Adsorption characteristics of Pb(Ⅱ) ions onto wasted iron ore tailing with phosphorus used as natural adsorbent from aqueous solution

摘要

Iron ore tailing with phosphorus (IOTP), as industrial solid waste was used to remove Pb(II) ion from aqueous solution. Factors influencing the adsorption process were analyzed, and the related adsorption mechanism was discussed. The results indicate that the adsorption of Pb(II) ion onto IOTP is strongly dependent with pH value of the solution. An optimum adsorption capability is achieved at pH = 6.0. Complexation acts the vital mechanism for Pb (II) ion removal when pH varies from 1.5 to 7.0. While chemical precipitation plays an important role with pH rising beyond 7.0. Kinetic studies show that the removal of Pb(II) ion by IOTP is rapid with the removal capacity over 95% in 30 min. Adsorption kinetics follow the pseudo-second-order model. Langmuir and Freundlich isothermals are used to simulate equilibrium adsorption data, and it fits well with Langmuir isothermal model. The maximum capacity of adsorption is found to be 17.03 mg/g at 60 degrees C. Thermodynamic study reveals that Pb (II) ion adsorption is spontaneous and endothermic. IOTP is a promising material for Pb (II) ion removal in wastewater treatment, due to the possession of both low cost and high adsorption capability.