Application of chalcone-based dithiocarbamate derivative incorporated sol–gel for the removal of Hg (II) ion from water

This study demonstrated the application of chalcone-based dithiocarbamate derivative as metal capturing ligand for the removal of mercury ion (Hg²⁺) in water. Chalcones are a group of naturally occurring compounds which can be obtained from fruits, vegetables, plants, and spice. In this study, chalcone was first chemically modified to produce dithiocarbamate derivative (ODPPNE). Chalcone and ODPPNE were then incorporated into sol–gel to produce SG-C and SG-ODPPNE, respectively, as adsorbents. The result from the adsorption study showed that with the presence of dithiocarbamate functional group, SG-ODPPNE exhibited the highest selectivity toward the adsorption of Hg²⁺ with lesser response to Cr³⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, and Pb²⁺. The adsorption of Hg²⁺ by SG-ODPPNE was found to be adsorbent size, adsorbent dosage, contact time, the initial concentration of sorbate and pH dependent. The obtained experimental data were also analyzed using Freundlich and Langmuir adsorption models. The results showed that the adsorption data were well-fitted to Langmuir isotherm, and the monolayer absorption capacity was found to be 13.5 mg/g. In the absorption kinetic study, the data was analyzed using pseudo-first-order, pseudo-second-order kinetic model, and intraparticle diffusion model. The obtained data were well-fitted to pseudo-second order model. According to intraparticle diffusion model, the adsorption process of Hg²⁺ by SG-ODPPNE involves film diffusion, intraparticle diffusion, and equilibrium stages.