Surface modification of polyethersulfone membrane to improve its hydrophobic characteristics for waste frying oil filtration: Radio frequency plasma treatment

In this study, polyethersulfone (PES) membrane was subjected to surface modification using hexamethyldisiloxane (HMDSO) and 1,1,1,3,3,3‐hexafluoro‐2‐propanol ( HFIP) in radio frequency (RF) plasma system to improve its hydrophobic property for recovery of waste frying oil. Structural and morphological changes on the membrane surfaces were characterized by contact angle measurements, Fourier transform infrared spectroscopy‐attenuated total reflection (FTIR‐ATR) and atomic force microscopy (AFM). Permeate fluxes, physical and chemical properties of waste frying oil and waste frying oil–methanol micella (oil/methanol 1/3, 1/1, 1/3, v/v) after filtration through unmodified and modified PES membranes were investigated. The results showed that PES membranes modified with HMDSO at 75 W for 5 min (discharge power–exposure time) selectively rejected total polar compounds (TPC) and free fatty acids (FFAs) of waste frying oil to the extent of 46.9–48% and 35.3–40%, respectively. Furthermore, the viscosity of waste frying oil was reduced to the extent of 9.4–12.8%. RF‐plasma‐treated PES membranes appeared to improve the regeneration of waste frying oils and allow these oils to be used for either repeated frying operations or biodiesel production. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123:3402–3411, 2012     

LSER modeling of extraction of succinic acid by tridodecylamine dissolved in 2-octanone and 1-octanol

Reactive extraction can be used for the recovery of carboxylic acids from fermentation broth. Through the formation of complex with extractants at the two-phase interface, the carboxylic acids are partitioned into organic solvents. But, the recovery of carboxylic acids is interrupted by the conditions of fermentation broth. In this work, kinetic studies for the extraction of succinic acid from aqueous solution with tridodecylamine diluted in 2-octanone and 1-octanol have been carried out. Equilibrium and kinetic studies for the extraction of succinic acid from aqueous solution with tridodecylamine diluted in two functional groups (alcohol and ketone) such as 2-octanone and 1-octanol are reported. All measurements have been carried out at 298.15 K. The results of the liquid–liquid equilibrium measurements have been correlated by a linear solvation energy relationship – LSER model which takes into account physical interactions.     

The metamorphosis of a historical city: From the Byzantine city Argyropolis to the Ottoman neighborhood Süleymaniye

Anatolia, which has hosted many civilizations since the early ages, is historically very important. While the majority of the settlements of these civilizations are still present where they were founded, there are some historical cities that have disappeared or moved to another place; while some are known with their names only in old sources, the ruins of some of them are found, and some continue to exist in other places because the original places of foundation of the cities were deserted. One of the cities which sought its continuity in another place is Argyropolis. The city which was founded on a sloping area with rich silver mines and which was spread along heights of 1400–1500 m, moved to a valley of a height of 1150 m and some 4 km away from its original place of foundation because of the loss of its socio-economic power. In its original place of foundation, the city was called as Argyropolis and Canca, respectively. After the city was left it was called Eski?ehir (Old City) and Eski Gümü?hane (Old Gümü?hane), respectively; and when it lost its status as a city and reduced to the status of a neighborhood it was called Süleymaniye (The City of Suleiman). The names given to the old city before it reduced to the status of a neighborhood and to the new city refer to the ‘silver mines’, which were an indication of the economic condition of the city. The closure of these mines was to the desertion of the city what the running of these mines was to its foundation and development.     

Removal of mercury species with dithiocarbamate-anchored polymer/organosmectite composites

Mercury is one of the most toxic heavy metals found in solid and liquid waste disposed by chloro-alkali, paint, paper/pulp, battery, pharmaceutical, oil refinery and mining companies. Any form of mercury introduced to nature through any means is converted into a more toxic form such as methylmercury chloride (as produced by aquatic organisms) which usually accumulates in the tissue of fish and birds.

The primary aim of this study was to investigate performance of dithiocarbamate-anchored polymer/organosmectite composites as sorbents for removal of mercury from aqueous solution. The modified smectite nanocomposites then were reacted with carbondisulfide to incorporate dithiocarbamate functional groups into the nanolayer of the organoclay. These dithiocarbamate-anchored composites were used for the removal of mercury species [Hg(II), CH₃Hg(I) and C₆H₅Hg(I)]. Mercury adsorption was found to be dependent on the solution pH, mercury concentration and the type of mercury species to be adsorbed. The maximum adsorption capacities were equal to 157.3 mg g⁻¹ (782.5 μmol g⁻¹) for Hg(II); 214.6 mg g⁻¹ (993.9 μmol g⁻¹) for CH₃Hg(I); 90.3 mg g⁻¹ (325 μmol g⁻¹) for C₆H₅Hg(I). The competitive adsorption capacities (i.e. adsorption capacities based on solutions containing all three mercuric ions) are 7.7 mg g^−l (38.3 μmol g⁻¹), 9.2 mg g^−l (42.6 μmol g⁻¹) and 12.7 mg g⁻¹ (45.7 μmol g⁻¹) for Hg(II), CH₃Hg(I) and C₆H₅Hg(I), respectively, at 10 ppm initial concentration. The adsorption capacities on molar basis were in order of C₆H₅Hg(I) > CH₃Hg(I) > Hg(II).     

