A novel, green and easy regeneration biosorbent, aminothiourea modified walnut shell (AMWNS), was synthesized, and its potential for removal of Pb(II) ions was also investigated. The AMWNS was synthesized with epichlorohydrin and aminothiourea as an etherifying agent and a modified monomer, respectively, and was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and X-ray diffraction (XRD). The influences of pH (3-11) and adsorbent dosage (0.5-2.5 g/L) on adsorption capacity of AMWNS were investigated. The maximum Pb(II) ions adsorption capacities (Qm) calculated by best fitting model (Langmuir) were 46.25 mg/g at 298 K. Thermodynamic studies demonstrated adsorption process by AMWNS was spontaneous and endothermic. Furthermore, the regeneration capability of AMWNS implied AMWNS was a cheap, excellent biosorbent for Pb(II) ions removal in wastewater treatment.

Keywords: adsorption; aminothiourea modified walnut shell (AMWNS); Pb(II) ions; thermodynamics