Polat, Hürriyet
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Polat, Hurriyet
Polat, H
Polat, H.
Polat, H
Polat, H.
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hurriyetpolat@iyte.edu.tr
Main Affiliation
04.01. Department of Chemistry
Status
Current Staff
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Sustainable Development Goals
1NO POVERTY
0
Research Products
2ZERO HUNGER
3
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3GOOD HEALTH AND WELL-BEING
6
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4QUALITY EDUCATION
2
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5GENDER EQUALITY
0
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6CLEAN WATER AND SANITATION
12
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7AFFORDABLE AND CLEAN ENERGY
11
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8DECENT WORK AND ECONOMIC GROWTH
1
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9INDUSTRY, INNOVATION AND INFRASTRUCTURE
14
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10REDUCED INEQUALITIES
0
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11SUSTAINABLE CITIES AND COMMUNITIES
0
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12RESPONSIBLE CONSUMPTION AND PRODUCTION
9
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13CLIMATE ACTION
14
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14LIFE BELOW WATER
3
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15LIFE ON LAND
1
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16PEACE, JUSTICE AND STRONG INSTITUTIONS
0
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17PARTNERSHIPS FOR THE GOALS
0
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Documents
36
Citations
1402
h-index
17
This researcher does not have a WoS ID.
Scholarly Output
55
Articles
30
Views / Downloads
68665/25788
Supervised MSc Theses
16
Supervised PhD Theses
2
WoS Citation Count
1165
Scopus Citation Count
1309
Patents
0
Projects
13
WoS Citations per Publication
21.18
Scopus Citations per Publication
23.80
Open Access Source
44
Supervised Theses
18
| Journal | Count |
|---|---|
| Colloids and Surfaces A: Physicochemical and Engineering Aspects | 5 |
| Journal of Hazardous Materials | 2 |
| Journal of the Australian Ceramic Society | 2 |
| Journal of the European Ceramic Society | 2 |
| Key Engineering Materials | 2 |
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55 results
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Now showing 1 - 10 of 55
Doctoral Thesis Development of Chitosan Based Biofoams(Izmir Institute of Technology, 2020) Olcay Kurt, Aybike Nil; Polat, Mehmet; Polat, Hürriyet; Polat, Mehmet; Polat, HürriyetChitosan is a preferred bio-foam material used in many research fields such as tissue engineering and drug delivery due to its unique structural features (wide pH stability, nontoxic-biocompatible-biodegradable, anti-inflammatory, antimicrobial). However, chitosan foams are mechanically too weak to maintain the desired shape until newly formed tissue natures. A wound infection and serious tissue necrosis, endanger human's lives. So, a dressing is required to protect loss of fluids and proteins from the wound area and prevents any bacterial invasion replacing the function of skin temporarily. Therefore controlled drug release from a wound dressing is necessary with a biocompatibility and enough mechanical strength. The aim of this study was the synthesis of mechanically durable - dual porosity chitosan bio-foams to provide a controlled drug release. For this purpose, oil droplets formed in a chitosan solution were used as templates to produce micropores that also contain vancomycin (a model antibiotic-hydrophylic) and curcumin (a model anti-inflammatory-hydrophobic) in the walls of the chitosan matrix with large structural voids. An anionic surfactant, sodium dodecyl sulfate (SDS) alone, was used as a crosslinking agent which was a new approach. Then the structures were characterized by SEM, FTIR, mechanical tests and BET analysis. The chitosan foams have dual pore structures. 1) The intrinsic micro pores that the walls of chitosan matrix have with different morphology that depends on the oil phase. 