Yazarlar
- Bulut, H. Alperen(11)
- Ertugay, Neşe(6)
- Gürses, Ahmet(6)
- Manga, Muge(6)
- Aka, Salih(5)
- Baş, Fatih İrfan(5)
- Destek, Mehmet Akif(5)
- Yavuz, Emre(5)
- Akoğuz, Harun(4)
- Akşit, Zeynep(4)
- Caglar, Bulent(4)
- Demirci, Oğuz Kürşat(4)
- Kandil, Ufuk(4)
- Kocakaplan, Nihal(4)
- Kumbasaroglu, Atila(4)
- Malkoç, Emine(4)
- Akın, Fatih(3)
- Açikyildiz, Metin(3)
- Bayata, Halim Ferit(3)
- Bayrak, Osman Ünsal(3)
- Dede, Tayfun(3)
- Doğan, Bilge(3)
- Doǧar, Çetin(3)
- El Nemr, Ahmed(3)
- Ertugay, Nese(3)
- Gençcelep, Hüseyin(3)
- Güner, Eda Keleş(3)
- Jagan, J.(3)
- Keleş, Ömer Faruk(3)
- Samui, Pijush(3)
- Turan, Ahmet İhsan(3)
- Ulusu, Hayati(3)
- Ulusu, İsmet(3)
- Yalciner, Hakan(3)
- Yavuz, Sevtap Caglar(3)
- Yılmaz, Mehmet(3)
- Çolak, Muhammed Ali(3)
- Özdemir, Agah Oktay(3)
- Şahin, Remzi(3)
- Acar, Filiz Nuran(2)
Yayınlar
- ArticleYalnız künye2024Experimental investigation on mechanical properties of sustainable roller compacted concrete pavement (RCCP) containing waste rubbers as alternative aggregates
Keleş, Ömer Faruk; Bayrak, Osman Ünsal; Bayata, Halim Ferit
Different types of solid waste are generated every year due to global industrialization. With the rapid growth of the automobile industry, the disposal of billions of waste rubbers (WR), which pollute the environment and cannot be disposed of properly, is emerging as an urgent matter of concern. Recycling waste rubbers by using them on pavements will contribute to the elimination of ecological and economic problems. In this study, the effects of waste rubbers on the mechanical properties of roller-compacted concrete pavement (RCCP) were investigated by obtaining sustainable RCCP mixtures using different types of waste rubbers as coarse and fine aggregate substitutes. In this context, waste rubbers with three different sizes (powder, crumb and shredded) were substituted for aggregate by volume at seven levels (0%, 2.5%, 5%, 7.5%, 10%, 20% and 30%) with a maximum of 30% in RCC mixtures. Unit weight, mechanical properties, modulus of elasticity and ultrasonic pulse velocity (UPV) were evaluated and compared according to the waste rubber content in the RCC mixtures. In addition, microstructural analysis of the mixtures was performed through scanning electron microscopy (SEM). The experimental results revealed that the compressive, flexural and splitting tensile strength and modulus of elasticity decreased with increasing waste rubber content in RCC. The utilization of waste rubber increased the ductility of RCC and decreased the density to produce lighter concrete. RCC with a compressive strength of about 30 MPa could be obtained by substituting 10% of waste rubber for aggregate. Thus, the utilization of high waste rubber content in pavements was feasible. This study can contribute to a more sustainable RCCP production by replacing natural aggregates with waste rubbers.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Impact of Internet Use on Ecological Footprint: Panel Data Analysis for Fragile Five Countries (Brazil, India, Indonesia, South Africa, and Turkiye); [Wpływ korzystania z Internetu na ślad ekologiczny: analiza danych panelowych dla pięciu krajów niestabilnych (Brazylia, Indie, Indonezja, Republika Południowej Afryki i Turcja)]
Akın, Fatih; Özgün, Fergül
In addition to the views that claim that the development of information and communication technologies will result in less environmental pollution and better environmental quality, there are also views that claim that it will increase environmental pollution. In this study, the relationship between environmental quality and information and communication technologies for the 1995–2021 period for the Fragile Five countries was examined using the panel augmented autoregressive distributed lag (ARDL) bounds test method. Ecological footprint was used to represent environmental quality, and the proportion of individuals using the internet was used to represent developments in information and communication technologies. In addition, economic growth, energy consumption, and financial development are included in the model as explanatory variables. According to the results of this study, internet use reduces the ecological footprint in both the short and long run. While financial development reduces the ecological footprint in the long run, energy consumption increases both in the short and long run. Economic growth, on the other hand, increases the ecological footprint in the short run. In line with these results, expanding internet use in the Fragile Five Countries may increase environmental quality.