Wisconsin's Role in Great Lakes Restoration - American Water ...

3. Removal of Methylene Blue from Water by Swelling Clays
*Sam Leick, Geosciences Department, University of Wisconsin – Parkside, Kenosha, WI
leick001@uwp.edu
Zhaohui Li, Geosciences Department, University of Wisconsin – Parkside, Kenosha, WI
li@uwp.edu
Extensive but separate studies have been conducted to focus on utilization of swelling clays
to removal cationic dyes from aqueous solution and to investigate the feasibility and
applicability of methylene blue (MB) adsorption for cation exchange capacity (CEC) and
specific surface area (SSA) determination. This research aimed at elucidating the mechanism
of MB adsorption on low charge montmorillonite in order to better understand the principles
behind MB removal using swelling clays and to validate the practices of using MB for CEC
and SSA determination. Stoichiometric desorption of exchangeable cations from the clays
accompanying MB adsorption as well as the close match between the MB adsorption capacity
and the CEC of the clays confirmed cation exchange as the most important mechanism for
MB removal. XRD and TG-DTG analyses revealed interlayer adsorption, thus, intercalation of
MB molecules. FTIR analyses suggested that hydrogen bonding may not play a major role in
MB adsorption. The results confirmed that the charge density, rather than the SSA was the
limiting factor for MB adsorption. For the treatment of wastewater containing cationic dyes,
swelling clays with a high CEC value would result in a greater removal of MB.
*Undergraduate student presentation
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