Prevalence of β‐Lactamase Producing Escherichia coli from Retail Meat in Turkey

Extended spectrum β‐lactamase (ESBL) and plasmid‐mediated AmpC β‐lactamase (pAmpC) producing Escherichia coli have been shown to be present in humans and animals representing a significant problem worldwide. This study aimed to search the presence of ESBL and/or AmpC‐producing E. coli in retail meats (chicken and beef) in Turkey. A total of 88 β‐lactamase‐producing E. coli were isolated from chicken (n = 81/100) and beef meat (n = 7/100) samples and their susceptibility to several antimicrobials were tested using disc diffusion method. E. coli isolates were further characterized for their phylogenetic groups. β‐Lactamase encoding (bla_TEM, bla_SHV, bla_OXA, bla_CTX‐M, and bla_AmpC) and quinolone resistance genes (qnrA, qnrB, qnrS, qepA, and acc(6′)‐Ib‐cr) were also secreened by polymerase chain reaction (PCR). However, in regard to β‐lactamase genes, 84 of 88 isolates were positive for bla_CTX‐M‐1 (n = 39), bla_CTX‐M‐3 (n = 5), bla_CTX‐M‐15 (n = 4), bla_TEM‐1b (n = 2), bla_SHV‐12 (n = 1), bla_CTX‐M‐1/bla_TEM‐1b (n = 10), bla_CTX‐M‐1/bla_TEM‐1b/bla_SHV‐5 (n = 1), bla_CTX‐M‐1/bla_CMY‐2 (n = 1) and bla_TEM‐1b/bla_CMY‐2 (n = 6), bla_CTX‐M‐15/bla_SHV‐12 (n = 1), bla_CTX‐M‐15/bla_TEM‐1b (n = 1), bla_TEM‐1b/bla_SHV‐12 (n = 1)_, and bla_CMY‐2 (n = 12) genes. Resistance to cefuroxime (75.6% and 85.7%), nalidixic acid (89% and 85.7%), tetracycline (91.4% and 100%), streptomycin (40.2% and 100%), and trimethoprim‐sulfamethoxazole (36.6% and 85.7%) was observed among strains isolated from chicken and beef, respectively. However, all isolates were found to be susceptible to amikacin, imipenem, and cefepime. Resistance to ampicillin and cefoxitin was significantly linked to bla_CMY‐2 gene, while there was a significant correlation between CTX‐M type ESBL and antimicrobial resistance to cefuroxime and streptomycin (P < 0.05). The results of this study suggest that raw chicken retail meats are highly contaminated with ESBL‐producing E. coli implementing a great risk to human health in Turkey.     

Application of Box-Wilson experimental design method for the photodegradation of bakery's yeast industry with UV/H2O2 and UV/H2O2/Fe(II) process

Decolorization and mineralization of bakery's yeast industry effluent by photochemical advanced oxidation processes (AOPs) utilizing UV with hydrogen peroxide and Photo-Fenton, were investigated in a laboratory scale photo-reactor equipped with a 16 W low-pressure mercury vapor lamp. The Box-Wilson experimental design method was employed to evaluate the effects of major process variables (e.g. pH, oxidant dose, and irradiation time) on the decolorization efficiency. Response function coefficients were determined by regression analysis of the experimental data and prediction results agreed with the experimental results. The optimum hydrogen peroxide concentration and irradiation time were found to be 5 mM and 50 min at pH 3, respectively, for UV/H2O2 process. In the Photo-Fenton process application, maximum decolorization efficiency (96.4%) was obtained at the optimum reaction conditions that were 100 mM H2O2 and 1 mM Fe(II) doses at pH 3, and 10 min of irradiation time.     

