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Öğe Boron rejection from aqueous solution and wastewater by direct contact membrane distillation(Yildiz Technical University, 2021) Tan, Burcu; Selengil, Uğur; Bektaş, Tijen EnnilBoron is widely used in various areas of modern technology. Due to the environmental problems arising during the production and use, the studies on the removal and recovery of boron from wastewater have been increased recently. Membrane distillation (MD) system is smaller in size with respect to other common distillation systems and needs lower operating temperatures. In addition, the equipment costs are reduced and the safety of the process increases since it operates at lower pressures. Moreover, the membrane distillation process can remove pollutants from water without using chemicals. In this study, boron rejection from aqueous solutions and wastewater was investigated by using direct contact membrane distillation (DCMD) system where both surfaces of a porous hydrophobic membrane were in contact with liquid streams. The effects of various parameters (pH, feed concentration, feed temperature, etc.) on boron rejection were investigated and the highest boron rejection was found to be 50 % when pH=10 at 50 °C and with feeding by a pump of 54 rpm. According to the test results of wastewater from Kırka Borax treatment plants, the mean distillate fluxes were found as 13, 16 and 14 L m-2 h-1 at the feed temperatures of 30, 40 and 50 °C, respectively. The boron removal percentages were found to be 47, 64 and 48 % at 30, 40 and 50 °C, respectively. It was observed in the XRD spectra that the crystals in wastewater mainly consist of Na2B(OH)4Cl and Mg2B2O5 structures.Öğe Boron Rejection from Aqueous Solution and Wastewater by Direct Contact Membrane Distillation(2020) Tan, Burcu; Selengil, Uğur; Bektaş, Tijen EnnilBoron is widely used in various areas of modern technology. Due to the environmental problems arising during the production and use, the studies on the removal and recovery of boron from wastewater have been increased recently. Membrane distillation (MD) system is smaller in size with respect to other common distillation systems and needs lower operating temperatures. In addition, the equipment costs are reduced and the safety of the process increases since it operates at lower pressures. Moreover, the membrane distillation process can remove pollutants from water without using chemicals. In this study, boron rejection from aqueous solutions and wastewater was investigated by using direct contact membrane distillation (DCMD) system where both surfaces of a porous hydrophobic membrane were in contact with liquid streams. The effects of various parameters (pH, feed concentration, feed temperature, etc.) on boron rejection were investigated and the highest boron rejection was found to be 50 % when pH=10 at 50 degrees C and with feeding by a pump of 54 rpm. According to the test results of wastewater from Kirka Borax treatment plants, the mean distillate fluxes were found as 13, 16 and 14 L/m(2)h at the feed temperatures of 30, 40 and 50 degrees C, respectively. The boron removal percentages were found to be 47, 64 and 48 % at 30, 40 and 50 degrees C, respectively. It was observed in the XRD spectra that the crystals in wastewater mainly consist of Na2B(OH)(4)Cl and Mg2B2O5 structures.Öğe Effect of activated carbon produced from biochar on removal of 2, 4-dichlorophenoxy acetic acid from aqueous solutions(National Institute of Science Communication and Information Resources, 2021) Angin, Dilek; Güneş, Sinem; Ateş, Asude; Selengil, Uğur; Altıntığ, Esra; Tan, Burcu; Demirel, HülyaThe toxicity of pesticides and their degradation products is making these chemical substances a potential hazard by contaminating our environment. Therefore, the removal of pesticides from water is one of the major environmental concerns these days. 2,4-Dichlorophenoxy acetic acid (2,4-D) belonging to the herbicide group, which is among the numerous pesticides used today, is widely used to control weeds due to its low cost and good selectivity. In order to offer an alternative to this environmental problem, the effect of activated carbon obtained by chemical activation from pyrolysis biochar on 2,4-dichlorophenoxy acetic acid removal from aqueous solutions has been investigated. The adsorption mechanism is explained by analyzing the effect of adsorption parameters. It is determined that the equilibrium data are suitable for Langmuir isotherm model among the applied isotherm models and the monolayer adsorption capacity is 344.83 mg g-1 at 318 K. The adsorption kinetics data of 2,4-D on activated carbon is better defined by the pseudo-second-order model. Thermodynamic calculations reveal that the adsorption process is spontaneous and endothermic. The activated carbon obtained from biochar has been observed to have a high adsorption capacity compared to adsorbent materials obtained from many other raw materials for the removal of 2,4-Dichlorophenoxy acetic acid.Öğe Investigation of the Usability of Perlite Waste for Dyestuff Removal from Aqueous Solution(2020) Selengil, Uğur; Bektaş, Tijen EnnilIn this study, unexpended perlite waste obtained from a factory producing expanded perlite was used as adsorbent. Malachite green (MG), which is a cationic dyestuff, was used as adsorbed material. The pore properties including the BET surface area, pore volume and average pore diameter were characterized. The chemical composition of the perlite was analysed by XRF. The effects of initial pH, the amount of adsorbent, contact time and initial dyestuff concentration were examined. The adsorption kinetics of dyestuff obeys the pseudo second-order kinetic model. The experimental data indicated that the adsorption isotherms are well described by the Langmuir isotherm equation. 99% dyestuff removal was obtained under optimum conditions. As a result, it was found that perlite waste was a suitable adsorbent for malachite green dyestuff.Keywords: Perlite waste, dyestuff, adsorption, isotherm