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Yogurt consumption in Türkiye, commercial use of yogurt yeast, and evaluation of consumers' attitudes toward yogurt-like products produced using different yeasts; [Türkiyede’ki yoğurt tüketimi, ticari olarak yoğurt mayasının kullanılması ve tüketicilerin farklı mayalıklar kullanılarak üretilen yoğurt benzeri ürünlere karşı tutumlarının değerlendirilmesi]
Yangilar, Filiz; Karaca, Özlem
This study aims to determine the consumption of ready-made and homemade yogurt, the level of knowledge about different yeasts (chickpea, dewdrop, sugar, cone, vinegar, etc.) that can be used while fermenting yogurt, and their attitudes toward using yogurt leavening in case it is sold commercially. The research was carried out with 500 participants, 427 females (85.4%) and 73 males (14.6%) between 18 and 74. 77.0% of the female participants and 61.6% of the men shared that they had fermented yogurt. 80.1% of the women and 84.9% of the men did not know about using different raw materials as leavening agents other than yogurt yeast. According to their educational status, 54.5% of associate degree graduates wanted yogurt yeast to be sold in the market, like rennet, 55.9% of postgraduate participants wanted to use it if it was sold, and 48.5% of them said yes to the reliability of yogurt yeast. In addition, the participants stated that they liked to consume yogurt in general, found homemade yogurt healthier, and made their yogurt.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2024Semiconductor Catalyst: Investigation for the Degradation of BB9 Azo Dye by Sonophotocatalytic Process
Ertugay, Neşe; Acar, Filiz Nuran
The degradability of an azo dye, Basic Blue 9 (BB9), by heterogeneous sonocatalytic, photocatalytic, and sonophotocatalytic oxidation process was examined using simultaneous irradiation of UV-C at 254 nm and power ultrasound at 20 kHz accompanied with a heterogeneous catalyst zinc oxide (ZnO) in the study. The effect of ZnO dose and initial dye concentration was investigated on the dye degradation in sonocatalytic, photocatalytic, and sonophotocatalytic processes at pH 5.5 (natural pH). The results obtained from the experimental studies were evaluated with the parameters of color removal, pseudo-first-order rate constant, and half-life time. It was observed that the degradation of BB9 dye by the sonophotocatalytic process was higher compared to both sonocatalytic and photocatalytic degradation. as follows: 97.46, 48.64 and 56.88 %. The combination of sono and photocatalytic showed a remarkable synergistic effect in BB9 degradation. The kinetics of sonophotocatalytic oxidations, depending on the initial BB9 dye concentration, were found to follow the Langmuir-Hinshelwood model. In addition, the effect of ZnO on the sonophotocatalytic oxidation process was higher compared to titanium dioxide and zero-valent iron as follows: 97.47, 80.77 and 80.62 %.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2024The effects of financial development, trade and energy consumption on environmental degradation: Evidence from APEC countries
Balli, Esra; Çatik, Abdurrahman Nazif; Uğur, Mehmet Sedat; Sigeze, Ciler
