WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/394
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Article Citation - WoS: 38Citation - Scopus: 41Ozonation Pre and Post-Treatment of Denim Textile Mill Effluents: Effect of Cleaner Production Measures(Elsevier Sci Ltd, 2016-11) Morali, E. Kaan; Uzal, Nigmet; Yetis, UlkuDenim production, which is one of the leading sub-sectors of textile industry that generates considerable amount of wastewater with high pollution load both from dyeing and finishing processes. This sub-sector is therefore to consider cleaner production opportunities for these processes to reduce its wastewater generation and pollution load. In a denim-producing plant, the wastewater treatability studies have revealed that the most technically applicable cleaner production alternatives are caustic recovery from alkaline finishing wastewaters, and reuse of indigo dyeing wastewaters via the application of membrane filtration. In the present study, impact of the changes in the final effluent quality due to the foreseen cleaner production measures were considered in reference to the evaluation of impact on ozonation treatment of the effluent from a denim-producing plant. Ozonation was applied as pretreatment to the effluent from the plant before the foreseen measures (chemical oxygen demand, COD = 2750 mg/L; color = 3950 Pt-Co), and to the simulated effluent after the foreseen measures (COD = 3100 mg/L; color = 4500 Pt-Co); and also as post-treatment to the biologically treated effluent (COD = 800 mg/L; color = 3700 Pt-Co) before the foreseen measures. When applied to the effluent before the foreseen measures as pretreatment, ozonation provided 86% color and 46% COD removal with 3240 mg/h ozone dose in 70 min. However, less satisfactory results were obtained with the wastewater after the measures; with 86% color and 31% COD removals at 3960 mg/h ozone dose in 80 min. In parallel to the decrease observed in COD removal, ozone consumption was also much higher than that for the wastewater before the cleaner production measures. The findings have indicated that the environmental benefits to be brought by cleaner production measures have to be balanced against the risks to be encountered in the treatment of the final effluent. (C) 2016 Elsevier Ltd. All rights reserved.Article Citation - WoS: 15Citation - Scopus: 23Multi-Dimensional Sustainability Evaluation of Indigo Rope Dyeing With a Life Cycle Approach and Hesitant Fuzzy Analytic Hierarchy Process(Elsevier Sci Ltd, 2021-08) Fidan, Fatma Sener; Aydogan, Emel Kizilkaya; Uzal, NigmetThe dyeing process of denim fabric production has the highest potential for significant environmental and human health impacts of denim production, consuming vast amounts of water, chemicals, and dyes. This study aims to assess the sustainability of indigo rope dyeing (IRD) obtained by designing a new recipe with the chemical alternative assessment method. Not only environmental impacts, but also social, economic, and product quality dimensions were included in the multidimensional sustainability assessment. The hesitant fuzzy analytical hierarchy process (HF-AHP) method was used to determine the criteria weights of the determined dimensions. The environmental and social impacts of the existing and newly designed IRD process were evaluated using the gateto-gate life cycle assessment (LCA) and social life cycle assessment (S-LCA) approach. According to the LCA results, the green IRD process exhibited better performance in terms of all environmental impacts evaluated and the abiotic depletion potential of the conventional indigo IRD process can be reduced by 62.55% by applying the green IRD process. According to the HF-AHP results, the most important criteria were environmental impact with 33%, followed by social impacts with 27%, quality results with 23%, and economic results with 17% in assessing the IRD process's sustainability denim production. These results showed that the sustainability of the IRD process could be improved by substituting the chemicals and dyestuff with green alternatives.Article Citation - WoS: 8Citation - Scopus: 8Characterizing Boron-Enhanced One-Part Alkaline-Activated Mortars: Mechanical Properties, Microstructure and Environmental Impacts(Elsevier Sci Ltd, 2024-05) Orklemez, Ezgi; Ilkentapar, Serhan; Durak, Ugur; Gulcimen, Sedat; Uzal, Nigmet; Uzal, Burak; Atis, Cengiz DuranSince alkali activators negatively effect the environmental impact assessment, it is necessary to develop the alternative activators from natural sources with low environmental impact. Therefore, in this study, the usage of boron refined products colemanite, ulexite and boron pentahydrate as activators in slag-based alkali-activated mortar systems was investigated in detail. Flexural and compressive strength tests, isothermal calorimetry measurement, thermogravimetric and differential thermal analysis, inductively coupled plasma mass spectrometry analysis, field emission scanning electron microscopy, and energy dispersive analysis and elemental mapping and X-ray diffraction analysis were carried out on the samples. In addition, sample production was subjected to life cycle analysis (LCA) with a cradle-to-gate approach using two different transportation scenarios. According to the results obtained, it was determined that colemanite, ulexite and boron penta hydrate, when used in optimum proportions, had a positive effect on strength (up to increase 40% compressive strength by 20% ulexite replacement) and could be used as an activator in slag-based alkali-activated systems. The positive results obtained in strength as a result of using boron-refined products are also supported by other test results conducted within the scope of the study. Furthermore, according to the LCA results, it was observed that there was a significant decrease in global warming potential with the substitution of 20% colemanite, ulexite or boron pentahydrate as activators, not only compared to the reference sample but also traditional cementitious systems.