LAUSR

Abstract Phytoliths are common biogenic silica materials which can be derived from heat-treatment of Si-rich plant residues. However, there have been few studies identifying its environmental applications. This work, based on the batch experiments with quantification of surface charge and determination of colloidal properties, is an attempt to evaluate the ability of phytolith-based material (PBM) for removing Fe from aqueous solution. Oxidation and aggregation of a synthetic Fe-rich solution were examined under the presence of a PBM sample (obtained from fern Dicranopteris linearis) as functions of pH and ionic strength. Obtained results showed that through electrostatic interaction, the PBM can affect oxidation and aggregation of newly-formed Fe oxides at different extents depending on pH change. The fastest aggregation of the newly-formed Fe oxides was found at the pH range from 4 to 6 and in the presence of phytolith. As the PBM can make the newly-formed Fe oxides less dispersive and less transportable in aqueous solution, it suggests that practices for treatment of Fe-rich drainage or remediation of Fe-contaminated groundwater by supporting aggregation need to consider this effect.