Removal of Cr+6 metal ions from industrial wastewater using synthesized coal fly ash

Chromium is one of the most important pollutants for surface and ground water. Because of its acute toxicity and non-biodegradability, chromium-containing liquid and solid wastes are considered as hazardous wastes. The aim of this research work is to investigate sorption characteristic of coal fly ash synthesized for the removal of Cr (VI) ions from aqueous solutions. The sorption of Cr (VI) ions by batch method is carried out. The optimum conditions of sorption were found to be: FA3 dose of 2 g l-1 in 25 mL of Cr (VI), contact time of 8 h, pH and temperature 6 and ±25 °C respectively. In the synthesis process, the inherent iron in the fly ash was rearran-ged and loaded on the surface of the fly ash by dissolution and precipitation processes. The adsorbent (FA3) was characterized by XRD, XRF, SEM, LPS and BET surface area. The BET surface area of FA3 was 18 times of those of the original fly ash, furthermore, the mean particle size of FA3 increased 3 times compared to the raw fly ash, thus effectively accelerated the solid/liquid separa-tion after the adsorptive treatment. The Lang-muir, Freundlich are subjected to sorption data to estimate sorption capacity. The data is fitted with Freundlich. Accordingly, it is believed that the adsorbent developed in this study is effective for hexavalent chromium polluted wastewater treatment.