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Öğe Artificial neural network (ANN) approach for modeling Zn(II) adsorption in batch process(KOREAN INSTITUTE CHEMICAL ENGINEERS, 2017) Yildiz, SayiterArtificial neural networks (ANN) were applied to predict adsorption efficiency of peanut shells for the removal of Zn(II) ions from aqueous solutions. Effects of initial pH, Zn(II) concentrations, temperature, contact duration and adsorbent dosage were determined in batch experiments. The sorption capacities of the sorbents were predicted with the aid of equilibrium and kinetic models. The Zn(II) ions adsorption onto peanut shell was better defined by the pseudo-second-order kinetic model, for both initial pH, and temperature. The highest R-2 value in isotherm studies was obtained from Freundlich isotherm for the inlet concentration and from Temkin isotherm for the sorbent amount. The high R-2 values prove that modeling the adsorption process with ANN is a satisfactory approach. The experimental results and the predicted results by the model with the ANN were found to be highly compatible with each other.Öğe ARTIFICIAL NEURAL NETWORK APPROACH FOR MODELING OF Ni(II) ADSORPTION FROM AQUEOUS SOLUTION BY PEANUT SHELL(SOC ECOLOGICAL CHEMISTRY & ENGINEERING, 2018) Yildiz, SayiterIn this study, ANN (artificial neural network) model was applied to estimate the Ni(II) removal efficiency of peanut shell based on batch adsorption tests. The effects of initial pH, metal concentrations, temperature, contact time and sorbent dosage were determined. Also, COD (chemical oxygen demand) was measured to evaluate the possible adverse effects of the sorbent during the tests performed with varying temperature, pH and sorbent dosage. COD was found as 96.21 mg/dm(3) at pH 2 and 54.72 mg/dm(3) at pH 7. Also, a significant increase in COD value was observed with increasing dosage of the used sorbent. COD was found as 12.48 mg/dm(3) after use of 0.05 g sorbent and as 282.78 mg/dm(3) after use of 1 g sorbent. During isotherm studies, the highest regression coefficient (R-2) value was obtained with Freundlich isotherm (R-2 = 0.97) for initial concentration and with Temkin isotherm for sorbent dosage. High pseudo-second order kinetic model regression constants were observed (R-2 = 0.95-0.99) during kinetic studies with varying pH values. In addition, Ni(II) ion adsorption on peanut shell was further defined with pseudo-second order kinetic model, since q(e) values in the second order kinetic equation were very close to the experimental values. The relation between the estimated results of the built ANN model and the experimental results were used to evaluate the success of ANN modeling. Consequently, experimental results of the study were found to be in good agreement with the estimated results of the model.Öğe BIOSORPTION OF COPPER FROM SYNTHETIC WATERS BY USING TOBACCO LEAF: EQUILIBRIUM, KINETIC AND THERMODYNAMIC TESTS(VILNIUS GEDIMINAS TECH UNIV, 2015) Cekim, Mehmet; Yildiz, Sayiter; Dere, TurgayIn this study, biosorption of Cu2+ ions on to tobacco leaves was investigated. The optimum conditions for biosorption of Cu2+ ions onto tobacco leaves were determined: pH - 4.0, temperature - 20 degrees C, shaking rate - 200rpm, biosorbent dose - 0.4g, and initial Cu2+ ion concentration - 25mg/L. The state of equilibrium lasted for 60 minutes. COD, TN and TP analyses were performed to determine the negative impacts of biosorbent on the system. Compliance of equilibrium data of tobacco biosorption of Cu2+ ions to Langmuir, Freundlich, Temkin and D-R isotherm models was also investigated. High correlations were achieved in all four isotherm models. Within the scope of kinetic tests, it was observed that biosorption of Cu2+ ions with tobacco biosorbent complied with the pseudo second-order kinetic rate constant. FTIR, SEM and EDX analyses were carried out to investigate the surface characteristics and chemical structure of tobacco biosorbent and absorption of Cu2+ ions were observed. It was concluded that tobacco leaves are a highly efficient (90.72%) sorbent that can remove Cu2+ ions from wastewater.Öğe Biosorption of Cu2+ and Ni2+ ions from aqueous solutions using waste dried activated sludge biomass(DE GRUYTER POLAND SP ZOO, 2018) Aslan, Sukru; Yildiz, Sayiter; Ozturk, MustafaAdsorption of Cu(II) and Ni(II) ions onto the waste powdered activated sludge biomass (PWB), which was obtained from the biological wastewater treatment plant, was investigated in this experimental study. The effects of contact time, pH, temperature, initial sorbate and sorbent concentrations on the adsorption were determined. The BET surface area, pore volume, and pore diameter of PWB were found to be about 0.51 m(2)/g, 0.0053 cm(3)/g, and 41.4 nm, respectively. Considering the R-2 value, q(exp) and q(cal), the Langmuir and Freundlich models were well described for Cu(II) and Ni(II) adsorption, respectively. The adsorption mechanism of Cu(II) and Ni(II) onto the PWB could be better simulated by the pseudo-second-order kinetic mechanism than the pseudo-first-order, intra particle diffusion and Elovich models. Thermodynamic aspects of the adsorption of heavy metals were also investigated. Considering the applied desorbing agents for reuse of PWB for Ni(II) recovery, desorption cycle is not feasible due to the deterioration of the PWB structure.