Cadmium biosorption potential of shell dust of the fresh water invasive snail Physa acuta

The ability of shell dust (PSD) of an invasive freshwater snail (Physa acuta) to remove cadmium from contaminated water was evaluated. The results indicate that PSD, a waste biomaterial, bear potential of cadmium removal from contaminated water with biosorption capacity of 16.66 mg g−1 at pH 6. The adsorption data at equilibrium fitted significantly more to Langmuir (R2 = 0.996) than Freundlich equations (R2 = 0.969). The kinetics of the adsorption process followed the pseudo-second order model (R2 = 0.996) better than the Lagergren model (R2 = 0.833). The FT-IR analyses support that the main mechanism of biosorption was cadmium chelating with different functional groups such as OH, CO, CC, and CC. The result obtained from the experiments show that the PSD can be used as an efficient, low cost, environmentally friendly biosorbent for cadmium from aqueous solution.