Exploring the potential of cellulose benzoate adsorbents modified with carbon nanotubes and magnetic carbon nanotubes for microplastic removal from water

[Display omitted] •Synthesis and verification of CNT- and MCNT-modified cellulose benzoate adsorbents.•Exceptional ability of both adsorbents to remove PS microplastics from water.•Efficiency due to aromatic structure, high zeta potential, and water dispersion.•MCNT-modified cellulose benzoate exhibited superior adsorption rate and capacity. As global plastic production continues to increase, the issue of microplastic pollution cannot be ignored. In this paper, we explore the potential of cellulose benzoate based adsorbents for removing small-sized microplastics from water. By esterifying cellulose in an ionic liquid, AmimCl, we successfully synthesized cellulose benzoate based adsorbents, which were verified using FTIR, XRD, and solid-state NMR technology. When tested for their ability to remove polystyrene (PS) microplastics from water, cellulose benzoate exhibited a significant improvement in removal efficiency compared to the original cellulose, with the percentage increasing from 9.0% to 68.3%. This improvement can be attributed to their aromatic ring structure that allows for π-π interaction, as well as a higher zeta potential, leading to stronger electrical attraction. When cellulose benzoate was further modified with carbon nanotubes (CNTs) or magnetic carbon nanotubes (MCNTs), its PS removal efficiency further increased to above 97%, owing to the increased zeta potential and the reduction in particle size, which enhances its dispersion in water. Kinetic and isotherm modeling revealed that MCNT-modified cellulose benzoate exhibited superior adsorption rate and capacity, indicating its better performance as an adsorbent. These findings offer a promising approach for microplastic removal and present a new application for lignocellulosic biomass.