TY - JOUR
T1 - A comparative study on metal sorption by brown seaweed
AU - Tsui, Martin T.K.
AU - Cheung, K. C.
AU - Tam, Nora F.Y.
AU - Wong, M. H.
N1 - Funding Information:
The authors thank Mr. Ben Yeung for collecting the macroalga and Mr. Eric Yuen for providing analytical support. Two anonymous reviewers and Dr. Silke Schiewer provided useful comments on this work. This study was fully supported by the Area of Excellence Scheme under the University Grants Committee of the Hong Kong Special Administrative Region, PR China (CityU, Project No. AoE/P-04/04).
PY - 2006/9
Y1 - 2006/9
N2 - This study compared the sorption of Ag, Cd, Co, Cd, Mn, Ni, Pb and Zn by a Ca-treated Sargassum biomass at pH 5.0, under low and high ionic strength (IS) conditions. The sorption isotherms of As [As(V)] and Cr [Cr(III) and Cr(VI)] were also determined at low IS. The isotherm data for the eight cationic metals and Cr(III) were well fitted by Langmuir equations. Generally, the maximum metal uptake (Umax) followed: Cr(III) > Pb ∼ Cu > Ag ∼ Zn ∼ Cd > Ni ∼ Mn ∼ Co ≫ Cr(VI) ≫ As(V) at low IS and Pb > Cu > Co > Mn ∼ Cd > Zn ∼ Ag > Ni at high IS. As(V) did not bind to the seaweed at pH 5.0. The results indicated that sorption of Pb was not affected by the increasing IS, though the percentage of free Pb ions in the water was greatly reduced as predicted by the speciation model. High IS lowered Umax by 10-36% (except Co and Pb), and lowered the affinity constant of the metal by 33-91% for all cationic metals, as compared to low IS. Moreover, the removal efficiency of the cationic metals and Cr decreased exponentially with initial metal concentrations and was lower at high IS. Ion-exchange was the mechanism responsible for the cationic metal sorption onto the seaweed, and Na ion interfered with the cationic metal binding through electrostatic interaction. In conclusion, this study showed the differential binding capacity of the Sargassm biomass for different metals and oxidation states and the differential effects of IS. According to the present results, Sargassum may be considered a good biosorbent for cationic metals (especially Pb) in both low and high-salt containing wastewater.
AB - This study compared the sorption of Ag, Cd, Co, Cd, Mn, Ni, Pb and Zn by a Ca-treated Sargassum biomass at pH 5.0, under low and high ionic strength (IS) conditions. The sorption isotherms of As [As(V)] and Cr [Cr(III) and Cr(VI)] were also determined at low IS. The isotherm data for the eight cationic metals and Cr(III) were well fitted by Langmuir equations. Generally, the maximum metal uptake (Umax) followed: Cr(III) > Pb ∼ Cu > Ag ∼ Zn ∼ Cd > Ni ∼ Mn ∼ Co ≫ Cr(VI) ≫ As(V) at low IS and Pb > Cu > Co > Mn ∼ Cd > Zn ∼ Ag > Ni at high IS. As(V) did not bind to the seaweed at pH 5.0. The results indicated that sorption of Pb was not affected by the increasing IS, though the percentage of free Pb ions in the water was greatly reduced as predicted by the speciation model. High IS lowered Umax by 10-36% (except Co and Pb), and lowered the affinity constant of the metal by 33-91% for all cationic metals, as compared to low IS. Moreover, the removal efficiency of the cationic metals and Cr decreased exponentially with initial metal concentrations and was lower at high IS. Ion-exchange was the mechanism responsible for the cationic metal sorption onto the seaweed, and Na ion interfered with the cationic metal binding through electrostatic interaction. In conclusion, this study showed the differential binding capacity of the Sargassm biomass for different metals and oxidation states and the differential effects of IS. According to the present results, Sargassum may be considered a good biosorbent for cationic metals (especially Pb) in both low and high-salt containing wastewater.
KW - Biosorption
KW - Heavy metals
KW - Ion exchange
KW - Ionic strength
KW - Sargassum hemiphyllum
UR - http://www.scopus.com/inward/record.url?scp=33746342833&partnerID=8YFLogxK
U2 - 10.1016/j.chemosphere.2006.03.002
DO - 10.1016/j.chemosphere.2006.03.002
M3 - Journal article
C2 - 16631232
AN - SCOPUS:33746342833
SN - 0045-6535
VL - 65
SP - 51
EP - 57
JO - Chemosphere
JF - Chemosphere
IS - 1
ER -