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

The 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? percent 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.