This paper investigates the relationship among CO2 emissions, energy consumption, economic growth, financial development, and trade in APEC countries based on quarterly data from 1985:Q4 to 2020:Q4 utilizing the Method of Moments Quantile Regression (MMQR). The results demonstrate that both GDP and energy consumption have a positive and statistically significant effect on CO2 emissions. However, this effect diminishes as the conditional quantile of CO2 increases. Additionally, the study reveals that financial development has a positive and significant impact on CO2 emissions, with its influence increasing at higher quantiles. The MMQR estimates suggest that increasing trade openness has led to improvements in environmental quality. Based on these findings, it is recommended that APEC countries implement environmentally friendly policies to achieve sustainable economic development in the region. Hence, it is essential for financial development, energy consumption, and trade openness policies to align with strategies aimed at reducing environmental degradation.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Investigating the usability of kevlar and steel fibers as a hybrid in concrete pavements
Mola, Erhan; Bayrak, Osman Ünsal; Baş, Fatih İrfan; Bayata, Halim Ferit
In this study, the hybrid usage of Kevlar and steel fiber in concrete pavements was investigated. For this purpose, the concrete was designed using the water/binder ratio (0.40, 0.45, 0.50), silica fume (instead of cement 0, 5, 10%), Kevlar fiber (0 gr/m3, 500 gr/m3, 1000 gr/m3) and steel fiber (0 gr/m3, 500 gr/m3, 1000 gr/m3). Taguchi method was used as the experimental design, and optimum levels of parameters were determined for 28-days compressive strength, flexural strength, and toughness. According to the experiments and observations, the positive effect of Kevlar fiber upon energy absorption capacity (toughness), compressive and flexural strength of concrete was determined. Using only Kevlar fiber increasing up to 5.1% in compressive strength and up to 14.5% in flexural strength were observed. Considering the obtained results, Kevlar was noticed as a possible recycling material to be introduced into the economy by adding concrete.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2024Investigation of Mazidagi phosphate ore in wet flue gas desulphurization
Mazlumoglu, Hayrunnisa; Gulaboglu, M. Sahin
The employment of Mazidagi phosphate ore for wet flue gas desulphurization was investigated. The ore was exposed to sulfation processes in a three-phase double-stirred reactor to determine the effects of certain parameters on SO2 absorption. The absorption rate significantly increased with inlet SO2 concentration, gas flow rate, stirring speeds, and solid concentration but not with temperature. The absorption rate increases as the mass transfer coefficients and interface area value increase with stirring speeds. These parameters have also a prominent impact on the absorption rate depending on the dissolution rate of CaCO3. Based on these, the most effective parameters on SO2 absorption are liquid-phase stirring speed and suspension concentration, and the process is diffusion-controlled in the liquid phase. In addition, optimum conditions were determined, and then the ore was exposed to sulfation processes via a semi-batch operation mode. A comparison between raw and sulfated ore was examined for the changes in physical structure and chemical composition. Although the ratios of fluorapatite and carbonate-fluorapatite remained nearly constant, the ratio of calcite decreased significantly. It was determined from these investigations that the calcite in the phosphate ore has been converted into the CaSO3∙½H2O compound. Consequently, both the calcite in the phosphate ore was utilized effectively for wet flue gas desulphurization, and a phosphate-rich industrial product was obtained.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024The Effect of Different Proportions of Waste Rubber Substitution on Alkali-Silica Reaction and Mechanical Properties in Mortars
Kandil, Ufuk; Bulut, H. Alperen
This study investigates the alkali-silica reaction (ASR) and mechanical properties of mortars containing crumb and powder rubber instead of river sand. In this regard, mortars were produced using waste rubber whose ratios in the mixture are 0%, 3%, 6%, 9%, 12%, 15%, 18%, and 21%. ASR expansion, compressive and flexural strength tests were conducted on the samples. ASR measurements were performed on days 3, 7, 14, 21, and 28. Besides, at the end of the ASR experiment, the microstructures of the mortars were examined using scanning electron microscope (SEM) images. Examining the results of this study reveals that the use of waste rubber in rising portions in the mortars led