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Objective & Scope
1. Screening of efficient biosorbent 2. Characterization of biosorption mechanism 3. Modeling of heavy metal removal by biosorbent 4. Development of biosorption process Main Contents The conventional process of heavy metal removal from industrial wastewater involves chemical precipitation of metals usually by lime followed by settling of the metal precipitates in a pond and/or a clarifier. The major shortcoming of conventional treatment include low efficiency at low concentration of heavy metals and expensive handling and safe disposal of toxic sludges. Adsorption on the ion exchange or activated carbon is a recognized method for the removal of heavy metals from wastewater. However, high costs of them have limited their use in the real electroplating wastewater treatment. Innovative methods for heavy metal removal including biosorption have been investigated in an ongoing effort to develop a better treatment for wastewater containing toxic heavy metals. A search for a low-cost and easily available adsorbent has led to the investigation of materials of agricultural and biological origin, along with industrial byproducts, as potential metal sorbents. The variety of materials tested as metal adsorbents includes coal, crushed coconut shell, peat, bark and straw. Recent developments in the field of environmental biotechnology include the search for microorganisms as sorbents for heavy metals. Bacteria, fungi, yeast and algae can remove heavy metals from aqueous solution in substantial quantities. The uptake of heavy metals by biomass can take place by an active mode (dependent on the metabolic activity) known as bioaccumulation or by a passive mode (sorption and/or complexation) termed as biosorption. The objective of this work was to investigate the treatment of tin-plating wastewater containing low concentration of chromium by using biosorption and to understand the principle of removal of heavy metals and to develop the process for removal of heavy metals from wastewater. Screening tests revealed a high passive biosorptive uptake of chromium in Ecklonia sp. and Sargassum I, II among eight seaweed biomass types. While Cr(III) was removed from aquatic system by cation exchange mechanism, Cr(VI) was removed from aquatic system by reduction reaction. During the reduction of Cr(VI) at the range of low pH, Cr(VI) reduced to Cr(III), which was eventually eluted into the solution phase. The pH of the solution strongly affected the degree of biosorption of chromium on biomass. The higher pH, the more removal of Cr(III) and the less removal of Cr(VI). Therefore the Two-Stages Cr-Removal Process to remove both Cr(VI) and total Cr was developed. Related Projects Title : Process Development for the Treatment of Wastewater Containing Low Concentration of Heavy Metal by Using Biosorption Period : 19990701-20000630 Support : RIST Title : Development of Low-Cost Biosorption Technology to Treat Heavy- Metal-Containing Wastewater Period : 20000101-20001231 Support : POSCO References 1) Chromium removal by biosorption using Ecklonia seaweed biomass Donghee Park, Thesis of Master(2002), POSTECH, KOREA 2) Biosorption of Trivalent Chromium on the Brown Seaweed Biomass Y.-S. Yun, D. Park, J.M. Park and B. Volesky, E.S.T.(2001), 35, 4353-4358. |
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