Yazarlar
- Tanyol, Mehtap(22)
- Yildirim, Numan(17)
- Karataş, Mehmet(14)
- Erguven, Gokhan Onder(13)
- Topal, Murat(13)
- Ince, Muharrem(12)
- Yildirim, Nuran Cikcikoglu(10)
- Kismet, Yilmaz(9)
- Öbek, Erdal(8)
- Arslan Topal, E. Işıl(7)
- Etli, Serkan(7)
- Goksu, Ali(7)
- Gul, Muhammet(7)
- Gülmez, Nihan(7)
- Ogedey, Aysenur(7)
- Uysal, Turan(7)
- Yonten, Vahap(7)
- Gürler, Nedim(6)
- Kaya, Sema Kayapinar(6)
- Sabanci, Serdal(6)
- Serdar, Osman(6)
- Yön, Merve Şahin(6)
- Alp, Hevidar(5)
- Aydoğmuş, Ercan(5)
- Benli, Ahmet(5)
- Cemalgil, Selim(5)
- Erdemoğlu, Murat(5)
- Erust, Ceren(5)
- Ince, Olcay Kaplan(5)
- Oguz, Ensar(5)
- Torğut, Gülben(5)
- Yilmaz, Mehmet(5)
- Yucesan, Melih(5)
- Celik, Erkan(4)
- Demir, Veysel(4)
- Dener, Murat(4)
- Doğan, Akar(4)
- Fırat, Tülay(4)
- Pekdemir, Mustafa Ersin(4)
- Tanaydin, Mehmet Kayra(4)
Yayınlar
- MakaleYalnız künye2023Scopus SJRQ2Aluminum Recovery by Acid Leaching of Variously Enriched Pyrophyllite Ore: Effects of Pre-treatment Methods for Activation
Aydoğmuş, Ramazan; Erdemoğlu, Murat; Uysal, Turan
Effects of pre-treatment methods such as calcination for thermal activation and intensive milling for mechanical activation on the aluminum (Al) recovery by acid leaching of preliminarily enriched pyrophyllite ore via attrition scrubbing and froth flotation were investigated. XRD patterns of the calcined and the intensively milled samples were compared to determine the changes during the pre-treatment processes. Hot HCl solution was used for dissolution of aluminum to determine the Al recoveries from variously enriched and variously pre-treated pyrophyllite ore samples. Specific thermal and milling energies consumed per unit amount of ore were calculated, and the ideal activation method was suggested by comparing the activation methods in terms of energy consumption. Mechanical activation of the pyrophyllite concentrate obtained by attrition scrubbing rather than froth flotation was suggested for higher recoveries of aluminum from by acidic leaching. It was determined that operating cost (in terms of energy) of the mechanical activation is lower and aluminum recovery is higher than thermal activation. It was concluded that mechanical activation instead of thermal activation is more economical and environmentally friendly method.
AtıfScopus5WoS4OpenAlex5
İncele - MakaleAçık Erişim2023Scopus SJRQ3Optimization of shape factor by the response surface method, and the effect on sphalerite flotation recovery
Uysal, T.
Various morphological parameters that affect the flotation recovery of sphalerite were modelled and optimized using the response surface method (RSM). The effects of roughness value, shape factor, and collector concentration were investigated using the central composite full design method. The results were evaluated by analysis of variance. The optimum roughening time was found to be 25 minutes, the optimum roughness value was 2.9071 μm, and the optimum collector concentration was 0.001 M. Using these values, a flotation recovery of 98.01% was obtained. Similarly, in shape factor studies, the optimum grinding time was 15 seconds, the optimum roundness value 0.7421, and the optimum collector concentration 0.0009 M, which resulted in a flotation recovery of 94.30%. The average error between the optimization results and the experimental results was estimated to be less than 6%, and the R2 values were greater than 90%. The study shows that RSM can be effectively applied in finding the economic optimum condition for obtaining maximum flotation recovery with minimum reagent consumption.
