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    Conversion of a renewable bio-resource to a functional composite material: Product design, comprehensive characterization and adsorption of 2,4-D herbicide
    (Elsevier, 2020) Saygili, Gulbahar Akkaya
    Based on the opinion of utilizing waste resources to treat waste, a sustainable resource waste was transformed into a useful and functional material by a comprehensive experimental setup. A high surface area lentil processing waste-based activated carbon was synthesized by microwave-assisted K2CO3 chemical activation and then successfully converted into a ferrospinel composite. The ferrospinel composite was characterized with BET, FTIR, XRD, XPS, FE-SEM, EDX mapping, Raman and VSM techniques and the detailed characterization analysis confirmed the successful formation of the ferrospinel composite. It was also applied as an effective adsorbent material in the treatment of 2,4-dichlorphenoxyacetic acid herbicide bearing wastewater. The pseudo-second order model better defined the kinetic pathway of the adsorption while the isothermal data indicated the best suitability to Langmuir model. The maximum adsorption capacity of the ferrospinel composite towards 2,4-dichlorophenoxyacetic acid was 400 mg/g at 45 degrees C. Thermodynamic studies showed the favorability and spontaneity of the adsorption process.
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    Development and physicochemical characterization of a new magnetic nanocomposite as an economic antibiotic remover
    (Inst Chemical Engineers, 2015) Saygili, Gulbahar Akkaya; Saygili, Hasan; Koyuncu, Filiz; Guzel, Fuat
    Maghemite (T-Fe2O3) nanoparticles were impregnated to nanoporous carbon obtained from tomato waste (TWNC). The prepared magnetic composite (MTWNC) was characterized and used to remove tetracycline (TC) from water and then easily be separated from the medium by a magnetic technique. The morphologies and surface chemistries of both magnetic and non-magnetic nanoporous carbons were studied by FTIR, XRD, SEM, SEM-EDX, VSM, BET surface area, proximate and elemental analysis determinations. Batch adsorption studies were carried out and the effects of pH, initial TC concentration, adsorbent dose, ionic strength and temperature were investigated. The adsorption kinetics of TC on MTWNC could be expressed well by the pseudo-second order model, and sorption isotherms were described by Langmuir equation with maximum adsorption capacity of 60.60 mg/g at pH 4 and 50 degrees C. Thermodynamic parameters showed that the adsorption of TC onto MTWNC was feasible, spontaneous and endothermic. Furthermore, the recyclability of the adsorbent was tested with 0.01M NaOH solution, and the results show that the synthesized composite adsorbent could be employed repeatedly in wastewater treatment. (C) 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
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    Elimination of anionic dye by using nanoporous carbon prepared from an industrial biowaste
    (Elsevier Science Bv, 2014) Guzel, Fuat; Saygili, Hasan; Saygili, Gulbahar Akkaya; Koyuncu, Filiz
    The preparation of nanoporous carbon from tomato waste (TWNC), and its ability to remove Orange II (OII) dye were reported. The TWNC was characterized by Fourier Transform Infrared Spectroscopy (FTIR), Brunauer Teller surface area (BET), Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). The effects of initial concentration, solution pH, adsorbent dosage and temperature were investigated. The kinetic data followed a pseudo-first order model. The mechanism of the process was determined from the intraparticle diffusion model. The isotherm analysis indicated that the adsorption data could be represented by the Langmuir model. The maximum monolayer adsorption capacity was determined as 312.5 mg g(-1), under determined optimum conditions of variables (pH 2.0, adsorbent dosage 0.1 g L-1, contact time 180 mm and temperature 50 degrees C). Thermodynamic study showed that the adsorption was spontaneous and endothermic. The results indicate that TWNC can be employed as low-cost alternative to expensive commercial activated carbon for treatment of industrial wastewater containing OIL. (C) 2014 Elsevier B.V. All rights reserved.
