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Öğe Adsorption of textile wastewater containing triple dye on the garden soil: optimisation and modelling by Taguchi method(Taylor & Francis Inc, 2021) Adar, Elanur; Acar, Filiz NuranThe textile industry is a sector that should be taken into account in terms of environmental pollution. There is excessive water consumption and there are different pollutants in the wastewater besides dyes. The adsorption to the garden soil of textile wastewater containing three different Astrazon dyes was investigated in terms of the following parameters; dye concentration, different dye content, salt concentration, temperature, pH, contact time, adsorbent dosage. It was observed that the parameters had different effects on organic matter and colour removal. Under optimum conditions, an organic matter removal of over 86% and colour removal of 100% were achieved. Moreover, the operating parameters’ relationship with ORP was evaluated and from the results of FTIR analysis, it was concluded that Astrazon dyes were very stable. The fact that organic matter removal was lower than colour removal shows that mineralisation is difficult. Textile dyes can be successfully removed by adsorption using the soil, which does not require chemical use except pH adjustment, which is a simple system and easy to operate. This study also shows that if textile wastewater is to be consciously or unconsciously discharged to the soil without treatment, a large percentage of the dyes in textile wastewater will be adsorbed by the soil and cause soil pollution. Since the environmental system is in a cycle, soil pollution means surface/groundwater pollution and hindrance for plant growth. For this reason, textile wastewater that contains toxic and stable pollutants should not be discharged without treatment.Öğe Characterisation of wastes collected from beaches, coastlines, marine surface cleaning processes and ships: A case study of Istanbul(Sage Publications, 2019) Bilgili, Mehmet Sinan; Adar, Elanur; Yıldız, Şenol; Sezer, KadirMarine waste management is crucial for Istanbul because of the significant location for intercontinental transition, international trade, tourism, industry and shipping. This study is the first one realised in Turkey for the detailed characterisation of marine waste. The amount and characteristics of solid wastes originating from beaches, coastlines, sea surface cleaning processes and ships (both cargo and cruise ships) were determined. It was observed that marine wastes includes a significant amount of recyclable materials. Although, it was ascertained that the amount and composition of waste differs according to the collecting sources, the majority of wastes are composed of different types of plastics. The average calorific value of marine waste was determined as 2500 kcalkg-1, which is higher than that of mixed municipal solid waste. There is a lack of studies on the pathways of disposal alternatives of marine waste after collection. As landfilling is the common pathway for disposal after collecting, it is clear that recycle/reuse and energy recovery options are possible for marine waste.Öğe Characteristics of liquid products in supercritical water gasification of municipal sewage sludge by continuous flow tubular reactor(Springer, 2019) Adar, Elanur; İnce, Mahir; Bilgili, Mehmet SinanSewage sludge is a by-product of wastewater treatment, containing high water and organic content. Supercritical water gasification provides sustainable treatment for biomass sources such as sewage sludge. In this study, the effects of operating conditions (temperature, solid matter content and catalyst) and raw material properties on the resulting liquid products were determined in order to exhibit the success of this innovative technology for treatment and disposal of municipal sewage sludge using a continuous flow pilot-scale tubular reactor for the first time in Turkey. As a result of the study, it was determined that the higher the temperature, the higher the quality of the liquid product. TOC removal efficiencies increased from 84.4% to 99% with increasing the temperature from 450 to 650 °C, for 1% solid matter content. The pollutant concentrations in the liquid products increased by increasing the solid matter content of the raw sludge from 1 to 2%. This situation has been eliminated by the catalyst (KOH) addition, resulting in a very transparent liquid product. Additionally, TOC removal of 99.8% was obtained after addition of 2% catalyst. Thus, supercritical water gasification (SCWG) has been considered as a notable technology for the treatment and disposal of sewage sludge without the need of additional pre- or post-treatment.