ORIGINAL RESEARCH
Cyclical Cadmium Adsorption and Desorption by
Activated Sludge Immobilized on Alginate Carriers
M. Kuczajowska-Zadrożna*, E. Klimiuk, I. Wojnowska-Baryła
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Faculty of Environmental Sciences and Fisheries, Department of Environmental Protection Engineering,
Institute of Ecological Engineering, University of Warmia and Mazury, ul. Warszawska 117a, 10-701 Olsztyn, Poland
Pol. J. Environ. Stud. 2004;13(2):161-169
KEYWORDS
ABSTRACT
This paper concerns cadmium desorption in subsequent cycles of adsorption/desorption by chemical
sorbents such as 2% sodium alginate, sodium alginate with the addition of poly(vinyl) alcohol (PVA) in
the following proportions: 1.5% alginate and 0.5% PVA, 2% alginate and 2% PVA, 2% alginate and 5%
PVA, and two kinds of activated sludge immobilized on alginate sorbents. It was proved that adsorption by
alginate and alginate with PVA obeys a second-order rate law. The higher the PVA amount in alginate, the
lower the reaction rate.
Mineral acids such as hydrochloric and sulphuric acids were used as desorption agents. It was observed
that all sorbents tested remove cadmium with high and almost constant efficiency from the solution containing
50 mgCd/dm3, whereas desorption effectiveness depended on the kind of sorbents and desorbing agents.