AtıfScopus2WoS2OpenAlex2İncele - MakaleYalnız künye2023Scopus SJRQ1Laboratory evaluation of oak ash waste for use in hot mix asphalt modification
Geçkil, Tacettin; Beyza İnce, Ceren; Aksağan, Zülfükar
In this study, the effect of Oak Ash (OA), a biomass waste, on the mechanical properties of hot mix asphalt (HMA) was investigated and its usability in road engineering was evaluated. For this purpose, firstly, various physical and chemical properties of B70/100 penetration class pure asphalt, OA and crushed limestone aggregate were determined. Then, the optimum asphalt content (OAC) of the mixture was determined according to the Marshall mix design method using aggregate and pure asphalt. Based on this determined content, pure and OA added (1%, 2%, 4% and 6% by weight of asphalt) modified hot mix specimens were prepared. Pure and OA added modified mixture specimens were subjected to Marshall stability, indirect tensile strength (ITS), moisture damage, indirect tensile stiffness modulus (ITSM), static-dynamic creep and calorie tests. According to the results obtained, it has been determined that the OA additive has an improving effect on all mechanical properties of the mixtures, especially on the permanent deformation resistance at high temperatures. It is considered that the use of this additive at a rate of 2% in the hot mixture can increase the resistance of the pavement against deterioration and reduce the maintenance and repair costs of the road.
AtıfScopus26WoS25OpenAlex24İncele - MakaleYalnız künye2023Scopus SJRQ1A novel two-phase group decision-making model for circular supplier selection under picture fuzzy environment
Kaya, Sema Kayapinar
Circular supply chain management (CSCM), which incorporates circular thinking into supply chain management, promotes supply chain sustainability by offering a novel and compelling viewpoint. In the CSCM, supplier selection is crucial in establishing a competitive edge among businesses by decreasing environmental degradation and related supply chain expenses. This paper aims to propose a novel two-phase group decision-making approach, which combines the picture fuzzy Analytical Hierarchical Process (PF-AHP) and grey Measurement of Alternatives and Ranking According to Compromise Solution (MARCOS-G) model to select railway material suppliers within the scope of circular economy perspective. In group decision-making, a picture fuzzy number-based approach aggregates individual decision makers’(DMs) opinions and provides a lower level of computing complexity and a higher level of performance. The PF-AHP has been used to produce the weights of the criteria, and the MARCOS-G technique has been used to rank the suppliers and choose the most appropriate one. The results and verification of the novel method are carried out throughout a comprehensive sensitivity analysis. For this purpose, 50 scenarios with changes in the weight values of criteria were developed. In the validation analysis, a comparison with other grey COPRAS, TOPSIS, ARAS and WASPAS methods were performed. Due to the ranking results obtained from Spearman’s correlation analyses, the MARCOS-G is almost consistent and it can be seen that the A4 remains the top supplier in all 50 scenarios.
AtıfScopus34WoS30OpenAlex39
İncele - MakaleYalnız künye2023Scopus SJRQ1Evaluation of container port sustainability using WASPAS technique using on type-2 neutrosophic fuzzy numbers
Kaya, Sema Kayapinar; Kundu, Pradip; Görçün, Ömer Faruk
According to the common opinion in the literature, the sustainability of container ports is a tremendously complex topic owing to the maritime sector's excessively dynamic form and many highly complex, predictable and unpredictable uncertainties in this industry. The current paper proposes two powerful, practical, inspiring approaches to fill these gaps. It proposes a novel type-2 neutrosophic fuzzy numbers (T2NFNs) based Delphi method to determine the criteria logically and optimal and extends the WASPAS technique based on the T2NFNs for evaluating the alternatives. The current paper presents practical managerial implications that many stakeholders can consider, such as port authorities, ship owners, logistics service providers, governments, and local authorities, when making strategic and managerial decisions. In addition, the results of a comprehensive sensitivity analysis performed to test the robustness and applicability of the model approve the validity of the proposed T2NFN-based integrated approach.
