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Adsorption of heavy metals from multi-metal aqueous solution by sunflower plant biomass-based carbons
Jain, M.; Garg, V.K.; Kadirvelu, K. & Sillanpää, M.
Abstract
This study reports the competitive adsorption
of Ni(II), Cd(II) and Cr(VI) onto sunflower waste biomass
carbons, viz. sunflower head carbon and sunflower stem
carbon from multi-metal aqueous solution. The adsorption
capacity of the adsorbents was highest in mono-metal
system but decreased with increase in the number of coions.
The adsorption capacity in mono-metal system was
0.32 and 0.44 mM/g for Ni(II), 0.25 and 0.32 mM/g for
Cd(II) and 0.20 and 0.28 for Cr(VI) by sunflower head
carbon and sunflower stem carbon, respectively, whereas,
in a binary system, adsorption capacity of sunflower head
carbon for Ni(II) was 0.24 mM/g in 0.5 mM Cd(II) solution
which was further reduced to 0.18 mM/g in 2.0 mM
Cd(II). The effect of co-cations was more pronounced in
tertiary systems. Similar behavior was observed for other
systems also. The interactive effect of multi-metal ions in
binary and tertiary component systems was antagonistic in
nature, i.e., the effect of mixture is less than the sum of
individual effect of the constituents or when the effect of
individual substances added together is less than the
expected in response to multiple substances. Langmuir
model best fitted the data for all the systems with r2 value
>0.95.
Keywords
Competitive adsorption; Chromium; Cadmium; Nickel; Helianthus annuus
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