Adsorption of Cu۲+ Ions From Aqueous Solutions Using Oxidized MultiWalled Carbon Nanotubes

Copper ion (Cu۲+) is one of the heavy metal ions that cause environmental pollution specifically in water. Copper ion cations are not biodegradable and tend to cumulate in living organisms. Consequently, the removal of Cu۲+ in environmental samples plays an important role in environmental pollution monitoring. The purpose of the present work was to prepare oxidized Multi-Walled Carbon Nano Tubes (MWCNTs) for removal of Cu۲+ ions from aqueous solutions. This study was conducted under laboratory conditions. Multi-Walled Carbon Nano Tubes were oxidized and characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM) and the Brunauer, Emmett, and Teller (BET) methods. The effects of various factors, such as solution pH (۳ - ۹), adsorbent dose (۰.۰۰۶ - ۰.۰۶ g) and contact time (۱۰ - ۱۲۰ minutes) were investigated. Results showed that the suitable pH for Cu۲+ ions removal was about ۶.۰, and the optimal dose was ۰.۰۳ g. Isotherm studies indicated that the Langmuir model fits the experimental data better than the Freundlich model. Maximum Cu۲+ adsorption capacity was calculated as ۲۰۰ mg g-۱. The kinetics of the adsorption process was tested for the pseudo-firstorder and pseudo-second-order models. The comparison among the models showed that the pseudo-second order model best described the adsorption kinetics. The results showed that oxidized MWCNTs can be used as a low cost adsorbent for the removal of Cu۲+ ions from aqueous solutions.