Starting materials are very significant to produce activated carbons because every starting material has a different chemical structure; hence they affect the surface functional groups and surface morphologies of obtained activated carbons. In this study, sycamore balls, ripe black locust seed pods, and Nerium oleander fruits have been used as starting materials by ZnCl2 chemical activations for the first time. Firstly, activated carbons were obtained from these starting materials with ZnCl2 chemical activation by changing production conditions (carbonization time, carbonization temperature, and impregnation ratio) also affecting the structural and textural properties of the resultant activated carbons. Then, the starting materials and resultant activated carbons were characterized by utilizing diverse analysis techniques, such as TGA, elemental analysis, proximate analysis, BET surface areas, pore volumes, pore size distributions, N2 adsorption–desorption isotherms, SEM, FTIR spectra, and H2 adsorption isotherms. The highest surface areas were determined to be 1492.89, 1564.84, and 1375.47 m2/g for the activated carbons obtained from sycamore balls, ripe black locust seed pods, and N. oleander fruits, respectively. The yields of these activated carbons with the highest surface areas were calculated to be around 40%. As the carbonization temperature increased with sufficient ZnCl2 amount, N2 adsorption–desorption isotherms began to turn into Type IV isotherms given by mesoporous adsorbents with its hysteresis loops. Also, their hysteresis loops resembled Type H4 loop generally associated with narrow slit-like pores. Moreover, hydrogen uptakes under 750 mmHg at 77 K were determined to be 1.31, 1.48, and 1.24 wt% for the activated carbons with the maximum surface areas produced from sycamore balls, ripe black locust seed pods, and N. oleander fruits, respectively. As a result, the highest surface areas of the activated carbons with different structural properties produced in this study were obtained with different production conditions.

    Abstract
    1 Introduction
    2 Experimental
        2.1 Materials
        2.2 AC syntheses
        2.3 AC characterizations
    3 Results and discussion
        3.1 TGA and proximate analyses
        3.2 AC yields
        3.3 BET surface areas
        3.4 N2 adsorption–desorption isotherms
        3.5 Pore volumes
        3.6 Pore size distributions
        3.7 Elemental analyses
        3.8 SEM images
        3.9 FTIR spectra
        3.10 Hydrogen adsorptions
        3.11 Relations of different analysis methods
    4 Conclusions
    Acknowledgements 
    References

• Osman Üner(Department of Chemistry, Science and Art Faculty, Kırklareli University)
• Ünal Geçgel(Arda Vocational College, Trakya University)
• Tarık Avcu(Institute of Science, Trakya University)