Comparative adsorption mechanism of rice straw activated carbon activated with NaOH and KOH
Activated carbon (AC) was produced from rice straw via a two-step method. Potassium hydroxide (KOH) and sodium hydroxide (NaOH) were used as activating agent. The activated carbon (AC) samples were used as adsorbent to remove methylene blue (MB) from aqueous solution. Characterizations using a sca...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Penerbit Universiti Kebangsaan Malaysia
2020
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| Online Access: | http://journalarticle.ukm.my/16002/ http://journalarticle.ukm.my/16002/1/11.pdf |
| Summary: | Activated carbon (AC) was produced from rice straw via a two-step method. Potassium hydroxide (KOH) and sodium
hydroxide (NaOH) were used as activating agent. The activated carbon (AC) samples were used as adsorbent to remove
methylene blue (MB) from aqueous solution. Characterizations using a scanning electron microscope (SEM), BrunauerEmmett-Teller surface area (BET), and Fourier transform infrared (FTIR) spectroscopy were performed on the samples
before the MB adsorption experiments. The adsorption isotherms and kinetics analyses were carried out under
different conditions of pH, temperature, and MB concentration to study the adsorption efficiency of the samples against
the MB solution. The adsorption kinetics of both activated carbon samples followed the pseudo-second-order model.
The adsorption capacity of the KOH rice straw activated carbon towards MB achieved a maximum adsorption 588
mg/g as compared to 232 mg/g of the NaOH rice straw activated carbon. The intraparticle diffusion model indicated
that the adsorption process of the activated carbon samples toward MB included the external mass transfer and
diffusion of MB molecules into the adsorbents. Adsorption isotherm results for MB on the activated carbon samples fit
the Langmuir isotherm, suggesting monolayer adsorption during the adsorption process. |
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