AtıfScopus20WoS16OpenAlex24İncele - MakaleYalnız künye2023Scopus SJRQ2Investigation of Leaching Kinetics of Molybdenum from MoO3 Concentrate in Ammonia–Ammonium Nitrate Solutions
Karacahan, Mehmet Kayra
MoO3 is a widely accessible foundation material and the primary compound used to produce numerous molybdenum products. The ore was first roasted, and the leaching behavior of concentrated molybdenite mineral was assessed. The optimal conditions for the leaching process were identified in the second step, and in a subsequent stage, the process' kinetics were assessed. Ammonia and ammonium nitrate concentration were used as independent variables in the trials, and the central composite design approach was used to analyze the results. At the conclusion of the tests, the optimum concentrations of ammonia and ammonium nitrate were found to be 2.42 mol/L and 1.86 mol/L, respectively. On the rate at which molybdenum leached from MoO3, the influences of temperature, stirring speed, solid-to-liquid ratio, and particle size were investigated. It was found that the leaching rate increased when temperature and stirring speed increased, along with decreasing the solid-to-liquid ratio and particle size. Leaching efficiency of molybdenum (93%) such as temperature 20 °C, 1.859 mol/L ammonium nitrate concentration, 2.419 mol/L ammonia concentration, solid/liquid ratio 6/100 g/mL, stirring speed 400 rpm, and average particle size 0.115 mm optimum conditions have been achieved. The kinetic study proposed a mathematical model for the leaching process, which revealed that the leaching kinetics matched the Avrami model. This process' activation energy was determined to be 22.66 kJ/mol. Calcium molybdate is used in various fields, such as construction, transportation, anti-corrosion pigments, and flame retardants. Graphical Abstract: [Figure not available: see fulltext.]
AtıfScopus8WoS7OpenAlex9İncele - MakaleAçık Erişim2023Scopus SJRQ2Binary PCL–waste photopolymer blends for biodegradable food packaging applications
Gürler, Nedim; Pekdemir, Mustafa Ersin; Torğut, Gülben; Kök, Mediha
The aim of this study is to prepare waste photopolymer (WPP) / poly ɛ-caprolactone (PCL) blends that can be used in food packaging with different ratios (5%, 10%, 20% and 30%) WPP. The structural properties of the blend films were characterized by attenuated total reflection-fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Opacity, surface color, water vapor permeability and shape memory properties of these films were examined. Pure PCL film exhibited more thermal stability compared to PCL/WPP blend films. Therewithal, the glass transition temperature of the pure PCL film showed a shift. Water vapor permeability improved with the addition of WPP. L*, a* and transmittance values reduced with increasing WPP, but b* value increased. It was thought that these polymer blends would enable to be used as packaging material in terms of compatibility and waste evaluation.
AtıfScopus14WoS13OpenAlex14İncele - MakaleYalnız künye2023Scopus SJRQ3Synthesis, Characterization and Biocompatibility of Cross-linked Dicarboxylic Acids from Waste Potato Peel Starch
Paşa, S.; Gürler, N.; Erdoğan, Ö.; Cevik, O.
Abstract: People have become conscious about recycling or reusing many things they use in the 21st century because diminishing vital resources make it necessary, both personally and socially. The evaluation of waste is also critical in terms of national economies. In this study, starch dicarboxylic compounds were synthesized using waste potato peels (WPP) in the presence of sodium hypophosphite monohydrate as a catalyst for the formation of the ester cross-links. Adipic acid, succinic acid, and glutaric acid were employed with waste potato starch (WPS) to obtain cross-linked samples: WPS-A, WPS-S, and WPS-G, respectively. The obtained compounds were characterized by attenuated total reflectance Fourier transform infrared (FTIR-ATR), scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX), X-ray diffraction (XRD), and their cytotoxicity properties were investigated. The biocompatibility of the obtained WPS-dicarboxylic acid compounds against NIH-3T3 and L929 murine fibroblast cells with MTT assay was determined. Studies have shown that these compounds do not harm healthy cells and are found to be bioavailable.
