Malays. Appl. Biol. (1997) 26(2): 83-90
BIOSORPTION OF HEXAVALENT CHROMIUM FROM AQUEOUS SOLUTION BY HYDRILLA VERTICILLATA
K.S. LOW*, C. K. LEE and S.C. YEAP
Chemistry Department, Faculty of Science and Environmental Studies, Universiti Putra Malaysia 43400 UPM Serdang, Selangor, Malaysia
ABSTRACT
The ability of non-living biomass of an aquatic plant, Hydrilla verticillata, to remove Cr(VI) from aqueous solution was studied at different initial concentrations, temperatures, pH, sorbent dosages, contact time and in the presence of competing anions. The uptake was pH dependent and maximum sorption occurred at pH 2. The Langmuir isotherm model was usec to describe the sorption of Cr(VI) on Hydrilla and the maximum uptake for Cr(Vl)-Hydrilla system was 30 mg/gm. Thermodynamic studies showed that the sorption process was exothermic. The interference effect of other anions on the Hydrilla was also studied. Results indicate the following order of suppression of Cr(VI) by the various anions: SO42- > HPO42- > NO3- > Cl-.
ABSTRAK
Kemampuan biojisim bagi satu tumbuhan akuatik, Hydrilla verticillata, yang tidak hidup, untuk mengalih Cr(VI) dari larutan akuas telah dikaji dengan mengubahkan kepekatan awal, suhu, pH, amaun penjerap, masa sentuh dan dalam kehadiran anion-anion bersaing. Penjerapan bergantung kepada pH dan penjerapan maksimum berlaku pada pH 2. Model isoterma Langmuir telah digunakan untuk menjelaskan penjerapan Cr(VI) pada Hydrilla dan penjerapan maksimum yang didapati untuk sistem ini adalah 30 mg/gm. Kajian termodinamik menunjukkan bahawa prosess penjerapan adalah eksotermik. Kesan gangguan dari anion-anion Iain pada penjerapan Hydrilla juga dikajikan. Keputusan menunjukkan tertib penindasan berikut: SO42- > HPO42- > NO3- > Cl-.
Key words: Biosorption, hexavalent chromium, Hydrilla verticillata
REFERRENCES
Cotton, F.A. and Wilkinson, G.M. 1976. BasicInorganic Chemistry. John Wiley & Sons, Inc.,Canada. 693pp.
Helfferich, F. 1962. Ion Exchange. McGraw Hill,New York.166pp.
Hilderbrand, H.F., Veron, C. and Martin, P. 1988.Ni, Cr, Co dental alloys and allergic reactions.Biomaterial, 10: 545-48.
Low, K.S., Lee, C.K. and Heng, L.L. 1994. Sorptionof basicdyesby Hydrillaverticillata.Environmental Technology, 14: 115-124.
McKay, GM., Blair, H.S. and Gardner, J.K. 1982.Adsorption of dyes on chitin:equilibriumstudies.Journal of Applied Polymer Science,27:3040-3057.
Sharma, D.C.1993. An examination into thetreatment of hexavalent chromium using lowcost adsorbents.Ph.D. Thesis. The Universityof Birmingham, U.K.
Sharma , D.C. and Forster, C.F. 1993.Removal oihexavalent chromium using sphagnum mosspeat.Water Research 27(7): 1201 -1208.
Sharma, D.C. and Forster, C.F. 1994a. A preliminaryexamination into the adsorptionofCr(VIJusing low cost adsorbents. BioresearchTechnology, 47: 257-264.
Sharma, D.C. and Forster, C.F. 1994b. The treatmenlof chromium wastewaters using the sorptivepotential ofleafmould. BioresearchTechnology, 49: 3-40.
Srivastava, H.C.P., Mathur, R.P. and Mehrotra, I.1986. Removal of chromium from industrialeffluents by adsorption on sawdust.Enviromental Technology Letters, 7: 55-63.
Tan, W.T, Ooi, S.T. and Lee, C.K. 1993. Removalof chromium(VI) from solution by coconut huskand palm-pressed fibre.EnviromentalTechnology, 14: 277-282.
US EPA.1976. Quality Criteria for Water. US Environmental Protection Agency, WashingtonDC 20460.
