In this work, gamma-alumina (γ-Al2O3) was synthesized from polyoxohydroxide aluminum (POHA) precursor. The POAH was formed after ethanolic treatment and then calcined at a temperature of 500 C. The result is gamma-alumina which characterized using X-ray diffracting (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), laser granularity instrument (LGI) and atomic force microscopy (AFM). It is found from the experimental results that synthesized gamma Al2O3 was successfully formed due to calcination at 500 C. The results also showed that the synthesized γ-Al2O3 was effective in reducing iron content in the produced water to 0.0014 ppm with removal efficiency of 99.9%.