Adsorption and Kinetic Study of Activated Carbon Produced from Post-Consumer Low-Density Polyethylene (LDPE) Wastes ()
ABSTRACT
Post-consumer polymeric wastes in form of
low-density polyethylene (LDPE) can now be considered suitable as a precursor
for the synthesis of low-cost activated carbon (AC). This study produced AC
from LDPE using sulphuric acid (H2SO4) and potassium hydroxide (KOH) as the
activating agent. The reaction conditions for pyrolysis were varied in the
range of 0.50 - 2.00 M, 400°C - 500°C, and 45 - 60 minutes. Physico-chemical
investigations reveal that AC yield is significantly dependent on both
carbonization temperatures and time. The obtained optimum values of 446.50°C
and 51.09 mins gave a yield of 24% for the base-activated carbon. The high
iodine numbers obtained strongly indicate the presence of large surface area
and pore volumes is further confirmed using the Scanning Electron Microscopy
(SEM) analysis which reveals the presence of pores on the external surface of
the carbons. Fourier Transform Infrared Technique (FTIR) analysis further shows
that the synthesized compounds are purely carbon with rich oxy-gen-surface
complexes on the surface which is as a result of the introduction of the
chemical oxidizing agents. The produced carbons were found to have high
adsorption affinity for selected inorganic ions which are: Mn7+, Co2+, and
Cr6+. Adsorption isotherm results show the adsorption process to be favourable
with the Langmuir isotherm parameter RL having values of <1, while the
Freudlich adsorption model was found to perfectly fit the data at selected
adsorbent dosages and adsorbate concentrations. The pseu-do-second-order model
provides the best correlation for the kinetic analysis. The acid-activated
carbon was found to have better adsorption capacities than the base-activated
carbon.
Share and Cite:
Alabi-Babalola, O. , Aransiola, E. and Shittu, T. (2021) Adsorption and Kinetic Study of Activated Carbon Produced from Post-Consumer Low-Density Polyethylene (LDPE) Wastes.
Advances in Chemical Engineering and Science,
11, 38-64. doi:
10.4236/aces.2021.111004.