Efficiency evaluation of the redox reaction using Fe(II)-g-C3N4 for the removal of hexavalent chromium from water

Chromium (Cr) exists in various forms in surface water and groundwater. The high solubility and mobility of Cr(VI) make it a very hazardous material that pollutes water and soil ecosystems. In this study, Fe(II)-g-C3N4 was synthesized using melamine and FeCl3.6H2O via the thermal calcination method. Fe(II)-g-C3N4 was analyzed by XRD, FTIR, SEM, and DLS. It was shown that the g-C3N4 structure is a suitable distributor and stabilizer for iron particles. g-C3N4 reduced the accumulation of iron particles, increasing the efficiency of the redox reaction between Fe(II) and Cr(VI). The removal efficiency of Cr(VI) was influenced by pH, temperature, and the concentrations of Fe(II)-g-C3N4 and Cr(VI). Lower pH values, higher Fe(II)-g-C3N4 concentrations, and elevated temperature improved the kobs and Cr(VI) elimination from water. Cr(VI) adsorption efficiency in the 30, 50, and 70 ppm solutions by Fe(II)-g-C3N4 nanoparticles was 99%, 93.9%, and 80.7%, respectively. Furthermore, the highest kobs (0.0835 min-1) was observed at a 30 ppm Cr(VI) concentration.