Improving the Adsorption Capacity of the Sorbent for Gaseous PbCl₂ during Incineration by Forming Pb₃(PO₄)₂: Preparation of the Sorbent and Evaluation of Adsorption Performance

Abstract

An efficient sorbent is of great significance in the removal of volatile heavy metal vapors in the municipal solid waste incineration process. In this paper, unlike traditional sorbents based on the formation of silicate, we attempt to develop more effective sorbents by loading phosphate anions on porous montmorillonite (MMT). The adsorption experiments and UV−vis spectrum show that the PbCl 2 adsorption capacities of H 3 PO 4 @MMT and Na 2 HPO 4 @MMT reach the highest values of 0.090 and 0.078 g/ g, respectively, when the corresponding loading amounts of phosphate anions are 0.296 and 0.085 g/g, respectively. Compared with traditional sorbents, the adsorption capacity of H 3 PO 4 @ MMT increases more than 3 times. The analysis of sorbents by Fourier transform infrared (FTIR), X-ray diffraction (XRD), nitrogen adsorption and desorption experiments, and other characterization methods confirm that the loading amount of phosphate anions on H 3 PO 4 @MMT is higher than that of Na 2 HPO 4 @MMT due to the larger surface area and pore volume formed by the replacement of metal cations with protons from H 3 PO 4 . Meanwhile, the prepared sorbent also shows excellent adsorption performance for CoCl 2 and NiCl 2 . Therefore, this study lays a good foundation for the development of new sorbents for the removal of heavy metals during incineration in the future.