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    Fabrication of a magnetic hydrochar composite via an in situ one-pot hydrocarbonization strategy for efficient herbicide removal
    (Elsevier Science Sa, 2022) Saygili, Gulbahar Akkaya; Saygili, Hasan
    This study explores the feasibility of the production of a new bioproduct from an abundantly available waste material to enhance resource recovery opportunities. A novel magnetic hydrochar was produced via hydrothermal carbonization of pomegranate waste (PW). The hydrothermal carbonization process needs to be optimized, hence we have investigated the effects of residence temperature (RT; 180-220 degrees C) and residence time (Rt; 6-24 h) on the hydrochar characteristics such as atomic carbon content, energy density and higher heating values. The optimum conditions were determined as 220 degrees C and 12 h and the synchronous carbonization and magnetization of PW were fulfilled under the aforementioned conditions by a one-step hydrothermal process. This new magnetic material (Fe@PWHC) was featured by exhaustive spectral analyses including XRF, XPS, XRD, SEM/EDX, FTIR, Raman and VSM measurements and then tested for its adsorption ability towards 2,4 dichlorophenoxyacetic acid (2,4-D). The formation mechanism of magnetic hydrochar was elucidated and the plausible uptake mechanism of 2,4-D by Fe@PWHC was also discussed. Freundlich model satisfactorily explains the adsorption process when compared to the Langmuir model. Thermodynamic studies revealed the endothermic spontaneous adsorption of 2,4-D. Good adsorption potential for 2,4-D (qmax: 101.10 mg/g) and easy separable feature of Fe@PWHC reveals that it could be a cost-effective, effectual and green adsorbent for decontamination of 2,4-D bearing water.
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    Hydrothermal co-carbonization of hazelnut and pistachio shells to hydrochar as potential energy source: Synergistic effects of process parameters on hydrochar characteristics
    (Pergamon-Elsevier Science Ltd, 2025) Saygili, Gulbahar Akkaya; Saygili, Hasan
    The synergistic effects of co-hydrothermal carbonization (co-HTC) of hazelnut and pistachio shells (HS and PS) were aimed to explore and the impacts of blending ratio of feedstocks and retention time on hydrochar characteristics were studied in detail. A remarkable synergistic increment revealed in terms of the mass yield, energy content, and carbon and nitrogen retentions. The higher energy parameters of co-hydrochars showed that coHTC application upgraded the fuel quality of the product. The support of co-HTC process for development of aromaticity and surface enriched with oxygenated functional groups was verified with FTIR spectrum. Anionic and cationic dye adsorptions were conducted to test the removal ability of both single and co-hydrochars. The possible adsorption mechanisms of the dyes were elucidated. This comprehensive research demonstrated that coHTC of HS and PS could be a promising pathway for designing high-performance products for energy and environmental fields.
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    Lead recovery from aqueous environment by using porous carbon of citrus fruits waste: equilibrium, kinetics and thermodynamic studies
    (Taylor & Francis Inc, 2020) Saygili, Gulbahar Akkaya; Saygili, Hasan; Yilmaz, Cumali; Guzel, Fuat
    The mixture of citrus fruits (orange, grapefruit, mandarin, and lemon) wastes was utilized to obtain high surface area activated carbon (AC) by H3PO4 activation. The production conditions were optimized and the optimum conditions were determined. The optimal-activated carbon (CFWAC) was characterized by various physicochemical techniques. CFWAC was also used as a sorbent for Pb (II) ions from water. Batch experiments were performed to explore the adsorption capacity and mechanism. The Langmuir isotherm and pseudo-second-order kinetic model showed good fitness to the experimental data. The maximum Pb (II) adsorption capacity of CFWAC was found to be 163.93 mg/g.
