Removal of Cadmium from Aqueous Solutions by a Synthesized Activated Carbon

Introduction: There are different methods for removal of cadmium from aqueous solutions. Adsorption based methods are among the bests. One of the most important aspects for adsorption techniques is the availability of an accessible and economical adsorbent. This study aims to investigate cadmium removal from aqueous solutions by walnuts shell waste. Materials and Methods: Walnut Shell (WS) was used as a carbon and was activated by a chemical agent. The surface characteristics of the synthesized Activated Carbon (AC), kinetic and isothermic variation were investigated under laboratory conditions. Results: The results showed that adsorption could be affected by the amount of adsorbent and pH. The adsorption of cadmium was in the maximum level when pH was 6. Between two investigated adsorption isotherms, Langmuir (R2=0.98) and Freundlich (R2 = 0.97) isotherms well described the cadmium adsorption on walnut shell produced activated carbon. Conclusion: Walnut shell as an agricultural waste can be synthesized into a suitable absorbent to absorb the toxic metal cadmium from aquatic solutions.