Optimisation and Surface Morphological Analysis Of Activated Carbon from Agricultural Waste Products
Date
2017-07
Authors
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Publisher
University Of Ghana
Abstract
Many conventional or agricultural by-products and wastes go unused in Ghana. These
wastes find their way into our water bodies and also sometimes become breeding grounds
for mosquitoes and other insect pest causing diseases leading to severe health problems.
These wastes sometimes are used as fillers in pot-holes which inadvertently blocks
drainages during rainfall thereby leading to flooding in flood prone areas. The precursors
used in this study to produce activated carbon were palm kernel shell and coconut shell.
The produced activated carbon was activated chemically using three different activating
agents, acid (H3PO4), base (NaOH) and a salt (CaCl2). The maximum yield of activated
carbon, 26.3 g (PKS) and 22.9 g (CS), using H3PO4 as an activating agent were obtained at
400 oC, 1 h carbonisation time and an impregnation ratio of 1.2. Similarly, maximum yield
of activated carbon, 22.4 g (PKS) and 17.3 g (CS), using NaOH as an activating agent was
also obtained at 500 oC, 2.5 h and impregnation ratio of 1.2. Using CaCl2 as activating
agent, the maximum yield of activated carbon were 25.5 g (PKS) and 20.8 g (CS), these
maximum values corresponded to 400 oC, 1 h carbonisation time and an impregnation ratio
of 1.2. The H3PO4 activated carbons were fairly better in the areas of ash content (7.17 %),
moisture content (1.94 %), bulk density (0.65 g/cm3), pore volume (0.94 ml/g), iodine
adsorption (743.02 mg/g) and porosity (0.49). On the other hand, the NaOH activated
carbon was also advantageous in terms of carbon content (57.78 %). CaCl2 activated
carbons, were also commendable in terms of volatile matter (30.46 %) and electrical
conductivity (2130 μS/cm). Scanning Electron Microscopy (SEM) technique was
employed to observe the surface physical morphology of the coconut shell and palm kernel
shell activated carbons. Prior to chemical activation the surface morphology of the raw
coconut shell compared to the palm kernel shell at a magnification of ×5000 did not show
porous surface, while the external surfaces of the chemically activated carbon were rich
with cavities.
Description
Keywords
Morphological Analysis, Activated Carbon, Agricultural Waste Products, agricultural by-products