Browsing by Author "Durmaz E."

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Adsorption of reactive dyes on lignocellulosic waste; characterization, equilibrium, kinetic and thermodynamic studies
(2019-07-10) Değermenci G.D.; Değermenci N.; Ayvaoğlu V.; Durmaz E.; Çakır D.; Akan E.
This study researched the use of the easily obtainable and economic agricultural waste of corn silk (CS) for removal of Reactive Blue 19 (RB19) and Reactive Red 218 (RR218) dyes with the adsorption process. Lignin, holocellulose, α-cellulose, thermogravimetric analysis (TGA), fourier transform infrared (FTIR) and scanning electron microscopy (SEM) analyses were completed with the aim of determining the physical and chemical characteristics of the lignocellulosic adsorbent and ash content was determined. Additionally, the contact duration of adsorption, concentration of dye, temperature and pH parameters were investigated with equilibrium, kinetic and thermodynamic parameters determined to research the mechanism of adsorption. For both reactive dyes the removal efficiency is linked to the effective pH. With initial dye concentration of 200 mg/L, temperature of 25 °C, and adsorbent concentration of 0.25 g/50 mL fixed, maximum removal efficiency was 99% obtained at pH 2.0. The study calculated 6 different two-parameter isotherms and according to the best R2 value, the Temkin and Freundlich isotherm models were selected. The maximum capacity of CS for adsorption of RB19 and RR218 was 71.6 mg/g and 63.3 mg/g at adsorbent dose of 0.25 g/50 mL for initial dye concentration of 500 mg/L, pH 2.0 and 25 °C. According to the kinetic model results calculated with the aid of experimental data, a good adsorption process occurred. Thermodynamic parameters like enthalpy variation (ΔH0), entropy variation (ΔS0) and free Gibbs energy variation (ΔG0) were calculated with the aid of data obtained at different temperatures. As temperature increased dye adsorption was observed to increase confirming this event is endothermic.
Characterisation of surfaces coated with different nanocellulose-based suspensions
(2023-01-01) Durmaz E.; Ates S.
In this study, plywood surfaces were coated with different nanocellulose-based suspensions. Moreover, we analysed the effect of boric acid (BA), polyvinyl alcohol (PVA) and melamine formaldehyde (MF) on surface properties for some coating suspensions. According to the results, gloss values of plywood surfaces coated with nanocellulose-based suspensions changed depending on nanocellulose type, matrix type and number of coating layers. It was determined that coated plywood surfaces had low and medium gloss properties. When surface hardness values of coated plywood samples were analysed, it was observed that increasing the number of coating layers and addition of different kind of matrixes increased surface hardness values of the coated wooden surfaces up to the highest level (7H). Furthermore, it was determined that addition of BA, PVA and MF with various concentrations to nanocellulose-based suspensions declined water contact angles (WCA) of wooden surfaces coated with these solutions by reducing surface hydrophobicity.
Characteristics of hot-compressed poplar wood boards
(2017-11-01) Ucuncu T.; Durmaz E.; Kaymakci A.
The influence of thermal modification by hot-compressing was investigated relative to the physical, mechanical, anatomical, crystallinity, and colour characteristics of poplar wood boards. The boards were modified by a hotcompressed method under various temperature stages. The physical and mechanical properties of hot-compressed poplar wood increased with increased pressing temperature. Likewise, the highest crystallinity index (68.7%) of X-ray diffraction (XRD) analyses was found in the samples pressed at 210 °C. Microscopic investigation, revealed that there were some structural deformations in early and late wood, annual ring, etc., of the compressed samples at 170 °C, 190 °C, and 210 °C. In a colour measurement test, it was determined that samples had different colour values in terms of temperature increase. The results achieved in this study demonstrated that the physical and mechanical properties of hotcompressed boards improved with increased press temperature. As a result, a thermal compression method could be preferred to advance endusage features of low-density wood materials produced from fast-growing tree species like poplar, Douglas fir, spruce, yellow pine, eucalyptus, etc.
Comparison of properties of cellulose nanomaterials(Cnms) obtained from sunflower stalks
(2021-01-01) Durmaz E.; Ateş S.
