Biosorption of some toxic metals by pine nut shell from contaminated waste water
By: Ali Umar, Adnan Sohail, Safdar Javed, Junaid Yaqoob, Abdul Hamid, Tayyeba Arshad, Muhammad Khalid, Muhammad Usman Khan, Muhammad Saleem Khan
Key Words: Heavy metals, Adsorption, Pine nut shell, Biosorption, Contaminated water
J. Bio. Env. Sci. 9(1), 465-473, July 2016.
Adsorption is a cost effective method to remove heavy metals from industrial effluents. This study uses batch adsorption techniques to determine the potential of pine nut shell (PNS) and its thermally treated form i.e. pine nut shell ash (PNSA) as an adsorbent for removal of Cu(II), Pb(II) and Cr(VI). PNS proved to be an appreciable sorbent for the removal of Cu, Pb and Cr metal ions (86%, 93% and 80%) respectively from aqueous solution. The chemical (HNO3 and K2CO3) and thermal activation (873 K for 6 hours) of pine nut shell increased the removal efficiency for toxic metal ions. Metal ion concentration of 9 ppm, 0.5 gram sorbent dose, 20 min agitation time, agitation speed of 100 rpm and 4pH were optimized conditions for sorption process. The sample was characterized by SEM & FTIR. Freundlich, Langmuir and Dubinin–Radushkevich (D-R) sorption isotherms was used to assess the sorption capacity. Adsorption isotherm parameters of Cu(II), Cr(VI) and Pb(II) onto PNS have been found to be 1.12, 1.23, 1.08 mmol g−1 by Freundlich, 0.031, 0.028, 0.026 mmol g-1 by Langmuir and 0.37, 0.39,0.36 mmol g-1 by D–R isotherms respectively. While the mean energy of sorption process 11.18, 15.81, 10.0 kJ mol-1 for Cu (II), Cr(VI) and Pb(II) is calculated by D–R isotherm. This study concluded that, the sorption process by pine nut shell under optimized conditions is stable, spontaneous, and exothermic and can be effectively used in adsorption of toxic metals from contaminated water.