<![CDATA[Iron (Fe)-contaminated wastewater from industrial activities poses significant environmental challenges, motivating the development of efficient and sustainable treatment technologies. This study investigated a chitosan–activated carbon composite adsorbent film for Fe²⁺ removal using a 2³ full factorial design. The material was prepared by solvent casting, with polyethylene glycol (PEG) used as a pore-forming agent and activated carbon as the principal adsorbent. The effects of PEG concentration, activated carbon loading, and stirring time on residual Fe concentration were evaluated. The term “membrane” in the original study is used here only in the fabrication sense; the material was evaluated as an adsorptive film rather than as a size-selective nanofiltration or microfiltration membrane. Direct porosity or pore-size characterization was not performed, so the proposed roles of PEG in pore formation and of chitosan/activated carbon in Fe²⁺ uptake are interpreted from the fabrication procedure, adsorption trends, and FTIR observations rather than from direct pore-structure measurements. FTIR spectra were consistent with retention of characteristic hydroxyl (–OH), amino (–NH₂), C–N, and C–O–C functional groups, although baseline drift and spectral noise limit the conclusiveness of the FTIR evidence. Among the eight experimental runs, the lowest residual Fe concentration observed was 7.750 mg L⁻¹ at 750 mg PEG, 40 wt% activated carbon, and 4 h stirring. The unreplicated factorial model gave R² = 0.924, but the overall model and individual factor effects were not statistically significant at the 95% confidence level (p > 0.05), with only one residual degree of freedom. Accordingly, the reported formulation is the best-performing experimental run within the tested design space, not a statistically validated optimum. Replicated experiments, porosity characterization, and microscopy are recommended to establish the controlling factors and adsorption mechanism more rigorously.]]>
