Effect of pH, flow rate and concentration on the sorption of Pb and Cd on montmorillonite: I. Experimental

Altin, O
Ozbelge, OH
Doğu, Timur
Continuous column adsorption of lead (Pb) and cadmium (Cd) was studied using pH adjustment and calcium-saturated montmorillonite in a short stainless steel column. Changing either pH or flow rate, while keeping inlet concentration of the ions constant, led to considerable changes in effluent concentrations and breakthrough curves (BTCs). At low pH values (2-4), H+ ions competed strongly with lead and cadmium ions; at intermediate pH (4-6), ionic size played the major role in adsorption and ion exchange and at high pH (6-9) precipitation was the major process taking place especially for lead sorption. At low flow rates less than 0.5 cm(3) min(-1), sorption of both lead and cadmium increased due to the long retention time in the column. When both lead and cadmium ions were present in the feed, adsorption remained the same while that of cadmium decreased compared with single ion experiments. (C) 1999 Society of Chemical Industry.


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A mathematical model is proposed and compared with experimental data for the migration of heavy metal ions (Pb and Cd) during the flow of aqueous solutions through calcium-saturated montmorillonite packing. The main system parameters are pH, flow rate and concentration. It is assumed that the Liquid phase in the porous montmorillonite can be divided into two regions, mobile and immobile; that adsorption and ion exchange on the clay surface are instantaneous, and that adsorption isotherms are Linear througho...
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Citation Formats
O. Altin, O. Ozbelge, and T. Doğu, “Effect of pH, flow rate and concentration on the sorption of Pb and Cd on montmorillonite: I. Experimental,” JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY, pp. 1131–1138, 1999, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/62845.