Conversion of Spiky Sweetgum tree (Liquidambar styraciflua) Seeds as into Bio-adsorbent: Static and Dynamic Adsorption Assessment

Abstract

Diverse biomass materials have been explored as bioadsorbents for water treatment owing to their natural abundance. This study evaluated the adsorption performances of sweetgum tree (Liquidambar styraciflua) seeds (spiky balls) to remove methylene blue (MB) and lead ions (Pb2+) from water. The pristine spiky balls yielded higher adsorption capacities than the thermally treated ones at 200°C. The static adsorption of 10 mg·L−1 methylene blue (MB) dye and 10 mg·L−1 lead (Pb2+) from water reached high removal rates of MB and Pb2+ up to 89.1±1.3% and 92±4% respectively. The adsorption kinetics of MB and Pb2+ on pristine spiky balls followed the pseudo-second-order and the pseudo-first-order models (R2 = 0.998, and 0.953, respectively), suggesting that MB and Pb2+ follows chemosorption and physisorption, respectively. Consequently, the adsorption capacity for MB (143.512 mg·g−1) was significantly greater than that for Pb2+ (0.900 mg·g−1). The isotherm analysis further reveals that spiky balls may have a heterogeneous surface with multilayered adsorption and stronger adsorption interactions with MB than with Pb2+. Finally, dynamic adsorption was evaluated in packed adsorption columns, which provide insightful information (e.g., adsorption capacity and break-through dynamics) in practical applications.