to an increase in the ASR expansions of the mortars. The study shows that the ASR expansions of the mortar samples that have 9% and 15% waste rubber replacement are comparatively higher than the other mortar samples. Furthermore, the results of the SEM analysis verified this finding. The study demonstrates that 3% of waste rubber mortar samples have the highest compressive and flexural strengths. On the other side, the ASR expansion of the mortars with 3% substituted waste rubber was considerably low compared to other mortars containing waste rubber. These findings (ASR, compressive and flexural strength tests results) show that using 3% waste rubber is ideal for producing mortars and supports a sustainable production approach in the sector.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Prussian blue modified magnetite decorated MW-CNT nanocomposite: synthesis, characterization and potential use as Photo-Fenton catalysts for phenol degradation
Gögen, Yusuf; Koçak, Çağrı Ceylan; Karabiberoğlu, Şükriye; Polatdemir, Elmas; Aslaner, Harun; Zorlu, Rabia; Çağlar, Bülent; Çirak, Çağrı; Özdokur, Kemal Volkan
Removal of organic pollutants with green and efficient methods is an important goal for researchers studying environmental pollution. Photo-Fenton systems with composite catalysts are a promising alternative for efficient water treatment. In this study, Prussian blue modified magnetite decorated multi-walled carbon nanotubes (MW-CNT) nanocomposite was prepared and for the first time applied to the Photo-Fenton degradation of phenol. The catalyst was prepared by rapid hydrothermal method. XPS, SEM–EDX, XRD, FTIR, UV–Vis–NIR, EIS techniques were used for characterizing the functionalities and morphology of the catalyst. The effect of initial H2O2 concentration, catalyst mass, and initial pH of the phenol solution was investigated. Experimental results showed that 100 mg dm−3 of phenol could be degraded completely in 15 min at pH 7. This study describes the synthesis of the new Photo-Fenton catalyst for highly effective phenol treatment.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2024Examination of mechanical, permeability, and durability properties of sustainable lightweight concrete composites with natural perlite aggregate
Bulut, H. Alperen
This article presents the outcomes of a comprehensive study utilizing all-natural perlite in producing lightweight aggregate concrete composites and investigating the mechanical, permeability, and durability properties. With this aim, lightweight concrete composites were produced using 10%, 20%, 30%, 40%, 50%, 75% and 100% of natural perlite aggregate in concrete production. In addition to fresh density, compressive strength, ultrasonic pulse velocity (UPV), dynamic modulus of elasticity, capillary absorption, electrical resistivity, acid and sulfate attack tests were carried out on 28–56–90-day-ϖold concretes. Accordingly, the highest compressive strength value was obtained after 90 days using 10% natural perlite (62.42 MPa for NP10/90). In terms of UPV values, concretes with natural perlite were able to produce good or excellent class concretes. The experimental results indicated that the increase in the dynamic modulus of elasticity of concretes cured for 90 days (35 GPa for NP100/90) can be up to 14% compared to concretes cured for 28 days (30.7 GPa for NP100/28). Capillary absorption coefficients decreased in all concretes at advanced ages. The electrical resistivity value of concrete with 100% natural perlite (139.75 kΩ-m for NP100/90) was 140% higher than the control concrete (58.14 kΩ-m for C/90). It was observed that insulating concrete could be produced with an increase in the use of natural perlite at advanced ages. It was determined that concretes with 75% and 100% natural perlite exhibited high resistance against acid and sulfate attacks. The 30% perlite ratio was the critical ratio against aggressive solutions. In line with the aim of the study, it has been proved that lightweight concretes with a high natural perlite dosage can be produced in terms of permeability and durability properties without compromising mechanical strength. Graphical abstract: (Figure presented.)
