Two-stage Batch Adsorber Design: A Time-Dependent Langmuir Model for Adsorption of Pb2+ and Cd2+ onto Modified Kaolinite Clay

作者：Unuabonah E I^*; Adebowale K O; Ofomaja A E

来源：Water, Air, and Soil Pollution, 2009, 200(1-4): 133-145.

DOI：10.1007/s11270-008-9899-1

• Adsorption
• Kaolinite
• Kinetic
• Optimized
• Two-stage
• Contact time

The kinetics of the adsorption of Pb2+ and Cd2+ by sodium tetraborate (NTB)-modified kaolinite clay adsorbent was studied. A one-stage and two-stage optimization of equilibrium data were carried out using the Langmuir and time-dependent Langmuir models, respectively. Increasing temperature was found to increase the pseudo-second order kinetic rate constant and kinetic data for Pb2+ adsorption were found to fit well with the pseudo-second order kinetic model (PSOM) while that for Cd2+ were found to show very good fit to the modified pseudo-first order kinetic model (MPFOM). Binary solutions of Pb2+ and Cd2+ reduced the adsorption capacity of the modified adsorbent for either metal ion with increased initial sorption rate due to competition of metal ions for available adsorption sites. The use of NTB-modified kaolinite clay adsorbent reduces by approximately 72.2% and 96.3% the amount of kaolinite clay needed to adsorb Pb2+ and Cd2+ from wastewater solutions. From the two-stage batch adsorber design study, the minimum operating time to determine a specified amount of Pb2+ and Cd2+ removal was developed. The two-stage batch adsorption process predicted less than half the minimum contact time to reach equilibrium in the one-stage process for the adsorption of Pb2+ and Cd2+ by NTB-modified kaolinite clay adsorbent and requires 0.05 times the mass of the adsorbent for the single-stage batch adsorption at the same operating conditions.

• 出版日期2009-6
• 单位中国石油大学（北京）