Novel Biosorbents from Tunisian Date Palm “Bouhattam” Seeds for Copper(II) Ion Adsorption

Abstract

The present study is focused on the removal of copper(II) ions on date palm “Bouhattam” seeds (DS), bleached date seed (BDS) and cellulose nanofibers from date seed (CNFs) biosorbents. The synthesized materials were characterized by several techniques, including FT-IR, SEM, TEM, N2 adsorption-desorption, and TGA/DTG. The effects of solution pH, temperature, heavy metal concentration, and contact time on adsorption capacities were presented. Thus, at 30 °C and pH 5, the adsorption capacity of DS, BDS, and CNFs was 22, 23, and 34 mg g−1, respectively. This study has proved the interesting properties of CNFs to be used as an effective adsorbent in the wastewater treatment. The adsorption isotherms were better fitted to the Freundlich model, whereas the kinetic data were successfully correlated to the pseudo-second order model, which suggested that chemisorption is involved in the adsorption process. The adsorption of copper(II) was a spontaneous, entropy-increasing, and endothermic process. In addition, the adsorbed copper was effectively desorbed by 0.1 mol L−1 HCl solution. These adsorbents have important potential for the removal of Cu(II) from aqueous solution.