Öğe Biosorption of Cu2+ and Ni2+ Ions from Synthetic Waters(SPRINGER, 2017) Yildiz, Sayiter; Cekim, Mehmet; Dere, TurgayIn this study, biosorption of Cu2+ and Ni2+ ions to tobacco stalks was investigated under different operational conditions. The effects of the initial pH, ion concentrations, temperature, and duration of contact and adsorbent dosage were determined in the batch experiments. Chemical oxygen demand (COD) analyses were also performed to identify the possible negative effects of the sorbent throughout biosorption process. The sorption capacities of this sorbent were predicted by use of the equilibrium and kinetic models. Within the scope of kinetic study, it was observed that biosorption fitted to second-order pseudo kinetic rate expression. The highest R (2) value in isotherm studies was obtained from Freundlich isotherm (R (2) = 0.9940-0.9929) for the inlet concentration. FTIR, SEM, and EDX analyses were performed to investigate the surface characteristics and chemical structure of the biosorbent. Under optimum conditions, qe value for Cu2+ was determined as 7.18 mg/g and removal efficiency was 86.24%; qe value for Ni2+ was determined as 6.45 mg/g and removal efficient was 77.4%. Sorbent recovery process was also performed within the scope of this study with 0.1 M H2SO4, 0.1 M HCl, and distilled water. A significant decrease was observed in efficiency when the recovered sorbent was reused.Öğe Biosorption of Cu2+ from synthetic wastewater by tea waste sorbent: kinetics, equilibrium and thermodynamics(Pamukkale Univ, 2021) Aslan, Sukru; Yildiz, Sayiter; Ozturk, MustafaThe biosorption of Cu2+ onto the tea wastes (TW) was investigated by performing the batch experiments. The removal efficiency and biosorption capacity (q(e)) of TW was investigated as a function of pH, contact time, initial Cu2+ concentration, temperature, and TW dose. The q(e) value of 7141 increased with the increase of solution temperatures. According to the R-2 value, q(exp) and q(coa), the adsorption equilibrium was well described by the Langmuir isotherm model The highest sorption of Cu2+ onto TW was observed at the initial pH value and temperature of 6.0 and 55 degrees C, respectively. Experimental results confirming that the biosorption reaction of Cu(2+)on the TW was thought to be endothermic. By the comparison of kinetic models, results demonstrated that the system was best described by the pseudo secondorder kinetic model The negative Delta G degrees value indicated that the Cu2+ sorption onto the TW is feasible.Öğe Density Functional Theory Computations and Experimental Analyses to Highlight the Degradation of Reactive Black 5 Dye(Wiley-V C H Verlag Gmbh, 2023) Yildiz, Sayiter; Canbaz, Gamze Topal; Kaya, Savas; Maslov, Mikhail M.The oxidative degradation of Reactive Black 5 (RB5) in aqueous solution was investigated using Fenton (FP), photo Fenton (P-FP), sono Fenton (S-FP), and sono photo Fenton (S-P-FP) processes. Degradation experiments showed efficient dye degradation for FP, P-FP, S-FP, and S-P-FP under optimal conditions. The half-life values of the reaction calculated for first-order reaction kinetics showed that the S-FP process is faster than the FP and P-FP processes. Using DFT calculations, the chemical reactivities of the studied chemical systems were analyzed. Especially the calculated chemical hardness values reflect the reactivities of the dye and the dye-Fe2+ complex. The calculated binding energy between the Fe2+ ion and RB5 of 15.836 eV is compatible with the prediction made in the light of the principle of hard and soft acids and bases. The computed data supported the experimental observations.Öğe Elucidating the mechanisms of AV17 and BB41 dye degradation through combined computational and applied analyses(Elsevier, 2024) Yildiz, Sayiter; Kaya, Savas; Canbaz, Gamze Topal; Maslov, Mikhail M.This study delved into the degradation efficiencies of Basic Blue 41 (BB41) and Acid Violet 17 (AV17) azo dyes employing various Fenton reactions, including Fenton (FP), photo-Fenton (P-FP), sono-Fenton (S-FP), and sonophoto-Fenton (S-P-FP) processes. The primary goal was to pinpoint the optimal degradation conditions by meticulously examining variables such as H2O2 and Fe2+ concentrations, reaction time, pH, and dye concentration. Density Functional Theory (DFT) calculations revealed the interaction between Fenton reagents and dye molecules, and crucial quantum chemical parameters reflecting the dye's reactivity were computed. The degradation efficiencies for AV17 in FP, P-FP, S-FP, and S-P-FP processes stood at 85 %, 92.6 %, 93.8 %, and 86.9 %, respectively. Meanwhile, for BB41, the corresponding efficiencies were 97.2 %, 98.1 %, 97.8 %, and 97.5 %. Notably, DFT-calculated data corroborated experimental observations, shedding light on the degradation mechanism. This study significantly advances existing research by demonstrating the efficacy and reliability of Fenton-like processes in degrading AV17 and BB41 dyes. The findings underscore the potential of these processes in addressing environmental concerns associated with azo dyes.