Highly efficient adsorption of Pb(II) from aqueous solution using amino-functionalized SBA-15/calcium alginate microspheres as adsorbent.

In this work, amino-functionalized Santa Barbara Amorphous-15/calcium alginate (ASBA-15@CA) microspheres were fabricated and characterized by FTIR, SEM, XRD, TGA, and XPS analyses. The Pb(II) adsorption properties of the ASBA-15@CA microspheres were studied in terms of the effects of the adsorption time, adsorbent dose, solution pH, temperature, and initial concentration of Pb(II) on the adsorption capacity. At pH 6 and 298 K, the adsorption reached equilibrium after 100 min and the sample exhibited a good adsorption effect, affording a maximum adsorption capacity of 1029.58 mg/g and a removal rate as high as 98.99%. The adsorption process conformed to the Langmuir model (R2 = 0.9937) and followed the pseudo-second-order kinetics model (R2 = 0.9995). Regeneration experiments showed that the removal rate of the sample reached 75% even after 6 cycles. Overall, this study provides new insights into the development of novel, highly efficient, and repeatable degradation materials for the removal of Pb(II).