Use of Carica papaya as a Bio-Sorbent for Removal of Heavy Metals in Wastewater

Authors: W. E. Igwegbe, B. C. Okoro, J. C. Osuagwu

Abstract:

The study assessed the effectiveness of Pawpaw (Carica papaya) wood in reducing the concentrations of heavy metals in wastewater acting as a bio-sorbent. The following heavy metals were considered; Zinc, Cadmium, Lead, Copper, Iron, Selenium, Nickel and Manganese. The physiochemical properties of Carica papaya stem were studied. The experimental sample was sourced from the trunk of a felled matured pawpaw tree. Wastewater for experimental use was prepared by dissolving soil samples collected from a dump site at Owerri, Imo state of Nigeria in water. The concentration of each metal remaining in solution as residual metal after bio-sorption was determined using Atomic absorption Spectrometer. The effects of pH and initial heavy metal concentration were studied in a batch reactor. The results of Spectrometer test showed that there were different functional groups detected in the Carica papaya stem biomass. There was increase in metal removal as the pH increased for all the metals considered except for Nickel and Manganese. Optimum bio-sorption occurred at pH 5.9 with 5g/100ml solution of bio-sorbent. The results of the study showed that the treated wastewater is fit for irrigation purpose based on Canada wastewater quality guideline for the protection of Agricultural standard. This approach thus provides a cost effective and environmentally friendly option for treating wastewater.

Keywords: Biomass, bio-sorption, Carica papaya, heavy metal, wastewater.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1110828

References:

[1] Volesky, B. (1994) Advances in biosorption of metals: selection of biomass types. FEMS Microbiology Reviews. (14): 291-302.
[2] Gadd, G.M. (1993) Interactions of fungi with toxic metals. New Phytologist. 124:25-60
[3] Weng, J. and Chen, J. P. (2006) Biosorption of heavy metals by Saccharomyces cerevisiae: a review. Biotechnol. Adv. 24: 427-451.
[4] Kapoor, A. and Viraraghavan, T. (1995). Fungal biosorption- an alternative treatment option for heavy metal bearing wastewaters: a review. Bioresourse. Technol. 53: 95-206.
[5] Nwala G. N., 1990. The removal of heavy-metal ions from aqueous solutions by using dried activated carbon, 7-10.
[6] Nriagu, J. O. (1989). A global Assessment of Natural Sources of Atmospheric Trace Metals, Nature, 338: 47-49.
[7] Weng, J. and Chen, J.P. (2006) Biosorption of heavy metals by Saccharomyces cerevisiae: a review. Biotechnol. Adv. 24: 427-451.
[8] Vijayaraghavan, K. and Yun, Y.S. (2008) Bacterial biosorbents and biosorption. Biotechnol. Adv. 26: 266-291.
[9] Gupta, R., Ahuja, P., Khan, S., Saxena, R. K. and Mohapatra, H. (2000) Microbial biosorbents: meeting challenges of heavy metal pollution in aqueous solutions. Curr. Sci. 78: 967-973.990).
[10] Dick, G. (2003). ”Papaya”: A tantalising taste of the Tropics. Maricopa County Master Gardener Volunteer information, University of Arizona Cooperative Extension. www.papaya [email protected].
[11] Ezeigbo C.U. (1990): “A Doppler Satellite Derived Datum for Nigeria”. Acta Geodaetica Geoph. Mont. Hung., Journal of Hungarian Academy of Science, Akadémiai Kiadó, Budapest. Vol. 25 (3 – 4), pp. 399 – 413 (1990).
[12] Saeed, A., Waheed Akhter, M. and Iqbal, M. 2005. Removal and recovery of heavy metals from aqueous solution using papaya wood as a new biosorbent. Sep. Purif. Technol. 45, 25–31.