This work reports utilization of apple leaves as a source of activated carbon. Activated carbon from apple leaves is prepared by two different methods, thermal activation where AC1 is obtained and chemical activation using H3PO4 and ZnCl2 where AC2 and AC3 are obtained, respectively. XRD analysis revealed that all types of prepared ACs have a semi-crystalline nature with a mean crystallite size of 13, 21.02, and 39.47 nm for AC1, AC2, and AC3, respectively. To identify the most suitable desorption temperature, the exothermic behavior was discovered for the three types of ACs by DSC. The exothermic onset temperatures are 340 °C, 200 °C, 400 °C, or AC1, AC2, and AC3, respectively. The point of zero charge for the three types of ACs is 8.6, 7.3, and 2.5 for AC1, AC2, and AC3, respectively. The BET surface area analysis data demonstrated that mesoporous structure was developed in AC1 and AC2, while a microporous structure was developed in AC3. Quantum chemical calculations for ACs is carried out using Density Functional Theory (DFT). Application of the prepared ACs in adsorption of basic dye C.I. base blue 47 is studied. The maximum removal efficiency was 65.1%, 96% and 99% for AC1, AC2, and AC3, respectively under the influence of different operating aspects. Adsorption data are modeled by Langmuir, Freundlich, and Temkin isotherms. The data revealed that adsorption of basic dye C.I. base blue 47 on AC1 follows Langmuir isotherm and adsorption on AC2 and AC3 follows Freundlich isotherm.

    Abstract
    1 Introduction
    2 Experimental part
        2.1 Materials
        2.2 Activated carbon preparation
        2.3 Sample characterization
    3 Results and discussion
        3.1 XRD analysis
        3.2 FT-IR spectroscopy
        3.3 Differential scanning calorimetry analysis (DSC)
        3.4 BET surface area analysis
        3.5 Point of zero charge 
        3.6 Density functional theory (DFT)
        3.7 Adsorption study
    4 Conclusion
    References

• Mohamed Helmy Abdel‑Aziz(Chemical and Materials Engineering Department, King Abdulaziz University, Chemical Engineering Department, Faculty of Engineering, Alexandria University)
• Elsayed Zakaria El‑Ashtoukhy( Chemical Engineering Department, Faculty of Engineering, Alexandria University)
• Mohamed Bassyouni(Department of Chemical Engineering, Faculty of Engineering, Port Said University, Materials Science Program, Zewail City of Science and Technology, University of Science and Technology)
• Ahmed Farouk Al‑Hossainy(Chemistry Department, Faculty of Science, New Valley University, Chemistry Department, Faculty of Science, Northern Border University)
• Eman M. Fawzy(Faculty of Science and Arts at Al‑Rass, Al‑Rass 51921, Qassim University, Chemistry Department, Faculty of Science, Aswan University)
• Shereen M. S. Abdel‑Hami(Department of Chemical Engineering, The Egyptian Academy for Engineering and Advanced Technology)
• Mohamed Shafick Zoromba(Chemical and Materials Engineering Department, King Abdulaziz University, Chemistry Department, Faculty of Science, Port Said University)