Treatment of Au(II), Ag(I), Cu(II), Ni(II) from Electroplating Wastewater by Laminaria japonica: Biosorption, Desorption and Recycling

The pretreated brown algae Laminaria japonica was used to adsorb and desorb Au²⁺, Ag⁺, Cu²⁺ and Ni²⁺ ions from electroplating wastewater in this article. The results indicated that the biosorption process of Au²⁺, Ag⁺, Cu²⁺ and Ni²⁺ ions could be divided into two steps. The first step was physical adsorption and reached equilibrium quickly, in less than 15 min. This adsorption process followed the pseudo-second order model well. The desorption process of Au²⁺, Ag⁺, Cu²⁺ and Ni²⁺ ions was similar to the adsorption process using this pretreated algae biosorbent. So as the desoption process also followed the pseudo-second order model well. We used HCl as the elution in the desorption experiment. The results showed that using HCl as the elution not only had a good desorption capacity of heavy metals ions, and the brown algae still had a certain desorption capacity after repeatly adsorption-desorption for 3 times. Although existing the impact of environmental conditions, the biosorption capacities could also reach above 75% basically in the field experiment. Laminaria japonica can be used as an efficient biosorbent material for the removal and recovery of heavy metal ions from electroplating wastewater.