REMOVAL OF CHROMIUM FROM WASTEWATER BY ACTIVATED CARBON AND SPIRULINA PLATENSIS: A COMPARATIVE STUDY

The results of a comparative study of chromium (initial concentration 9.4 mg/L) removal from wastewater by activated carbon AG-5 and Spirulina platensis biomass are reported. The process of chromium adsorption was studied at a carbon dosage of 0.2 g over a 24 hr period. The results obtained by NAA and AAS showed that only 4% of chromium was adsorbed from wastewater. The NAA data pointed to an increase of Fe, Ni and Cu content in activated carbon after wastewater treatment, which is indicative of competitive adsorption. For Spirulina platensis (time of experiment 1 hr), a rapid rate of chromium adsorption within the first 15 min of the reaction was observed. ASS data showed that during an hour, approximately 90% of chromium was removed from wastewater. Furthermore, a high amount of iron, nickel and copper were removed from the chromium containing industrial effluents by the spirulina biomass. Fourier transform infrared spectroscopy was used to identify functional groups responsible for metal binding. Surface morphology of activated carbon and cyanobacterial biomass was analyzed by scanning electron microscopy.