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Öğe Characteristics and mechanisms for highly efficient adsorption of Pb(II) from aqueous solutions by engineered vinasse biochar with cold oxygen plasma process(Elsevier Science Sa, 2022) Kazak, Omer; Tor, AliVinasse based biochar was engineered by cold oxygen plasma for different treatment time between 1 and 10 min to obtain highly efficient adsorbent for Pb(II) in the aqueous solutions. The engineered biochar with largest surface area (307 m(2)/g) and primarily microporous structure was achieved when cold oxygen plasma is processed for 3 min, providing the highest adsorption capacity (481 mg/g) derived from 500 mg/L of Pb(II) solution. For the equilibrium time (90 min) and the favorite solution pH (5.0), the best-fitting isotherm model was Langmuir isotherm one with Q(o) (714 mg/g), which is superior to those of many biochar based Pb(II) adsorbents in the literature. On the basis of XRD, XPS, FT-IR instruments and surface charge measurements, the adsorption mechanisms included ion-exchange, precipitation, electrostatic attraction, cation-pi interaction and complexation. The reusable engineered vinasse biochar has also applicability to real water samples without matrix effects.Öğe Fabrication of in situ magnetic activated carbon by co-pyrolysis of sucrose with waste red mud for removal of Cr(VI) from waters(Elsevier, 2021) Kazak, OmerHerein, a novel in situ magnetic activated carbon was prepared by co-pyrolysis treatment of sucrose, a renewable and rich carbon-based material, with waste red mud which industrial waste emerged as a result of aluminum oxide production from bauxite. Characterization studies were carried out by TGA, XRD, FT-IR, XPS, FE-SEM, VSM techniques, and N-2 adsorption-desorption measurements and pHpzc. During the co-pyrolysis, while the metal oxides in the red mud show catalytic effect, the CO released from sucrose turns Fe2O3 into magnetic Fe3O4, which was confirmed by characterization studies. Adsorption efficiency of inorganic model pollutant Cr(VI) in aqueous solution was evaluated for magnetic activated carbon material with the most suitable surface properties. Maximum removal of Cr(VI) favored at solution pH of 2.10 +/- 0.05, adsorption equilibrium time was 120 min and Freundlich isotherm model better modeled the adsorption data than Langmuir isotherm model. The experiments on the real water sample fortified with Cr(VI) indicated that the magnetic activated carbon could be successfully used for real sample without matrix effects. (C) 2021 Elsevier B.V. All rights reserved.Öğe Green preparation of a novel red mud@carbon composite and its application for adsorption of 2,4-dichlorophenoxyacetic acid from aqueous solution(Springer Heidelberg, 2017) Kazak, Omer; Eker, Yasin Ramazan; Akin, Ilker; Bingol, Haluk; Tor, AliThis study reports the eco-friendly preparation of a novel composite material consisting of red mud and carbon spheres, denoted as red mud@C composite, and its application for the removal of 2,4-dichlorophenoxyacetic acid herbicide (2,4-D) from aqueous solution. The preparation route has a green approach because it follows the low-energy consuming one-step hydrothermal process by using starch as a renewable carbon precursor and red mud as a waste from aluminum production industry. Characterization of the red mud@C composite was performed by FT-IR, TGA, SEM, TEM, BET, XRD, and Raman microscopy analyses. The batch adsorption studies revealed that the red mud@C composite has higher 2,4-D adsorption efficiency than those of the red mud and the naked carbon spheres. The maximum removal at initial pH of 3.0 is explained by considering the pKa of 2,4-D and pH of point of zero charge (pH(pzc)) of the composite material. The adsorption equilibrium time was 60 min, which followed the pseudo-second-order kinetic model together with intra-particle diffusion model. The isotherm analysis indicated that Freundlich isotherm model better represented the adsorption data, with isotherm parameters of k [15.849 (mg/g) (mg/L)(-1/n) ] and n (2.985). The prepared composite is reusable at least 5 cycles of adsorption-desorption with no significant decrease in the adsorption capacity.