Öğe Decision analysis related to the renewable energy investments in Turkey based on a Fuzzy AHP-EDAS-Fuzzy FMEA approach(Elsevier, 2020) Karatop, Buket; Taşkan, Büşra; Adar, Elanur; Kubat, CemalettinDue to the factors such as technological developments, industrialization, population growth, etc. the energy need in the world is constantly increasing and the available resources are insufficient to meet this need. Therefore, the search for alternative energy sources has accelerated recently and this situation has directed the countries to renewable energy. Although the use of renewable energy had gone until before of the first industrial revolution, it has become a very popular area today due to significantly eliminating the increasing concerns related to the security of energy supply, being environmentally friendly, and has positive economic effects. For this reason, nowadays countries form their strategies, policies, and goals related to the energy sector with a focus on renewable energy and make serious investments in this field. Owing to the current importance of the issue, in this study it is aimed to determine how the optimum investment decisions could be taken at the renewable energy sector in Turkey. Five renewable energy alternatives which are hydropower, solar energy, wind energy, geothermal energy and biomass energy, were taken into consideration. First of all, using the Fuzzy Analytical Hierarchy Process and the Evaluation Based on Distance from Average Solution methods, the importance weights of renewable energy alternatives were found and they were prioritized. Afterwards, the risks of renewable energy alternatives were found with the Fuzzy Failure Mode and Effect Analysis. Finally, the best alternatives were determined by comparing the evaluation results. When the results of study were analyzed it was clearly seen Turkey should focus on hydropower and wind energy in renewable energy investments.Öğe The determination of microorganisms in indoor and outdoor atmosphere in the Y.T.U. Davutpasa campus([y.y.], 2019) Baysal, Feysa; Adar, Elanur; Sakar, Süleyman; Nuhoğlu, YaşarAir can contain a number of foreign matters and microorganisms in various sizes, which may be harmful to human health besides essential substances necessary for respiration such as oxygen. The air quality in terms of microbiology in indoor and outdoor environments plays an important role in determining the possible risks and the precautions to be taken. The aim of this study is to examine the microorganisms in indoor and outdoor air in the Davutpasa campus of Yildiz Technical University. The active and passive sampling methods were used in nine different indoor and outdoor atmospheric environments. The best results were obtained by active sampling and membrane filtration methods. In the samples taken in March, the highest bacterial colony was detected in the wastewater laboratory at 35 degrees C. The highest bacterial and fungal colonies were found in the wastewater laboratory and in the middle garden, respectively. In the samples taken in April, the highest the number of bacteria at 20 degrees C was in the microbiology laboratory while the number of fungi showed differences according to the type of cultivation methods. In the gram staining, gram positive bacteria belonging to Sarcina sp, gram negative Monococcus sp., gram positive Diplococcus sp., gram positive Tetracoccus sp., gram-negative actinomycetes (branched bacteria), gram-negative Vibrio sp. and miscellaneous fungi have been observed. As a result, it has observed that there are various bacteria and fungi in the indoor and outdoor air we breathe. The number of microorganisms has changed according to the environment conditions.