Alginate-cotton blended aerogel fibers: synthesis, characterization, and oil/water separation

The rise in oil spill incidents has led to a surge in environmental and ecological issues, making it crucial to create efficient oil-cleaning materials. Green approaches to address various aquatic pollution nowadays is the most important subject of environmental remediation. Among the available options, aerogel material stands out due to its low density, high porosity, and exceptional surface area, making it a remarkable choice for oil–water separation. Nonetheless, the usage of aerogels is limited by their low strength and flexibility, which hinder their application. In this study, strong alginate aerogel fibers reinforced with cotton have been synthesized with 88% porosity, 123 nm average pore size, and 0.24 g cm⁻³ density using a wet spinning technique followed by freeze-drying for the separation of oil/water mixtures. The morphology, chemical, and microstructural characterization of the prepared alginate aerogel fibers were performed by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. These characterization results demonstrated the three-dimensional porous, rough structure of aerogel fibers and cotton fibers are successfully incorporated into the aerogel fiber structure. Single fiber strength tester indicated that the addition of cotton increased the strength from 2 to 16 cN of aerogel fibers but decreased the elongation. The prepared alginate aerogel fibers showed good oleophobicity underwater and excellent oil/water separation efficiency (up to 99.4%). Therefore, synthesized aerogel fiber with ease of fabrication and excellent separation of oil/water mixture is a promising candidate for commercial applications in water filtration.