A comparative study on dielectric behaviours of Au/(Zn-doped PVA)/<Emphasis Type="Italic">n</Emphasis>-4H-SiC (MPS) structures with different interlayer thicknesses using impedance spectroscopy methods

Three different thicknesses (50, 150 and 500 nm) Zn-doped polyvinyl alcohol (PVA) was deposited on n-4H-SiC wafer as interlayer by electrospinning method and so, Au/(Zn-doped PVA)/n-4H-SiC metal–polymer–semiconductor structures were fabricated. The thickness effect of Zn-doped PVA on the dielectric constant (\(\varepsilon ^{\prime }\)), dielectric loss (\(\varepsilon ^{{\prime }{\prime }}\)), loss-tangent (tan \(\delta \)), real and imaginary parts of electric modulus (\(M^{\prime }\) and \(M^{{\prime }{\prime }})\) and ac electrical conductivity \((\sigma _{\mathrm{ac}})\) of them were analysed and compared using experimental capacitance (C) and conductance (\(G/\omega \)) data in the frequency range of 1–500 kHz at room temperature. According to these results, the values of \(\varepsilon ^{\prime }\) and \(\varepsilon ^{{\prime }{\prime }}\) decrease with increasing frequency almost exponentially, \(\sigma _{\mathrm{ac}}\) increases especially, at high frequencies. The \(M^{\prime }\) and \(M^{{\prime }{\prime }}\) values were obtained from the \(\varepsilon ^{\prime }\) and \(\varepsilon ^{{\prime }{\prime }}\) data and the \(M^{\prime }\) and \(M^{{\prime }{\prime }}\) vs. f plots were drawn for these structures. While the values of \(\varepsilon ^{\prime }\), \(\varepsilon ^{{\prime }{\prime }}\) and tan \(\delta \) increase with increasing interlayer thickness, the values of \(M^{\prime }\) and \(M^{{\prime }{\prime }}\) decrease with increasing interlayer thickness. The double logarithmic \(\sigma _{\mathrm{ac}}\) vs. f plots for each structure have two distinct linear regimes with different slopes, which correspond to low and high frequencies, respectively, and it is prominent that there exist two different conduction mechanisms. Obtained results were found as a strong function of frequency and interlayer thickness.     

Effect of roasting on the physico-chemical properties,fatty acids,polyphenols and mineral contents of tobacco (Nicotiana tabacum L.) seed and oils

The physico-chemical properties, phytochemicals, mineral contents of tobacco (Nicotiana tabacum L.) seeds grown at Samsun province in Turkey were evaluated. The oil contents of tobacco seeds ranged from 20.6% (control) to 29.0% (microwave-roasted). L*, a* and b* values of tobacco seeds ranged from 32.38 to 35.61; from 6.32 to 6.78; from 13.72 to 14.27, respectively. Total phenolic contents of tobacco seed extract and oils were reported between 31.02 (oven-roasted) and 34.42 mg GAE/100 g (microwave-roasted) to 4.60 (microwave-roasted) and 6.45 mg GAE/100 g (oven-roasted), respectively. Total flavonoid values of raw and roasted tobacco seed extract and oils were determined between 26.62 (oven) and 67.10 mg/100 g (control) to 21.57 (control) and 44.71 mg/100 g (microwave-roasted), respectively. Gallic acid, 3,4-dihydroxybenzoic acid and catechin are the predominant phenolic components of raw and roasted tobacco seed oils. The amounts of oleic and linoleic acid in raw and roasted tobacco seed oils ranged from 10.23% (oven-roasted) to 12.48% (control) and 73.72% (control) to 76.63% (oven-roasted), respectively. The abundant elements found in seeds were K, P, Ca, Mg, S and Fe. The mineral amounts of the roasted seeds were found higher than that of the control. The highest increase was detected in oven roasted tobacco seeds.     

Determination of the quality and purity characteristics of olive oils obtained from different regions of Turkey,depending on climatic changes

Virgin olive oils (VOOs) obtained from olives grown in different regions of Turkey under changing climatic conditions sometimes show different sensory and chemical properties. This study was planned to determine whether these deviations are due to climatic changes or not. For this purpose, five different olive varieties (Ayvalık, Memecik, Gemlik, Nizip Yağlık, Kilis Yağlık) of commercial importance were harvested from the provinces/districts (four different region) where cultivation is intense during the 2017/2018–2020/2021 harvest years. Every year, olive samples were collected from 3 orchards from 13 provinces/districts. One hundred and fifty-six samples were subjected to the purity, quality and sensory analysis. Basic climatic values (average, minimum and maximum temperature, humidity and precipitation) were examined for four consecutive years. All of the examined olive oil samples were determined within the legal limits in terms of fatty acid composition and fatty acid ethyl ester values. However, delta-7-stigmastenol value from the sterol composition was found to be above 0.5% in some samples in all the years studied (total 21 samples). Delta-7-stigmastenol values of olive oil samples varied between 0.16% and 1.14%. Multiple linear regression analysis was applied using a genetic algorithm-based inverse least squares method to determine whether there is a relationship between climate data and delta-7-stigmastenol values. According to this result, it has been determined that the delta-7-stigmastenol value is high when the annual average relative humidity is low and the annual average temperature is high. There is an urgent need to make forward-looking plans due to climate change.