Öğe Determination of the focus strategies related to renewable energy for turkey by using the fuzzy sectional SWOT(Harun TAŞKIN, 2022) Karatop, Buket; Taşkan, Büşra; Adar, ElanurDetermining the strategies that Turkey need to focus at the renewable energy field is aimed in this study. For this, an integrated method called the Fuzzy Sectional SWOT consisting of the Fuzzy AHP and the Sectional SWOT methods was used. Some disadvantages of the traditional SWOT analysis are eliminated with the method used. Firstly, the renewable energy field was divided into 6 sub-sections (hyropower, solar, wind, biomass, hydrogen and geothermal) according to the logic of Sectional SWOT analysis. Then strengths, weaknesses, opportunities and threats for each of these sub-sections were determined using the Sectional SWOT analysis. Weights were found with the Fuzzy AHP method for each of the renewable energy sources and they were prioritized according to these weights. Finally, focus strategies related to renewable energy field for Turkey were obtained with the creation of strategies related to renewable energy sources. Consequently, the focus strategies which should be primarily addressed are related to use of renewable energy potential, social awareness about the renewable energy, government supports and incentives related to the renewable energy, selection of suitable areas for renewable energy plants and domestic production of the constituent parts of renewable energy plants.Öğe Different methods applied to remove pollutants from real epoxy paint wastewater: modeling using the response surface method(Bellwether Publishing, Ltd., 2021) Adar, Elanur; İlhan, Fatih; Aygun, AhmetComparing between classical and advanced methods for the treatment of industrial wastewater is extremely important to optimize factory operations and cost, and reduce the effects on environment. In the present study, some classical and advanced processes were assessed for chemical oxygen demand (COD) removal, the biggest problem in the wastewater from a factory producing epoxy paints. The response surface methodology was used for optimization. While the chemical coagulation (CC) and classical Fenton (CF) processes were used as the traditional methods, the electrocoagulation (EC) and electro-Fenton (EF) processes were used as the advanced methods to treat wastewater. As a result, the highest COD removal efficiencies were obtained in EF (97.8%) and CF (88.6%), respectively. Low COD removal efficiencies (43.5% and 47.5% respectively) were achieved in coagulation-based processes (CC and EC). Operating cost for CF calculated as 2.15 €/m3. Considering in terms of treatment efficiency, sludge volume and operating cost, CF is the most suitable option for the management of epoxy paint wastewater (EPW). These results also show that Fenton-based methods provide higher removal yields for the treatment of EPW. In other words, it is stable wastewater and the presence of hydroxyl radicals is required for its successful management.Öğe Evaluation of development in supercritical water oxidation technology(Desalination Publ, 2019) Adar, Elanur; İnce, Mahir; Bilgili, Mehmet SinanSupercritical water oxidation (SCWO) has been an innovative technology for the treatment of aqueous and hazardous organic wastes for 35 years. The technology provides cleaner output products and energy recovery. The purpose of this study is to evaluate the latest state of SCWO, which is an innovative and promising technology, according to the information obtained from the lab-scale, pilot-scale and full-scale applications. The process has been extensively used mostly in laboratory or pilot scale plants for model and real wastewater treatment. Industrial SCWO plants have usually closed due to corrosion, clogging and high cost problems. In order to operate this innovative technology efficiently, the main suitable wastewater should be selected, appropriate reactor design should be used, more durable materials should be produced, efficient pre-treatment should be determined so as to decrease operating costs and technical solutions should be determined. Otherwise, SCWO studies may be limited to laboratory and R&D studies.Öğe Investigation on microbial biodeterioration of the stone monuments in Yildiz Technical University—Yildiz Campus—Istanbul—Turkey(Springer, 2020) Özdemir, Aysun; Ergüven, Önder Gökhan; Adar, Elanur; Nuhoğlu, YaşarThe stone samples of historical monuments around Yıldız Technical University Besiktas Campus were investigated using DNA extraction-PCR-DGGE methods, scanning electron microscopy (SEM), XRF, and other analytical methods to assess stone decay over the centuries. Microbial diversity was examined by classical cultivation and modern diagnostic methods besides modern analysis techniques. The number of the microorganisms in per gram of stone samples was calculated by microbial culture methods. SEM analysis showed that stone surfaces have too many pores, decaying pieces and microbial colony. It is put forth by XRF analysis that stone materials have some elements serving the growth of microorganisms. It was concluded that there is a close connection the stone structure and microbial growth, most likely mineralogical composition, hardness and porosity of stone. Cyanobacterial microorganisms lived on stone surfaces were also determined using denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA gene fragments. It was revealed DNA-based molecular analysis of 16S rRNA that 23 bacterial/Cyanobacterial clones were inhabited to stone materials.