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- MakaleYalnız künye2026Scopus SJRQ1Upcycling marble waste into construction materials and heavy metal adsorbents via hot-pressed geopolymerization technique
Öksüzer, Nurullah; Uslu, Emin; Gökçe, H. Süleyman
This study presents a sustainable approach to utilizing marble dust waste by producing bifunctional metakaolin-based geopolymers via a synchronized hot-pressing technique. In this study, the environmental footprint was minimized by designing mixtures in which marble waste constituted 50% of the total volume. Three stoichiometric series were investigated by varying the activator modulus (SiO2/Na2O = 3 and 4) and the Si/Al ratio (2 and 3) under two curing temperatures (150 and 300 °C) and three compaction stresses (5, 25, and 50 MPa). Thus, a high-volume industrial byproduct was transformed into a functional component. In this context, it investigated the transformation of industrial products into next-generation materials by using them to produce cementless composite geopolymers for civil engineering and to adsorb heavy metal (Cu2+). As a result of the research, an early compressive strength of 58 MPa was obtained through heat treatment and pressing applied at 300 °C and 50 MPa. This optimum strength was achieved in the SiO2/Na2O = 3, Si/Al = 3 series, whereas excess silica (SiO2/Na2O = 4) and excess aluminum (Si/Al = 2) limited the strength to 16.8 and 35.2 MPa, respectively. Microstructural analyses (SEM/EDS and FT-IR) revealed that marble dust was used as a filler material in the microstructure to produce an N-A-S-H-containing matrix. The produced materials were then ground after their service life and used to purify water containing heavy metals. More than 99.75% of Cu2+ was removed through ion exchange between copper ions used as heavy metals. The residual Cu2+ concentration fell below 0.25 mg/L from an initial concentration of 100 mg/L, and the released Na+-to-adsorbed Cu2+ molar ratio of approximately 1.8–2.3 confirmed an ion-exchange-dominated uptake mechanism. This structural and environmental impact demonstrates that marble waste, which is otherwise discarded as waste, is considered inert, offering an alternative model for the circular economy and environmental applications.
- MakaleYalnız künye2025Scopus SJRQ1Extraction of Bioactive Compounds from Celery Root Peels Using an Ultrasound-Assisted Method with Choline Chloride–Based Deep Eutectic Solvents
Kamiloğlu, Aybike; Kutlu, Naciye; Elbir Abca, Tuğba; Yılmaz, Özlem
The concepts of sustainable and green technology have come to the forefront due to problems such as increasing environmental pollution, depletion of resources, and uncontrolled increases in industrialization. Green chemistry aims to reduce or completely eliminate pollution in the environment. In this study, both the ultrasonic method, which is a form of green technology, and deep eutectic solvents, which are among green solvents, were used, and a perspective on creating economic value from a waste product (celery root peel) is presented. In this context, phytochemical compounds (total flavonoid content and antioxidant activities) were obtained from celery root peels by ultrasonic-assisted extraction using 10 different choline chloride–based deep eutectic solvents, and the results were compared with methanol, an organic solvent. As a result, according to the total flavonoid content, the most effective deep eutectic solvent was choline chloride to sucrose, while according to the antioxidant activity value, choline chloride to lactic acid was found to be effective. For all of the analyzed bioactive compounds, higher or equal yields were obtained with all deep eutectic solvent extracts compared to methanol, and deep eutectic solvents could be alternatives to organic solvents (such as methanol) that may have toxic effects on humans or the environment.
AtıfScopus9WoS9OpenAlex10
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