Adsorption of Zn2+ by Sargassum horneri and desorption at simulated marine environment

The adsorption of Zn2+ from simulated seawater onto biomaterial derived from the macroalgae Sargassum horneri was investigated via batch experiments. The highest adsorption rate was 96.9%, which found in the lower Zn2+ concentration solution where pH was 8.0 and temperature was 15 degrees C, and the maximum adsorption capacity of dead Sargassum homeri particle to Zn2+ could arrive to more than 0.20 mg.g(-1). Sargassum horneri pretreated with CaCl2 can increase the adsorption rate. Infrared analysis results showed that carboxylic acid groups have an important contribution to Zn2+ adsorption. The adsorption equilibrium of Zn2+ could be represented by pseudo-second-order model and the capacity of dead alga for Zn2+ was approximately constant. Conclusions could be drawn that Sargassum horneri is a kind of efficient biosorbent for the treatment of waste waters containing heavy metals. It was because Zn2+ can easily be desorbed by competition between the hydrogen ions and metal ions on the cell surface binding sites, that hydrochloric acid was proved to have economic feasibility.