Öğe Kendiliğinden yerleşen betonun işlenebilirliğine ve yüksek sıcaklık direncine polipropilen lifin etkisi(Bitlis Eren Üniversitesi, 2020) Adar, Muhammet; Bingöl, Ahmet Ferhat; Adar, ElanurKonvansiyonel betona kıyasla yüksek işlenebilirlik, düşük işçilik maliyeti ve yüksek dayanım gibi avantajlar sağlayan kendiliğinden yerleşen beton (KYB) yüksek performanslıdır. Bu çalışma ile kendiliğinden yerleşen betonlarda, polipropilen lif miktarının (0,25; 0,50; 0,75 ve 1,00 kg/m3 ) taze betonun işlenebilirliği ve sertleşmiş betonların da bazı mekanik dayanım özellikleri üzerindeki etkisi belirlenerek; farklı sıcaklıkların (25, 250, 500 ve 750 °C) sertleşmiş KYLB’lar üzerindeki etkilerinin araştırılması amaçlanmaktadır. Sertleşmiş numuneler 25, 250, 500 ve 750°C sıcaklıklarına tabi tutulmuştur. Ayrıca, numunelerin boşluk yapıları hakkında fikir edinmek için ultrases geçiş hızı ölçümleri gerçekleştirilmiştir. Çalışma sonucunda, polipropilen lif miktarının artması ile kendiliğinden yerleşen betonun akıcılığının olumsuz yönde etkilendiği, basınç dayanımının değişmediği ve çekme dayanımının olumlu yönde değiştiği gözlenmiştir. 500ºC ve üzeri sıcaklıklarda, beton basınç dayanımının ve ultrases geçiş hızlarının azaldığı tespit edilmiştir. Sıcaklık arttıkça polipropilen liflerin eridiği ve bunun sonucu olarak betonda oluşan boşlukların artması ile dayanımının azaldığı gözlenmiştir. 750 ºC’de en fazla mukavemet kaybı görülmüştür.Öğe Optimization of cattle manure liquid fraction anaerobic digestion at different temperatures: modelling by taguchi method(Yıldız Teknik Üniversitesi, 2020) Adar, ElanurIn this study, the effect of different parameters (mixing speed, temperature, substrate/inoculation ratio) on the anaerobic digestion of cattle manure liquid fraction was analyzed and optimized with Taguchi method. As a result, it was concluded that mixing speed has an increase of 29% on methane gas production. Optimum operating conditions were determined as 120 rpm, 35 ?C, and 1.5 S/I ratio. Under these conditions, 465 mL methane in 30 days was produced. 84% COD removal was provided. It has been observed that the liquid fraction of cattle manure can be decomposed under anaerobic conditions and transformed into energy rather than leaving it to the environment. It can be said that the farmers can efficiently digest the liquid part together with the municipal sewage sludge in the farms where solid-liquid separation is performed. Thus, environmental pollution will be prevented.Öğe Optimization of triple dye mixture removal by oxidation with Fenton(Springer, 2020) Adar, ElanurAzo dyes are widely used in textile industry due to their easy production, high stability during washing and variety of colors. It raises concern over the ecosystem because of its structural features. Some advanced oxidation process that is tertiary treatment is one of the conventional treatment methods. Pollutants that cannot be removed by primary and secondary treatment are treated by tertiary treatment methods. Primary and secondary treatment methods are not generally sufcient for removal of azo dyes. For this reason, it has an important place in its treatment with advanced oxidation processes. The aim of this study is to investigate the efect of diferent parameters on color and COD removal yields of triple dye mixtures by Fenton method and to optimize with the Taguchi method. Moreover, the aim is to examine the relationship between these parameters and ORP by regression analysis, and the change of organic groups by FTIR analysis in the efuent. As a result of the study, it was observed that the parameters considered had diferent efects on COD and color removal. There was an increase in both color and COD removal only with the increase in H2O2 concentration. The highest COD and color removal yields were 95.8% and 99.3%, respectively. As a conclusion, Fenton process is a method that can be preferred in