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Preparation of porous carbon from date palm seeds and process optimization
Reddy, K. S. K.; Shoaibi, A. Al & Srinivasakannan, C.
Abstract
The agricultural wastes like date palm seeds to
be a suitable precursor for the preparation of porous carbon
has been explored in the present work, utilizing phosphoric
acid as the activating agent. The experimental methods
reported in literature were chosen with certain modification
in order to simplify the process. The process optimization
was performed using the popular response surface methodology
adopting a Box-Behnken design. Process optimization
was performed to maximize the porous carbon
Brunauer–Emmett–Teller (BET) surface area and the
methylene blue (MB) adsorption capacity, with the process
variables being the activation temperature, impregnation
ratio (IR) and the activation time. The textural characteristics
were assessed based on nitrogen adsorption isotherms,
scanning electron microscopy, while the adsorption
capacity was estimated using the MB adsorption. The
optimized experimental conditions were identified to be an
activation temperature of 500 °C, IR of 3.1 and activation
time of 71.4 min, with the resultant porous carbon having
BET surface area of 846.7 m2/g and MB adsorption
capacity of 445.7 mg/g. The popular Langmuir and
Freundlich adsorption isotherm models were tested, and a
maximum monolayer adsorption capacity of the MB was
estimated to be 345 mg/g, which compares with the highest
of MB reported in literature, evidencing the suitability of
the porous carbon for adsorption of macro-molecular
compounds.
Keywords
Porous carbon; Methylene blue; BET surface area; Optimization
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