Optimization and application of solid phase extraction of Cu(II) from aqueous solutions using new environmentally friendly modification of silica gel

A new solid phase extractor named silica gel immobilized indapamide (4-chloro-N-(2-methyl-2,3-dihydroindol-1-yl)-3-sulfamoylbenzamide) (SG-INDP) was synthesized by microwave free-solvent technique as a new environmentally friendly modification method. This new phase was investigated for removal of copper ions from aqueousmedia. It was characterized by the FT-IR, scan electron microscope and X- ray diffraction analyses. The effects of sample pH, time of equilibrium, sorbent weight, copper ions concentrations and interfering ions were studied and optimized using batch technique at room temperature. The maximumpercentage of extraction of Cu(II) (99.90 +/- 0.1%) using SG-INDP was achieved. The fast adsorption equilibrium could be reached within 20 min and the kinetic data were fitted well by a pseudo-second-order equation (r(2) = 0.999). Results of sorption isotherms of the sorbent were better fitted with the Langmuir (r(2) = 0.994) and Freundlich (r(2) = 0.985) models. The new synthesized solid phase extractor was applied for removal of Cu( II) from natural water samples. (C) 2014 Elsevier Ltd. All rights reserved.