AtıfScopus6OpenAlex6İncele - MakaleYalnız künye2023Scopus SJRQ1Adsorption potential of neodymium/alginate beads for removal of Congo red and Brilliant blue G from aqueous solution
Seker, S.; Karaaslan Ayhan, N.
In this study, neodymium/alginate (Nd/Alg) beads were prepared to removal of Congo Red (CR) and Brilliant Blue G (BBG) dyes from aqueous solution and the adsorption potentials of these dyes were investigated. For this, Nd/Alg beads prepared using crosslinking were characterized by FTIR, SEM–EDS and TGA. For the adsorption of CR and BBG dyes, the effects of various parameters including the amount of Nd in adsorbent (bead), pH, contact time, adsorbent amount, initial dye concentration and temperature were investigated. The optimum conditions for the effective removal of CR and BBG dyes were determined as Nd amount in bead: 3%, pH: 7, contact time: 60 min, bead amount: 15 mg, initial dye concentration: 25 mg/L and temperature 298 K. Adsorption isotherm studies (Langmuir and Freundlich isotherms) and kinetic studies (pseudo-first-order and pseudo-second-order) were carried out under optimum conditions. The adsorption data were found to completely follow Langmuir model for CR and BBG dyes. The maximum adsorption capacities were found to be 46.03 mg/g for CR and 25.25 mg/g for BBG under optimum conditions. The adsorption kinetic data of both dyes were found to be compatible with pseudo-first-order and adsorption processes were explained by intraparticle diffusion. According to thermodynamic studies, nature of adsorption reaction was spontaneous, exothermic and increasing randomness for both dyes. As a result, it can be concluded that Nd/Alg beads obtained with a natural polymer have low cost and high efficiency and even small amounts of these beads have high potential for treatment of high concentration dye wastewater.
AtıfScopus10WoS8OpenAlex10İncele - MakaleYalnız künye2023Scopus SJRQ1Carbide slag recycling to fabricate shape-stable phase change composites for thermal energy storage
Xiong, Yaxuan; Wang, Huixiang; Ren, Jing; Nevzat, Akkurt; Xu, Qian; Nie, Binjian; Li, Chuan; Ding, Yulong
The mining and processing of traditional skeleton materials inevitably generates carbon emissions and pollutes the surrounding environment. To make full use of industrial solid waste, this work innovatively used carbide slag as skeleton material and Na2CO3 as phase change material (PCM) to fabricate shape-stable phase change composites (SSPCCs) via the cold-compression & hot-sintering method. Seven SSPCCs were fabricated with different mass ratios of carbide slag to Na2CO3. Then, the thermal energy storage (TES) performance, mechanical property, micromorphology, chemical compatibility as well as thermal cycling stability were investigated. The results showed that the carbide slag could combine with Na2CO3 to fabricate SSPCCs; Sample CN5 achieved the optimal performance with the mass ratio 52.5:47.5 of carbide slag to Na2CO3; Sample CN5 achieved a TES density of 993 J/g in the range of 100 to 900 °C, a compressive strength of 22.02 MPa and a maximal thermal conductivity of 0.62 W/(m·K); Both carbide slag and Na2CO3 were distributed uniformly in sample CN5, while good thermal stability after the 100 heating/cooling cycles and good chemical compatibility between the carbide slag components and the Na2CO3 were observed.
