Study on mechanisms of silver biosorption by laminaria japonica

The study on mechanisms of metal biosorption is helpful to improve the biosorption ability of organism.Mechanisms of silver biosorption by Laminaria japonica were discussed from several aspects such as electrostatic(adsorption,) ion exchange,complexation and deposition.The results show that silver biosorption by Laminaria(japonica) doesn′t depend on electrostatic adsorption,while ion exchange is responsible for biosorption because of(increase) of the mass concentration of Na~+,K~+,Mg~(2+) in solution before and after biosorption.Adsorptive capacity of Ag~+ distinctly decreases after functional groups such as carboxyl,amino and lipid groups in Laminaria japonica cell wall are chemically modified respectively.Combined with FTIR spectra,carboxyl and amino groups are(confirmed) to be the main active groups which can combine with silver ion.Precipitation can take place on the cell wall of Laminaria japonica through SEM characterization.