55th Inaugural Lecture - 2007 by Prof. O. Akaranta - University of ...

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(Azbar et al 2004). The methods include chemicalprecipitation, electro deposition, cementation, ultra filtration orreverse osmosis, ion exchange and activated carbonadsorption. Cation exchange resins are particularly effective inremoving metal ions and other positively charged species fromaqueous solutions. Activated carbons are finding increased useas metal ions scavengers because of the high cost of cationexchange resins derived from petroleum resources. The needfor effective and economic removal of toxic/valuable heavymetal ions and organic pollutants in industrial effluents hasresulted in a search for unconventional methods and materialsthat might be useful in industrial effluents treatment (Kumarand Dara, 1981).Agricultural residues, especially those from widelygrown commodity crops, are quite inexpensive and have beenshown to possess natural adsorbent properties (Waiss et al,1973; Young et al, 1973, Waiss and Friedman, 1972). Theadsorbent properties of the unmodified agricultural residuesare due to the presence of carboxylic, phenolic and hydroxylgroups in the substrates. However, the sorption capacities of24
agricultural residues can be enhanced by chemicalmodifications.Alkali Treated Agricultural ResiduesAzab and Peterson (1989) reported that alkali treated peanuthull removed 99% cadmium ion from solution in columnapplications. This is an improvement over the untreated peanuthull which removed 68% cadmium ion. Akali treatment ofcrystalline lignocellulosic agricultural residues helps inloosening the crystalline structures thus improving theexchange capacities of the treated substrates. The resultsobtained with the alkali treated peanut hull in the uptake ofcadmium ion is an indication that other agricultural residueswith similar chemical compositions as peanut hull would beexpected to show improved exchange capacities when treatedwith alkalis. Hence increasing the number of agriculturalresidues, that can effectively remove metal ions from industrialeffluents.Polymerised Agricultural ResiduesUsing polymerised agricultural residues in effluents treatment,Kumar and Dara (1981) reported that formaldehyde25
Page 1 and 2: UNIVERSITY OF PORT HARCOURTAGRO WAS
Page 3 and 4: The Vice - Chancellor, Sir,Members
Page 6 and 7: Table 1: Residues from the Processi
Page 8 and 9: usually used in the production of s
Page 10 and 11: Orange Seed and Peel OilsAll seeds
Page 12 and 13: satisfied International Standards O
Page 14 and 15: Figure 2:A Red Onion Skin Extract A
Page 16 and 17: of lignocellulosic materials for ch
Page 18 and 19: Pentosan an aldopentose furfural(in
Page 20 and 21: HOHOOH + ClCH 2COONaalkalinesolutio
Page 22 and 23: peel has been reported as a good po
Page 24 and 25: with superphosphates and used as co
Page 28 and 29: polymerized onion skin is highly ef
Page 30 and 31: substrate is in the following decre
Page 32 and 33: Figure 3: A Schematic Representatio
Page 34 and 35: alternatives to the non-renewable r
Page 36 and 37: into our environment. The guideline
Page 38 and 39: CONCLUDING REMARKSMr. Vice - Chance
Page 40 and 41: REFERENCESAdebowale, E.A (1985), No
Page 42 and 43: Akaranta, O. and Anusiem, A.C. I. (
Page 44 and 45: Halliday, D. (1975), Animal Blood a
Page 46 and 47: Thickeners in Latex Paints, Carbohy
Page 48 and 49: Critical Review on Current Treatmen

55th Inaugural Lecture - 2007 by Prof. O. Akaranta - University of ...

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