Decontamination of Cd2+ and Pb2+ from aqueous solution using a magnetic nanocomposite of eggshell/starch/Fe3O4

Abstract

In the present study, to remove heavy metal ions Cd2+ and Pb2+ from aqueous solution and industrial effluent, a new magnetic nanocomposite based on eggshell/starch/Fe3O4 nanoparticles was used as an effective adsorbent. FTIR analysis showed that the magnetic composite is well synthesized and has different functional groups that can be effective in the adsorption process. In addition, the VSM test showed that the magnetic nanocomposite had a superparamagnetic property. The BET value for magnetic nanocomposite of eggshell/starch/Fe3O4 nanoparticles was determined to be 35.648 m2/g, higher than eggshell nanoparticles. The maximum decontamination efficiency of Cd2+ (96.38%) and Pb2+ (97.86%) was obtained at pH 7 and 6, respectively, temperature 25 °C, contact time of 60 min, metal concentration of 10 mg/L, and adsorbent dose of 1 g/L. The results showed that the adsorption process of the desired ions using eggshell/starch/Fe3O4 nanoparticles follows a pseudo-second-order and the Langmuir models. The Langmuir capacity for Cd2+ and Pb2+ adsorption using eggshell/starch/Fe3O4 was computed at 48.54 and 57.14 mg/g, respectively. The value of the ∆G° parameter for the adsorption process of Cd2+ and Pb2+ was determined in the span of −20 < ∆G° < 0 kJ/mol, which suggests that the adsorption process was performed physically and spontaneously. The value of the parameter ∆H° was also negative, which confirms the exothermic of the process and indicates that the increase in temperature harms the adsorption process. The adsorbent of this study had vital properties like being economical (due to its recyclability) and practicality for wastewater treatment.