Herein we examine the adsorption behavior of anionic-cellulose nanofibers (a-CNFs) having a carboxymethyl group concentration of 1.14 mmol/g of nanofibers. The effects of key parameters governing the efficiency of the adsorption process in the batch mode were investigated. Electrospinning was employed to fabricate cellulose acetate nanofibers (CANFs). The fabricated nanofibers were then deacetylated to convert them into CNFs that were subsequently anionized by a pad-batch process. The a-CNF web was characterized through scanning electron microscopy (SEM), thermogravimetric analysis, and IR spectroscopy. SEM revealed 315 +/- 10 nm average nanofiber diameters in the a-CNF web. Moreover, zeta-potential measurements revealed isoelectric point at ca. pH 4. The Freundlich isotherm and the Pseudo-second-order kinetic models fit the adsorption data well. Also, the Langmuir adsorption capacities of a-CNFs for Ca2+ and Mg2+ were 57.66 and 65.55 mg/g, respectively. [GRAPHICS] .