Lala clam (Orbicularia orbiculata) shell as an eco-friendly adsorbent for Cd(II), Cu(II) and Pb(II) ions

Abstract

In this study, the effectiveness of lala clam (Orbicularia orbiculata) shell, a fishery waste, as an adsorbent for removal of Cd(II), Cu(II) and Pb(II) ions from contaminated water was evaluated by characterization and adsorption studies. The characterization study was performed using Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray (EDX) Spectroscopy and Fourier Transform Infrared (FTIR) Spectroscopy techniques. The effects of solution pH (pH 1.0 to 6.0), adsorbent dosage (0.125 to 0.750 g) and initial adsorbate concentration (10 to 200 mg/L) on adsorption capacity of lala clam shell were studied. The capability of lala clam shell to remove metal ions from aqueous solution was assessed in both single- and mix-metal systems. The adsorption equilibrium data were fitted to Freundlich and Langmuir isotherm models. At an optimum solution pH of 6.0 and initial metal ion concentration of 200 mg/L, the maximum adsorption capacity (Qmax) values of Cd(II), Cu(II) and Pb(II) ions were determined as 66.66, 64.94 and 100.00 mg/g, respectively. The removal performance of lala clam shell (63.80 to 93.79%) for metal ions from battery manufacturing wastewater was comparable to that of three commercial activated carbons derived from olive tree wood (73.01 to 94.83%), coconut shell (68.10 to 95.17%) and bamboo (69.33 to 94.48%), which are commonly used for water treatment in Libya, Malaysia and Indonesia, respectively. The results obtained from this study suggest that lala clam shell exhibits a great potential to be used as an effective alternative to expensive adsorbents for water treatment.