Yazar "Akdag, Sultan" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim Yok
    Öğe
    Peroxydisulfate-assisted sonocatalytic degradation of metribuzin by La-doped ZnFe layered double hydroxide
    (Elsevier, 2022) Akdag, Sultan; Rad, Tannaz Sadeghi; Keyikoglu, Ramazan; Orooji, Yasin; Yoon, Yeojoon; Khataee, Alireza
    Metribuzin is an herbicide that easily contaminates ground and surface water. Herein, La-doped ZnFe layered double hydroxide (LDH) was synthesized for the first time and used for the degradation of metribuzin via ultrasonic (US) assisted peroxydisulfate (PDS) activation. The synthesized LDH had a lamellar structure, an average thickness of 26 nm, and showed mesoporous characteristics, including specific surface area 110.93 m(2) g(-1), pore volume 0.27 cm(3) g(-1), and pore diameter 9.67 nm. The degradation efficiency of the US/La-doped ZnFe LDH/PDS process (79.1 %) was much greater than those of the sole processes, and the synergy factor was calculated as 3.73. The impact of the reactive species on the sonocatalytic process was evaluated using different scavengers. After four consecutive cycles, 10.8 % loss occurred in the sonocatalytic activity of the La-doped LDH. Moreover, the efficiency of the US/La-doped LDH/PDS process was studied with respect to the degradation of metribuzin in a wastewater matrix. According to GC-MS analysis, six by-products were detected during the degradation of metribuzin. Our results indicate that the US/La-doped ZnFe LDH/PDS process has great potential for efficient degradation of metribuzin-contaminated water and wastewater.
  • Küçük Resim Yok
    Öğe
    Recent advances in boron species removal and recovery using layered double hydroxides
    (Elsevier, 2023) Akdag, Sultan; Keyikoglu, Ramazan; Karagunduz, Ahmet; Keskinler, Bulent; Khataee, Alireza; Yoon, Yeojoon
    Anthropogenic boron discharge threatens ecosystem health and water quality. Although boron is a micronutrient necessary for plants, animals, and humans, excessive concentrations can have toxic effects. Layered double hydroxides (LDH) are two-dimensional anionic clay materials that exhibit intrinsic anion-exchange properties. In this paper, the use of LDH for the removal and recovery of boron species from water is presented. The main factors that affect boron removal, including the LDH dosage, initial boron concentration, solution pH, temperature, and the presence of other anions, are outlined. For boron removal, LDH containing Mg, Fe, Zn, or Ca cations have been mostly used owing to their limited toxicities and abundance in the environment. The boron removal capacity of LDH can be improved by transforming the layered structure into bimetallic oxides through calcination, increasing not only the surface area but also the interaction with anionic species during their regeneration. The main boron-removal mechanism of LDH is ion exchange with intercalated anions or the surface complexation with the surface groups of the LDH. A major advantage of using LDH for boron removal is the possibility of recovering and reusing the extracted boron. LDH synthesized with boron as the interlayer anion showed slow-release fertilizer properties, suggesting the use of boron-loaded LDH as plant growth regulators.