Cadmium removal from aqueous solution by green synthesis iron oxide nanoparticles with tangerine peel extract

Background The adsorption process by metal oxide nanoparticles has been investigated an effective agent for removing organic and inorganic contaminants from water and wastewater. In this study, iron oxide nanoparticles were synthesized in the presence of tangerine peel extract as adsorbent for cadmium ions removal from contaminated solution. Iron oxide nanoparticles prepared by co-precipitation method and tangerine peel extract was used to prevent accumulation and reduce the diameter of the particles. Effect of various parameters such as contact time, pH, metal concentration and adsorbent dosage was determined on the removal efficiency. Results The different concentrations of tangerine peel had an impact on the size of nanoparticles. As, increasing the concentration of tangerine peel extract from 2 to 6 % the average size of synthesized iron oxide nanoparticles decreased 200 nm to 50 nm. The maximum removal of cadmium ions (90 %) occurred at pH of 4 and adsorbent dose of 0.4 g/100 ml. Adsorption of cadmium ions by synthesized iron oxide nanoparticles followed Freundlich adsorption model and pseudo-second-order equation. Conclusion The cadmium ions are usually soluble in acidic pH and the maximum removal of cadmium by green synthesis iron oxide nanoparticles was obtained in the pH of 4, so these nanoparticles can be a good adsorbent for the removal of cadmium from wastewater.