Aca. Dacosta et al., BATCH AND CONTINUOUS HEAVY-METALS BIOSORPTION BY A BROWN SEAWEED FROMA ZINC-PRODUCING PLANT, Minerals engineering, 9(8), 1996, pp. 811-824
Citations number
12
Categorie Soggetti
Engineering, Chemical","Mining & Mineral Processing",Mineralogy
The removal of heavy metals by a dry biomass of a brown seaweed was ev
aluated. A continuous system was used, with an effluent from a Brazili
an zinc-producing industry, containing zinc (88.0 mg/L), cadmium (1.4
mg/L), and manganese (11.7 mg/L), as well as high levels of calcium (4
44 mg/L), magnesium (100 mg/L) and sodium (37.0 mg/L). Preliminary res
ults, in batch conditions, indicated fast uptake kinetics for the heav
y metals, whose equilibria were reached in a maximum of 30 minutes. Th
e continuous run was conducted in a laboratory acrylic column, 1m high
, containing several samplers, filled with the dry biomass. The system
operated in upflow condition, at a flow rate of 25 mL/min, for approx
imately 70 hours, with high operational stability. The results showed
high efficiency in the biosorption of heavy metals. Sodium, calcium an
d magnesium were not incorporated by the biomass, probably as they are
present in the structural polysaccharides of the biomass, thus preven
ting the establishment of an effective ion-exchange process. Analysis
of the obtained results did not indicate selective uptake of the metal
s, probably due to their marked concentration differences in solution.
The continuous laboratory system initially showed an efficiency close
to 100% in the biosorption of all heavy metals, followed by a gradual
decrease, as a function of the saturation of binding sites in the bio
mass. A mathematical adjustment of the curves obtained for the uptake
of the different metals was used for estimating the amount of biosorbe
d metals, through mathematical computer integration. Copyright (C) 199
6 Elsevier Science Ltd