Yazar "Gumus, Dilek" seçeneğine göre listele
Listeleniyor 1 - 10 / 10
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe A comparative study of ozonation, iron coated zeolite catalyzed ozonation and granular activated carbon catalyzed ozonation of humic acid(Pergamon-Elsevier Science Ltd, 2017) Gumus, Dilek; Akbal, FeryalThis study compares ozonation (O-3), iron coated zeolite catalyzed ozonation (ICZ-O-3) and granular activated carbon catalyzed ozonation (GAC-O-3) for removal of humic acid from an aqueous solution. The results were evaluated by the removal of DOC that specifies organic matter, UV254 absorbance, SUVA (Specific Ultraviolet Absorbance at 254 nm) and absorbance at 436 nm. When ozonation was used alone, DOC removal was 21.4% at an ozone concentration of 10 mg/L, pH 6.50 and oxidation time of 60 min. The results showed that the use of ICZ or GAC as a catalyst increased the decomposition of humic acid compared to ozonation alone. DOC removal efficiencies were 62% and 48.1% at pH 6.5, at a catalyst loading of 0.75 g/L, and oxidation time of 60 min for ICZ and GAC, respectively. The oxidation experiments were also carried out using <100 kDa and <50 kDa molecular size fractions of humic acid in the presence of ICZ or GAC. Catalytic ozonation also yielded better DOC and UV254 reduction in both <50 kDa and <100 kDa fractions of HA compared to ozonation. (C) 2017 Elsevier Ltd. All rights reserved.Öğe Biosorptive application of defatted Laurus nobilis leaves as a waste material for treatment of water contaminated with heavy metal(Taylor & Francis Inc, 2019) Gumus, DilekDefatted Laurus nobilis leaves as a natural biosorbent was first evaluated for elimination of toxic heavy metals such as Pb(II), Cd(II), Zn(II), Cu(II) from aqueous solutions for its wide availability as forest industry waste, in this study. The effects of solution pH, contact time, biosorbent dosage, initial metal ions concentration, ionic strength, humic acid effect, and their competitive effect on the biosorption of lead(II), cadmium(II), Copper(II), and zinc(II) by defatted Laurus nobilis leaves waste (LW) were studied for each metal. The biosorbent was characterized using FT-IR and SEM images. Comparative isotherm and kinetic studies were performed. The sorption of Cd(II) and Zn(II) on LW fitted better in the Freundlich model but Pb(II) and Cu(II) sorption fitted better in the Langmuir model. From the obtained results, the pseudo-second-order kinetic model described the biosorption of cadmium, lead, zinc copper ions the best. The biosorbent showed the maximum biosorption capacities (q(m)) of 96.2, 8.6, 8.7, and 6.0 mg g(-1) for lead, cadmium, zinc, and copper, respectively. These results indicated that LW may be used as an effective and inexpensive heavy metal remediation material. Comparison to previous studies showed that LW is also comparable to (or better than) several other biosorbents.Öğe Comparison of Fenton and electro-Fenton processes for oxidation of phenol(Elsevier, 2016) Gumus, Dilek; Akbal, FeryalThis study compares the performance of Fenton and electro-Fenton processes for phenol degradation. The effects of operational parameters such as initial pH, current density, concentration of phenol and hydrogen peroxide on phenol removal was investigated in electro-Fenton process. The degradation and mineralization efficiency increased with an increase in hydrogen peroxide concentration and current density and decreased with an increase in initial phenol concentration and initial pH. It was found that optimum pH, current density and H2O2 concentration were 3.0, 1 mA/cm(2) and 500 mg/L, respectively. Under the optimized conditions, the phenol and chemical oxygen demand (COD) removal efficiency reached 93.32% and 87.5%, respectively. In conventional-Fenton process, the effect of hydrogen peroxide and Fe2+ concentrations on the degradation and mineralization of phenol removal were investigated. The results indicated that the conventional-Fenton process only yields 59% mineralization. An estimation of the operating costs of the processes investigated showed that electro-Fenton was the more economical system to treat the phenol containing wastewater. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.