Synthesis and application of sugarcane bagasse cellulose mixed esters. Part I: Removal of Co and Ni from single spiked aqueous solutions in batch mode using sugarcane bagasse cellulose succinate phthalate.

Sugarcane bagasse cellulose mixed ester succinate phthalate (SBSPh) was synthesized by a novel one-pot reaction method. The effects of temperature, time and mole fraction of succinic anhydride (χ) on the responses weight gain (wg), number of carboxylic acid groups (n), and adsorption capacity (q) of Co and Ni were evaluated by a 2 experimental design. The chemical structure of the material was elucidated by Fourier transform infrared, C Multiple Cross-Polarization solid-state NMR spectroscopy and H NMR relaxometry. The best SBSPh synthesis condition (100 °C, 11 h, χ of 0.2) yielded a wg of 59.1%, n of 3.41 mmol g, and values of q and q of 0.348 and 0.346 mmol g, respectively. The Sips model fitted better the equilibrium data, and the maximum adsorption capacities (pH 5.75 and 25 °C) estimated by this model were 0.62 and 0.53 mmol g for Co and Ni, respectively. The ΔH° values estimated by isothermal titration calorimetry were 8.43 and 7.79 kJ mol for Co and Ni, respectively. Desorption and re-adsorption efficiencies were evaluated by a 2 experimental design, which showed that SBSPh adsorbent can be recovered and reused without significant loss of adsorption capacity.