Lead Pb(II) contamination represents a major environmental concern due to its persistence and toxicity in
soil and water systems. This study evaluated the efficiency and mechanisms of Pb(II) removal from aqueous
solution using ethylenediaminetetraacetic acid (EDTA) and black soldier fly (Hermetia illucens) frass as
reactive materials under varying application rates (10 – 40 gL-1) and contact times (0–240 min). A factorial
batch experiment (2 × 4 × 7) was conducted to assess the combined effects of material type (EDTA,Black
Soldier Fly frass), dosage, and contact duration on Pb(II) removal performance. The results demonstrated a
rapid decline in residual Pb(II) concentration during the initial contact period, followed by a gradual
stabilization toward equilibrium. Increasing the application rate significantly enhanced Pb(II) removal
efficiency, with EDTA consistently outperforming frass across all conditions. Surface characterization using
scanning electron microscopy (SEM) revealed distinct morphological features for both materials (EDTA,Black
Soldier Fly frass),, including rough and porous structures that favor Pb(II) interaction. X-ray diffraction (XRD)
analysis indicated that Pb(II) removal by EDTA occurred predominantly through chemical complexation
without formation of crystalline Pb(II) phases, whereas frass exhibited evidence of Pb(II)-associated mineral
phases after exposure, suggesting precipitation and surface complexation mechanisms. Fourier-transform
infrared spectroscopy (FTIR) confirmed the involvement of carboxylate, amine, hydroxyl, carbonate, and
phosphate functional groups in Pb(II) binding for both materials. Overall, the findings highlight the contrasting
Pb(II) immobilization pathways of EDTA and black soldier fly frass and demonstrate their potential
applicability in aqueous Pb(II) remediation systems. |
