Adsorptive Removal of Copper by Using Surfactant Modified Laterite Soil

Removal of copper ion (cu2+) by using surfactant modified laterite (sml) was investigated in the present study. characterizations of laterite were examined by x-ray diffraction (xrd),fourier transform infrared spectroscopy (ft-ir),inductively coupled plasma mass spectrometry (icp-ms),and total carbon analysis. the optimum conditions for removal of cu2+ by adsorption using sml were systematically studied and found as ph 6,contact time 90 min,adsorbent dosage 5 mg/ml,and ionic strength 10 mm nacl. the equilibrium concentration of copper ions was measured by flame atomic absorption spectrometry (f-aas). surface modification of laterite by anionic surfactant sodium dodecyl sulfate (sds) induced a significant increase of the removal efficiency of cu2+. the surface modifications of laterite by preadsorption of sds and sequential adsorption of cu2+ were also evaluated by xrd and ft-ir. the adsorption of cu2+ onto sml increases with increasing nacl concentration from 1 to 10 mm,but at high salt concentration this trend is reversed because desorption of sds from laterite surface was enhanced by increasing salt concentration. experimental results of cu2+/sml adsorption isotherms at different ionic strengths can be represented well by a two-step adsorption model. based on adsorption isotherms,surface charge effects,and surface modification,we suggest that the adsorption mechanism of cu2+ onto sml was induced by electrostatic attraction between cu2+ and the negatively charged sml surface and nonelectrostatic interactions between cu2+ and organic substances in the laterite. © 2017 tien duc pham et al.