Preparation of sugarcane bagasse succinate/alginate porous gel beads via a self-assembly strategy: Improving the structural stability and adsorption efficiency for heavy metal ions

Sugarcane bagasse, a kind of agricultural waste, was esterified by mechanical activation-assisted solid phase reaction with succinic anhydride as esterifying agent to prepare SB succinate (SBS) with rich carboxyl and ester functional groups. The layer-by-layer (LbL) self-assembly technology was used to prepare SBS/alginate (Alg) porous gel beads (SAPGB) with outstanding mechanical strength and desired porous structure from external surface to interior through the formation of gel network structure of SBS/Ca2+/Alg. The adsorption kinetics and isotherm indicated that the adsorption of metal ions onto SAPGB followed the pseudo-second-order kinetics and Langmuir isotherm mode (Qmax = 354.60 and 176.36 mg g-1 for Pb2+ and Cd2+, respectively). The adsorption behavior of SAPGB for metal ions was mainly amonolayer chemical adsorption process. The adsorption was fast and reached equilibrium within 60 min, ascribed to rapid diffusion from porous surface into internal pores. In addition, the stable SAPGB adsorbent exhibited excellent regeneration performance.