[01] B. O. Olusola, Department of Microbiology, Faculty of Science, University of Ibadan, Ibadan, Nigeria. [02] M. N. Aransiola, Department of Microbiology, Faculty of Science, University of Ibadan, Ibadan, Nigeria.

One of the most serious environmental problems being faced by the world today is heavy metal pollution. Biosorption, being a cost-effective and efficient, has emerged as alternative technology for removal of heavy metals. The potential of two immobilized algae species for removal of Zinc (Zn2+) and Iron (Fe2+) from industrial wastewater was analysed through batch studies. Algal bloom water samples were obtained from fish ponds in Prof. Olu Odeyemi’s Farm, Ilesa. Wastewater was collected from industrial discharge system around Ile–Ife (Nigeria). Algae were isolated from the water samples using pour plate technique on modified Allen agar medium at pH 7.1. The identity of the algae isolates was established using Identification guide to Freshwater and Terrestrial algae. Algae were immobilized with 3% sodium alginate and 2% calcium chloride dihydrate. The beads of approximately 4mm were formed by allowing the algae/alginate mixture to drip through a syringe barrel in to a beaker of calcium chloride dihydrate solution. Biosorption batch studies was carried out by the addition of 100 beads into 100ml solution (50 ml of wastewater and 50 ml of media) in 250ml conical flask at 150rpm, room temperature and pH 3, 5 and 7. Concentration of Zinc (Zn2+) and Iron (Fe2+) was determined in 2 days interval using atomic absorption spectrophotometer at their respective detection limit. The algal isolates were identified as Botrydium granulatum and Euglena texta. The percentage removal of Zinc (Zn2+) and Iron (Fe2+) (at their respective detection limit) by these algae varies with pH and time. At pH 5, Botrydium granulatum had the best percentage removal rate (100%) (that is not detectable in the wastewater) for the two metals while Euglena texta performed best (100%) at pH 3 and 5 for the two metals over the period of time. At pH 7, the percentage removal of the two metals decreases with time for both algae species. At pH 5, Euglena texta performed better by complete (100%) removal of both metals starting from day 1 while Botrydium granulatum completely (100%) remove Iron (Fe2+) and Zinc (Zn2+) starting from day 7 and 5 respectively. Zinc (Zn2+) was more effectively removed than Iron (Fe2+) by Botrydium granulatum at pH 5. Since the algae isolates showed appreciable sorption of the metals, they can be used for biosorption of metals from industrial wastewater prior to its discharge to avoid environmental pollution.

Biosorption, Botrydium Granulatum, Immobilization, Wastewater, Zinc (Zn2+)

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