Browsing by Author "Benek, Veysel"

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Citation - WoS: 7
Citation - Scopus: 7
Efficient Removal of Ciprofloxacin From Water Using High-Surface Activated Carbon Derived From Rice Husks: Adsorption Isotherms, Kinetics, and Thermodynamic Evaluation
(MDPI, 2025) Demirdag, Esra; Demirel, Mehmet Ferit; Benek, Veysel; Dogru, Elif; Onal, Yunus; Alkan, Mehmet Huseyin; Alacabey, Ihsan
Activated carbon is widely recognized as an effective material for removing pollutants, especially pharmaceutical residues, from water. In this study, high-surface-area activated carbon derived from rice husks (RHAC) was synthesized via KOH activation and used for the adsorption of ciprofloxacin, a widely used fluoroquinolone antibiotic. Its adsorption behavior was systematically investigated through batch experiments varying the pH, adsorbent dosage, contact time, initial concentration, and temperature. The RHAC exhibited a high surface area of 1539.7 m(2)/g and achieved a maximum adsorption capacity of 398.4 mgg(-1). The Freundlich isotherm best describes its adsorption equilibrium, suggesting multilayer adsorption on a heterogeneous surface. Kinetic modeling revealed that the adsorption process followed a pseudo second-order model (R-2 = 0.9981), indicating chemisorption as the rate-limiting mechanism. Thermodynamic parameters (Delta H degrees = 6.61 kJ/mol, Delta G degrees < 0) confirmed that the process was endothermic and spontaneous. These findings demonstrate that RHAC is a highly efficient, low-cost, and sustainable adsorbent for removing ciprofloxacin from aqueous environments.
Citation - Scopus: 7
Reactive Blue 19 Adsorption on Activated Carbon from Pumpkin (Cucurbita Pepo) Seed Waste: Kinetic, Isotherm and Thermodynamic Studies
(Kauno Technologijos Universitetas, 2024) Kızıl, Yusuf; Benek, Veysel; Teğin, İbrahim; Önal, Yunus; Erol, Kadir; Alacabey, İhsan
In this study, the removal of reactive blue 19 dyestuffs in aqueous systems was investigated by the adsorption method using activated carbon obtained from pumpkin seed waste. Activated carbon obtained from pumpkin seed waste functionalized with ZnCl2 was used as an absorbent. Pumpkin seed hydrochar was characterized by FT-IR, SEM, TGA-DTA, BET, and XPS. In the experimental stages, the adsorption equilibrium time was determined as 45 minutes, the adsorbent dosage was 0.8 g and the optimum pH was 6.0. After this step, the adsorption parameters of Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherms were investigated. It has been pointed out that the adsorption process fits better with the Freundlich isotherm model, and the adhesion occurs in a multilayered manner and on a heterogeneous surface. Freundlich and Dubinin-Radushkevich isotherms support that the bonding mechanism is realized by physical interactions. When the kinetic data were evaluated, adsorption mechanism was found to be compatible with the pseudo-second-order kinetic model. The thermodynamic parameters of adsorption indicate that the system is endothermic, and the adsorption of reactive blue 19 on activated carbon is a spontaneous process.