This study aimed to investigate the usability of sunflower stalks, which is one of the most significant agricultural residues in Turkey, in the production of cellulose nanomaterials (CNMs). Cellulose nanofibrils (CNFs) and cellulose nanocrystals (CNCs) were produced by using a grinding method and acid hydrolysis, respectively. The average width and length of CNCs were found as 13.91 ± 3.09 nm and 60.44 ± 21.06 nm, respectively. Besides, the average width of CNFs was determined as 15.03 ± 3.68 nm. The crystallinity index of CNFs and CNCs was determined as 82.64% and 83.09%, respectively. Although the main thermal degradation stage of CNCs started at higher temperature than that of CNFs, the latter were more stable than CNCs at high temperatures. Furthermore, the chemical bonds in the raw material, bleached fiber, CNCs and CNFs were investigated with FTIR analysis. Consequently, it was seen that sunflower stalks can be a suitable raw material for the production of CNMs.
EFFECT OF NANOCELLULOSE TYPE AND MATRIX MATERIAL ON PRODUCTION OF NANOCOMPOSITE FILMS
(2023-05-01) Durmaz E.; Ates S.
Effects of heat treatment on some characteristics of Scots pine (Pinus sylvestris L.) wood
(2019-01-01) Durmaz E.; Ucuncu T.; Karamanoglu M.; Kaymakci A.
Heat treatment of wood materials is generally performed to improve the physical, mechanical, chemical, surface, thermal, and crystallinity characteristics. In this way, the usage areas of wood material in different purposes can be expanded by means of heat treatment. The goal of this study was to determine the physical, mechanical, chemical, crystallinity, and surface properties of heat-treated Scots pine (Pinus sylvestris L.) wood. The test samples were heat-treated at 120 °C, 150 °C, 180 °C, and 210 °C for 4 and 6 h in a laboratory-scale oven. The shrinking and swelling chracteristics of wood was decreased as a function of heat treatment processes. Bending strength, compression strength, and modulus of elasticity decreased. In addition, lignin ratios and crystallinity index increased as temperature and duration of the treatment were increased. Consequently, heat-treated wood materials can be used in various areas by developing some of their properties.
Lignocellulosic Bionanomaterials for Biosensor Applications
(2023-07-01) Durmaz E.; Sertkaya S.; Yilmaz H.; Olgun C.; Ozcelik O.; Tozluoglu A.; Candan Z.
Nanocellulose in Paper and Board Coating
(2022-01-01) Tozluoglu A.; Ates S.; Durmaz E.; Sertkaya S.; Arslan R.; Ozcelik O.; Candan Z.
With the increase in social environmental consciousness, the interest in the production of cellulose-based nanomaterials from renewable natural resources has swiftly increased in recent years. Renewable nanotechnology displays distinguished properties of traditional petroleum-based materials, and also creates new properties such as renewability, biocompatibility, and biodegradability. Nanocellulosic materials allow the design of special materials with high performance that can eliminate present environmental and sustainability problems. Growing interest in such new generation products, which are called bio-based nanomaterials, will substitute conventional petroleum-based materials because of fluctuations in oil prices and scarcity of sources. The generation of these new nanomaterials will lead to the production of materials with high performance while eliminating environmental problems. This chapter presents a unique literature survey on the production methods, characterization, and modification of nanocellulose, and also on the effects of nanocellulose as a coating and additive material on paper and board.
Preparation and properties of nanopolysaccharides
(2019-01-01) Lavoine N.; Durmaz E.; Trovagunta R.
With the raising environmental awareness of the society, the interest in exploiting nanomaterials from renewable resources is rapidly increasing. Renewable nanotechnology not only features the outstanding properties of common synthetic nanomaterials, but also combines renewability, biodegradability and biocompatibility. These past two decades have seen the emergence of so-called nanopolysaccharides, namely nanoscale particles isolated and/or produced from renewable and abundant materials such as cellulose, chitin and starch. These particles are paving the way for the design of high-performance tailored materials, which can address the current environmental and sustainability concerns of our society. Their potential in replacing plastics from petroleum-based polymers is especially the key driver behind this global and raising research effort. This chapter introduces the different preparation routes and main properties of nanopolysaccharides from cellulose, chitin and starch; three of the most abundant biopolymers available and exploited today. This chapter suggests as well potential applications and usages for these nanoparticles, as a preamble of the following next chapters, which will illustrate much more in details how these nanoparticles can change our society of tomorrow.