Synthesis and characterization of dithiocarbamate chelating resin and its adsorption performance toward Hg(II), Cd(II) and Pb(II) by batch and fixed-bed column methods

A new chelating resin (DTMAN) containing dithiocarbamate group was synthesized by copolymerization of acrylonitrile with N,N′-methylenebisacrylamide, the obtained resin was subsequently treated with ethylenediamine and carbon disulphide, respectively. The prepared chelating resin was characterized using FT-IR spectroscopy, scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), water regain, and was further morphologically characterized using Brunauer–Emmett–Teller (BET) method. Various experimental parameters such as solution pH, metal ions concentration, contact time and adsorption temperature were studied in batch method. The prepared chelating resin showed high affinity toward Hg(II), Cd(II) and Pb(II) ions. The maximum sorption capacities were found to be 2.3, 1.94 and 1.14 mmol g−1 resin for Hg(II), Cd(II) and Pb(II), respectively. The adsorption isotherms were analyzed using the Langmuir, Freundlich and Temkin isotherms. The results showed that the adsorption process was well described by Langmuir isotherm model. The kinetic and thermodynamic parameters of the adsorption process were calculated. These parameters showed that the adsorption process is spontaneous and followed the pseudo-second-order kinetics. Moreover, the adsorption behavior of chelating resin toward metal ions using fixed bed column technique was studied. Regeneration of DTMAN resin loaded with metal ions was efficiently done and the investigated resin could be used repetitively for five times with a small decrease in sorption capacity.