Applied Chemical Engineering

Acid-activated carbon from Coconut Shell waste for effective removal of Toxic Malachite green dye from aqueous medium and study of regenerative Cycles.

Shaimaa Mohsen Essa

Department of Chemistry, College of Education, University of Al-Qadisiyah, Al-Qadisiyah, Iraq

Aseel M. Aljeboree

Department of chemistry, college of sciences for women, University of Babylon, Iraq

Mohammed Abed Jawad

Department of Medical Laboratories Technology, Al-Nisour University College, Nisour Seq. Karkh, Baghdad, Iraq

Ayad F. Alkaim

Department of chemistry, college of sciences for women, University of Babylon, Iraq

DOI: https://doi.org/10.59429/ace.v8i2.5687

Keywords: Adsorption; dye; malachite green (MG); mechanism, agricultural waste; regeneration

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Abstract

A preparation of activated carbon from coconut shell residue, activated by phosphoric acid. By controlling the ratio of phosphoric acid to coconut shell mass and activation temperature, the textural property and surface chemistry of the prepared activated carbon could be optimized. Characterization results of FESEM and TEM showed that the as-prepared AC had a perfect porous structure and rich surface functional groups. The moderate acid dosages were conducive to the creation of a well-developed porous structure and the incorporation of favorable acidic surface function groups, which is beneficial for excellent adsorption capability. The optimal phosphoric acid loading also reduced the effectiveness of activation if the loading was too high. The over-acidification of the biomass led to extensive crosslinking and the collapse or blockage of micropores, resulting in a decrease in specific surface area and pore volume. This also led to a reduction in the adsorption of the activated carbon. The activated carbon achieved a high adsorption capacity for malachite green (MG), reaching 90.88%. The reuse of the adsorbent was studied by regeneration with three types of eluents: deionised water (neutral), 0.1 M NaOH (alkaline), and 0.1 M HCl (acidic). Among the three, the acidic regeneration agent (HCl) was the most effective in restoring the adsorption performance, surface features, and structural integrity of active sites during the recycling operation. These results highlight the potential of phosphoric acid-activated coconut shell as a sustainable and efficient material for large-scale treatment of dye wastewater, as well as the valorisation of agricultural residues.

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