Flat asymmetric pH-responsive poly(vinylidene fluoride-co-hexafluro propylene) (PVDF-co-HFP) membranes were prepared using N-methyl pyrrolidone (NMP) as the solvent. Green synthesis of iron nanoparticles (NPs) by cardamom extract from FeCl3 solution was performed. Iron NPs-embedded pH-responsive PVDF-co-HFP membranes were used to study nitrobenzene (NB) reduction. NB reduction along with aniline (AN) formation was found to be dependent on the pH. Field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) and high-pressure liquid chromatography (HPLC) were used for characterization. Optimization was performed by Design Expert Software 9.0 TRIAL through analysis of variance (ANOVA) by a combination of response surface methodology (RSM) and central composite design (CCD).