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Analyzing the load capacity curve hypothesis for the Turkiye: A perspective for the sustainable environment
Caglar, Abdullah Emre; Destek, Mehmet Akif; Manga, Muge
Although it takes time to achieve a sustainable environment, this goal can be possible with the Sustainable Development Goals. The transition from gray energy sources to green in the 21st century is among the important policy goals of global economies. Since this process is long, countries focus on energy efficiency as part of their carbon reduction policies. In this context, this study investigates the impact of clean energy technologies on environmental quality in Turkiye. Using the load capacity curve (LCC) hypothesis, human capital, income, and natural resources are theoretically added to the balance model. The novel Augmented ARDL with Fourier terms approach is used in the empirical analysis. As a result of the analysis, the LCC hypothesis is valid, and income will support environmental quality after a certain level. While human capital increases environmental quality, natural resources bring environmental pollution. Finally, it is determined that clean energy technologies have not yet reached the level that enables carbon reduction. The finding that clean energy technologies are insufficient for Turkiye, as a result of empirical analysis, shows the uniqueness of this study. With our new findings, policymakers can take action for a sustainable environment. Since Turkiye has to ensure energy security due to its regional characteristics, it should increase investments in clean energy technologies. Based on empirical findings, clean energy technologies will gain momentum as policymakers support human capital.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Mechanical properties of cement-based composites incorporating eco-friendly aggregate of waste rubber
Bulut, H. Alperen; Kandil, Ufuk
The purpose of this study is to evaluate the waste tires that harm the environment as aggregate in concrete and to examine the effect on the mechanical properties of concrete. Three different classes (powder, crumb and chips) of waste rubber with seven different ratios (0%, 4%, 8%, 12%, 16%, 20% and 24%) and two different water to cement ratio (0.4 and 0.5) were used in concrete production. In this regard, this study conducted various experiments consisting of 28 and 90 days of the curing process to determine the properties of unit weight, compressive, flexural, and splitting tensile strength, along with ultrasonic pulse velocity (UPV) and dynamic modulus of elasticity. The waste rubber concrete with the highest compressive strength at the end of 90 days is the concrete that includes 4% waste rubber (0.4WR4) with 58.81 MPa. Concrete containing 8% waste rubber has the highest UPV of 5660 m/s after 90 days. The increase in the water/cement ratio from 0.4 to 0.5 and the waste rubber ratio cause deterioration in the mechanical properties of concrete. Although the use of waste rubbers does not bring an increase in strength, it is feasible to produce high strength concretes with 4% and 8% waste rubber substitution ratios. The water/cement ratio and curing time were highly effective on the mechanical properties of rubberized concrete.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024A different approach for green concrete production: Determination of the effect of e-waste and waste rubber powder on durability properties of concrete
Bulut, H. Alperen
This study was carried out to present a different approach to green concrete production by utilizing electronic waste (e-waste) and waste rubber powders in order to provide a solution to both the cost and carbon footprint problems arising from the rapid consumption of aggregate resources and cement. For this purpose, 0%, 5% and 10% of ewaste was utilized instead of aggregate and 0%, 2.5% and 5% of waste rubber powder was utilized instead of cement. In addition, mixtures in which both wastes were combined in concrete were also prepared and comparisons were conducted. Capillary water absorption, acid and sulfate attack tests were carried out on the concretes with different wastes at the end of 28 and 90 days. The capillary water absorption of concrete produced with 5% waste rubber powder at the end of 28 days (P5E0/28) was 80% less than the control concrete (C/28) (these values were 0.46, 2.36 respectively). It was determined that the utilization of waste rubber powder had a decreasing effect on the compressive strength losses of the concretes after acid attack compared to the control concrete, while e-waste had an increasing effect. It was determined