Study Of The Characterization And The Mechanisms Of Iodine Ion Biosorption By Baker’s Yeast And E.coli

Disposal of radioactive nuclide leakage and nuclear waste drawn increasing attention around theworld since the extent application of nuclear energy started from early20th century. I131was one ofthese nuclear waste. To provide a solution, Baker’s yeast and E.coli were found to be utilized asbiosorbents to adsorb I－in aqueous solution. Furthermore, they could be used with a low cost.Therefore, they became promising adsorbents for adsorbing I－from wastewater. Removal of I－fromaqueous solution by biosorption on baker’s yeast and E.coli, respectively, was studied in batch mode.The equilibrium adsorptive quantity was determined to be a function of contact time, yeast dose,solution pH, competing ions, contact temperature and initial concentration of I－. The experimentalresults obeyed well not only the Pseudo-first-order kenetic model and Pseudo-second-order keneticmodel, but also the Langmuir and Freundlich model isotherms. According to the parameters ofLangmuir isotherm, the maximum biosorption capacities of I－onto baker’s yeast and E.coli were0.1207mmol g1and0.0372mmol g1, respectively. The binding capacity of Bakers yeast was greaterthan E.coli. The mechanism of I－binding by biomass was investigated by FTIR spectra and SEM. Itturned out that the carboxyl, amino, amide and hydroxyl on the surface of biomass could be availablefor bonding with I－. In addition, SEM also showed that the surface of both biomass were destroyed,which confirmed that chemical reaction might also be involved in adsorption.