Polyaniline/akaganéite superparamagnetic nanocomposite for cadmium uptake from polluted water

The uptake of low concentration toxic cadmium ions from polluted water by polyaniline/akaganéite superparamagnetic nanocomposite was investigated. Akaganéite superparamagnetic nanoparticles (NPs) and polyaniline (PANI) doped with hydrochloric acid were synthesized by co-precipitation and chemical polymerization methods, respectively. Polyaniline/akaganéite superparamagnetic nano-composite was formed using facile polymerization method. High resolution transmission microscope image of PANI/akaganéite nanocomposite revealed that it is composed of sheets of spherical shaped PANI as a matrix including nanocrystals of akaganéite NPs. These sheets have diameter ranging from 9.03 to 16.10 nm. It was noted that the hysteresis loops of akaganéite NPs and PANI/akaganéite nanocomposite shows no remanence or coercivity, suggesting a superparamagnetic property with magnetization saturation values of 45.66 and 52.73 emu g–1, respectively. The effect of pH solution, initial Cd(II) concentration, nanocomposite amount and adsorption time on the efficiency of Cd(II) uptake was studied. The amount of 0.4 g L–1 of polyaniline/akaganéite nanocomposite was found to be sufficient to remove 94.7% from 25 ml of polluted solution of 5.0 mg L–1 Cd(II) ions at pH 7.0 for 5 min contact time at ambient temperature. It was observed that Langmuir maximum adsorption capacity of PANI/akaganéite nanocomposite was 33.7 mg g–1.