ORIGINAL RESEARCH
The Effect of Poly(vinyl Alcohol)
on Cadmium Adsorption and Desorption
from Alginate Adsorbents
E. Klimiuk, M. Kuczajowska-Zadrożna
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Faculty of Environmental Sciences and Fisheries, Department of Environmental Protection Engineering,
Institute of Ecological Engineering
University of Warmia and Mazury, Prawoche.skiego 10, 10-957 Olsztyn, Poland
Pol. J. Environ. Stud. 2002;11(4):375-384
KEYWORDS
ABSTRACT
Cadmium adsorption onto and desorption from sodium alginate and sodium alginate with poly(vinyl
alcohol) (PVA) were studied. Intraparticular diffusion was demonstrated to limit adsorption kinetics during
the first 20 min of process. The Deff value was dependent on adsorbent chemical composition and ranged
from 3.35 ´ 10-10 m2/s to 1.86 ´ 10-10 m2/s for the 1.5% alginate with 0.5% PVA and for the 2% alginate with
5% PVA, respectively.
At equilibrium the adsorption was more effective onto the 2% alginate and was lower for the alginate
sorbent containing poly(vinyl alcohol). The dimensionless separation factor RL increased from 0.26 to 0.68
for the 2% alginate and the 2% alginate + 5% PVA, respectively. The maximum adsorption capacities in
Langmuir isotherm for both the 2% and 1.5% alginate with 0.5% PVA were similar and were 176 and 178
mg/g dry weight, respectively. However, the adsorption capacity decreased to 48 mg/g dry weight for the 2%
alginate with the 5% PVA (in proportion to the polymer amount increase in the adsorbent).
Cadmium desorption was more effective for nitric acid than for sulfuric and hydrochloric acids (desorption
pH 2.2). More cadmium was desorbed from 2% alginate with 5% PVA than from 2% alginate or 1.5%
alginate with 0.5% PVA.