that the compressive strength losses of the concretes in which waste rubber powder and e-waste were combined against sulfate attack were positively differentiated from both control concrete and concretes produced with single waste type. In parallel with the weight and compressive strength losses obtained after acid and sulfate attack, the results of the visual analyses of the concretes were similar. The use of 5% waste rubber powder in the concrete produced the greatest results. In addition, the ideal ratio between concretes in which e-waste and waste rubber powder used together was determined as 5% waste rubber powder and 5% e-waste. The results verified that e-waste and waste rubber powder can be considered for the production of green concrete.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Evaluation of the effect of E-waste on the permeability properties of polymer concrete composites and their behavior in aggressive environments
Aydın, Merve; Bulut, H. Alperen
The rapid increase in the number of electronic products worldwide, in terms of both variety and advanced technology, together with the decrease in costs, has led to the generation of a large amount of electronic waste (e-waste), which has significantly increased environmental pollution. This study was conducted to investigate the hypothesis that the adhesion of polymer binders and plastic origin e-waste will be more effective and stronger, and therefore have a positive effect on the permeability properties of polymer concrete and its behavior against aggressive solutions. For this purpose, quartz aggregates and gravel used as an aggregate in polymer concrete were replaced with 0%, 3%, 6%, 9%, 12% and 15% e-waste. In the study where unsaturated polyester resin was used as a binder, the changes in the permeability properties (capillary water absorption, rapid chloride permeability) of the e-waste polymer concrete and its behavior against aggressive solutions (acid and sulfate attacks) were evaluated after 7, 28 and 90 days. In addition, mechanical experiments were conducted and comparisons were made. After the control concrete, the highest compressive strengths were obtained from the polymer concrete specimens using 3% e-waste, measured as 59.05 MPa, 64.5 MPa and 73.05 MPa after 7, 28 and 90 days, respectively. The research showed that polymer concretes with capillary water absorption coefficient values close to zero after 90 days can be produced with using up to 9% e-waste. The use of e-waste as an aggregate in polymer concrete at 3%, 6% and 9% e-waste, in particular, produced concrete with a high resistance to acid and sulfate attacks. The hypothesis of the study was confirmed after extensive experiments. Graphical Abstract: (Figure presented.)
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Mandarin biochar-CO-TETA was utilized for Acid Red 73 dye adsorption from water, and its isotherm and kinetic studies were investigated
Eleryan, Ahmed; Güner, Eda Keleş; Hassaan, Mohamed; El-Nemr, Mohamed A.; Ragab, Safaa; El Nemr, Ahmed
Environmental pollution is a major issue today due to the release of dyestuff waste into the environment through industrial wastewater. There is a need for affordable and effective adsorbents to remove harmful dyes from industrial waste. In this study, Mandarin biochar-CO-TETA (MBCOT) adsorbent was prepared and used to remove Acid Red 73 (AR73) dye from aqueous solutions. The efficiency of dye removal was influenced by various factors such as solution pH, contact time, initial AR73 dye concentration, and MBCOT dosage. All experiments were conducted at 25 ± 2 °C, and the optimal pH was determined to be 1.5. The optimal conditions for dye removal were found to be an AR73 dye concentration of 100 mg/L, an MBCOT dosage of 1.5 g/L, and a contact time of 150 min, resulting in a 98.08% removal rate. Various models such as pseudo-first-order (PFO), pseudo-second-order (PSO), film diffusion (FD), and intraparticle diffusion (IPD) were used to determine the adsorption kinetics of AR73 dye onto MBCOT. The results showed that the PSO model best explains the AR73 dye adsorption. Furthermore, Langmuir and Freundlich's isotherm models were studied to explain the adsorption mechanism using experimental data. The adsorption capacities at equilibrium (qe) in eliminating AR73 dye varied from 92.05 to 32.15, 128.9 to 65.39, 129.25 to 91.69, 123.73 to 111.77, and 130.54 to 125.01 mg/g. The maximum adsorption capacity (Qm) was found to be 140.85 mg/g. In conclusion, this study demonstrates that biochar produced from mandarin peels has the potential to be an effective and promising adsorbent for removing AR73 dye from water.
