Lignocellulosic fraction of the pericarps of the acorns of Quercus suber and Quercus ilex: isolation, characterization, and biosorption studies in the removal of copper from aqueous solutions

Pericarps of Algerian Quercus ilex (Q. ilex) and Quercus suber (Q. suber) were used as copper adsorbents in artificially contaminated solutions. Exposing accessible lignocellulosic binding sites enhanced adsorption. The lignocellulosic fractions of Q. suber and Q. ilex (36.47±9.1 and 47.66±9.3, respectively) were characterized by FTIR before and after adsorption. The aim was to identify the functional groups adsorbing Cu(II). SEM/EDX determined lignocellulose surface morphology and composition. The amount of adsorbent-bound Cu(II) increased with initial [Cu(II)]. Cu(II) adsorption range was 23.59–48.06 mg.g⁻¹ for Q. Suber and 22.56–38.19 mg.g⁻¹ for Q. ilex when [Cu(II)] was 100–500 mg.L⁻¹. Adsorption isotherms and Langmuir and Freundlich models of the Q. suber and Q. ilex lignocellulosic fractions indicated natural Cu(II)adsorption capacities (Q_max) of 53.76 mg.g⁻¹ and 36.06 mg.g⁻¹ and KF of 5.9 mg.g⁻¹ and 7.43 mg.g⁻¹, respectively.