Öğe In situ preparation of magnetic hydrochar by co-hydrothermal treatment of waste vinasse with red mud and its adsorption property for Pb(II) in aqueous solution(Elsevier, 2020) Kazak, Omer; Tor, AliHerein, a new magnetic hydrochar was prepared through co-hydrothermal treatment of vinasse with red mud, two abundant industrial wastes, and its adsorption property was evaluated on Pb(II), selected model ion in aqueous solution. During co-hydrothermal process, Fe2O3 species in red mud was reduced to Fe3O4 form, hereby, in situ magnetization of hydrochar was achieved, which was confirmed by characterization studies. Produced hydrochar with porous structure (V-total = 0.071 cm(3)/g and BET surface area = 23 m(2)/g) had saturation magnetization (44.7 emu/g), providing easier separation from water by a magnet. Maximum Pb(II) adsorption was favored at pH >= 5.0 within 120 min of equilibrium time and Freundlich isotherm model was preferable. The contribution percentage of different mechanisms including cation-exchange (40.8 %), (electrostatic attraction + cation-pi interaction) (31.2 %), precipitation (25.4 %) and complexation (2.6 %) to overall Pb(II) adsorption indicated that cation-exchange was the dominant mechanism. Finally, application to fortified real water demonstrated that in situ magnetic hydrochar produced by suggested approach was successful at adsorptive removal of Pb(II) from water with no matrix effects.Öğe In-situ magnetization of porous carbon beads by pyrolysis of waste red mud doped polysulfone beads for efficient oil sorption(Elsevier Science Sa, 2020) Kazak, Omer; Eker, Yasin Ramazan; Tor, AliThis study describes for the first time the preparation of in-situ magnetic porous carbon beads (MPC beads) through simple phase inversion and subsequent pyrolysis of red mud doped polysulfone beads. Red mud, which is the main industrial waste resulted from the aluminium production, contains an important amount of Fe2O3. Characterization studies demonstrated the in-situ carbo-reduction of Fe2O3 species into magnetic Fe3O4 thanks to polysulfone carbon source, involving then the synthesis of MPC beads. Owing to hydrophobic surface and macroporous structure, the MPC beads were evaluated on the sorption of various oils, including gasoline, diesel oil, mineral oil and olive oil from water. The maximum sorption capacity of the MPC beads for examined oils were determined as olive oil (2.018 +/- 0.162 g/g)>mineral oil (1.418 +/- 0.138 g/g)> diesel oil (1.316 +/- 0.062 g/g)>gasoline (1.235 +/- 0.028 g/g). Moreover, the MPC beads were regenerable by heat treatment and there was no change in their sorption capacities in the first ten consecutive sorption-desorption cycles. Consequently, the suggested approach on the pyrolysis of waste red mud doped polysulfone beads was successful at preparing in-situ MPC beads, which can be efficiently used for oil spills clean-up from water with easier separation by a magnet.Öğe Novel preparation of activated carbon by cold oxygen plasma treatment combined with pyrolysis(Elsevier Science Sa, 2017) Kazak, Omer; Eker, Yasin Ramazan; Bingol, Haluk; Tor, AliThis study reports an original approach based on the inserting of a cold oxygen plasma treatment as oxidation stage between two pyrolysis processes for the preparation of an activated carbon from vinasse as a waste from the distillation of fermented sugar beet. The effects of pyrolysis temperature and plasma application time on the structural and morphological properties of the prepared carbon materials were investigated by Thermal Gravimetric Analysis (TGA), Fourier Transform Infrared Spectroscopy (FT-IR), Raman Spectroscopy, Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDX) techniques and gas adsorption measurements (BET). The results of the different conditions indicated that the structure properties of the obtained activated carbon were significantly dependent on the pyrolysis temperature. As an optimum condition, the application of oxygen plasma for 5 min between pyrolysis processes at 1000 C-omicron provided an eligible activated carbon with surface area (832.3 m(2)/g) and mainly microporous structure. After preliminary examinations on various dyes, the adsorption performance of the activated carbon with highest surface area was specifically evaluated using methylene blue as a model dye in aqueous solution as functions of various operating parameters. Langmuir adsorption capacity (909.091 mg/g) of the prepared activated carbon toward methylene blue was superior than most of the other adsorbents. (C) 2017 Elsevier B.V. All rights reserved.