Surface Modification and Characterization of Coconut Shell-Based Activated Carbon Subjected to Acidic and Alkaline Treatments

  • Tan I. A. W. Department of Chemical Engineering and Energy Sustainability, Universiti Malaysia Sarawak, 94300 Kota Samarahan, Malaysia.
  • Abdullah M. O. Department of Chemical Engineering and Energy Sustainability, Universiti Malaysia Sarawak, 94300 Kota Samarahan, Malaysia.
  • Lim L. L. P. Department of Civil Engineering, Universiti Malaysia Sarawak, 94300 Kota Samarahan, Malaysia
  • Yeo T. H. C. Department of Chemical Engineering and Energy Sustainability, Universiti Malaysia Sarawak, 94300 Kota Samarahan, Malaysia.
Keywords: Activated carbon, Surface modification, Surface characteristics, Surface morphology.


Activated carbon derived from agricultural biomass has been increasingly recognized as a multifunctional material for various applications according to its physicochemical characteristics. The application of activated carbon in adsorption process mainly depends on the surface chemistry and pore structure which is greatly influenced by the treatment method. This study aims to compare the textural characteristics, surface chemistry and surface morphology of coconut shell-based activated carbon modified using chemical surface treatments with hydrochloric acid (HCl) and sodium hydroxide (NaOH). The untreated and treated activated carbons were characterized for their physical and chemical properties including the Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and textural characterization. The FTIR spectra displayed bands confirming the presence of carboxyl, hydroxyl and carbonyl functional groups. The Brunauer–Emmett–Teller (BET) surface area of the untreated activated carbon was 436 m2/g whereas the surface area of the activated carbon modified using 1M NaOH, 1M HCl and 2M HCl was 346, 525 and 372 m2/g, respectively. SEM micrographs showed that many large pores in a honeycomb shape were clearly found on the surface of 1M HCl sample. The pore structure of the activated carbon treated with 2M HCl and NaOH was partially destroyed or enlarged, which decreased the BET surface area. The modification of the coconut shell-based activated carbon with acidic and alkaline treatments has successfully altered the surface functional groups, surface morphology and textural properties of the activated carbon which could improve its adsorptive selectivity on a certain adsorbate.


Bhatnagar, A., Hogland, W., Marques, M. and Sillanpaa, M. (2013). An overview of the modification methods of activated carbon for its water treatment applications, Chem. Eng. J. 219, 499-511.

Botomé, M.L., Poletto, P., Junges, J., Perondi, D., Dettmer, A. and Godinho, M. (2017). Preparation and characterization of a metal-rich activated carbon from CCA-treated wood for CO2 capture, Chem. Eng. J. 321, 614-621.

Björklund, K. and Li, L.Y. (2017). Adsorption of organic stormwater pollutants onto activated carbon from sewage sludge, J. Environ. Manage. 197, 490-497.

Kumar, A. and Jena, H.M. (2017). Adsorption of Cr(VI) from aqueous phase by high surface area activated carbon prepared by chemical activation with ZnCl2, Process Safety Environ. Protection 109, 63-71.

Ncibi, M.C. and Sillanpää, M. (2017). Optimizing the removal of pharmaceutical drugs Carbamazepine and Dorzolamide from aqueous solutions using mesoporous activated carbons and multi-walled carbon nanotubes, J. Molecular Liquids 238, 379-388.

Tan, I.A.W., Ahmad, A.L. and Hameed, B.H. (2008). Adsorption of basic dye on high-surface-area activated carbon prepared from coconut husk: Equilibrium, kinetic and thermodynamic studies, J. Hazard. Mater. 154, 337-346.

Chun, Y.Y., Aroua, M.K. and Daud, W.M.A.W. (2007). Review of modification of activated carbon for enhancing contaminant uptakes from aqueous solutions, Sep. Purif. Technol. 52, 403-415.

Figueredo, J.L., Pereira, M.F.R., Freitas, M.M.A. and O'rfao, J.J.M.O. (1999). Modification of the surface chemistry of activated carbons, Carbon 37, 1379-1389.

Shen, W., Li, Z. and Liu, Y. (2008). Surface chemical functional groups modification of porous carbon, Recent Patents Chem. Eng. 1, 27-40.

Park, S.J. and Jang, Y.S. (2002). Pore structure and surface properties of chemically modified activated carbons for adsorption mechanism and rate of Cr (IV), J. Colloid Interf. Sci. 249, 458-463.

Ahmad, A.L., Loh, M.M. and Aziz, J.A. (2007). Preparation and characterization of activated carbon from oil palm wood and its evaluation on methylene blue adsorption, Dyes Pigments 263, 263-272.

Babatunde, O.A., Garba, S. and Ali, Z. N. (2016). Surface modification of activated carbon for improved iodine and carbon tetrachloride adsorption, Am. J. Chem. 6, 74-79.

Shim, J.W., Park, S.J. and Ryu, S.K. (2001). Effect of modification with HNO3 and NaOH on metal adsorption by pitch-based activated carbon fibers, Carbon 39, 1635-1642.

Zawadzki, J. (1989). Infrared spectroscopy in surface chemistry of carbons, Chem. and Phys. Carbon 21, 147-380.

Jia, Y.F. and Thomas, K.M. (2000). Adsorption of cadmium ions on oxygen surface sites in activated carbon, Langmuir 16, 1114-1122.

Chiang, H.L., Huang, C.P. and Chiang, P.C. (2002). The surface characteristics of activated carbon as affected by ozone and alkaline treatment, Chemosphere 47, 257-265.

Li, L., Liu, S. and Liu, J. (2011). Surface modification of coconut shell based activated carbon for the improvement of hydrophobic VOC removal, J. Haz. Mater. 192, 683-690.

Yakout, S.M., Daifullah, A.E.H.M. and El-Reefy, S.A. (2015). Pore structure characterization of chemically modified biochar derived from rice straw, Environ. Eng. Manage. J. 14, 473-480.

Vladimir, S.J. and Malik, D. (2002). Characterization and metal sorptive properties of oxidized active carbon, J. Colloid Interf. Sci. 250, 213-220.

Lua, A.C. and Guo, J. (2001). Preparation and characterization of activated carbons from oil-palm stones for gas-phase adsorption, Colloid. Surface. A 179, 151-162.

El-Guendi, M. (1991). Homogeneous surface diffusion model of basic dyestuffs onto natural clay in batch adsorbers, Adsorpt. Sci. Technol. 8, 217-225.

Gregg, S.J. and Sing. K.S.W. (1982). Adsorption, Surface Area and Porosity. London: Academic Press.

How to Cite
I. A. W., T., M. O., A., L. L. P., L., & T. H. C., Y. (2017). Surface Modification and Characterization of Coconut Shell-Based Activated Carbon Subjected to Acidic and Alkaline Treatments. Journal of Applied Science & Process Engineering, 4(2), 186-194.