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    Effective Biosorption of Auramin O Dye with Sustainable Chickpea Pods Waste; Isotherms, Kinetics and Thermodynamic Analysis
    (2024) Keskin, Zehra Saba
    This study investigated biosorbent properties in removing Auramin O (AO) dye from the aqueous solution of agricultural wastes released from chickpea (Cicer arietinum L.), which is widely produced in Turkey and the world. Biosorption studies were carried out using different values of parameters such as initial AO concentration, dye pH, contact time, temperature, and biosorbent amount. Characterization analyses of the biosorbent used before and after biosorption were carried out by scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Brunauer–Emmett–Teller (BET), Fourier transform infrared spectroscopy (FTIR), and point of zero charge (PZC). Biosorption isotherms were evaluated using Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm models. As a result of experimental data, it has been shown that the Langmuir isotherm model (R2 = 0.930) is the most compatible model for biosorption, while the biosorption kinetic mechanism proceeds through the pseudo-second-order (PSO) kinetic model (R2 = 0.965) and the intra-particle diffusion model. As a result of thermodynamic studies, it has been reported that biosorption is endothermic (?H0>0), spontaneous (?S0>0), and entropy-increasing (?G0 <0).
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    Influential lead uptake using dried and inactivated-fungal biomass obtained from Panaeolus papilionaceus: biological activity, equilibrium, and mechanism
    (Springer Heidelberg, 2024) Senol, Zeynep Mine; Keskin, Zehra Saba; Dincer, Emine; Ben Ayed, Amina
    In this study, the use of fungal (Panaeolus papilionaceus) biomass as a biosorbent was investigated to effectively remove Pb2+ ions from aquatic medium. The removal of Pb2+ ions using a fungal biosorbent was examined in a batch system in terms of initial solution pH, temperature, time, and initial Pb2+ concentration. Optimal operating conditions for biosorption of Pb2+ ions; pH: 4.5, T: 25 degrees C, and t: 24 h. The max biosorption capacity for Pb2+ ions was found to be 31.2 mg g(-1) from the Langmuir model. Thermodynamic studies showed that Pb2+ ions biosorption into fungal biomass was possible, spontaneous, and endothermic. Additionally, the antimicrobial activity and antibiofilm activity of the extract of fungus were also investigated. It was determined that the fungal extract did not have antimicrobial properties. On the other hand, the extract has been shown to have the potential to prevent biofilm formation. 1 mg of the extract prevented the biofilm formation of Staphylococcus aureus by 87.85%. It has been observed that the biosorption mechanism of Pb2+ ions into fungal biomass includes the steps of surface biosorption, film diffusion, and intra-particle diffusion.
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    Öğe
    The valorization of Prunus mahaleb shell through acid modification for the sorption of Pb2+ removal from aqueous solution
    (Springer Heidelberg, 2024) Keskin, Zehra Saba; Senol, Zeynep Mine; Simsek, Selcuk
    This study aimed to investigate the biosorption performance of acid-modified waste Prunus mahaleb (PMA) shells in the removal of Pb2+ ions from aqueous solutions. Changes in the morphological properties and functional components of PMA biosorbent were characterized using SEM-EDX, FT-IR, BET, and PZC analyses. The effect of various parameters such as initial Pb2+ concentration, pH, PMA dosage, contact time, and temperature on biosorption was investigated using a batch biosorption procedure. The maximum biosorption capacity, determined using the Langmuir isotherm, was calculated to be 119 mg g(-1). It was found that the biosorption kinetic mechanism followed pseudo-second-order kinetics and intraparticle diffusion model. According to the determined thermodynamic parameters, the biosorption mechanism was found to be endothermic (Delta H degrees > 0), spontaneous (Delta S degrees > 0), and entropy-increasing (Delta G degrees < 0). The outcomes of the experiment were evaluated in comparison to other sorbents that have been previously commonly used in the literature. It was demonstrated that PMA could be a promising, environmentally friendly, cost-effective, and sustainable potential biosorbent for the removal of Pb2+ ions.