Biosorption of Heavy Metals by Oscillatoria Species

Abstract

Background: Several anthropogenic activities have led to serious health and environmental problems as a result of releasing different contaminants in to the ecosystem including heavy metals. This called for search of possible methods that could be used to ameliorate the environment and biosorption was found to be promising. Aim: The potential of Oscillatoria sp. was investigated with a view to determining its suitability in the biosorption of Cr2+ and Pb2+. Place and duration of Study: The study was conducted at the Research Laboratory, Department of Microbiology, Usmanu Danfodiyo University Sokoto, between January and July, 2016. Methodology: Samples of the algal species were collected from an irrigation site at Kwalkwalawa area of Usmanu Danfodiyo University Sokoto. The samples were dried and powdered for biosorption studies. Biosorbents were prepared and used for sorption of heavy metals at different time and substrate concentration. Results: It was observed that Oscillatoria sp. biomass could adsorb appreciable amounts of the metals in a dose and contact time-dependent manner. At lower biomass doses, lower rates were recorded with a mean of 0.002 mg/g and increased to 0.1mg/g when 2 g and 5 g biomass were used respectively in both cases of the metals uptake. Based on contact time, Cr2+ uptake was initially slow with mean value of 0.002 mg/g for the first 50 minutes and rapidly increased to optimum at 60 minutes of contact time. For Pb2+ however, uptake was rapid with peak value of 0.1mg/g for the first 20 minutes. The uptake drastically decreased at 35 and 50 minutes and equilibrium was attained at 60 minutes of contact time. Conclusion: Oscillatoria sp. has the potentials of Cr2+ and Pb2+ uptake and thus suitable for biosorption of low heavy metals concentrations.