Based on the balance analysis between cations released and Cd sorbed onto BC450 in combination
with SEM-EDX and XPS data, ion-exchange followed by surface complexation is proposed as the
dominant mechanism responsible for Cd immobilization by BC450. In parallel, XRD analysis also suggested
the formation of insoluble Cd minerals (CdCO3, Cd3P2, Cd3(PO4)2 and K4CdCl6) from either (co)-
precipitation or ion exchange. Results from this study highlighted that the conversion of water hyacinth
into biochar is a promising method to achieve effective Cd immobilization and improved management of
this highly problematic invasive species.