Removing Cadmium from Aqueous Environments using L-cysteine Functionalized Single-Walled Carbon Nanotubes

Background and Cadmium is a very toxic metal that have adverse effects on human health and aquatic environments even at low concentrations, therefore, efforts should be made to eliminate this metal from aquatic ecosystem. The aim of this study was to investigate the efficacy of L-cysteine functionalized single-walled carbon nanotubes in removing cadmium from aqueous environments. This study also assessed the role of some parameters such as pH, adsorbent dose, contact time and concentration of cadmium. Single-walled carbon nanotubes were functionalized with L-cysteine. Then the optimum level of pH, carbon nanotubes dose, contact time, and cadmium concentration were determined during the adsorption process. The experimental data were compared with the Langmuir and Freundlich adsorption isotherm models. qe increased when the pH level increased, while contact time and Cd concentration decreased by increase in the number of carbon nanotubes. The Langmuir adsorption model agreed well with the experimental data (R2 = 0.997). Efficiency of single-walled carbon nanotubes in optimal condition was 94.26%. The results showed that L-cysteine functionalized single-walled carbon nanotubes could be effective for the removal of cadmium.