2) The structural voids that the chitosan matrix have, present even in the absence of an oil phase that depends on the experimental conditions. The mechanical strength of the foams were found to be much higher (up to 250 kPa) compare to the foams produced in literature and suggested to be suitable to use for wound dressing applications. The drug release mechanism of foams were found to depend on the conditions used for foam development and the released kinetics were presented with a mathematical model.Conference Object Citation - WoS: 2Citation - Scopus: 2Effects of Mechanical Treatment on the Formation of Α-Al 2o3 From Gibbsite(Trans Tech Publications, 2004) Şakar Deliormanlı, Aylin; Çiftçioğlu, Muhsin; Polat, HürriyetIn this study preparation of fine alpha alumina powders derived from Bayer gibbsite was studied. Preparation of the alumina powders was performed by decomposition of the gibbsite into transition alumina phase followed by controlled transformation to the alpha phase. Gibbsite was thermally treated at 350°C and 900°C to obtain a transition form of alumina. The purpose of the heat treatment at 350°C was to increase the surface area of the gibbsite particles and obtain a loosely packed structure that may reduce the size of the rather coarse precursor gibbsite during the grinding step. Mechanical treatment (by using ultrasonic forces and impact forces) was utilized to increase the transformation rate to the alpha alumina in the transition phase matrix and influence the nucleation and growth rate of the solid -solid phase transformation. These powders were calcined at 1100, 1200 and 1450°C for 1 to 8 hours. Results indicated that transformation to the alpha phase was accomplished in the powders preheated at 900°C, ultrasonically treated or ground, and then calcined at 1200°C for 2 to 8 hours or at 1450°C for 2 hours. Ultrasonic treatment accelerated the transformation rate to the alpha phase at 1100°C in 2 hours. Powders that were calcined at 1100 to 1200°C for 1 hour had a significant kappa content together with the alpha phase. Additionally the powder prepared without mechanical treatment and calcined at 1100°C was mainly in the kappa phase.Article Citation - WoS: 6Citation - Scopus: 7Designing Robust Xylan/Chitosan Composite Shells Around Drug-Loaded Msns: Stability in Upper Git and Degradation in the Colon Microbiota(Elsevier, 2023) Zeybek, Nüket; Büyükkileci, Ali Oğuz; Güleç, Şükrü; Polat, Mehmet; Polat, Hürriyetong residence times, near-neutral pH values, and release triggered by the enzymatic action of the resident microbiota offer unique opportunities for improved drug delivery in the colon. The fact that a delivery agent must also pass through the complete GI tract without degradation presents a challenge due to widely changing pH conditions. In this study, a promising colon-targeted drug delivery system was composed of a xylan/chitosan composite shell formed on curcumin-loaded mesoporous silica nanoparticles (MSNs). A novel synthesis approach was employed to facilitate precipitation of negatively charged xylan on negatively charged MSNs by concurrent chitosan polymerization. Curcumin-loaded xylan/chitosan-coated MSNs (C-MSNs) were determined to contain nearly 42% xylan by the inclusion of chitosan in a one-to-one ratio with xylan. The xylan/chitosan composite shell demonstrated excellent stability in the acidic upper GI tract. The hydrolysis of glycosidic bonds by resident microbiota was the triggering mechanism for xylan degradation and curcumin release in the colon. The presence of xylan has the further benefit of increasing the number of beneficial bacteria and improving short-chain fatty acid production for improved colon health.Article Citation - WoS: 2Citation - Scopus: 3A Phenomenological Kinetic Flotation Model: Distinct Time-Variant Floatability Distributions for the Pulp and Froth Materials(Elsevier, 2023) Polat, Mehmet; Polat, HürriyetA simple and easy-to-use phenomenological kinetic flotation model, strongly connected with the physics of the process, is proposed in this paper. The model explicitly contains the cell volume, aeration rate, volumetric holdup, mean bubble size, and particle density as input variables. It can be employed to characterize the floatability distributions of the particles in the pulp and the froth separately any time during the flotation process. Two new time-dependent kinetic parameters, the bubble loading factor & phi;(t) and the maximum cell mass transfer capacity Mmax(t) also appear in the model expression. & phi;(t) is a measure of the degree of crowding of the bubble surfaces and accounts for the deviations from the first-order rate equation. Mmax(t) describes the maximum amount of mass that can be transported to the froth phase by the bubble population in the cell. Screen fractionation of each froth product collected at different time intervals during a single kinetic flotation test is sufficient to generate the data required by the model for analysis. Application of the model to this data yields directly time-dependent functions for the floatability of the particles reporting to froth Kf(t) or remaining in the cell Kp(t) for each size fraction separately, without