Adsorption of Pd(Ⅱ)from Aqueous Solution by the Biomass Residue of Brown Alga Laminaria Japonica

The biomass residue of Laminaria japonica (namely ROLJ) was prepared by treating Laminaria japonica with ethanol. The adsorption property of ROLJ for Pd(II) from aqueous solution was investigated. The effects of various parameters such as the initial pH, contact time, temperature and initial metal ion concentration on the adsorption efficiency of Pd(II) were studied. The experimental results showed that the optimum adsorption pH of ROLJ for Pd(II) was 3～4,the adsorption equilibrium time was 80min. The adsorption of Pd (II) on the ROLJ was found to follow the pseudo second order kinetics equation and agree well with Langmuir adsorption isotherm model. Thermodynamic parameters indicated that the adsorption was spontaneous, endothermic accompanied by increase in entropy under the experimental conditions. The recovery of Pd (II) was eluted with 0.1M HCl+5% thiourea solution, which indicated that ROLJ is a promising material for recovery of palladium.