RDL Kalıcı Kaydıİncele - Review ArticleAçık Erişim2024Wastes in Automotive Maintenance Businesses, Its Effects on Employees and Precautions
Çetin, Murat; Demirci, Oğuz Kürşat
This study offers an exhaustive analysis of the emissions and waste produced by vehicle maintenance and repair activities, underscoring their detrimental impacts on the health and ergonomic conditions of service workers. It underscores the critical need for the implementation of straightforward yet effective measures to mitigate these adverse effects. The paper delineates a variety of strategies aimed at enhancing the well-being of maintenance personnel by minimizing their exposure to harmful substances and improving workplace ergonomics. Heightened environmental awareness has positively influenced research on waste disposal methods. Implementing environmentally friendly waste and emission disposal methods in automotive maintenance is projected to reduce costs for mechanics and operators. Furthermore, the study elaborated on the comprehensive processes undertaken in automotive maintenance facilities, detailing the journey of waste from its origin to its final disposal. Effective management of these processes provides significant environmental and economic benefits. Additionally, the study presents a series of evidence-based recommendations designed to cultivate a safer and healthier working environment for automotive service professionals. These recommendations aim to improve overall working conditions in the industry by contributing to the enhancement of occupational health and safety standards. Through these measures, the research advocates for a comprehensive approach to occupational health within the automotive repair industry.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Synthesis and characterization of iron oxide-commercial activated carbon nanocomposite for removal of hexavalent chromium (Cr6+) ions and Mordant Violet 40 (MV40) dye
Mohamed, Soha Mahrous Ismail; Yılmaz, Murat; Güner, Eda Keleş; El Nemr, Ahmed
Iron Oxide-commercial activated carbon nanocomposite (CAC-IO) was prepared from commercial activated carbon (CAC) by the co-precipitation method, and the resulting nanocomposite was used as an adsorbent to remove hexavalent chromium (Cr6+) ions and Mordant Violet 40 (MV40) dye from wastewater. The produced materials (CAC, CAC after oxidation, and CAC-IO) were comparatively characterized using FTIR, BET, SEM, EDX TEM, VSM, and XRD techniques. The adsorption mechanism of Cr6+ ions and MV40 dye on CAC-IO was examined using Langmuir and Freundlich isotherm models. Different models were applied to know the adsorption mechanism and it was obtained that Pseudo-second order fits the experimental data better. This means that the adsorption of the adsorbate on the nanocomposite was chemisorption. The maximum removal percent of Cr6+ ions by CAC-IO nanocomposite was 98.6% determined as 2 g L–1 adsorbent concentration, 100 mg L–1 initial pollutant concentration, solution pH = 1.6, the contact time was 3 h and the temperature was room temperature. The maximum removal percentage of Mordant Violet 40 dye (C.I. 14,745) from its solutions by CAC-IO nanocomposite was 99.92% in 100 mg L–1 of initial dye concentrations, 1.0 g L–1 of adsorbent concentration, solution pH = 2.07, the contact time was 3 h. The MV40 dye adsorption on CAC-IO was the most fitted to the Freundlich isotherm model. The maximum adsorption capacity was calculated according to the Langmuir model as 833.3 mg g–1 at 2 g L–1 of adsorbent concentration and 400 mg L–1 of initial MV40 dye concentration. The Cr6+ ions adsorption on CAC-IO was more fitted to the Freundlich model with Qmax, equal to 312.50 mg g–1 at 1 g L–1 adsorbent concentration and 400 mg L–1 of Cr6+ ions initial concentrations.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2024Removal of manganese (Mn2+) from water samples using a biocomposite sorbent
Çalışır, Aykut; Çağlar Yavuz, Sevtap; Yavuz, Emre; Arar, Özgür; Arda, Müşerref
