Removal efficiency of cadmium(II) from electroplating wastewater by chemically modified cottonseed cake carbon

The present research aims to reduce the toxicity of cadmium(II) ions to environment and health, the sulfuric acid-treated cottonseed cake (SCSC) used as an adsorbent to remove cadmium(II) ions from aqueous solution and electroplating wastewater. Batch experimental results showed that the optimum equilibrium time and pH were found to be 3 h and 4.0-8.0. The Freundlich and Langmuir models were applied to investigate the equilibrium isotherms and the equilibrium data fitted well with the Langmuir model and the maximum adsorption capacity of SCSC was found to be 156.76 mg g(-1). Thermodynamic parameters such as Delta G degrees, Delta H degrees, and Delta S degrees have also been calculated and found that the adsorption process was spontaneous, feasible, and exothermic in nature. Kinetic data were studies using pseudo-first-order, pseudo-second-order and intraparticle diffusion models and results showed that the adsorption data has the most conformity with pseudo-second-order model followed by film diffusion process. A single-stage batch adsorber was designed for different SCSC dose using the Langmuir equation. The adsorbent efficiency was tested to remove cadmium(II)ions from industrial electroplating wastewater. The regeneration studies are also showed to evaluate the reusability of the adsorbent.