Abstract
Carbonized multi-walled carbon nanotubes/epxoy composites are made to absorb Cu2+ in aqueous solution and CNTs are found retrievable after repeated experiments. Carbonized composites, consisting of multi-walled carbon nanotubes and epoxy resin in different ratios, are used to remove copper ions in the solution after carbonization and acidification processes. Adsorptive experiments are divided into two parts; first, the samples powdered and are used as Adsorbents; second, samples are made as thin films and ionic absorption is carried out using CDI technology. Samples are also characterized in order to establish the relationship between sample structure and chemical treatments. Results show that acidification decreases resistivity of powdered samples and specific surface area whereas porosity and density of functional groups increase. Accordingly, samples change from hydrophobic into hydrophilic property and the maximum adsorption capacity of Cu(II) calculated by Langmuir model reaches 19.49 mg•g-1, fit better with Freundlich model than that of Langmuir model. Samples can be reused through regeneration procedure. In CDI adsorption experiment, the adsorption capacity of film samples increases by three-fold at applied 1.2 V between electrodes. The adsorption mechanism is found as a result of combined electrosorption and ion exchange at low concentration situation. At high concentration, adsorption of copper(II) sulfate proceeds through electrolysis and amount of removed ions from solution decreases to 80 % at the 1st run. Absorption curves become stabilized after the 1st regeneration process.