by Kratochvil and Volesky (1998). Hence this species seem
to be a good biosorbent for Pb2? as it has high qmax and
low b. Oscillatoria laete-virens was also found to be a good
biosorbent of Cr6? from aqueous solutions (Miranda et al.
2012).
Using Langmuir adsorption isotherm, the obtained qmax
values for viable Lyngbya majuscula and Spirulina subsalsa
were 20.96 and 16.72 mg g-1 respectively in 250 mg
L-1 of Pb2? solution (Chakraborty et al. 2011). Raungsomboon
et al. (2008) reported a qmax as high as
232.56 mg g-1 in Gloeocapsa sp. Live Oscillatoria sp.
NTMS01 and Phormidium sp. NTMS02 have shown a qmax
value of 86.20 and 92.592 mg g-1 respectively (Kumar
et al. 2011). Calothrix marchica cells adsorbed
3.42 mg g-1 of lead (Ruangsomboon et al. 2007). However,
the qmax reported in the present study is much lower
than some of the cyanobacteria reported earlier. But, the
The maximum adsorption capacity (qmax) is 20.36 mg g-1,
which is almost similar to the experimental value
(21.6 mg g-1) indicating that the isotherm data fitted well
to the Langmuir plot. The maximum adsorption capacity
(Kf) of lead ions based on Freundlich model, the adsorption
intensity value (n), and determination coefficient are given
in Table 7. Although the value of n is greater than 1, the Kf
value (5.12 mg g-1) is by far, much lower than the
experimental adsorption capacity, which indicates that the
adsorption of lead ions does not fit well with Freundlich
model.