the treatment of textile dyestufs since the chemicals used are non-toxic, abundant and economical, and therefore, the operation cost of the system is quite favorable, providing advantages to compete with other advanced oxidation processesÖğe Phenol removal from synthetic wastewater with powdered activated carbon: Isotherms, kinetics and thermodynamics(Yıldız Teknik Üniversitesi, 2020) Adar, Elanur; Atay, İpeknur; Büncü, Kubilay; Bilgili, MehmetPhenol is the 11th most toxic 126 chemical substance and causes cancer by accumulating in the food chain. Adsorption of phenol is an effective and also environmentally friendly method for its removal. In this study, phenol removal by using powdered activated carbon (PAC) was optimized and modeled for various isotherms at constant mixing rate (150 rpm) and sample volume (100 mL); adsorbent dose (0.01-2 g), contact time (1-180 min), and initial phenol concentration (50-1000 mg L-1). Moreover, adsorption studies were carried out at different temperatures for kinetic and thermodynamic calculations. In this study, optimum adsorbent dose and contact time of PAC were determined as 0.3 g 100 mL-1 (3 g L-1) and 10 minute, respectively. It can be concluded that it provides discharge standards for a wastewater containing 100 mg L-1 phenol. It was observed that the adsorption capacity decreased with increasing temperature and the adsorption process fits well with Langmuir isotherm. It has been concluded that the adsorption of phenol with PAC is an exothermic reaction. As a result of the kinetic studies, it was found to be suitable for the Pseudo Second Order (R2 0.9999-1.0000). ?S, ?H and ?G were calculated as -0.02 J mol-1 K-1, -14.15 kJ mol-1 and between -8.16 and -7.76 kJ mol-1, respectively.Öğe Prioritization of the treatment and disposal methods of wastes containing polychlorinated biphenyl by fuzzy multi-criteria decision-making and risk assessment(Springer, 2020) Adar, Elanur; Karatop, Buket; Bilgili, Mehmet Sinan; İnce, MahirA total of 209 different types of polychlorinated biphenyls (PCBs) with various properties have been produced from 1930 to 1970s in which they have been banned due to their toxic effects. Total produced PCBs in the world are around 15 to 20 million tons, and up to now, 5.4 million tons of PCB-containing or PCB-contaminated equipment/materials has been eliminated. The remaining 10–15 million tons still needs to be removed or managed. Moreover, PCBs are pollutants still being unintentionally formed. These pollutants can be treated or disposed of various methods. However, there is a lack of knowledge about the selection of the treatment and disposal methods and their environmental, technological, cost, and social/ergonomic evaluation perspectives and the risk assessment during method selection. In this study, a projection was presented for the management of PCBs with an integrated multi-criteria decision-making (MCDM)-risk analysis focusing on these questions. Treatment (physical, chemical, biological) and disposal (incineration, landfill, supercritical water oxidation/gasification (SCWO/G), and pyrolysis/gasification) methods for the management of PCB-containing waste have been prioritized by fuzzy-analytical hierarchy process (F-AHP) in terms of environmental, technology, cost, and social/ergonomic criteria. Risk analysis was also made in terms of these criteria for considered alternatives, and compliance with risk and MCDM was evaluated. As a result of the study, priority methods among alternatives were determined as chemical treatment and SCWO/G. It has been determined that the weight values of the main criteria of environmental, technology, cost, and social/ergonomics were close to each other, but the emission criterion of the sub-criteria was determined to be of higher priority. In the risk analysis, chemical treatment and SCWO/G methods have been found to carry a more acceptable risk. Thus, it has been evaluated that these methods provide more superiority than other methods. © 2020, Springer Nature Switzerland AG.