A comparative Isothermal and Kinetic Study of the Removal of Lead (II) from Aqueous Solution using different sorbents
Abstract
This study investigated the performance of activated carbon prepared from date pits (ADP), commercial activated carbon (CAC), and zeolite pellets (ZP) in removing lead from aqueous solution. Batch tests were performed to characterize the equilibrium sorption properties of the sorbents. Factorsninfluencing sorption suchias contactitime, initialnpH of theisolution, adsorbentndosage, agitation speed, and initialiconcentration of contaminant have been studied. The sorption data for Pb+2 obtained by batch experiments, have been subjected to the Langmuir, and Freundlich isotherm models. The results showed that the Freundlich isotherm model described well the sorption of contaminant for all sorbent materials. The maximum lead sorption capacities q (mg/g) were measured for the three sorbents and it was found that ADP is more effective foriremovalهof Pb (II) than CAC, and ZP from aqueousisolution with q(mg/g) equal to 24.625, 12.125, and 4.45 mg/g for ADP, CAC, and ZP, respectively. The kinetic data were analyzed using various kineticimodels particularlyipseudo-first-order, pseudo-second-order, and intraparticle diffusion.Theipseudo-first-order kineticnmodel was found tonagree well with thenexperimental data for ADP, and CAC, while for ZP the pseudo-second-order kinetic model agree well with the experimental data.Theiintraparticle diffusion wasithe rate-controllingistep in the sorptioniprocess using ADP and CAC, while the intraparticleidiffusion wasinot the ratecontrollingistep in the sorption process using ZP, with rate constants Kd of 3.459, 1.592, and 0.45 mg g-1 min-0.5 for ADP, CAC, and ZP, respectively.