AtıfScopus34OpenAlex30İncele - MakaleYalnız künye2023Scopus SJRQ2Contribution of Mechanical Activation for Obtaining Potassium Chloride from Microcline
Alyosif, Bahaa; Uysal, Turan; Aydemir, Muhammet Kürşat; Erdemoğlu, Murat
The effect of intensive milling on the conversion of microcline (KAlSi3O8) to potassium chloride (KCl) occurred during the chlorination roasting process for artificial KCl production was investigated. A feldspar ore with 10.89% K2O grade and containing microcline was dry milled by a planetary ball mill for mechanical activation. Milled ore mixed with calcium chloride was roasted at temperatures between 500 and 1000 °C to get the chlorination roasting process. The product was then leached in water to dissolve KCl occurring during the roasting, which will be precipitated from the pregnant leach solution by evaporation. Results showed that potassium recovery from the unmilled ore increased rapidly up to 800 °C, and dramatically decreased at higher temperatures due to the removal of KCl from the furnace by means of evaporation. A potassium recovery of 31.95% was achieved by the unmilled ore, whereas it was 88.43% when 15 min milled ore was roasted at 750 °C. It was concluded that intensive milling caused mechanical activation of microcline to reduce the roasting temperature of the chlorination roasting process.
AtıfScopus12WoS11OpenAlex10İncele - MakaleYalnız künye2023Scopus SJRQ2Engineering Properties of Geopolymer Mortars Containing Industrial Steel Shavings
Gülmez, Nihan; Koçkal, Niyazi Uğur
The purpose of using waste materials is to prevent the unnecessary use of resources and to reduce the amount of waste. Geopolymer, developed as an alternative to cementitious materials, prevents the depletion of natural resources and saves a large amount of energy. This paper presents the effect of waste steel shavings on the improvement of physical and mechanical properties of geopolymer mortars. For this purpose, geopolymer mortars were produced by using two binder types [slag (BFSb) and silica fume] as well as steel shavings in five different replacement percentages (0%, 2.5%, 5%, 7.5% and 10%) by volume instead of aggregate. A series of experiments on geopolymer mortars were carried out to determine properties such as bulk density, water absorption, apparent porosity, sorptivity coefficient, splitting tensile strength, flexural strength and compressive strength. Results showed that steel shavings recovered from metal processing and forming sector were highly effective at improving engineering properties of geopolymer mortars. Furthermore, although replacement of 20% by volume of BFSb with silica fume improved properties of geopolymer mortar, it was observed that the use of silica fume at higher ratios reduced mechanical properties by increasing porosity and sorptivity of BFSb-based geopolymer mortars.
AtıfScopus1OpenAlex1İncele - MakaleAçık Erişim2023Scopus SJRQ4The influence of microwave curing on the strength of silica fume-added fly ash-based geopolymer mortars
Yilmazer Polat, Berivan
Geopolymer concretes a substitute for traditional Portland cement as a more environmentally sustainable alternative. In addition, one of the most significant advantages of geopolymer concrete is the high setting speed that can be achieved with thermal curing, that is, the short curing period. Research on geopolymer concrete has focused on curing, where curing is usually done with conventional ovens. Microwave curing initiates heat generation at the molecular level, which results in a minimal heat increase on the surface of the specimens compared to traditional thermal curing methods. In addition, it provides internal, rapid, and homogeneous heating and rapid strength development. This study is based on research that examined the effect of microwave cure on the compressive strength of silica füme-modified geopolymer mortar. In the study, sodium silicate and sodium hydroxide were used for activation, and first of all, fly ash substituted geopolymer mortar specimens were subjected to conventional thermal curing in an oven. On the other hand, the mortar specimens with the same composition were subjected to short-duration (10 minutes) microwave curing at power levels of between 200-600 W. When the results were compared regarding compressive strength, void and per-cent water absorption, UPV, and SEM-internal structure examination, it was revealed that microwave curing could be used faster than the conventional oven curing method in silica füme-added fly ash-based geopolymer mortars. This research can be considered an essential step for further optimizing and popularising geopolymer concrete and microwave curing and proposes a method that should be considered in the future development of more sustainable construction materials.
