Application of iron oxide nanoparticles in the adsorption of chromium (vi) and copper (ii)

Due to the infinite size of nanoparticles, the surface area is relatively large and as a result, they usually have high reactivity and sorption to various heavy metals. In this work, we synthesized Fe3O4 nanoparticles by cost effective Co-precipitation method. The prepared nanoparticles were characterized using Scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The results from SEM, XRD & FTIR reveals that the synthesized nanoparticles Fe3O4 were having spherical shape with the particle size ranging between 8.69nm-56.58nm (<100nm). We investigated the adsorption behavior of the iron oxide (Fe3O4) nanoparticles and its applicability in the removal of toxic heavy metals like Copper (Cu-II) and Chromium (Cr-VI). A batch experiment was performed in which 100mL of aqueous solutions contaminated with each metal were artificially prepared from their standard stock solutions and treated with the nanoparticles under different conditions of pH, contact time, dosage Fe3O4, metal concentration and temperature. The adsorption behavior was studied using UV-VIS spectrophotometer by changing one of the conditions while keeping the others fixed. According to the results, maximum metal removal Efficiency (%) for Cu(II) & Cr(VI) were obtained at: pH=6 for Cu(II) and pH=2 for Cr(VI); Contact time=60minutes; dosag Fe3O4 e=0.2grams; Temperature=30°C; Metal concentration=10ppm for Cu(II) & 20ppm for Cr(VI). Langmuir isotherm fits the data having R2=0.997 for Cu(II) & R2=0.996 for Cr(VI) with maximum adsorption capacity (Qo) of 31.25mg/g for Cu(II) and 55.56mg/g for Cr(VI).