Öğe Electrochemical Treatment of a Real Textile Wastewater Using Cheap Electrodes and Improvement in Cod Removal(Springer Int Publ Ag, 2023) Gumus, DilekVarious types of dyes and other hazardous pollutants used in the textile industry are one of the leading pollutants of surface water. In this study, real textile wastewater was electrochemically treated with two different electrode combinations (graphite/graphite and iron/graphite) by changing the anode electrode type. Comparison studies were carried out by adding Fe2+ or H2O2 to these combinations to improve Chemical Oxygen Demand (COD) removal. Current density (5, 7.5, 10 mA cm(-2)), initial pH (2.5-8), and electrochemical (EC) oxidation time (0-120 min) were investigated to determine the optimum electrooxidation conditions. The results showed that in the electro-oxidation (EO) process, 100% colour removal, and 75.39% COD degradation efficiencies were achieved at pH 5.5, current density (I) 7.5 mA cm (-2), and electrolysis time (t) 40 min. In the peroxi-coagulation (PC) process, 89.41% colour removal, and 74.28% COD degradation efficiencies were achieved at pH 3, current density 7.5 mA cm (-2), and electrolysis time 120 min. In the EO + Fe+2 and PC + H2O2 processes, 99.9% colour removal efficiencies, 96.38 and 90.63% COD degradation efficiencies were reached at pH 3, current density 7.5 mA cm (-2), and electrolysis time 40 min., respectively. In systems using EO, PC, EO + Fe(2+)and PC + H2O2, energy consumption, and operating cost were estimated as 2.85, 2.34, 0.54, 0.62 kWh m(-3), and 0.304, 0.249, 0.199, 3.466 US$ m(-3), respectively. Among all processes applied in the study, the most efficient one in terms of COD removal performance, energy, and cost is the (EO + Fe2+) system.Öğe Evaluation of adsorptive and synergistic effects for elimination of crystal violet from aqueous solution(Desalination Publ, 2018) Gumus, DilekThis study investigated removal of crystal violet ( CV) from aqueous solutions by iron oxide-coated zeolite (ICZ), potassium permanganate-coated zeolite (MCZ), and zero-valent iron (ZVI) and evaluated synergistic effect of sequential system. The adsorbents were characterized using energy-dispersive X-ray analysis and scanning electron microscopy images. The effects of various parameters were examined. The results showed that basic pH generally favored adsorption for ICZ and MCZ but significant CV removal was possible even under neutral conditions. ICZ and MCZ exhibited the best performance at pH 11. ZVI displayed the best performance at pH 7, and the adsorption was very fast. The experimentally obtained data for the adsorption of CV onto ICZ, MCZ, and ZVI were modeled using the isotherm models of Freundlich and Langmuir. The kinetics of CV onto ICZ, MCZ, and ZVI was best described by the pseudo-second-order kinetic model. This study reveals that it is possible to use ICZ, MCZ, and ZVI as nanoparticles, an alternative for the adsorbents that are already being used, in the removal of CV from industrial wastewater. Furthermore, the combination of ZVI and MCZ enhances the decolorization of the solutions. The best result was found with the ZVI-MCZ sequential system.Öğe Modeling heavy metal removal by retention on Laurus nobilis leaves biomass: linear and nonlinear isotherms and design(Taylor & Francis Inc, 2020) Gumus, Dilek; Gumus, FatihHeavy metal industries pose a serious threat to the environment. Conventional methods used for heavy metal removal are generally not always low-cost and environmentally friendly. So, researchers focused to investigate alternative biosorbents for the uptake of heavy metal. In this study, Laurus nobilis leaves (LNL) were used as a biosorbent for the uptake of toxic metals such as Pb2+ and Cd2+ from aqueous solutions. Batch biosorption experiments under varied conditions, such as biosorbent dosage, solution pH, heavy metal concentration, biosorption time, ionic strength, humic acid effect and competitive metal ions (Cd(II), Pb(II), Cu(II) and Zn(II)) were performed. The biomass was characterized using FT-IR spectra and SEM images. The nonlinearized and linearized isotherm models were compared and discussed. A single-stage batch bioreactor system for each heavy metal based on the best fit nonlinear isotherm model also has been presented. The biosorption of Pb(II) on LNL fitted better in the Langmuir model and Cd(II) biosorption fitted better in the Freundlich model by nonlinearized equations. The LNL exhibited the maximum monolayer biosorption capacities (q(max)) of 7.1 and 32.5 mg/g for cadmium and lead, respectively. LNL showed great potential especially in Pb(II) uptake. LNL may be promising for heavy metal removal from aqueous environment.Öğe Removal of Cefdinir from Water Using Waste Material-Derived Activated Biochar as a Rapid, Effective, and Sustainable Adsorbent(Wiley, 2021) Gumus, Dilek; Yumak, Tugrul; Gumus, FatihCefdinir adsorption onto non-activated biochar (WL-BC) and activated biochars (WL-BC-H, WL-BC-OH) prepared from waste biomass (WL) is comparatively investigated in view of adsorption factors, adsorption isotherms and adsorption kinetics. Batch experiments are conducted to assess the effects of pH, adsorption time and initial antibiotic concentration. Various advanced techniques are applied to characterize the prepared biochars (BCs). Characterization of the new BCs reveal that the activation process do not have a significant effect on the chemical structure of activated carbons, but it increases the surface area up to eight times. The equilibrium data are simulated with the Langmuir adsorption model indicating monolayer adsorption for both activated biochars WL-BC and WL-BC-H. However, the adsorption isotherm for WL-BC-OH is represented well by the Freundlich model, which shows that multilayer adsorption took place. The kinetic data are analyzed using various kinetic models. The maximum adsorption capacity of the activated biochar is approximately tenfold in comparison to the non-activated biochar. Additionally, the real wastewater experiments with treated campus wastewater show that the adsorptive performance of the activated biochar is not affected by other ions. Consequently, BCs derived from defatted laurel leaves could be effective and eco-friendly adsorbents for removing cefdinir from wastewater.