AtıfScopus7OpenAlex7TR Dizin4
İncele - MakaleYalnız künye2023Scopus SJRQ1Ultrasound assisted adsorptive removal of Cd+2 ions from the water system using Bi2S3 nano/micro flowers
Kurnaz Yetim, N.; Aslan, N.; Özcan, C.; Koç, M.M.
Heavy metal ions threaten public health and marine life; thus, removal of heavy metals is essential for the environment. Bi2S3 nanostructures are active materials which used in various applications. In this work, we produced Bi2S3 nanoflowers using hydrothermal synthesis and assessed their Cd2+ ions removal capability. Structural properties of the Bi2S3 nanoflowers were assessed by various like scanning electron microscopy, X-ray diffraction. Chemical characteristics of the materials were confirmed using energy dispersive X-ray spectra. Different parameters affecting the Cd2+ ion recovery was worked some of which are adsorbent amount, Cd2+ ion concentration, pH, adsorbent time, eluent type and amount, etc. For cadmium, the optimum pH was determined 8.0 for 1 M HNO3 eluent. Optimum adsorbent amount was determined as 150 mg while optimum recovery duration was found as 30 min. Bi2S3 nanoparticles managed to achieve 99.3% Cd2+ recovery rate in 5 mL eluent volume, for optimum condition. The adsorption capacity of the Bi2S3 nanoflowers was found to be promising and therefore, it was illustrated that Bi2S3 nanoflowers are good candidates as sorbent for water remediation applications.
AtıfScopus3WoS3OpenAlex3İncele - MakaleYalnız künye2022Cevap Yüzey Metodolojisi Kullanılarak P(NIPAM-co-AN)/Kil Kompozit Üzerine İndigo Karmin Adsorpsiyonunun Modellenmesi ve Optimizasyonu
Tanyol, Mehtap; Pıhtılı, Güzin
Bu çalışmada yeni bir polimerik adsorban olan Poli(NIPAM-co-AN)/kil kompoziti yerinde polimerizasyon ile hazırlanmıştır. N-izopropilakrilamid, akrilonitril ve uygun miktarda alınan kilin (yaklaşık %5 w/w) kopolimerizasyonu, 10 mL 1,4-dioksan varlığında 65°C'de, AIBN (azobisizobütironitril) başlatıcısı varlığında gerçekleştirildi. NIPAM-AN/kil kompoziti IC (indigo karmin) boyasını sentetik atık sulardan uzaklaştırmak için yeni bir adsorban olarak kullanılmıştır. Üç önemli proses parametresi olan başlangıç indigo karmin konsantrasyonu (5-30 mg/L), adsorban dozu (10-80 mg) ve temas süresi (10-180 dakika) yanıt yüzeyi metodolojisi (RSM) ile birleştirilmiş. Merkezi Kompozit Tasarım (CCD) kullanılarak modelleme yapıldı ve en iyi indigo karmin giderme yanıtını elde etmek için optimize edildi. Çözeltideki indigo karmin miktarı, 650 nm dalga boyunda bir UV-görünür spektrofotometre kullanılarak ölçülmüştür. ANOVA (varyans analizi) istatistiksel değerine dayalı olarak, indigo karminin P(NIPAM-co-AN)/kil kompoziti üzerine adsorpsiyonu, çok düşük olasılık değeriyle (p
AtıfOpenAlex4TR Dizin1İncele - MakaleAçık Erişim2022Scopus SJRQ4Biyo-hidrometalurjik yöntemler ile kullanılmış vanadyum katalizörlerden vanadyumun geri kazanımı ve pilot ölçekli uygulamalar için tekno-ekonomik analiz
Erüst, Ceren
Sülfürik asit üretiminde katalitik indirgemeyi sağlayan vanadyum katalizörlerinin yaygın kullanımı, tehlikeli atık olarak kabul edilen kullanılmış katalizörlerin zamanla daha da artmasına neden olmaktadır. Kullanılmış vanadyum katalizörler (KVK), yüksek oranda SiO₂ ve ağır metal içeriğinin yanında kritik metal listesinde yer alan vanadyumu da içermektedir. Döngüsel ekonomi politikası uygulamalarına yönelik artan talep, bu atıklardan vanadyumun kazanımı için tekno-ekonomik açıdan uygun bir yol geliştirmeyi gerektirmektedir. Bu çalışmada, kimyasal liç (1 M sülfürik asit