This study investigates the adsorption performance of G-BAC, a spherical activated carbon produced by Kureha Corporation, for the removal of heavy metals including arsenic (As), thallium (Tl), selenium (Se), and antimony (Sb). G-BAC is manufactured from petroleum pitch through a binder-free synthesis with a highly uniform morphology and excellent mechanical stability. Three replicates were prepared for each metal. Each replicate consisted of approximately 0.1 grams of G-BAC contacted with 0.5 mL of an aqueous solution containing the metal at an initial concentration of 700–800 ppm. The pH was adjusted close to neutrality. The samples were agitated mechanically at room temperature for 24 hours, then centrifuged to separate the solid and liquid phases. The solid residues were dried and analyzed using thermal analysis techniques (TG, DTG, DTA) and X-ray diffraction (XRD). At the same time, the liquid phase was examined by inductively coupled plasma mass spectrometry (ICP-MS). Thermal analyses revealed alterations in the profiles of the post-adsorption samples, suggesting structural changes in the material due to metal interaction. Notably, DTG and DTA spectra exhibited slight but consistent shifts in thermal signals, indicating modifications in the decomposition behavior of surface functional groups. XRD analysis revealed three characteristic peaks of the G-BAC structure [1], which were shifted in all metal-treated samples. In particular, the first peak moved to higher angles, indicating a reduction in interlayer spacing as calculated via Bragg’s law. This shift was most pronounced in the arsenic-treated sample, implying a deeper or more invasive structural interaction. Possible explanations for this phenomenon include: (i) the formation of bonds between heavy metals and oxygen-containing surface functional groups, leading to partial collapse of graphitic microstructures and/or (ii) the removal of interlayer species (e.g., water, oxygen), resulting in closer stacking of graphene layers [2]. ICP-MS analysis of the post-treatment solutions confirmed effective metal removal, except in the case of antimony, for which inconsistent results were probably due to its chemical instability in solution. The removal percentages indicate high adsorption efficiency, especially for arsenic. These results emphasize the potential of G-BAC as an effective adsorbent for the removal of heavy metals from aqueous solutions and support further research on the structural modifications induced by adsorption processes. [1] Wibawa P.J., Nur M., Asy’ari M., Nur H. SEM, XRD and FTIR analyses of both ultrasonic and heat generated activated carbon black microstructures, 2020. Heliyon 3, 6. https://doi.org/10.1016/j.heliyon.2020.e03546 [2] Fisher K., Vreugdenhil A.. Metal-Impregnated Petroleum Coke-Derived Activated Carbon for the Adsorption of Arsenic in Acidic Waters, 2023. ACS Omega, 32, 8. https://doi.org/10.1021/acsomega.3c02078
Study on Heavy Metals Adsorption using spherical activated carbon (G-BAC)
Luca, Adami
;Maura, Mancinelli;Annalisa Martucci
2025
Abstract
This study investigates the adsorption performance of G-BAC, a spherical activated carbon produced by Kureha Corporation, for the removal of heavy metals including arsenic (As), thallium (Tl), selenium (Se), and antimony (Sb). G-BAC is manufactured from petroleum pitch through a binder-free synthesis with a highly uniform morphology and excellent mechanical stability. Three replicates were prepared for each metal. Each replicate consisted of approximately 0.1 grams of G-BAC contacted with 0.5 mL of an aqueous solution containing the metal at an initial concentration of 700–800 ppm. The pH was adjusted close to neutrality. The samples were agitated mechanically at room temperature for 24 hours, then centrifuged to separate the solid and liquid phases. The solid residues were dried and analyzed using thermal analysis techniques (TG, DTG, DTA) and X-ray diffraction (XRD). At the same time, the liquid phase was examined by inductively coupled plasma mass spectrometry (ICP-MS). Thermal analyses revealed alterations in the profiles of the post-adsorption samples, suggesting structural changes in the material due to metal interaction. Notably, DTG and DTA spectra exhibited slight but consistent shifts in thermal signals, indicating modifications in the decomposition behavior of surface functional groups. XRD analysis revealed three characteristic peaks of the G-BAC structure [1], which were shifted in all metal-treated samples. In particular, the first peak moved to higher angles, indicating a reduction in interlayer spacing as calculated via Bragg’s law. This shift was most pronounced in the arsenic-treated sample, implying a deeper or more invasive structural interaction. Possible explanations for this phenomenon include: (i) the formation of bonds between heavy metals and oxygen-containing surface functional groups, leading to partial collapse of graphitic microstructures and/or (ii) the removal of interlayer species (e.g., water, oxygen), resulting in closer stacking of graphene layers [2]. ICP-MS analysis of the post-treatment solutions confirmed effective metal removal, except in the case of antimony, for which inconsistent results were probably due to its chemical instability in solution. The removal percentages indicate high adsorption efficiency, especially for arsenic. These results emphasize the potential of G-BAC as an effective adsorbent for the removal of heavy metals from aqueous solutions and support further research on the structural modifications induced by adsorption processes. [1] Wibawa P.J., Nur M., Asy’ari M., Nur H. SEM, XRD and FTIR analyses of both ultrasonic and heat generated activated carbon black microstructures, 2020. Heliyon 3, 6. https://doi.org/10.1016/j.heliyon.2020.e03546 [2] Fisher K., Vreugdenhil A.. Metal-Impregnated Petroleum Coke-Derived Activated Carbon for the Adsorption of Arsenic in Acidic Waters, 2023. ACS Omega, 32, 8. https://doi.org/10.1021/acsomega.3c02078I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
