A novel approach to developing a reusable marine macro-algae adsorbent with chitosan and ferric oxide for simultaneous efficient heavy metal removal and easy magnetic separation.

Chitosan modified magnetic kelp biochar (Chi-KBm) was successfully synthesized for efficient removal of heavy metals (Cu2+) from wastewater. Interestingly, the characterization results indicated that Chi-KBm showed 6 times higher surface area (6.17 m2/g) than the pristine magnetic kelp biochar KBm (0.97 m2/g). In addition, new functional groups, such as NH and CN group, have been created on the surface of biochar as a result of chitosan modification process, which in turns led to improve the Cu2+ adsorption capacity. The effect of pH and chitosan loading on heavy metal adsorption, and competition reaction of different metal ions adsorption were also investigated. Chi-KBm exhibited a separation efficiency of more than 99.8%, which allows to recovery and reusability of the adsorbent material and heavy metals simultaneously. Overall, this study highlighted the Chi-KBm is a promise adsorbent for heavy metal removal without sacrificing of the separation ability using magnetism.