ve %1 h/h hidrojen peroksit) ve biyoliç (Acidithiobacillus ferrooksidans, Acidithiobacillus thiooxidans ve Leptospirillum ferrooxidans içeren karışık bakteri kültürü) yöntemleri kullanılmış ve KVK’lardan vanadyum kazanımı değerlendirilmiştir. Katalizörlerde bulunan vanadyum, hidrometalurjik ve biyohidrometalurjik yöntemlerle yüksek verimle (%96,8 ve %97,1) kazanılmıştır. Geliştirilen modelleme de biyohidrometalurjik yöntemin yatırım maliyetinin 3,8 yılda geri karşılanacağı ve geri ödeme yüzdesi %89,32 olarak öngörülmüştür. Hidrometalurjik yöntemde ise, yatırım maliyetinin 1,2 yılda karşılanacağı ve geri ödeme yüzdesinin %80,3 olduğu belirlenmiştir. Bu sonuçlar hidrometalurjik yaklaşımın daha hızlı, biyohidrometalurjik yaklaşımın ise daha ekonomik bir yöntem olduğunu göstermiştir.
- Derleme MakaleAçık Erişim2022Scopus SJRQ4Kritik Hammaddelerin Geri Dönüşüm ile Döngüsel Ekonomiye Kazandırılması
Okudan, Mediha Demet; Akcil, Ata; Erust, Ceren
Endüstri 4.0 devrimi ve Nesnelerin İnterneti (IoT) gibi teknolojilerle dijitalleşme, kaynaklarımızın ve ekonomilerimizin döngüsel olmasını gerektirmektedir. Başta Avrupa Birliği olmak üzere tüm ülkeler, kritik hammaddelerin sorumlu tüketiminin, üretiminin ve geri dönüşümünün sürdürülebilir kalkınma hedeflerine ulaşmanın bir yolu olarak çok önemli olduğu konusunda hemfikirdir. Ömrünü tamamlamış ürünlerden kritik hammaddelerin geri kazanılması için uygun maliyetli bir geri dönüşüm yöntemi, madencilikten çok daha az çevresel etkiye sahiptir. Biyo & hidrometalurjik yöntemler, kritik hammaddelerin, özellikle nadir toprak elementlerinin (NTE) çıkarılması için hızlı gelişen, seçici, çevre dostu ve uygun maliyetli teknolojilerdir. Bu makale, ikincil kaynaklara genel bir bakış sağlamakta ve kritik hammaddelerin kazanımı için ekonomik bir yol olarak hizmet edebilecek bazı umut verici yöntemlerin kullanımına ilişkin yürütülen çalışmaların senaryosunu özetlemektedir.
AtıfOpenAlex4TR Dizin1İncele - MakaleAçık Erişim2022The Mechanical and Thermal Behavior of Electrostatic Powder Coating Waste Reinforced Epoxy Composites
Kismet, Yilmaz; Doğan, Akar
The present study investigates the mechanical and thermal behavior of polyurethane electrostatic powder coating waste reinforced epoxy composites. Different percentages of electrostatic powder coating waste (3, 6, and 9 wt. %) reinforced epoxy composites were manufactured. The mixture of polyurethane powder coating waste and epoxy was mixed with a magnetic stirrer to ensure that the polyurethane powder coating waste was dispersed well in the epoxy, and then the mixture was placed under vacuum and air bubbles were removed. Tensile and three-point tests were performed to determine the changes in the mechanical properties of the materials, and thermogravimetric analysis was conducted to determine the thermal properties. In addition, images were taken with scanning electron microscopy for morphological features. The study revealed that the three-point flexural strength was increased by up to 8% and 15%, respectively, in the samples with 3 wt% and 6 wt% powder coating waste additives. The material's tensile strength decreased by up to 27% with powder coating waste reinforcement. However, the opposite trend was observed in the modulus of elasticity. Additionally, no significant difference was observed in the thermal properties of the materials. Also, from scanning electron microscopy analysis, it was observed that the inclusion of powder coating waste changed the damage mechanism of the material.
