A silica gel-bound macrocycle system for the selective separation of toxic cadmium from metal-affluent aqueous matrix

Abstract

Abstract Abstract Selective separation of cadmium(II) on a macrocycle immobilized solid phase extraction (SPE) system namely AnaLig Cd-01, and commonly known as molecular recognition technology (MRT) gel, have been examined. The MRT-SPE able to retain the cadmium from the metal-affluent aqueous matrix at the pH range of 2 to 8, and the captured species can be recovered via elution with 1 and 6 M HNO3. Besides the effects of solution pH and eluent concentration, the impacts of sample loading flow rates and coexisting matrix ions were also investigated and optimized. The Cd(II) retention capacity of the MRT-SPE was 0.26 mmol g-1, and it can be reused for more than 100 loading and elution cycles. The Cd(II) recovery attained from the metal-spiked natural waters was satisfactory (95.3–98.1%). However, the Cd(II) retention ability of the MRT-SPE was significantly decreased when excess of chelant remain in the aqueous waste matrix. Graphical abstract