Browsing by Author "Gubbuk, Ilkay Hilal"

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Decolorization of Rhodamine B by Silver Nanoparticle-Loaded Magnetic Sporopollenin: Characterization and Process Optimization
(Springer Heidelberg, 2022) Ecer, Umit; Sahan, Tekin; Zengin, Adem; Gubbuk, Ilkay Hilal
Silver nanoparticles (Ag NPs) were reduced on the surface of magnetic sporopollenin (Fe3O4@SP) modified with polydopamine to enhance the degradation capability for Rhodamine B (RhB). The polydopamine-coated Fe3O4@SP (PDA@Fe3O4@SP) acts as a self-reducing agent for Ag+ ions to Ag-0. The structural properties of the synthesized nanocomposite were determined using Fourier transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), inductively coupled plasma mass spectrometry (ICP-MS), and vibrating sample magnetometer (VSM). The systematic study of the degradation process was performed using Response Surface Methodology (RSM) to determine the relationship between the four process variables, namely, initial RhB concentration, NaBH4 amount, catalyst amount, and time. Optimum points were determined for these four parameters using both matrix and numerical optimization methods. Under optimum conditions, RhB was decolorized with a yield of 98.11%. The apparent activation energy (E-a) and rate constant (k) for the degradation were 24.13 kJ/mol and 0.77 min(-1), respectively. The reusability studies of the Ag@PDA@Fe3O4@SP exhibited more than 85% degradation ability of the dye even after five cycles. As a result, Ag@PDA@Fe3O4@SP possessed high catalytic activity, fast reduction rate, good reusability, easy separation, and simple preparation, endowing this catalyst to be used as a promising catalyst for the decolorization of dyes in aqueous solutions.
Efficient Removal of 2,4-Dichlorophenoxyacetic Acid From Aqueous Medium Using Polydopamine/Polyacrylamide Co-Deposited Magnetic Sporopollenin and Optimization With Response Surface Methodology Approach
(Springer, 2023) Yilmaz, Sakir; Zengin, Adem; Sahan, Tekin; Gubbuk, Ilkay Hilal
In this study, a novel binary grafted polydopamine/polyacrylamide onto magnetic sporopollenin (PDA/PAAm@Fe3O4@SP) was synthesized in one step polymerization strategy to investigate its removal performance of 2,4-dichlorophenoxyacetic acid (2,4-D). The response surface methodology (RSM) was applied to evaluate the effects of the process factors including pH (2-8), adsorbent concentration (0.5-2 g/L), initial 2,4-D concentration (C-o) (20-80 mg/L), and contact time (30-180 min) for the 2,4-D removal performance. The central composite design (CCD) through RSM was utilized to design the experiments as well as to optimize and model the 2,4-D adsorption process. The ANOVA results clearly shows that the quadratic model (p < 0.0001) was sufficient to the best predicting of the removal performance of 2,4-D (R-2 = 0.99). The optimum conditions for the maximum 2,4-D removal (88.31%) was achieved at pH of 3.51, adsorbent concentration of 0.75 g/L, C-o of 52.85 mg/L, and contact time of 148.53 min. The adsorption kinetic was represented by both Weber-Morris (R-2 = 0.99) and pseudo-second-order models (R-2 = 0.99). The isotherm for 2,4-D completely fitted the Dubinin-Radushkevich (D-R) and Langmuir models with R-2 values of 0.98. The obtained outcomes indicated that the prepared material may be utilized as an alternative adsorbent for the removal of 2,4-D from waterbodies and the RSM method can be utilized as an eco-friendly and low-cost statistical approach for the elimination of 2,4-D.