Synthesis of porous lignin xanthate resin for Pb2+ removal from aqueous solution

A new lignin xanthate resin (LXR) was synthesized by a two-step reaction from alkaline lignin and carbon disulfide. It was characterized by FT-IR, SEM and element analysis. An ordered porous structure is observed on LXR. Batch adsorption including equilibrium isotherms, kinetics, and the effects of pH, dosage and temperature on the adsorption of Pb2+ by LXR were systematically studied. LXR shows a 4.8 times higher adsorption capacity than alkaline lignin at 30 degrees C that is attributed to the incorporation of xanthate groups and porous structure. Thermodynamic parameters, involving Delta H degrees, Delta S degrees and Delta G degrees were also calculated from graphical interpretation of the experimental data. Negative values of Delta G degrees indicate the adsorption process of Pb2+ by LXR is spontaneous. The positive value of Delta H degrees confirms the endothermic adsorption in nature. The high adsorption capacity of LXR, together with its feasible preparation, bio-compatibility and environmentally friendliness, open new perspectives in the potential use for wastewater treatment. (C) 2015 Elsevier B.V. All rights reserved.