Abstract:
Eragrostis tef (Teff) is one of the most important staple crops in
Ethiopia. The straw obtained from teff is a plentiful source of
lignocellulosic biomass. In the present study, straw obtained
from teff grass was exploited as a carbon precursor to synthe sise the activated carbon via chemical activation followed by
microwave-aided pyrolysis. The prepared activated carbon by
microwave aided method from teff straw (MATSAC) was uti lised as a bio-adsorbent to examine the lead II ions adsorption
potential from the aqueous medium. RSM technique was
employed to explore a process model which correlates the
four independent variables namely Pb(II) ions initial concentra tion, MATSAC dose, adsorption time, and solution pH. Further,
the model was statistically optimised to achieve optimum
Pb(II) ions removal. They were discovered to be Pb(II) ions
initial concentration: 94.35 mg/L, MATSAC dose: 0.655 g/
100 mL, adsorption time: 87.6 min, and solution pH: 5.4 to
achieve the maximised removal of Pb(II) (90.89%). In the inves tigation on the models of isotherm, it was inferred that
Langmuir isotherm fitted excellently to the equilibrium data
of the adsorption. The adsorption capacity of Pb(II) on MATSAC
was 42.97 mg/g. In addition, the kinetic analysis confirmed
that the process of adsorption was statistically significant to
pseudo 2nd order. The thermodynamic study indicated that the
negative value of ∆Go deep-rooted the practicability and spon taneity of MATSAC for Pb(II) ions removal. In a nutshell,
MATSAC, which is derived from locally available agricultural
waste, can remove toxic Pb(II) ions from contaminated water
at a minimal cost.
