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The adsorption characteristics of
As(V) on stem powder of Ficus benghalensis, a low-cost natural
biosorbent, were studied through batch mode of experimental
investigation, resulting into reasonably remarkable As(V) removal
efficiency over a wide range of pH (3.0–11.0). The kinetics studies
evidenced that the removal of As(V) by above-mentioned biosorbent
which is favored by pseudo-first-order kinetics. The equilibrium
data of the adsorption were modeled using Langmuir, Freundlich,
Temkin, and DR isotherm. The adsorption isotherm was well described
by Freundlich isotherm model, with maximum correlation coefficient
(R2 = 0.999), adsorption intensity (n = 1.920), and adsorption
capacity (KF = 1.303). Thermodynamic parameters such as the positive
value of ∆H°, ∆S°, and negative results of ∆G° indicated that
adsorption process is endothermic, increased randomness, and
spontaneous in nature, respectively. The presence of interfering
ions such as anion F- , Cl- , NO3 - , and SO4 2- significantly
reduces the As(V) removal efficiency of the biosorbent while cations
such as Fe(III), Cu(II), Ni(II), Zn(II), Pb(II), Ca2+, and K+
increases the adsorption efficiency. On the other hand, desorption
studies revealed that As(V) can be easily desorbed by (0.1 0.01 M)
HCl and HNO3 and such biosorbent can be reused. |
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Key words: Arsenic,
Biosorbent, Adsorption isotherm, Stem powder of Ficus benghalensis,
Desorption. |
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