Öğe A novel red mud@sucrose based carbon composite: Preparation, characterization and its adsorption performance toward methylene blue in aqueous solution(Elsevier Sci Ltd, 2017) Kazak, Omer; Eker, Yasin Ramazan; Akin, Ilker; Bingol, Haluk; Tor, AliA novel carbonaceous composite material containing red mud and sucrose based carbon spheres, named as RM@ C composite, has been prepared via one-step hydrothermal carbonization (HTC) process. The prepared RM@ C composite is an environmentally friendly material because it utilized the red mud, a waste emerged from aluminium manufacturing, and sucrose, a renewable carbon precursor, in the one-step HTC process. After characterization of the composite material by XRD, FT-IR, TGA and SEM-EDX techniques, and specific surface area, pore size distribution and pH of zero point of charge (pHzpc) measurements, its batch adsorption performance was examined on the methylene blue in aqueous solution. The effective adsorption was achieved at pH = 11. At pH 11, the adsorption performance of RM@ C was superior to both red mud and naked carbon spheres. Kinetic analysis revealed that adsorption equilibrium is attained in 60 min and it is governed by the pseudo-second-order kinetic model together with intra-particle diffusion model. On the basis of isotherm analysis, Langmuir isotherm model better expressed the experimental data than Freundlich model. The Langmuir adsorption capacity of the composite material toward methylene blue was determined as 76.92 mg/g. The adsorption of methylene blue gradually decreased with increasing the ionic strength of the solution. The RM@ C composite can be reused at least five cycles of adsorption-desorption without significant changes in the adsorption efficiency.Öğe Preparation and characterization of novel polysulfone-red mud composite capsules for the removal of fluoride from aqueous solutions(Royal Soc Chemistry, 2016) Kazak, Omer; Tor, Ali; Akin, Ilker; Arslan, GulsinThis study is the first investigation on the encapsulation of red mud by a polysulfone matrix through a phase inversion process to obtain composite capsules for the removal of fluoride from aqueous solutions. This approach facilitates the use of red mud in batch and column sorption techniques because the polysulfone matrix renders efficient aqueous diffusivity. The produced polysulfone-red mud composite capsules (red mud@ PSF capsules) were characterized by using FT-IR, TGA, SEM and BET. The batch sorption experiments showed that the red mud@ PSF capsules prepared with a mass ratio of red mud to polysulfone (1 : 1, g : g) provided maximum removal at equilibrium pH between 3.2 and 4.7. The batch equilibrium was attained within 30 minutes and sorption behavior was governed by pseudo-second-order kinetics together with intra-particle diffusion. Isotherm analyses showed that the Freundlich and Redlich-Peterson isotherm models better represented the sorption data, which was confirmed by the Chi-square (chi(2)) statistical test. The capsules could be reused for at least two sorption-desorption cycles without significant change in their sorption efficiency. Batch and column experiments on a real mineral water sample fortified with fluoride (final concentration 10 mg L-1) showed that the red mud@ PSF capsules could be applied to real water samples to reduce the fluoride concentration below the limit value (1.5 mg L-1) recommended by the World Health Organization (WHO) for drinking water.Öğe Preparation of activated carbon from molasses-to-ethanol process waste vinasse and its performance as adsorbent material(Elsevier Sci Ltd, 2017) Kazak, Omer; Eker, Yasin Ramazan; Bingol, Haluk; Tor, AliHerein, the preparation of activated carbon from waste vinasse by using hydrothermal H2O2 oxidation combined with a two-step pyrolysis process has been described for the first time as a new utilization approach for the waste vinasse. The characterization studies were performed by TGA, FT-IR, Raman spectroscopy, SEM-EDX and gas adsorption measurements. The approach generated a microporous activated carbon with high specific surface area ( 989 m(2)/g) from waste vinasse. After simple experiments on various dye solutions, adsorption performance of the activated carbon was specifically studied on the methylene blue solution as functions of solution pH, contact time, adsorbent amount and reusability. The obtained activated carbon had a higher Langmuir adsorption capacity towards methylene blue ( 909.091 +/- 31.900 mg/g) than many other adsorbents and it is reusable for at least six cycles. The adsorption performance of the obtained activated carbon was also evaluated using both simulated and real dyehouse effluents. (C) 2017 Elsevier Ltd. All rights reserved.