Soybean hulls residue adsorbent for rapid removal of lead ions

Abstract

Soybean hulls residue (SHR) is a kind of typical biocompatible and edible natural polymer with containing cellulose, glycoprotein and lignin. In this paper, SHR is extracted by simple method and characterized by FTIR, XRD, SEM, elemental and XPS analysis. Then, this natural polymer adsorbent is applied to remove Pb(II), and main factors on Pb(II) removal by SHR are investigated in details, such as initial concentration of lead, pH value, SHR dosage, oscillating time and temperature. It shows that the removal rate of Pb(II) quickly increases more than 90 % within the first 5 min, and the removal rate get to 99 % within 20 min. The isotherm, kinetic models and thermodynamic parameters are applied to test the experimental data, respectively. It indicates that Pb(II) adsorption on SHR is an endothermic and spontaneous process. The adsorption mechanism has also been investigated. In summary, SHR exhibits excellent adsorption ability for removing Pb(II), which could be used as a fast edible antidote in emergency, especially in cases of mass poisoning by lead. © 2014 IUPAC & De Gruyter.