- MakaleAçık Erişim2022Kyb'de kullanılan cam kumun kyb yük-deplasman ilişkisinin davranışı üzerindeki etkisinin araştırılması
Etli, Serkan
Doğada atık olarak bulunan cam, özellikle son yıllarda sıcaklığın artmasıyla birlikte ormanlık alanlarda ve düzenli depolama alanlarında çıkan yangınların sebepleri arasında görünmektedir. Çalışma kapsamında atık sahalarından ve doğal ortamdan toplanan atık soda cam şişeleri öğütüldükten sonra 0.25-0.5 mm arasında eleklerden geçirilerek ayrıştırılmıştır. Bu cam kum ile üretilen kendiliğinden yerleşen beton (KYB), içindeki doğal kum ile değiştirilmiştir. Doğal kum ve cam kumu, hacimce %5 ila %35 arasında %5'lik artışlarla ikame edilmiştir. KYB, yönetmeliklerle ilgili standartları sağladığı taze özellik testleri ile test edilmiştir. Elde edilen karışımlardan 7 ve 28 günlük numunelerde gerilme-şekil değiştirme ilişkileri elde edilmiştir. Elde edilen bu ilişkiler literatürde sıklıkla kullanılan beton modeli ile karşılaştırılarak değerlendirilmiştir. Ortaya çıkan yük-deplasman ilişkilerinin özellikle 7 günlük yaşta iyi bir şekilde seçilen modele yakınsadığı ancak özellikle başlangıç kısmında 28 günlük yaşta kullanılan modelden ayrıldığı görülmüştür.
AtıfOpenAlex10TR Dizin3İncele - MakaleAçık Erişim2022Hidrojel Esaslı Kompozit Kullanılarak Naftol Yeşili B içeren Atıksuların Arıtımında Ortam Parametrelerinin Etkisi
Tanyol, Mehtap; Pıhtılı, Güzin
Bu çalışmada, EuCl3 ile katkılanmış poli (4-vinilpridin-ko-akrilamid) {P(4-VP-ko-AAm)/EuCl3} hidrojel kompozit adsorbent olarak kullanılarak atıksulardan naftol yeşili B boyasının giderim verimliliği araştırılmıştır. Naftol yeşili B adsorpsiyon verimliliğinin pH, adsorbent madde miktarı, başlangıç naftol yeşili B boya konsantrasyonu, sıcaklık ve temas süresi gibi değişkenlere bağımlılığı kesikli sistemde incelenmiştir. En yüksek giderim verimi 30 mg/L başlangıç naftol yeşili B konsantrasyonu, 0,05 g/100 mL P(4-VP-ko-AAm)/EuCl3 dozajı, pH=5,42 ve 25 °C sıcaklıkta %98,40 olarak elde edilmiştir. Deneysel denge verileri Langmuir izoterm modeli ile daha iyi uyum sağlamıştır. Kinetik sonuçlar, adsorpsiyon prosesinin hız belirleme basamaklarından biri olarak iç difüzyon ile yalancı ikinci derece kinetiği ile tanımlanabileceğini göstermiştir. Elde edilen deneysel sonuçlar, adsorbent olarak P(4-VP-ko-AAm)/EuCl3 hidrojeli kullanılarak naftol yeşili B boyasının başarılı bir şekilde atıksulardan giderilebileceğini göstermiştir.
