Adsorption of Cr (VI) from Aqueous Solution with nano B-FeOOH

In resent years, various types of iron-based materials have been used as sorbents to remove heavy metals from wastewater. It is reported that the adsorption capacities of heavy metals on different kinds of iron oxides are quite high. However, researchers have not done much work on the Cr (VI) adsorption onto β-FeOOH. This study aims to investigate the removal of Cr (VI) with β-FeOOH, including the effect of pH and time on the adsorption process, and the Cr (VI) adsorption thermodynamic. The X-ray diffraction (XRD) pattern verified that the synthesized particle was β-FeOOH. Transmission electron microscopy (TEM) image revealed that it was nano-scaled. Experimental results indicated that the reaction rate between the adsorbent and adsorbate was quite high, and the adsorption equilibrium was gained within one hour. The adsorption of Cr (VI) on β-FeOOH was favorable in acidulous water, and the highest removal efficiency was obtained at pH 5. The Langmuir isotherm was suitable for describing the adsorption process, and the adsorption capacity increases with the increasing temperature. The examination of thermodynamic parameters showed that the adsorption process of Cr (VI) onto β-FeOOH nanoparticles was endothermic and spontaneous at the temperature studied. The adsorption experimental results indicated that removal of Cr (VI) from water with β-FeOOH nanoparticles was viable. The adsorption capacities were 15.45 mg/g, 16.87 mg/g and 18.48 mg/g at 293 K, 303 K and 313 K, respectively.