Cationization of Cellulose Nanofibers for the Removal of Sulfate Ions from Aqueous Solutions

In this study, the adsorption properties of cationized cellulose nanofibers (c-CNF) were examined for the removal of sulfate (SO42–) ions from aqueous solutions under diverse experimental conditions. Nanofiber mats were fabricated through electrospinning and cationized with 3-chloro-2-hydroxypropyl trimethylammonium chloride (CHTAC). The resultant c-CNF with an ammonium content of 0.134 mmol/g showed the maximum adsorption capacity of 24.5 mg of SO42– per gram of sorbent using a Langmuir isotherm model. A pseudo-second-order (PSO) kinetic model was fitted to the adsorption rate data, showing a higher adsorption rate of 0.0022 mg g–1 min–1. Scanning electron microscopy (SEM) micrographs revealed the average fiber diameter to be 280 ± 10 nm, and a BET surface area of 5.04 m2/g was obtained with a BET surface area and porosity analyzer. Fourier transform infrared (FTIR) spectroscopy confirmed the conversion of cellulose acetate (CA) to cellulose and its subsequent cationization. Furthermore, the consequences of cationization were evaluated by zeta potential measurements and thermogravimetric analysis (TGA).