Equilibrium and Kinetic Studies on Biosorption of Cu(II) by Immobilized Brown Algae Laminaria japonica

Abstract

The process of biosorption of heavy metal ion Cu(II) by immobilized brown algae Laminaria japonica is discussed in this paper, with the adsorption characteristics of L. japonica investigated as a parameter of initial pH, initial concentration of Cu(II), particle size, algal dose and temperature. The maximum adsorption of Cu(II) ion on L. japonica biomass was observed at pH 3-5. The higher initial concentration of Cu(II) and temperature allowed better biosorption capacity. The increasing biomass concentration resulted in enhancement in percent removal of Cu(II). Kinetics experiments indicated that adsorption process was quick, reaching equilibrium state in less than 60 min, and the biosorption kinetics followed the pseudo- second order model. FT-IR spectrum analysis of algal biomass told us that some changes occurred at the functional group structure of L. japonica after adsorption. The existence of amino, hydroxyl, carbonyl and carboxyl groups plays a definitely important role on biosorption of Cu(II). IR spectrum analysis suggested immobilization has little effect on biosorption mechanism. Desorption experiments showed that 0.1 mol/L HCl was an efficient desorbent for the recovery of Cu(II) from biomass and the maximum desorption of 87.2% was obtained.