Öğe Preparation of chemically-activated high surface area carbon from waste vinasse and its efficiency as adsorbent material(Elsevier, 2018) Kazak, Omer; Eker, Yasin Ramazan; Bingol, Haluk; Tor, AliHerein, a chemically activated carbon (AC) has been prepared from molasses-to-ethanol-process waste (vinasse). The procedure involves the preparation of carbonaceous spheres (CS) from the hydrothermal carbonization of the vinasse followed by activation with KOH at 800 degrees C. The effects of sole thermal treatment (without KOH) and the chemical activation on the structure and morphology of CS were evaluated by means of TGA, FT-IR, XPS, Raman spectroscopy, SEM and BET techniques. The sole thermal treatment produced a carbonaceous material with equal micro-mesoporous contents and a specific surface area (189 m(2)/g). On the other hand, the KOH-based activation produced a mainly microporous AC (V-micro = 0.574 cm(3)/g, V-total = 0.691 cm(3)/g, V-micro/V-total = 0.83) with a high specific surface area (1042 m(2)/g). Batch adsorption efficiency of AC was determined by using Victoria Blue B as a model dye in aqueous solution as functions of several operation parameters. Based on the non-linear regression analysis, the Langmuir isotherm model with monolayer adsorption capacity of 713.254 mg/g was preferable. The obtained AC was reusable for at least five cycles of adsorption-desorption. All results showed that the prepared AC has potential usability for the treatment of water polluted by dye-stuffs. (C) 2018 Elsevier B.V. All rights reserved.Öğe Preparation of new polysulfone capsules containing Cyanex 272 and their properties for Co(II) removal from aqueous solution(Elsevier Sci Ltd, 2015) Kazak, Omer; Tor, Ali; Akin, Ilker; Arslan, GulsinIn this study, new polysulfone capsules containing Cyanex 272 (Cyanex 272@PSF capsules) were prepared by phase inversion technique for the sorption of Co(II) from aqueous solution. The characterization of the Cyanex 272@PSF capsules which were performed by using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and thermal gravimetric analysis (TGA) indicated that Cyanex 272 was successfully encapsulated by polysulfone. For the Cyanex 272@PSF capsules having the highest sorption efficiency, the encapsulation efficiency was determined as 7.2%. The batch sorption experiments showed that removal of Co(II) from aqueous solutions occurred through the cation-exchange and chelation mechanisms and maximum removal was achieved at an initial pH of 8.0 (final pH of 5.9). The Cyanex 272@PSF capsules produced with dispersed phase containing 2.0% of Cyanex 272 (by wt.) provided the highest Co(II) removal. The sorption equilibrium time was attained within 120 min. By confirming the non-linear Chi-square (x(2)) statistical test, Langmuir isotherm model was the best fit model. Langmuir sorption capacity (Q(o)) and sorption constant (b) were 2.014 mg/g and 0.281 L/mg, respectively. The regenerated capsules could be used three times with no change in their sorption capacities. Based on the experiments performed at initial pH of 8.0 for other metal ions, including Ni(II), Pb(II) and Cd(II), sorption ability of Cyanex 272@PSF capsules was in the order: Co(II) approximate to Ni(II)>Cd(II)>Pb( II). Consequently, Cyanex 272@PSF capsules have potential for removing Co(II) from aqueous solutions. (C) 2015 Elsevier Ltd. All rights reserved.