Removal of heavy metals from aqueous solution by lipopeptides and lipopeptides modified Na-montmorillonite.

The removal of Cu(2+), Zn(2+), Cd(2+), Pb(2+) and Hg(2+) from aqueous solution by lipopeptides produced from solid-state fermentation (LPSSF) and LPSSF modified Na-montmorillonite clays (LPSSF/Na-MMT) was investigated. The results showed that the LPSSF had certain adsorption capability for the metal ions and the modification of Na-MMT with LPSSF at a weight ratio of 1:50 (LPSSF:Na-MMT) had the best adsorption capacity and adsorption rate. The adsorption of heavy metal ion on these adsorbents was monolayer sorption. And the rate limiting step of the adsorption process was thought as chemical sorption. The N-C-O and CC/CN groups of the LPSSF are the functional groups that were responsible for complexing the metal ions. The desorption rate of metal ions reached over 80% at 500 mg/L of LPSSF. The LPSSF/Na-MMT (1:50) was reusable and performed well in the complex system, indicating its potential application in wastewater treatment.