Chin.J.Chem.Eng. ›› 2018, Vol. 26 ›› Issue (5): 1003-1011.doi: 10.1016/j.cjche.2017.11.004

• Separation Science and Engineering • Previous Articles     Next Articles

Synthesis of activated carbon from spent tea leaves for aspirin removal

Syieluing Wong1, Yowjeng Lee1, Norzita Ngadi1, Ibrahim Mohammed Inuwa2, Nurul Balqis Mohamed1   

  1. 1 Department of Chemical Engineering, Faculty of Chemical and Energy Engineering, Universiti Teknologi Malaysia, Malaysia;
    2 Department of Industrial Chemistry, Kaduna State University, Kaduna, Nigeria
  • Received:2017-07-05 Revised:2017-11-07 Online:2018-05-28 Published:2018-06-29
  • Contact: Norzita Ngadi,E-mail

Abstract: Adsorption capacity of activated carbon prepared from spent tea leaves (STL-AC) for the removal of aspirin from aqueous solution was investigated in this study. Preliminary studies have shown that treatment with phosphoric acid (H3PO4) increased removal efficiency of STL-AC. Characterizations on STL-AC revealed excellent textural properties (1200 m2·g-1, 51% mesoporosity), as well as distinctive surface chemistry (1.08 mmol·g-1 and 0.54 mmol·g-1 for acidic and basic oxygenated groups, pHpzc=2.02). Maximum removal efficiency of aspirin observed was 94.28% after 60 min when the initial concentration was 100 mg·L-1, 0.5 g of adsorbent used, pH 3 and at a temperature of 30℃. The adsorption data were well fitted to the Freundlich isotherm model and obeyed the pseudo-second order kinetics model. The adsorption of aspirin onto STL-AC was exothermic in nature (ΔHΘ=-13.808 kJ·mol-1) and had a negative entropy change, ΔSΘ (-41.444 J·mol-1). A negative Gibbs free energy, ΔGΘ was obtained indicating feasibility and spontaneity of the adsorption process. The adsorption capacity of AC-STL (178.57 mg·g-1) is considerably high compared to most adsorbents synthesized from various sources, due to the well-defined textural properties coupled with surface chemistry of STL-AC which favors aspirin adsorption. The results demonstrate the potential of STL-AC as aspirin adsorbent.

Key words: Activated carbon, Spent tea leaves, Aspirin, Adsorption, Kinetics, Isotherm