Öğe A simple and green preparation of red mud-coated membrane for efficient separation of oil-in-water emulsions(Elsevier Sci Ltd, 2022) Turk, Bahri; Kazak, Omer; Akkaya, Gulizar Kurtoglu; Tor, AliThis study presented a novel, low-cost and environmentally-friendly underwater superoleophobic membrane for influential separation of oil-in-water emulsions. The membrane was prepared by single-step deposition of waste red mud with sodium alginate on the nitrocellulose support through a vacuum pumping. The red mud-coated membrane had a superamphiphilic characteristic in air, whereas it demonstrated an underwater superoleophobic feature with contact angle values above 159(+/- 2)degrees. The prepared membranes with different amount of red mud showed effective separation performance having rejection and flux values greater than (98.5% and 945 L/m(2) h; 99.1% and 1033 L/m(2) h; 93.7% and 1186 L/m(2) h; 99.8% and 1224 L/m(2) h; 99.9% and 1028 L/m(2) h) for emulsions of various oils and solvents (diesel, mineral oil, toluene, kerosene and petroleum ether)-in-water, respectively. The oil rejection and permeate flux remained stable at the end of 5 cycles of the emulsion separation and also in the corrosive solutions, including NaOH, HCl and NaCl at 0.5 M of each one. Consequently, the usage of waste red mud in the preparation of underwater superoleophobic membrane through the suggested way can be offered as economical, practical and environmentally benign option for both implementing the efficient separation of oil-in-water emulsions and reuse of the industrial by-products.Öğe Sustainable and efficient removal of cationic, anionic and neutral dyes from water by pre-deposited vinasse biochar membrane(Elsevier Sci Ltd, 2023) Kazak, Omer; Akkaya, Gulizar Kurtoglu; Tor, AliThis study demonstrated a simple and sustainable approach for removing dyes from water through a new predeposited vinasse biochar (PDVB) membrane, which was developed by single-step deposition of vinasse biochar powder on a filter paper support via vacuum pumping. The PDVB membrane combined advantages of adsorption and membrane filtration processes in one-stage. Performance of the PDVB membranes with waterwettable surface was examined on methylene blue (as a model dye) solution as functions of pyrolysis temperature, amount of biochar on the membrane unit area, solution pH, initial concentration and temperature of dye solution in a dead-end filtration mode. The best performance (removal efficiency >99%, flux: 8017 L/(m2.h)) was obtained at a wide pH range (2-11) by using membrane (7.95 mg biochar/cm2, derived from pyrolysis of vinasse at 900 degrees C). Moreover, initial dye concentration and solution temperature had no considerable effect on membrane performance, which was stable even after ten cycles of filtration-regeneration by ethanol-washing. At pH 2, the membrane was also quite good at removing Congo red (anionic dye) with efficiency of 98%, which decreased when increasing pH from 2 to 11. Behavior of membrane towards dyes with different characteristics was explained by considering high surface area (756 m2/g) of the biochar and phenomenon, including aromatic stacking and electrostatic-attraction between dye molecule and biochar surface. All findings and application to a real textile industry effluent demonstrated that developed membrane was easy-to-use and sustainable material for effective treatment of water and wastewater containing dyes with different molecular weights and ionic characteristics.Öğe Tuning active sites of N-doped porous carbon catalysts derived from vinasse for high-performance electrochemical sensing(Taylor & Francis Inc, 2023) Ipekci, Hasan H.; Kazak, Omer; Tor, Ali; Uzunoglu, AytekinN-doped biomass-derived porous carbon was synthesized by the pyrolysis of sugarcane-vinasse to develop a novel metal-free catalyst in electrochemical sensing. Vinasse samples were subjected to different pyrolysis temperatures under nitrogen flow to investigate the effect of the pyrolysis temperature on the physical properties of the biomass-derived products. The XPS results displayed that as-pyrolyzed samples contain N atoms with an atomic ratio of 3.02%. While a low surface area of 1.5 m(2)/g was measured from the sample pyrolyzed at 600 degrees C, the increase in the temperature yielded a large surface area of 620 m(2)/g. Additional heat treatment was implemented to tailor N-binding sites. Samples were then used as electroactive catalysts for hydrogen peroxide (H2O2) electrochemical sensing. Vinasse-P-10@N-based sensors showed much-improved sensor performance in a linear range of 0.03-12 mM with a high sensitivity of 208.97 mu A mM(-1) cm(-2).
