Yazar "Alterkaoui, Aya" seçeneğine göre listele

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    A novel green approach for Cr(VI) removal: application of tomato stem-based hydrochar assisted Fenton-like process
    (Taylor & Francis Ltd, 2024) Alterkaoui, Aya; Belibagli, Pinar; Gun, Melis; Isik, Zelal; Eskikaya, Ozan; Yabalak, Erdal; Dizge, Nadir
    Environmentally friendly catalysts have come to the forefront due to the cost of chemically produced catalysts and the formation of by-products harmful to the environment. Millions of tons of plant waste are produced every year, some of which is disposed directly. In this study, tomato stem hydrochar (TSCH) was produced from waste tomato stems by the hydrothermal carbonisation (HTC) method, and its use as a catalyst was investigated. The optimisation of Cr(VI) removal from water was carried out using a Fenton-like process with a TSCH catalyst and resulted in 100% of Cr(VI) removal efficiency at 10 mg/L of Cr(VI) concentration, pH 2.00, 0.2 g/L of TSCH catalyst, 10 mu L/L of H2O2 and 60 minutes of reaction time. Fenton-like thermodynamic and kinetic data were analyzed, and the results were found to comply with the second-order in Cr(VI) removal. The reusability of the TSCH catalyst in Cr(VI) removal was investigated and it was emphasized that it was reusable for more than 5 uses. In conclusion, TSCH, which is an environmentally friendly, inexpensive and effective catalyst for Cr(VI) treatment in a Fenton-like process, can be used as an alternative catalyst for wastewater treatment in terms of both waste management and economic and environmentally friendly.
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    Antifouling and antibacterial performance evaluation of polyethersulfone membranes modified with AZ63 alloy
    (Iwa Publishing, 2023) Ozay, Yasin; Alterkaoui, Aya; Kahya, Kursat; Ozdemir, Sadin; Gonca, Serpil; Dizge, Nadir; Ocakoglu, Kasim
    Antibacterial membranes have attracted researchers' interest in recent years as a possible approach for dealing with biofouling on the membrane surface. This research aims to see if blending AZ63 Mg alloy into a polyethersulphone (PES) membrane can improve antifouling and separation. The composite membranes' pure water flux continued to increase from pristine PES to PES/AZ63 2.00 wt%. The results showed that PES/AZ63 2.00 wt% membrane supplied the highest permeate flux of E. coli. The steady-state fluxes of AZ63 composite membranes were 113.24, 104.38 and 44.79 L/m(2)h for PES/AZ63 2.00 wt%, 1.00 wt%, and 0.50 wt%, respectively. The enhanced biological activity of AZ63 was studied based on antioxidant activity, DNA cleavage, antimicrobial, anti-biofilm, bacterial viability inhibition and photodynamic antimicrobial therapy studies. The maximum DPPH scavenging activity was determined as 81.25% with AZ63. AZ63 indicated good chemical nuclease activity and also showed moderate antimicrobial activity against studied strains. The highest biofilm inhibition of AZ63 was 83.25% and 71.63% towards P. aeruginosa and S. aureus, respectively. The cell viability inhibition activity of AZ63 was found as 96.34% against E. coli. The photodynamic antimicrobial therapy results displayed that AZ63 demonstrated 100% bacterial inhibition when using E. coli.
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    Caustic recovery from caustic-containing polyethylene terephthalate (PET) washing wastewater generated during the recycling of plastic bottles
    (Nature Portfolio, 2025) Alterkaoui, Aya; Eskikaya, Ozan; Keskinler, Bulent; Dizge, Nadir; Balakrishnan, Deepanraj; Hiremath, Pavan; Naik, Nithesh
    To prevent water scarcity, wastewater must be discharged to the surface or groundwater after being treated. Another method is to reuse wastewater in some areas after treatment and evaluate it as much as possible. In this study, it is aimed to recover and reuse the caustic (sodium hydroxide, NaOH) used in the recycling of plastic bottles from polyethylene terephthalate (PET) washing wastewater. Chemical substances used in the industry will be significantly reduced with chemical recovery from wastewater. Ultrafiltration (UP150) and nanofiltration (NP010 and NP030) membranes were used for this purpose in our study. Before using nanofiltration membranes, pre-treatment was performed with coagulation-flocculation process to reduce the pollutant accumulation on the membranes. Different coagulants and flocculants were used to find suitable coagulants and flocculants in pre-treatment. The pre-treated wastewater using aluminum oxide, which supplied the highest chemical oxygen demand (COD) removal (76.0%), was used in a dead-end filtration system to be filtered through NP010 and NP030 membranes at different pressures (10-30 bar). In the same filtration system, raw wastewater was filtered through a UP150 membrane. Among these treatment scenarios, the best method that could remove pollutants and provide NaOH recovery was selected. After each treatment, pH, conductivity, COD, and NaOH analyses were performed. The maximum NaOH recovery (98.6%) was obtained with the UP150 membrane at 5 bar.