Öğe Prioritizing novel wastewater-to-hydrogen production technologies based on different decision-making approaches(Springer, 2021) Adar, ElanurWith the increasing population, the amount of wastewater that needs to be managed is also increasing. Population growth also increases energy demand. While treating wastewater containing organic matter and water, hydrogen energy can be produced at the same time. In this study, microbial fuel cells, dark fermentation, supercritical water gasification, and photobioreactors that produce hydrogen from wastewater have been evaluated and prioritized for the first time in terms of benefit, opportunity, cost, and risk criteria. The analytic hierarchy process (AHP) technique and benefit, opportunity, cost, and risk (BOCR) model have been used to achieve this aim. In addition, a sensitivity analysis was performed to determine critical criteria for prioritizing technologies. With the analytic hierarchy process technique, it was determined that the criterion with the highest priority was benefit (53%), while the sub-criterion with the highest priority was technological development (33%) followed by operating cost (15%) and compliance with sustainability (12%). Supercritical water gasification technology was found to be the top priority with the AHP technique. In the BOCR model, dark fermentation was determined to be the highest priority technology. In the sensitivity analysis, changes in the weights of the opportunity and cost criteria showed that these criteria were critical. The results obtained show that dark fermentation, which is a technology close to the development, is preferred in the first rank because it has less risk and can produce a high rate of hydrogen. This study could spur more R&D work for researchers to industrialize this technology. It can also give an idea for different studies to researchers. Graphic abstractÖğe Prioritizing of industrial wastewater management processes using an integrated AHP–CoCoSo model: comparative and sensitivity analyses(Springer Science and Business Media Deutschland GmbH, 2021) Adar, Elanur; Delice, Elif Kılıç; Adar, TubaThe increase in individuals’ consumption and needs and the rapid development of technology result in different types of industrial wastewaters. A vast majority of industrial wastewaters are harmful to humans and other animals, as well as the environment. This study aimed to identify the priorities for the industrial wastewater management processes based on multiple contradictory criteria. For this purpose, the analytical hierarchy process (AHP) and combined compromise solution (CoCoSo) techniques were used. Sensitivity analyses were conducted by changing the criteria weights, and comparative analyses were conducted using the Multi-Objective Optimization on the Basis of Ratio Analysis, the Combinative Distance-Based Assessment, and the Technique for Order Preference by Similarity to an Ideal Solution. Although the criteria weights were obtained using the AHP, alternative rankings were determined using the CoCoSo. Within the scope of the study, alternatives were determined for industrial wastewater management based on four groups—physical, chemical, biological, and thermal—that were further divided into 3 main and 14 subcriteria. Although the AHP method revealed that the most important criterion was operating costs, the membrane processes, electrochemical oxidation, membrane bioreactor and supercritical water oxidation/gasification were determined to be priorities for the physical, chemical, biological, and thermal alternatives, respectively, which provide high efficiency and comply with environmental impact criteria. As a result, it is suggested that membrane bioreactor is the top ranking alternative, followed by electrochemical oxidation.Öğe Removal of acid yellow 17 from textile wastewater by adsorption and heterogeneous persulfate oxidation(Springer Science and Business Media Deutschland GmbH, 2020) Adar, ElanurAzo dyes commonly used in various industries have a stable and toxic structure. Wastewater containing AY17 dye as a model contaminant was investigated in terms of color and COD removal by both adsorption and persulfate oxidation activated with the PAC. In this study, the effects of temperature (25–50 °C), pH (3–10), persulfate concentration (1000–4000 mg/L), adsorbent dosage (0.1–0.5 g), reaction time (5–60 min), dye concentration (300–1000 mg/L) and NaCI concentration (0–1000 mg/L) on both color and COD removals from wastewater containing AY17 dye were examined. As a result of the study, it was seen that the dosage of adsorbent, pH and reaction time are important parameters in both systems. The use of the PAC as an adsorbent caused to shortening of the reaction time in the HPS system. It also showed that acidic and neu-tral pH values are more suitable for the removal of AY17 with both systems. Color and COD removal were determined as 100–88.4% and 100–96.6%, respectively, at optimum values obtained for the adsorption and HPS system. An experimental design was applied for various operating parameters in order to analyze experimental data. Models have been proposed for both color removal and COD removal estimates for both systems.