Characterizing Phosphorus Removal and Recovery Performance of a 3D Printed Iron-Embedded Polylactic Acid Composite

Abstract

Green infrastructure (GI) has been heralded as a solution for reducing phosphorus (P) pollution through increasing stormwater runoff infiltration and improving water quality. Despite its global implementation, GI struggles to improve the effluent water quality discharged from these systems consistently. This research evaluates the P removal performance and recovery potential of iron-embedded polylactic acid (PLA) composites through a novel application of three-dimensional (3D) printed representative unit cells (RUC) that could be used to improve effluent quality in GI. The RUC required chemical oxidation to convert the embedded iron to hematite (Fe2O3) to facilitate P adsorption. Batch experiments were conducted to determine the P removal performance of the RUC. Next, the RUC was subjected to a desorption solution with pH 12 to evaluate the potential to recover the adsorbed P. The RUC consistently removed P from the solution at the pH and temperatures tested when P concentrations were within the range typically observed in stormwater (0.19±1.24 mg-PO43−-P L−1) but was more sensitive to pH and temperature at higher P concentrations. Recovery of P from the RUC was successful at the expense of destroying the RUC. Total suspended solid (TSS) concentrations (0.06–0.10 mg L−1) in the final test solution were much less than the TSS concentrations in GI stormwater influent and effluent (126 and 50.2 mg-TSS L−1, respectively). Further materials development and field experiments using 3D printed structures is recommended.