Water availability substantially influences many human activities; however, concerns have arisen about its quality due to the expansion of the industrial sector, population, urbanization, and the climate crisis. The release of oil can have severe consequences for ecosystems, including biota, coastlines, seafloors, and all living organisms. Most oil sorbents currently used for water treatment are synthetic, which cannot be decomposed by natural processes, leading to additional pollution problems. Researchers have increasingly turned to biodegradable organic materials derived from plants such as wood, cotton, and kapok fibers to address this issue. Cellulose is a biopolymer that is widely sourced and produced on an annual basis of up to 1.5 billion tons. This renewable and biodegradable resource has been a valuable asset to humanity for centuries, from papyrus to paper and textiles. There has been growing interest in discovering new applications for cellulose due to its unique properties, which are closely linked to its molecular structure. Advanced porous cellulose-based materials that can absorb oily targets in an aqueous phase have been developed, providing advantages such as high absorption speed, high separation efficiency, reuse performance, and compatibility with large-area applications. The potential of cellulose-based absorbents in oil-water separation applications is increasingly being recognized.
The objective of this study was to investigate the hydrophobic properties of cellulose-based sorbents, prepared from Kraft and half-bleached chemo-thermomechanical pulp (BCTMP), through silanization and alkyl ketene dimer hydrophobization techniques. The cellulose-based adsorbents were prepared by saturating cellulose fibers in water, followed by freeze-drying and lyophilization. Silanization was carried out via vapor deposition using methyltrimethoxysilane, n-octyltriethoxysilane, and N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane. The results demonstrated that these processes effectively imparted hydrophobic properties to the materials. The sorption selectivity of the materials was achieved, and the water sorption capacity was successfully reduced without affecting the sorption capacity of non-polar liquids. Hydrophobized sorbents had a water contact angle between 120-140°, confirming their hydrophobicity. Silane hydrophobization reduced sorbents’ water vapor absorption by 3-6%. The density of the sorbents significantly affected their sorption capacities.
The produced materials exhibited excellent selectivity, hydrophobicity, and oleophilicity, indicating their high potential as effective sorbents for water-oil separation. Future research will focus on physical methods for hydrophobizing cellulose-based sorbents and will investigate the impact of the cellulose structure on its sorption and mechanical properties, as well as the effects of mechanical modification of fibers on these properties.
Keywords: cellulose-based absorbents, freeze-drying, silanization, alkyl ketene dimer, sorbents
Authors
Karolina Tomkowiak
Faculty of Forestry and Wood Technology, Poznań University of Life Sciences, Poznań, Poland
Bartłomiej Mazela
Faculty of Forestry and Wood Technology, Poznań University of Life Sciences, Poznań, Poland
Zuzanna Szubert
Faculty of Forestry and Wood Technology, Poznań University of Life Sciences, Poznań, Poland
Waldemar Perdoch
Faculty of Forestry and Wood Technology, Poznań University of Life Sciences, Poznań, Poland
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