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

✍ Scribed by Orhan Altin; Onder H Ozbelge; Timur Dogu

• Publisher: Wiley (John Wiley & Sons)
• Year: 1999
• Tongue: English
• Weight: 128 KB
• Volume: 74
• Category: Article
• ISSN: 0268-2575
• DOI: 10.1002/(sici)1097-4660(199912)74:12<1139::aid-jctb159>3.0.co;2-q

✦ Synopsis

A mathematical model is proposed and compared with experimental data for the migration of heavy metal ions (Pb and Cd) during the ¯ow of aqueous solutions through calcium-saturated montmorillonite packing. The main system parameters are pH, ¯ow 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 throughout the modelling considered. The Ranges of experimental parameters are: pH 2.5±7.3, solution ¯ow rate of 0.1±1 cm 3 min À1 and heavy metal concentrations of 5±10 ppm. Breakthrough curves (BTCs) obtained experimentally are affected by changes in pH and ¯ow rates. Between pH 2.5 and 4, the model equations describe the process quite well but from 4 to 7 a large deviation between the model and experimental data is observed due to precipitation of metals.