Preparation, Characterization And Applications Of Activated Carbon From Cocoa (Theobroma Cacao)Nibs Waste
The production of activated carbon in the commercial market is considered expensive. This is because it is made of non-renewable and cost-effective precursor such as bituminous coal. Thus. this study was conducted to assess the potential of cocoa nibs waste as a cheap activated carbon precursor. Th...
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| Summary: | The production of activated carbon in the commercial market is considered expensive.
This is because it is made of non-renewable and cost-effective precursor such as bituminous coal. Thus. this study was conducted to assess the potential of cocoa nibs waste as a cheap activated carbon precursor. The resulting activated carbon can be used to remove the methylene blue dyes, phenol and salicylic acid, and dissolved Paracetamol in aqueous solution. The activated carbon is produced using chemical activation with potassium carbonate (K2CO3) as and activating agent and carbonized in an inert state with the presence of nitrogen gas (N2). The experimental results showed that the carbonization temperatures and K2CO3 impregnation ratios were importantfactors affecting the results and performance of adsorption of methylene blue dyes, phenol, salicylic acid and Paracetamol 1by activated carbon. Activated carbon with high
surface area and highly microporous that were produced with carbonization temperature at 800 oC and impregnation ratio of K2CO3 to charcoal at 3: 1. showed the best adsorption results. This were due to the high surface area of the activated carbon (1.313 m/g) and the micropore surface area was 1,019 m2/g. The prepared activated carbon comprises a mixture of micro- and meso- pores (67% of the micro pore volume) with average pore width (median) of 3.8 nm. It was supported by the results of scanning electron microscope( SEM) that exhibited a carbon surface micrograph with a diverse pore structure. The analysis using Fourier Transform Infrared (FTIR) technique showed the presence of oxygen functional groups on the surface. When activated carbon was treated with hydrochloric acid, the surface area increased to 1,932 m2/g and the
micropore surface area increased to 1,276 m2/g. Eventually, the micropore volume decreased to 57% and the average pore width decreased to 3.3 nm. The adsorption of blue methylene dyes and Paracetamol onto the treated activated carbon showed an increase compared to the untreated activated carbon. The highest removal efficiency for methylene blue dye was recorded at pH 5 while for paracetamol was at pH 3.2. The adsorption process of methylene blue dye was well described by the Langmuir isotherm model .Paracetarno1 adsorption was well described with the Langmuir and Freundlich isoterms. The adsorption mechanisms for both adsorbates (methylene blue and Paracetamol) were best represented by pseudo-second-order kinetic model. |
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