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    New low-cost nanoporous carbonaceous adsorbent developed from carob (Ceratonia siliqua) processing industry waste for the adsorption of anionic textile dye: Characterization, equilibrium and kinetic modeling
    (Elsevier Science Bv, 2015) Guzel, Fuat; Saygili, Hasan; Saygili, Gulbahar Akkaya; Koyuncu, Filiz
    Carob (Ceratonia siliqua) processing industry waste (an) has been applied as an abundant, cheap and available precursor to produce a new nanoporous carbon (CWNC) for removal of an anionic textile dye, Reactive Black 5 (RB5), which is frequently used in the textile industry, from aqueous phase. CWNC was characterized by BET, FTIR, SEM, and XRD techniques, proximate and ultimate analyses, Boehm titration Method, pH(pzc), measurement iodine and Methylene blue numbers. Its surface area, total pore volume, average pore diameter was found as 921.07 m(2)g(-1), 0.571 cm(3) g(-1) and 2.482 nm, respectively. The influences on RB5 adsorption of various experimental factors such as adsorbent dose, solution pH, initial RB5 concentration, temperature and ionic strength were investigated. Adsorption kinetics was found to be best represented by the pseudo-second order model. The isotherm analysis indicated that the adsorption data could be represented by the langmuir model. The maximum adsorption capacity for RB5 was 36.90 mg g(-1) at 50 degrees C. Thermodynamic parameters showed that the process was spontaneous and endothermic. (C) 2015 Elsevier B.V. All rights reserved.
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    Optimal oxidation with nitric acid of biochar derived from pyrolysis of weeds and its application in removal of hazardous dye methylene blue from aqueous solution
    (Elsevier Sci Ltd, 2017) Guzel, Fuat; Saygili, Hasan; Saygili, Gulbahar Akkaya; Koyuncu, Filiz; Yilmaz, Cumali
    In this study, the optimal oxidized weeds-based biochar (OWC) with HNO3 was used as a sorbent to remove methylene blue (MB) dye from aqueous solution. The optimal oxidation conditions were determined according to the MB index (MI) of samples. Weeds-based biochar (WC) and its oxidized samples were characterized by their pore and chemical properties. The results showed that the oxidized WCs have a lower BET (Brunauer-Emmett-Teller) surface area, more oxygen functional groups, lower pH(pzc) and higher MI compared with the WC. Optimum conditions were determined considering the effect of process parameters such as the solution pH, initial MB concentration, agitation time and solution temperature for MB removal by the optimal OWC. The kinetic data followed the pseudo-second order kinetic model. The equilibrium data were best represented by the Langmuir isotherm model. The maximum MB sorption capacities of WC and optimal OWC were determined as 39.68 and 161.29 mg/g, respectively, under detected optimum conditions (pH 7.4, OWC dosage 0.1 g/50 mL, agitation time 480 min and temperature 50 degrees C). (C) 2017 Elsevier Ltd. All rights reserved.
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    Performance of grape (Vitis vinifera L.) industrial processing solid waste-derived nanoporous carbon in copper(II) removal
    (Springer Heidelberg, 2021) Guzel, Fuat; Saygili, Gulbahar Akkaya; Saygili, Hasan; Koyuncu, Filiz; Kaya, Nafiye; Guzel, Sureyya
    In this study, copper removal performance of new nanoporous carbon adsorbent (grape waste nanoporous carbon (GWNC)) produced from industrial grape processing solid waste (grape waste) under optimized conditions was investigated. The optimization of removal conditions was determined by examining the effects of GWNC dosage, pH, initial Cu(II) concentration, contact time, and temperature. Kinetic and isotherm data were evaluated in pseudo-first-order and pseudo-second-order kinetic models and Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models, respectively. Kinetic and isotherm data displayed that the Cu(II) adsorption onto GWNC can be well defined by the pseudo-second-order kinetic model and the Langmuir isotherm model. The diffusion mechanism of adsorption was explained using the intra-particle diffusion model. The Cu(II) removal capacity of GWNC at determined optimized conditions was determined to be 80.0 mg g(-1). The calculated thermodynamic data revealed the spontaneous and endothermic nature of the Cu(II) adsorption. Desorption studies showed that H2SO4 was the effective desorption agent with the desorption rate of 89.14%. The results in this study emphasized that GWNC is an alternative effective adsorbent to commercial adsorbents for Cu(II) removal.
