Materials and Methods |
Tur dal (Cajanus cajan) husk (seed coat) was collected from a legume seed-splitting mill. The tur dal husk (TDH) was thoroughly washed in running tap water to remove dirt and other particulate matter. This was later subjected to colour removal through washing and boiling in distilled water repeatedly. Subsequently the husk was oven dried at 105oC for 24 hr, stored in a desiccator and used for biosorption studies in the original piece size.
Batch mode adsorption studies using processed TDH were carried out to determine the adsorption of Cr (VI) and Fe (III). The synthetic stock solution (1000 ppm) of ferrous ammonium sulphate and potassium dichromate prepared in the laboratory was diluted to different concentrations and to each 100 ml; 1 g of the biosorbent (husk of Cajanus cajan) was added and agitated in a rotary shaker at 150 rpm for pre-determined time intervals. The adsorbate and the adsorbent were separated using whatman no. 1 filter paper. The residual metal concentration was determined spectrophotometrically using standard procedures of Eaton et al., 1995 for Cr (VI) and Snell and Snell, 1961 for Fe (III). Infrared spectroscopic studies of TDH before and after treatment with Cr (VI) and Fe (III) was carried out to determine the functional groups responsible for adsorption.
