Preparation, Kinetics, and Adsorption Mechanism Study of Microcrystalline Cellulose-Modified Bone Char as an Efficient Pb (II) Adsorbent

This work focuses on the preparation of eco-friendly adsorbents from waste pork bone to remove heavy metal ions. Two adsorbents, bone char (BC) and cellulose-modified BC (MCC-BC), are prepared successfully and characterized by FTIR, XRD, BET, and Zeta potential. The influences of pH, temperature, contact time, adsorbent dosage, and initial concentration of Pb (II) on the removal performance are investigated, and the maximum adsorption capacity of Pb (II) by BC and MCC-BC can reach 89.9 and 115.7 mg/g, respectively. By the analysis of kinetics, adsorption isotherms, and thermodynamics, combined with XPS characterization, the adsorption process is found to be spontaneous and endothermic, and the mechanisms are the chemical precipitation of CaxPb(10-x)(PO4)(6)(OH)(2)via ion exchange of Ca (II) and Pb (II), accompanied by the coordination of Pb (II) with hydroxyl groups. Furthermore, MCC-BC can be regenerated with high adsorption efficiency after 5 adsorption/desorption cycles.