Biosorption of lead ion by chemically-modified biomass of marine brown algae Laminaria japonica

In this paper, marine brown algae Laminaria japonica was chemically-modified by crosslinking with epichlorohydrin (EC1, EC2), or oxidizing by potassium permanganate (PC), or only washed by distilled water (DW). They were used for equilibrium sorption uptake studies with lead. As can be seen from the experimental results that biosorption equilibriums were rapidly established in about 2 h. The lead adsorption was strictly pH dependent, and maximum removal of lead on biosorbents were observed at pH 5.3. The effects solid/liquid ratio on lead biosorption was also investigated. The maximum lead uptakes were 1.67 mmol g−1, 1.62 mmol g−1, 1.54 mmol g−1 and 1.21 mmol g−1, respectively for EC1, EC2, PC and DW. The order of maximum lead uptakes for different pretreated and raw alga was EC1 > EC2 > PC > DW. A comparison of different isotherm models revealed that the combination of Langmuir and Freundlich (L–F) isotherm model fitted the experimental data best.