Öğe Removal of Hydroxychloroquine Using Engineered Biochar from Algal Biodiesel Industry Waste: Characterization and Design of Experiment (DoE)(Springer Heidelberg, 2022) Gumus, Dilek; Gumus, FatihAdsorption of hydroxychloroquine (HCQ) onto H3PO4-activated Cystoseira barbata (Stackhouse) C. Agardh (derived from algal biodiesel industry waste) biochar was investigated via batch experiments and mathematical models. The activated biochar (BC-H) was produced in a single step by using the microwave irradiation method. Thus, it was obtained with a low cost, energy efficiency and by promoting clean production processes. BC-H exhibited a remarkable adsorption efficiency (98.9%) and large surface area (1088.806 m(2) g(-1)) for removal of HCQ. The Langmuir isotherm and the pseudo-second-order kinetic models were the best fit for the equilibrium adsorption and kinetics experiments, and the maximum monolayer adsorption capacity (qmax) was found to be 353.58 mu g g(-1). Additionally, the experiments with real wastewater showed that BC-H's ability to adsorb HCQ was not affected by competitive ions in the water. The Taguchi orthogonal array (L16 OA) experimental design was applied for the effective cost optimization analyses of the adsorption process by considering four levels and four controllable factors (initial pH, HCQ concentration, amount of adsorbent and contact time). Scanning electron microscopy, Fourier transform infrared spectroscopy and Brunauer-Emmett-Teller analyses were used for characterizing the adsorbent. The findings showed that BC-H can be used as an effective and low-cost adsorbent in the removal of HCQ from water.Öğe REMOVAL OF NATURAL ORGANIC MATTER IN DRINKING WATERS AND PREVENTION OF TRIHALOMETHANES FORMATION(Yildiz Technical Univ, 2013) Gumus, Dilek; Akbal, FeryalNatural waters contain natural organic matter (NOM) ubiquitously as a result of the interactions between the hydrological cycle and the biosphere and geosphere. During the chlorination of raw water, chlorine reacts with natural organic matter to produce disinfection by-products (DBPs), such as trihalomethanes (THMs) and haloacetic acids (HAAs), which are believed to be harmful to human health. Among the most commonly formed DBPs are the THMs. Many countries have focused on DBPs and promulgated regulations and they have regulated THMs. Because of concerns over the health effects of these organic by-products, treatment of drinking waters contain NOM have become inevitable. Natural organic matter in drinking water treatment are removed by conventional coagulation/flocculation, actived carbon adsorption, ozonation, MIEX resin and membrane filtration.Öğe The use of a wetland plant as a new biosorbent for treatment of water contaminated with heavy metals: Nonlinear analyses, modification, competitive effects(Elsevier, 2019) Gumus, Dilek; Gumus, FatihThe aim of this study was to evaluate the biosorption capacity of a wetland plant Juncus effusus for elimination of toxic heavy metals such as Cd2+ and Cu2+ from aqueous solutions. The effects of pH, biosorbent amount, biosorption time, heavy metal concentration, ionic strength, humic acid (HA), modification and competitive metal ions such as cadmium, lead, copper and zinc on biosorption efficiency were investigated in a batch biosorption process. J. effusus biomass was characterized by using SEM analysis and FT-IR spectra. The Freundlich, Langmuir and Temkin isotherm models were used to describe the biosorption equilibrium of Cd2+ and Cu2+ for J. effusus. The isotherms of biosorption of Cu2+ and Cd2+ ions were best described by the Freundlich and Langmuir models, respectively. The kinetic data of biosorption were modeled with the Elovich, the pseudo-first-order, pseudo-second-order and intra-particle diffusion model equations. The kinetic data were successfully described by the pseudo-firstorder model. The biosorption processes, which used sodium hydroxide as the chemical modification material, exhibited the best performance in a wide pH range (4-7). The results confirmed that the biosorbent, which was prepared out of a wetland plant, could be used as an inexpensive and abundant biosorbent for removing metal ions from waters contaminated with heavy metals. (C) 2019 Elsevier B.V. All rights reserved.