the need for any empirical parameters. The test of the model was carried out using published kinetic flotation data from the literature.Article Citation - WoS: 5Citation - Scopus: 5Tannery Wastewater Sediments Produced by Clinoptiolite/Polyacrylamide-aided Flocculation as a Clay Additive in Brick Making(Springer Verlag, 2017) Köseoğlu, Kemal; Cengizler, H.; İsrail, L. İ.; Polat, HürriyetToxic tannery wastewater(s) (TWW) pose(s) a great risk to the environment. This study explores the potential of mitigating the harmful effects of TWW through sedimentation using clinoptiolite in the presence of various anionic, cationic and non-ionic flocculants with different molecular weights and charge densities followed by encapsulation in a brick structure for stability. Compressive strength (CS), size reduction after firing (SRAF), water absorption (WA) and colouring parameters of bricks were determined. X-Ray diffraction (XRD) and scanning electron microscopy (SEM)-energy dispersive X-ray (EDX) analyses were conducted on brick bodies. Kinetic leaching experiments were conducted for possible heavy metal release from the bricks. Bricks containing 10 wt% leather waste and 5 wt% clinoptiolite sintered at 800 °C instead of 920 °C possessed similar properties to the standard brick (SB).Master Thesis Design of Micelle Embedded Chitosan Nanocomposites for Targeted Delivery of Hydrophobic Drugs(Izmir Institute of Technology, 2016) Cihan, Esra; Polat, HürriyetWhen successed to synthesize in a nanoparticulate form, chitosan has found to be a very effective biomaterial for drug delivery purposes owing to its extremely attractive characteristics such as its positive charge and pH sensitivity in aqueous medium. However, its structure as it is, is not suitable for oil soluble drugs. Even a close control on the size and shape of chitosan particles alone becomes a state of art and the production of chitosan nanoparticles is very difficult. Therefore, in this study, several methods were designed and used for synthesis of chitosan nanoparticles (<100 nm) with a hydrophobic core that are suitable for oil soluble drugs. Characterization of these nanoparticles were done by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Scanning Transmission Microscope (STEM), Transmission Electron Microscope (TEM), surface tension and zeta potential measurements. It was concluded that the best method was the coupling of drug loading with simple ionic gelation method among all the others. Hydrophobic drug loaded micelle embedded chitosan nano particles were able to manufactured successfully. The sizes of chitosan particles that embed Pluronic-123 micelles were larger (<100 nm) than the sizes of Pluronic-123 micelles (20 nm) alone. It was also possible to obtain smaller chitosan nanoparticles (<50 nm) that embed drug loaded Pluronic-123 micelles when their structure is modified by Sodiumdodecylsulfate.Article Citation - WoS: 13Citation - Scopus: 15Ancillary Effects of Surfactants on Filtration of Low Molecular Weight Contaminants Through Cellulose Nitrate Membrane Filters(Elsevier Ltd., 2016) Olcay, Aybike Nil; Polat, Mehmet; Polat, HürriyetRemoval of contaminants with low molecular weight (<800 Dalton) requires the use of advanced separation techniques such as ultrafiltration (UF) or micellar enhanced ultrafiltration (MEUF). However, surface active agents invariably co-exist in waste waters along with these contaminants or they may be added intentionally as part of the separation process as in the case of MEUF. Though it is quite likely that both the filter medium and the contaminants would interact with the surfactant molecules or their micelles, there is not sufficient emphasis in the literature on the concomitant aspects of such interactions.The ancillary effects created by anionic (sodium dodecyl sulfate, SDS), cationic (hexadecyltrimethyl ammonium bromide, CTAB) and non-ionic (ethoxylated octylphenol, TX-100) surfactants on the mechanism and efficiency of the filtration process were investigated in this study. Methylene blue (MB) and cellulose nitrate membrane (CNM) filters were employed as model retentate and the separation medium. A combination of surface tension, contact angle and charge measurements demonstrated that the addition of surfactants had a remarkable effect on the filtration outcome. The effect depended on both the type and concentration of the surfactant and was manifested mainly through the creation of MB-surfactant entities which acted differently than the MB alone; but more importantly, through the interactions of the surfactant molecules/micelles and the MB-surfactant pairs with the separation membrane.Master Thesis Comparative Adsorption