide concentrations (1–4%). The morphology of copper sulfide was characterized by scanning electronmicroscopy before and after milling, and the coated membranes were also analyzed to confirm the presence of poly-dimethylsiloxane (PDMS) and copper sulfide. Fourier transform infrared spectroscopy analysis confirmed the presence ofPDMS and copper sulfide through their characteristic functional groups, while X-ray diffraction analysis confirmed theformation of the anilite phase. Membranes with hierarchical copper sulfide structures and copper sulfide nanostructuresshowed high hydrophobicity and stability through multiple filtration cycles. Contact angle measurements showed thatcopper sulfide nanostructure coatings provided a higher degree of hydrophobicity, achieving superhydrophobic angles of155–165°, depending on the concentration. In contrast, membranes with hierarchical structures exhibited slightly lowerhydrophobicity, with contact angles ranging from 146° to 154°. Filtration tests further supported these findings: mem-branes with copper sulfide nanostructures retained 96% efficiency even after ten cycles, while those with hierarchicalstructures dropped to 87%, underscoring the superior durability and performance of copper sulfide nanostructuredmembranes for separation applications.