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    Pharmaceutical analysis by a novel spinel ferrite nanocomposite derived from a biomaterial-based activated carbon
    (Elsevier, 2020) Saygili, Gulbahar Akkaya; Saygili, Hasan
    Microwave-assisted activated carbon was fabricated from lentil waste (LW) by K2CO3 chemical activation at optimum production conditions and the synthesized optimal activated carbon (LWAC) with a high surface area (1875 m(2)/g) was used as a matrix for spinel ferrite composite production. CuFe2O4 nanoparticles were embedded to LWAC and a novel magnetic composite material (M-LWAC) was synthesized. A detailed structural and textural analysis of M-LWAC was made by using various characterization techniques. M-LWAC was also used as an effectual remover for tetracycline (TC) bearing wastewater with 384.62 mg/g of adsorption capacity. Kinetic, isotherm and thermodynamic analyses indicated the fast, effective and spontaneous adsorption of TC by M-LWAC. (C) 2019 Elsevier B.V. All rights reserved.
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    Synthesis, characterization and adsorption properties of a novel biomagnetic composite for the removal of Congo red from aqueous medium
    (Elsevier, 2015) Saygili, Gulbahar Akkaya
    A novel biomagnetic composite (MnFe2O4/PW) was synthesized and used for the removal of Congo red (CR) from aqueous solutions. Adsorption of CR on the composite adsorbent was studied as a function of time (5-300 min), initial CR concentration (100-200 mg/L), composite dose (0.05-0.1 g), pH (6-10), and temperature (25-55 degrees C). The properties of the biomagnetic composite were measured by BET, SEM, SEM-EDX, FTIR, XRD, and VSM techniques. The kinetics and isotherm studies were carried out under optimum removal conditions of CR by MnFe2O4/PW. The kinetics and equilibrium data fitted to the pseudo-first-order kinetics and Langmuir isotherm models. Using CR as model pollutant, the prepared composite adsorbent showed good adsorption capacity of 86.96 mg/g. Thermodynamic analysis showed that the adsorption was favorable, spontaneous and endothermic. The adsorbent could be regenerated using 50% of ethanol-water solution, remaining 87.36% of its original capacity after the first regeneration cycle and reaching 65.68% of the original capacity after the fifth cycle. This study shows that the synthesized biomagnetic composite could be utilized as an efficient and magnetically separable adsorbent for the dye removal applications. (C) 2015 Elsevier B.V. All rights reserved.
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    Use of a novel bio-magnetic nanocomposite synthesized from industrial tomato processing waste for methylene blue removal: sorption optimization, kinetic and isotherm studies
    (Springer, 2020) Teymur, Yekbun Avsar; Guzel, Fuat; Koyuncu, Filiz; Saygili, Gulbahar Akkaya
    In the current study, the methylene blue (MB) dye sorption performance of a new biomagnetic composite (MTNC) synthesized by modification with Fe(3)O(4)nanoparticles of industrial tomato processing (Lycopersicon esculentumMill.) processing solid waste (TW) was investigated. The XRD, BET, SEM, FT-IR and VSM analysis techniques were used in the characterization of MTNC. The specific surface area, total pore volume, micropore volume, mesopore volume, and mean pore diameter values of MTNC are 28.21 m(2)/g, 0.082 cm(3)/g, 0.003 cm(3)/g, 0.079 and 11.06 nm, respectively. Also, its saturation magnetization value was determined to be 24.80 emu/g. The maximum MB sorption capacity of the MTNC determined to be 90.09 mg/g under optimized conditions of the solution pH of 7.0, WPC dosage of 50 mg, contact time of 180 min, and solution temperature of 50 degrees C. The kinetics and isotherm data were well fitted to the pseudo-second order kinetic and Langmuir isotherm models, respectively. The thermodynamic parameters calculated for the MTNC-MB sorption system proved that the process was spontaneous and endothermic in nature.