Studies of Heavy Metal Ions on Chitin and Chitosan Biopolymers(İzmir Institute of Technology, 2007) Keleşoğlu, Serkan; Polat, Hürriyet; Polat, HürriyetIn this study comparative adsorption studies of heavy metal ions (Cu2+, Pb2+,Cd2+, Ni2+) on chitin and chitosan biopolymers were performed to investigate the uptake performances. For this purpose chitosan was prepared from chitin in controlled experimental conditions and then these biopolymers were characterized with Elemental Analysis, Viscosity, FT-IR, Potentiometric Titration, XRD, SEM, Zeta Potential,Particle Size Distribution and TGA/DTA measurements. Batch adsorption experiments were performed at eight different initial heavy metal ion concentrations (10, 25, 50, 100, 250, 500, 750, 1000 m/L), two different temperatures (298.15 K and 328.15 K), time period ranging from 5 minutes to 1 day and pH of solutions ranging from 1 to 7. The results indicated that the uptake performence of chitin and chitosan biopolymer significantly changed with pH, adsorbent dosage,concentration and temperature. In general, chitosan biopolymer demonstrated greater fixation abbility for heavy metal ions than chitin. However the fixation trend of heavy metal ions on chitin and chitosan biopolymers was the same (Cu2+ > Pb2+ > Cd2+ > Ni2+). Moreover Irwing-Williams Series support the dominancy of the binding mechanism for Cu2+, Cd2+ and Ni2+ ions on both biopolymers. Adsorption of heavy metal ions on both chitin and chitosan biopolymers followed pseudo second order kinetics with the rate constant indicating faster adsorption on chitin for Cu2+ and Pb2+ ions and faster adsorption on chitosan for Cd2+ and Ni2+ ions.Both of the Freundlich and Langmuir adsorption isotherms seem to adequately represent the adsorption data obtained in this study. The positive value of enthalpy change (Ho) and negative value of free energy change (Go) shows the adsorption process is endothermic and spontaneous. Moreover obtained positive entropy changes (So) show that an increase in randomness, is associating the adsorption of metal ions onto chitin and chitosan biopolymers.Master Thesis Removal of Heavy Metals From Wastewaters by Ion Flotation(Izmir Institute of Technology, 2005) Erdoğan, Demet; Polat, HürriyetIn this study, ion flotation experiments were performed to investigate the removal of heavy metals (copper, zinc, silver and chromium) from wastewaters.Various parameters such as pH, surfactant and frother concentrations and airflow rate values were tested to determine the optimum flotation conditions. Sodium dodecyl sulfate and Hexadecyltrimethyl ammonium bromide were used as collectors. Ethanol /MIBC were used as frothers.For 10 mg/L initial concentrations of copper, zinc, silver and chromium (III), the highest recoveries obtained were 90%, 71%, 73% and 97%, respectively. When the initial concentration of metals increased the recovery decreased. This proves the attachment of metal ions on surfactant molecules.The presence of Na+, Mg2+, Ca2+ ions in solution reduced the recoveries in case of all the metals since the presence of excess Na, Mg, Ca ions compete with metals and the metal ions can not find enough surfactant molecules to attach to.Selective flotation experiments were conducted in the presence of metal ion mixture solutions. It was possible to separate copper and chromium from zinc and silver, and also possible to separate chromium from zinc and copper and zinc from copper and chromium under suitable conditions.The classical first order equation fitted the results on flotation. Zinc and chromium floated not only more in an amount but also floated faster than copper.Surface tension measurements were conducted to investigate both the collector surfactants and the frothers at air/water interface since air bubbles carry the surfactant-metal ion complexes to the froth and separate from solution.Article Citation - WoS: 2Reduction of Carbon Dioxide During the Synthesis of Metal Nano-Particles in Water(Elsevier Ltd., 2003) Polat, Hürriyet; Cohen, H; Meyerstein, D; Rusonik, I.An effort was made to synthesize "carbon-free" metal (Fe-0, Co-0, Ni-0) nano-particles via the reduction of their salts with BH4- in aqueous solutions. Surprisingly it was found that when the synthesis is carried out in the presence of CO2, e.g., in aerated solutions, the CO2 is catalytically reduced by BH(4)(-)on the surface of the metal particles. Carbon-free metals can be prepared by reduction under an inert atmosphere. Thus metal surfaces might have acted as catalysts for CO2 fixation, probably via the initial formation of carbon clusters, in the reductive atmosphere in the prebiotic era. (C) 2003 Elsevier B.V. All rights reserved.