Herein, tannic acid–tethered cellulose was developed as an efficient and selective sorbent for Mn2⁺ removal from aqueous solutions. The modified cellulose was characterized through scanning electron microscopy, infrared spectroscopy, and elemental analyses. Sorption performance was evaluated using various parameters, including pH, initial Mn2⁺ concentration, contact time, and the presence of interfering ions. Results indicated that Mn2⁺ removal was highly pH-dependent, with removal efficiency increasing from 8% at pH 2 to99% at pH 9, achieving a remarkable 99% removal rate within only 30 min, highlighting the rapidity of the cellulose sorption kinetics. The results of isotherm studies confirmed that the sorption conformed to the Langmuir model with a monolayer sorption mechanism. Using a sorbent dose of 0.05 g, 99% of Mn2⁺ could be effectively eliminated from water, achieving a maximum sorption capacity of 32.2 mg/g dry-sorbent. The modified cellulose could be effectively regenerated using 0.5-M HCl or 0.1-M H₂SO₄, with no considerable deterioration in sorption performance after three sorption–regeneration cycles. The presence of Na⁺ and K⁺ had minimal impact on Mn2⁺ removal, whereas the presence of Ca2⁺ and Mg2⁺ at low concentrations facilitated moderate-level Mn2⁺ removal.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2024Examination of the permeability of rubberized concrete with different water/cement ratios and their resistance against acid and sulfate attack
Kandil, Ufuk; Bulut, H Alperen
This study aims to examine the permeability and acid and sulfate attack of waste rubber-substituted concrete containing recycled rubber in three different grain size classes (chips, crumb and powder) with two different water/cement (w/c) ratios (0.4 and 0.5). Waste rubber at different ratios (0%, 4%, 8%, 12%, 16%, 20%, and 24%) was used in concrete by replacing fine and coarse aggregates. Sorptivity, electrical resistivity, and acid and sulfate attack tests were conducted on concrete cured for 90 days. Although the capillarity coefficient values increased with the waste rubber replacement ratio increase, a decrease occurred after the 20% waste rubber replacement ratio. In 12% waste rubber-substituted concrete (0.4WR12) with a water/cement ratio of 0.4, the electrical resistivity value (8.3 kΩ.cm) was the highest, and concretes with low permeability could be produced. As a result of the use of 16% waste rubber in the concrete, 75% less compressive strength loss was observed after the acid attack compared to the control concrete. In concrete with a water/cement ratio of 0.5, when the waste rubber ratio increased by up to 16%, the compressive strength losses caused by the sulfate attack decreased dramatically (95.76% less) compared to the control concrete. The rubberized concrete with a water/cement ratio of 0.5 showed high resistance to acid and sulfate attacks. The experiment results showed that 12% to 16% waste rubbers are ideal ratios. In this study, the water/cement ratio was a valuable parameter for the waste rubber ratio in rubberized concrete.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2023Travel option-based environmental comparison between passenger aircraft and high-speed rail
Çam, Ömer; Kilic, Ugur
The short-haul flights have higher emission values than medium or long-haul flights when emissions per distance are considered. In this study, the potential to reduce greenhouse gas emissions by replacing short-haul flights which carried out by a narrow-body commercial aircraft from/to Konya City in Turkey with regional jets or high-speed trains (HSRs) has been investigated. The flight trajectory is selected from Konya Airport to İstanbul Sabiha Gökçen Airport, and that trajectory is a frequently performed domestic flight between Konya and İstanbul. The IMPACT platform is used for the calculation of fuel burn and gas emissions. According to the results, traveling with regional jets or high-speed trains from/to Konya City which is the most 15th polluted city in Europe, provides advantages in terms of environmental impact. Traveling with HSR which is the best traveling option in this study, provides approximately 3.3 times more green travel than the currently used narrow-body passenger aircraft between Konya and İstanbul. In addition, this mode of transportation can become more environmentally friendly by using renewable energy sources to produce its electricity needs. It is expected that this study will serve as a guide for airline and high-speed rail operators and regulators to determine the most environmentally efficient travel options based on fuel burn and emission parameters.
RDL Kalıcı Kaydıİncele
