a b s t r a c tThere is serious concern regarding copper and nickel, due to their persistent, non-biodegradable and toxic characteristics. This present study concerns the adsorption of copper (Cu(II)) and nickel (Ni(II)) ions onto nano zero valent iron (nZVI) from single and binary systems. Apart from low efficiency conventional adsorbents, nanoparticles such as nZVI and carbon nanotubes are promising adsorbents, as they have a higher adsorbent surface area and nano sized pores. Removal efficiencies are investigated for single and binary adsorption by considering the initial concentrations of copper and nickel. While the removal of copper was as high as 92% with the absence of nickel ion in aqueous solution, it decreased to 61% with 50 mg/L nickel ion concentration. Likewise, the 88% removal rate of nickel ion with the absence of copper, decreased to 70% with 50 mg/L copper ion concentration. Higher metal ion concentrations achieved even poorer results, by having 26% of removal efficiency, or less. It was also observed that the adsorption capacity of copper ion was higher than nickel ions in the binary system. For the highest total metal ion concentrations (300 mg/L), the adsorption capacity obtained was 960 mg/g in the binary system.

Copper is from one of the most important heavy metals, which adheres to the ecological system by harmful human activities. It is toxic, persistent, and non-biodegradable metal, which causes environmental pollution in both the atmosphere and aquatic environment. Copper pollution found in undesirable concentrations in industrial wastewaters especially from electronics industries, cooling systems and plating industry. Physical methods are mostly applied to remove Cu(II) including adsorption and membrane processes. Nanoparticles (e.g. nano zero valent iron (nZVI), carbon nanotubes, titanium dioxide nanoparticle) have been considered to be promising alternatives to conventional adsorbents. They have advantages by having more surface area and nano-sized pores, which helps to adsorb more molecules. In this study, in order to enhance adsorption by activated carbon and lower the cost of nanoparticle synthesis, nZVI is synthesized on activated carbon(AC-nZVI). It was investigated for its effectiveness in copper removal from aqueous solution. The effect of AC-nZVI dosage, pH and the initial concentration of Cu were investigated. Adsorption capacities are obtained for nZVI and AC-nZVI as 414 mg/g and 510 mg/g, respectively. 200mg/L AC-nZVI concentration was determined as sufficient for %96 removal rate. Langmuir isotherm gave the best fit and the maximum adsorption capacity according to Langmuir isotherm is calculated as 588,24 mg/g.