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    Heterogeneous catalyst production from waste cucumber stems and investigation of production potential in biodiesel
    (Elsevier, 2025) Alterkaoui, Aya; Belibagli, Pinar; Arslan, Hudaverdi; Dizge, Nadir; Balakrishnan, Deepanraj
    The use of heterogeneous catalysts obtained from waste in biodiesel production is of great importance in terms of waste management and waste recovery. In this study, heterogeneous catalyst was successfully obtained from waste cucumber stems (WCS) and its potential for biodiesel production via transesterification was investigated. The heterogeneous catalyst contains Ca, K, Mg, Si elements that play a role in biodiesel production. Biodiesel production potential was designed by selecting different temperature, time, methanol/oil molar ratio, and catalyst amount using response surface methodology (RSM). Waste cooking oil (WCO) was used for biodiesel production. The optimum values of these parameters were found to be 70 degrees C, 120 min, 15 wt% and 20:1, respectively. 93.7 % FAME yield was obtained using the obtained CaO catalyst. The heterogeneous catalyst obtained from WCS showed multiple reuse capacity up to 5 cycles. All these results showed that the heterogeneous catalyst obtained from WCS has strong biodiesel production activity and this approach has great potential in biodiesel production with its economic, sustainability and environmental benefits.
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    Hydrothermal Synthesis of Waste Black Tea Pulp and Tomato Stem Hydrochars and Comparison of Their Adsorption Performance of Safranin Dye
    (Springer Int Publ Ag, 2023) Alterkaoui, Aya; Belibagli, Pinar; Gun, Melis; Isik, Zelal; Dizge, Nadir; Yabalak, Erdal
    In this study, hydrochar prepared from black tea (BT) and tomato stem (TS) using subcritical water (SW) conditions was used as an adsorbent for color removal from Safranin-O (SO-Basic Red 2) dye wastewater. The use of black tea hydrochar (BTH) and tomato stem hydrochar (TSH) was investigated in the removal of Safranin-O dye from aqueous solutions by the adsorption process. In optimization studies, variables impacting the adsorption process such as adsorbent size, pH, dye concentration, adsorbent dosage, and shaking time were examined. As a result of optimization studies, removal efficiencies of 85.15% for BTH and 81.5% for TSH were achieved. In this study, the reuse cycle was also examined. Adsorption isotherm models, adsorption kinetic models, and thermodynamic studies have been studied to explain the relationships between the adsorption processes taking place. Data appropriate for the Freundlich and D-R isotherm models as well as the PSO kinetic model were obtained for TSH while defining the Freundlich isotherm model and the pseudo-second-order (PSO) kinetic model for BTH.
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    Investigation of Antimicrobial Activity of Iron Oxide Nanoparticles (FeONPs) and Zinc Oxide Nanoparticles (ZnONPs) Produced with Aerial Part Extract of Cucumber
    (Springer, 2024) Alterkaoui, Aya; Eskikaya, Ozan; Ozdemir, Sadin; Yalcin, M. Serkan; Dizge, Nadir
    One of the most threatening factors to human and living health today, as in the past, is pathogens, which cause significant damage to health. Many materials are used to destroy such bacteria. The investigation of antibacterial properties of materials containing heavy metals produced with plant extracts continues. In this study, iron and zinc oxide nanoparticles (FeONPs and ZnONPs) were produced with cucumber aerial part extract. The nanoparticles have diameters ranging from 60 to 120 nm for FeONPs and 70 to 130 nm for ZnONPs. The antibacterial properties of the produced materials were investigated. The biological evaluation of the ZnONPs and FeONPs was also reported in this study. The antioxidant activity of ZnONPs and FeONPs was found 48.00%, and 40.65%, respectively, at 100 mg/L concentration. ZnONPs exhibited significantly antimicrobial activity than FeONPs. Both NPs showed excellent DNA nuclease activity and also E. coli cell viability was strongly inhibited at all tested doses. At 250 mg/L, ZnONPs inhibited P. aeruginosa and S. aureus biofilms by 90.1% and 94.0%, respectively. FeONPs also reduced biofilm formation against P. aeruginosa and S. aureus by 87.8% and 93.4% at 250 mg/L, respectively. However, when all the results were compared, it was observed that ZnONP had a slightly higher antioxidant effect than FeONPs. The antibacterial effect of cucumber, particularly extracted from its waste aerial parts, demonstrated promising potential in combating microbial infections. This effect is evidenced by the utilization of cucumber extract in the synthesis of nanoparticles, namely FeONPs and ZnONPs, which exhibited significant antibacterial properties. The study underscores the importance of exploring natural sources like cucumber in developing novel antimicrobial agents. Further research in this area could unveil additional mechanisms underlying cucumber's antibacterial activity and facilitate the development of effective antibacterial treatments derived from natural sources.
