Study on the Adsorption of L-Alanine on a Spherical Lignin Adsorbent

The spherical lignin adsorbent was prepared by applying reverse-phase suspension polymerization technique with alkali lignin as raw material. Then the spherical lignin beads were adopted to adsorb the L-alanine. And, the adsorption conditions were also optimized. The results indicated the adsorption of L-alanine on the spherical lignin beads has been found to be time, initial mass concentration and solution pH dependent. The equilibrium adsorption capacity could reach 83.28 mg/g under such conditions as 120 min of the adsorption time, 400 mg/L of the initial mass concentration of L-alanine aqueous solution and 2.0 of solution pH. Moreover, NH(4)Cl and NaCl also showed great effect on the adsorption efficiency when existed in large amount. The adsorption percentage decreased from 83.28% to 4.35% with an increase of salt concentration in aqueous solutions among the concentration range of 0.5 and 1.5 mol/L. Simultaneously, L-alanine could be desorbed with ammonia of 1.0 mol/L, and the regeneration capacity of lignin bead was good.