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- MakaleAçık Erişim2024Scopus SJRQ3Influence of Congored on the Optical, Dielectric and Thermal Behavior of Polymethyl Methacrylate and Polyvinyl Chloride
Yıldırım, Turgay; Barım, Esra; Tuncer, Hülya; Demirelli, Kadir
Polymethyl methacrylate (PMMA)/Congo Red (CR) and polyvinyl chloride (PVC)/CR composite films were prepared on optical glass by the drop method for optical measurements and also prepared as tablets under pressure for dielectrical measurements. The optical transmission spectra measurements for PMMA and PVC film doped with CR showed a highly absorption in the ultraviolet-visible (UV-Vis) optical range (at 353 nm and 518 nm) and considerably blocking in broad visible range (190 nm–640 nm). PMMA/CR and PVC/CR composite films containing congo red at a concentration of 1 wt% showed maximum absorption bands at 290 nm and 416 nm, but their transmittance percentages were reasonably reduced compared to those of pure PMMA and PVC. Both of composites indicated high transmittances between 640 nm and 800 nm. The optical constants of the PMMA/CR and PVC/CR composite films such as optical band energy gaps (Eg) estimated using Tauc’s model, refractive index and reflectance (%) were calculated. UV–Vis, Fourier transform infrared spectroscopy (FTIR) and Thermogravimetry Analysis (TGA) measurements were used to confirm the breakdown of the -N = N- azo group bonds attached to the aromatic ring as a result of thermal decomposition of CR at 500 °C, and it was suggested that N2 gas was eliminated from the CR above 360 °C. The dielectric plots showed that the dielectric constant increased when the CR is doped up to 70 wt% in the polymer matrices. A further increase in the doping concentration of CR resulted in an increase of the dielectric constant. The dielectric constant decreased with an increase in the frequency for all of the samples. The ac (alternating current) conductivity values of PMMA and PVC showed an increase with increasing CR dopant in the polymer composites, while the ac conductivity values were found to be values between those of the pure polymers and CR.
AtıfScopus4WoS4OpenAlex5
İncele - MakaleYalnız künye2023Scopus SJRQ1Adsorption potential of neodymium/alginate beads for removal of Congo red and Brilliant blue G from aqueous solution
Seker, S.; Karaaslan Ayhan, N.
In this study, neodymium/alginate (Nd/Alg) beads were prepared to removal of Congo Red (CR) and Brilliant Blue G (BBG) dyes from aqueous solution and the adsorption potentials of these dyes were investigated. For this, Nd/Alg beads prepared using crosslinking were characterized by FTIR, SEM–EDS and TGA. For the adsorption of CR and BBG dyes, the effects of various parameters including the amount of Nd in adsorbent (bead), pH, contact time, adsorbent amount, initial dye concentration and temperature were investigated. The optimum conditions for the effective removal of CR and BBG dyes were determined as Nd amount in bead: 3%, pH: 7, contact time: 60 min, bead amount: 15 mg, initial dye concentration: 25 mg/L and temperature 298 K. Adsorption isotherm studies (Langmuir and Freundlich isotherms) and kinetic studies (pseudo-first-order and pseudo-second-order) were carried out under optimum conditions. The adsorption data were found to completely follow Langmuir model for CR and BBG dyes. The maximum adsorption capacities were found to be 46.03 mg/g for CR and 25.25 mg/g for BBG under optimum conditions. The adsorption kinetic data of both dyes were found to be compatible with pseudo-first-order and adsorption processes were explained by intraparticle diffusion. According to thermodynamic studies, nature of adsorption reaction was spontaneous, exothermic and increasing randomness for both dyes. As a result, it can be concluded that Nd/Alg beads obtained with a natural polymer have low cost and high efficiency and even small amounts of these beads have high potential for treatment of high concentration dye wastewater.
AtıfScopus10WoS8OpenAlex10İncele - MakaleYalnız künye2015Scopus SJRQ3Capacity of a newly isolated fungus Pleurotus eryngii from Tunceli, Ovacik for chemical oxygen demand reduction and biodecolorization of Azo-Dye Congo Red
Yildirim, N.; Gonen, U.
Biodecolorization of Congo red dye in both agar-plate and agitated liquid culture mediums by newly isolated white rot fungus Pleurotus eryngii has been studied. This fungus isolated from Tunceli-Ovacik province of Turkey. We have also examined the chemical oxygen demand reduction after decolorization under agitated liquid culture medium. For agar plate screening the decolorization capacity of P. eryngii, growth and decolorization halos were determined on saboroud dextrose agar (SDA) plates containing 0.05, 0.1, 0.5, 1 and 2 g/l of Congo red. P. eryngii showed certain decolorization capacities and was able to decolorize all studied concentrations of Congo red, but not to the same extent. Our results indicated that the new isolate P. eryngii had maximum decolorization (87% at 100 mg/l initial dye concentration) and chemical oxygen demand reduction (82% at 25 mg/l initial dye concentration) activities after 7 days under agitated submerged culture conditions. This new isolate could be an effective bioremediation tool for treatment of Congo red containing textile wastewater.
