Electron exchange columns through entrapment of a nickel cyclam in a sol-gel matrix

An electron exchange column (analogous to ion exchange columns) was developed using the unique redox properties of the nickel-tetraazamacrocyclic complexes (nickel cyclam [Ni ^IIL ¹] ²⁺) and nickel-trans-III-meso-5,7,7,12,14,14-hexamethyl-1,4,8,11- tetraazacyclotetradecane, ([Ni ^IIL ²] ²⁺), and the physical and chemical stability of the ceramic materials using the sol-gel process to entrap the complexes. The entrapment by the biphasic sol-gel method is based on non-covalent bonds between the matrix and the complex; therefore the main problem was leaching. Parameters controlling the leaching were investigated. Redox cycles with the reducing agent ascorbic acid, and persulfate as the oxidizing agent were performed.