Öğe The removal of Astrazon Black MBL with an innovative adsorbent: Optimization of operating parameters with Taguchi method(Pamukkale University, 2021) Adar, ElanurVarious dyes are used in the textile industry. Azo dyes, stable and toxic, constitute the majority of these dyes. In this study, the removal of Astrazon Black MBL belonging to azo group with an innovative adsorbent was investigated. The efficiency of adsorbent was evaluated in terms of color removal, oxidation and reduction potential (ORP), FTIR (Fourier Transform Infrared Spectrometer), pH and ion count, and the results were optimized with Taguchi method. As a result of the study, color removal efficiency in the range of 98.4%-99.6% was obtained with the innovative adsorbent used. The pH and ORP of the liquid products after adsorption was measured in the range of 6.10-6.89 and in the range of 18.1-64.2 mV, respectively. From FTIR analysis results, Astrazon Black MBL dye was observed to be very stable. As a result, it was observed that waste can be evaluated successfully with adsorbent used in the study. In addition, since the adsorbent used does not have a cost, it provides the applicability of the method in terms of cost because the operating cost is low.Öğe Supercritical water gasification of sewage sludge by continuous flow tubular reactor: A pilot scale study(Elsevier, 2020) Adar, Elanur; İnce, Mahir; Bilgili, Mehmet SinanTreatment and disposal of sewage sludge constitute one of the major problems of wastewater treatment plants due to high water content and more stringent environmental regulations. Supercritical water gasification (SCWG) technology is accepted as a promising method for sustainable sludge disposal because of the elimination of need for costly water reduction and drying processes before disposal by conventional methods. The aim of this study is to determine the effect of temperature (450–650 °C), solid matter content (1–2%) and catalyst addition (0.5–2% KOH) on supercritical gasification of sewage sludge in a continuous-flow pilot scale tubular reactor. The results indicate that the gasification efficiency is generally temperature dependent. Furthermore, catalyst addition improves the gasification efficiency at high solids content. The produced gas contains 60% of H2 and 22% of CH4 at experimentally determined optimal conditions (650 °C, 2% solid matter content, 2% KOH). The resulting gas contains H2S and CO below detection limits and there is no need for additional treatment. Consequently, SCWG technology provides complete decomposition of organic matter in a short time, clean gas formation with higher energy content, and volumetric reduction compared to conventional methods.Öğe Usability of spent Salvia officinalis as a low-cost adsorbent in the removal of toxic dyes: waste assessment and circular economy(Taylor & Francis Inc, 2021) Bingül, Züleyha; Adar, ElanurThe removal of methylene blue (MB) and maxilon yellow (MY) dyes from aqueous solutions was investigated by an adsorption process using spent Salvia officinalis (SSO) for the first time. The operating conditions and mechanisms for the MB-SSO and MY-SSO adsorption systems were determined. FTIR-ATR and SEM-EDAX analyses were also performed to characterise the adsorbent. Optimum conditions in each system were similarly obtained, excluding pH (5.7 for MB and 6.5 for MY). The dye removal efficiency was 78% for MB and 56% for MY. It was observed that experimental data fits Freundlich isotherm (R2 ? 0.97) and pseudo-second-order kinetic (R2 ? 0.99) model in both systems. The maximum adsorption capacities of SSO for MB and MY dyes were determined as 16.53 and 11.79 mg g?1, respectively. The pseudo-second-order kinetic model revealed that adsorption efficiency was affected by a number of active sites on the adsorbent and the concentration of the dye. The thermodynamic parameters confirmed that adsorption was spontaneous, exothermic and physisorption in both adsorption systems. The results indicate that SSO can be used as a promising adsorbent material for removal of MB and MY dye from aqueous solutions. However, in order to remove high dye concentrations, SSO must be activated.