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    Production of Waste Tomato Stem Hydrochar (TS-HC) in Subcritical Water Medium and Application in Real Textile Wastewater using Photocatalytic Treatment System
    (Springer Int Publ Ag, 2022) Alterkaoui, Aya; Eskikaya, Ozan; Gun, Melis; Yabalak, Erdal; Arslan, Hudaverdi; Dizge, Nadir
    Dye-containing wastewater emerges in many fields, especially in the textile industry. This type of wastewater has to be treated because of its negative effects on the environment. The treatment of wastewater containing dyes employs a variety of treatment techniques. However, it is important to use treatment systems that use nanoparticles of biomaterial origin. In this study, the use of photocatalytic treatment system with hydrochar obtained from tomato stems (TS-HC) in the purification of Methylene Blue (MB) and Remazol Brilliant Blue R (RBBR) dyes was investigated. For the optimization of the photocatalytic treatment system, light source, pH, TS-HC amount and initial dye concentration were tested. Furthermore, TS-HC reuse tests were carried out at the found optimal conditions and it was determined that both dyes had 10 reuse cycles. Optimum conditions for MB dye was obtained by adding 1 g/L catalyst into the solution with a pH value of 8 and an initial concentration of 15 mg/L, and 100% dye removal efficiency under UVA light. 97.4% dye removal efficiency was obtained by adding 2 g/L catalyst to the wastewater (pH 2) containing 15 mg/L RBBR dye under UVA light. Characterization analyzes with SEM, EDX and XRD of hydrochar obtained from waste tomato stem were performed. As a result of the photocatalytic experiments, TS-HC catalyst was used in the decolorization of real wastewater. It has been determined that the catalyst can decolorize the dye-containing real wastewater up to the lower limit of the appropriate value (260 Pt-Co) of the Turkish Water Pollution Control Regulation.
  • Küçük Resim
    Öğe
    Synthesis of PES membranes modified with polyurethane–paraffin wax nanocapsules and performance of bovine serum albumin and humic acid rejection
    (IWA Publishing, 2023) Sert, Buse; Kaya, Gul; Ozay, Yasin; Alterkaoui, Aya; Ocakoglu, Kasım; Dizge, Nadir
    Membrane fouling is a serious handicap of membrane-based separation, as it reduces permeation flux and hence increases operational and maintenance expenses. Polyurethane–paraffin wax (PU/PW) nanocapsules were integrated into the polyethersulfone membrane to manufacture a composite membrane with higher antifouling and permeability performance against humic acid (HA) and bovine serum albumin (BSA) foulants. All manufactured membranes were characterized by scanning electron microscopy (SEM), scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), and contact angle. The contact angle of the pristine polyethersulfone (PES) membrane was measured 73.40 + 1.32. With the embedding of nanocapsules, the contact angle decreased to 64.55 + 1.23 for PES/PU/PW 2.0 wt%, and the pure water flux of all composite membranes increased when compared to pristine PES. The pristine PES membrane also has shown the lowest steady-state fluxes at 45.84 and 46.59 L/m2 h for BSA and HA, respectively. With the increase of PU/PW nanocapsule ratio from 0.5 to 1.0 wt%, steady-state fluxes increased from 51.96 to 71.61 and from 67.87 to 98.73 L/m2 h, respectively, for BSA and HA. The results depicted that BSA and HA rejection efficiencies of PU/PW nanocapsules blended PES membranes increased when compared to pristine PES membranes