Efficient Removal of Lead(II), Cadmium(II) and Zinc(II) from Aqueous Solutions by Bis[2‐(1H‐benzimidazol‐2‐il)phenyl]disulfide, a Solid Chelating Agent

Abstract

AbstractThe bis[2‐(1H‐benzimidazol‐2‐yl)phenyl]disulfide [bis(2phSbz)] was characterized by SEM, nitrogen adsorption and desorption, PXRD, and TGA analysis. It was evaluated as a solid chelating adsorbent to remove lead(II), cadmium(II), and zinc(II) ions from aqueous solutions. Bis(2phSbz) consists of agglomerated, rectangular particles of non‐uniform size, lacking porosity and roughness. Metal ion sorption is pH dependent. The equilibrium data are described by the Langmuir model, while the pseudo‐second‐order model fits metal ions′ adsorption kinetics best. The maximum adsorption capacities for lead(II), cadmium(II), and zinc(II) were 543.82, 482.56, and 306.96 mg/g, respectively. In a competitive test, bis(2phSbz) was found to be able to selectively remove lead(II) from multicomponent solutions. Desorption efficiencies higher than 65 % can be achieved using EDTA 0.1 M as a desorption agent. From a theoretical standpoint, we corroborate the experimental results in terms of some significant quantum mechanics descriptors. Bis(2phSbz) may be a novel and potentially valuable chelating adsorbent for lead(II) removal.