Removal of cadmium ions from Na-Feldspar, a soil component, by rhamnolipid biosurfactant

Soil contains various components such as clay, feldspar, quartz, etc. In this study, the removal of Cd(II) ions from Na-feldspar and soil by rhamnolipid biosurfactant was investigated. The parameters studied were; rhamnolipid concentration, pH, and initial Cd(II) ion concentration. To investigate Cd(II) complexation by rhamnolipids, firstly the surfaces of Na-feldspar and soil were loaded with Cd(II) ions. The highest Cd(II) sorption efficiency on Na-feldspar and soil was obtained as 62.6, 92.6 %, respectively. A maximum Cd(II) removal efficiency of 99.0 % for Na-feldspar was obtained at pH 6.8, at 0.92 mM Cd(II) ion concentration, and at 50 mM rhamnolipid concentration. The Cd(II) desorption efficiency from soil also increased with increasing pH up to 6.8-7.0. In this pH range, maximum Cd(II) desorption efficiency was 63.5%, at 1.5 mM Cd(II) ion concentration and at 70 mM rhamnolipid concentration.