Equilibrium and kinetic studies on the removal of cadmium(II) by Fe3O4 loaded activated carbon prepared from castor seed shell

This study focused to construct a new Fe3O4 magnetic nanoparticles loaded activated carbon (MCSSC) generated from castor seed shell and compare it to raw castor seed shell (CSS) to remove cadmium(II) from wastewater and aqueous solution. The magnetic adsorbent and raw materials are characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, transmission electron microscopy and Brunauer-Emmett- Teller surface area. The maximum cadmium(II) removal ability of MCSSC and CSS were optimized by various factors of contact time, pH, MCSSC and CSS dose, initial cadmium(II) ion concentrations and temperature using a batch experiment. The maximum monolayer adsorption capacities of cadmium(II) ions onto MCSSC was about 20 times greater than that of CSS and the thermodynamic parameters showed that the exothermic and spontaneous adsorption in nature. The kinetic result demonstrated that followed by pseudo-second-order equation and the rate-limiting step was governed by chemisorption with film diffusion process. The batch experiment with electroplating wastewater and reusability result showed that the MCSSC could be effectively applied for industrial wastewater and exhibited a good reusability up to five cycles as compared to that of CSS.