Öğe Estimation of irrigation water quality index with development of an optimum model: a case study(Springer, 2020) Yildiz, Sayiter; Karakus, Can BulentSurface water quality parameters are important means for determination of water's suitability for irrigation. In this research, data from 32 irrigation stations were used to calculate the sodium adsorption rate (SAR), sodium percentage (Na%), Kelly index (KI), permeability index (PI) and irrigation water quality index (IWQI) for evaluation of surface water quality. The obtained SAR, KI and Na% values, respectively, varied between 0.10 and 9.43, 0.03-1.37 meq/l and 3.16-57.82%. The calculated PI values indicate that, 93.75% of the water samples is in suitable category, and 6.25% is in non-suitable category. The IWQI values obtained from the research area varied between 30.59 and 81.09. In terms of irrigation water quality, 12.5% of the samples is of good quality, 15.62% is of poor quality, 68.75% is of very poor quality, and 3.12% is of non-suitable quality. Accordingly, IWQI value was estimated on the basis of SAR, Na%, KI and PI values using multiple regression and artificial neural network (ANN) model. The regression coefficient (R-2) was determined as 0.6 in multiple regression analysis, and a moderately significant relationship (p < 0.05) was detected. As the calculated F value was higher than the tabulated F value, a real relationship between the dependent and independent variables is inferred. Four different models were built with ANN, and the statistical performance of the models was determined using statistical parameters such as average value (mu), standard error (SE), standard deviation (sigma), R-2, root mean square error (RMSE) and mean absolute percentage error (MAPE). The training R-2 value belonging to the best model was found to be significantly high (0.99). The relation between the estimation results of ANN model and the experimental data (R-2 = 0.92) verifies the model's success. As a result, ANN proved to be a successful means for IWQI estimation using different water quality parameters.Öğe Evaluation for Irrigation Water Purposes of Groundwater Quality in the Vicinity of Sivas City Centre (Turkey) by Using Gis and an Irrigation Water Quality Index(Wiley, 2020) Karakus, Can Bulent; Yildiz, SayiterIn this study, the physical and chemical characteristics of wet and dry season groundwater quality parameters of 35 wells within the provincial boundaries of Sivas were used for calculations such as sodium adsorption ratio (SAR), Kelly's ratio (KR), sodium percentage (Na%), permeability index (PI), residual sodium carbonate (RSC) and magnesium hazard (MH), which are used in irrigation water quality ratings. Also, the irrigation water quality index (IWQI) was calculated for all groundwater sources within the study area. Groundwater quality parameters and the spatial distribution of the parameters calculated throughout the study were mapped using GIS, and irrigation water quality evaluation was performed in accordance with USA Salinity Laboratory diagram and irrigation water quality standards. The correlations between the irrigation water quality parameters were determined using Pearson correlation analysis. IWQI values showed that the majority of groundwater samples (45.7%) are in the 'weak' (MR: medium rating) category for the dry season, whereas 42.9% of groundwater samples fall within the 'very weak' (HR: high restriction) category for the wet season. (c) 2019 John Wiley & Sons, Ltd.Öğe HEAVY METAL ADSORPTION BY DEWATERED IRON-CONTAINING WASTE SLUDGE(SOC ECOLOGICAL CHEMISTRY & ENGINEERING, 2018) Yildiz, Sayiter; Sevinc, SelahattinDrinking water treatment plants produce significant amounts of waste sludge. In this study, removal of Nickel ion by use of wastewater sludge was aimed. The adsorption capability of waste sludge was optimized with varying physical parameters such as pH, adsorbent dosage, adsorbate concentration, contact time, shaking speed and temperature. Initial concentration was set as 25 mg/dm(3), absorbent dose was set as 0.3 g/cm(3), and temperature was set as 25 degrees C. Compliance of balance data with Langmuir, Freundlich, Temkin and D-R isotherm models was investigated. The highest R-2 values were obtained with Freundlich isotherm (R-2 = 0.92-0.95). Adsorption kinetics was analysed using pseudo-first order, pseudo-second order, Weber and Morris intraparticle diffusion and Elovich kinetic models, and the system was found to be in a better compliance with pseudo-second order kinetic model. Iron sludge was used as sorbent, and accordingly total iron ion measurements were carried out to determine its possible effects on water. Additionally, SEM, EDX, FTIR spectroscopy, XRD spectrum and atomic force microscope (AFM) measurements were conducted to determine the interaction between the sorbent and metal ions, in addition to characterization of the sorbent. As indicated by research results, drinking water treatment sludge proved to be a potential adsorbent for removal of nickel(II) ions from the solution.Öğe KINETIC AND ISOTHERM ANALYSIS OF Cu(II) ADSORPTION ONTO ALMOND SHELL (Prunus dulcis)(SOC ECOLOGICAL CHEMISTRY & ENGINEERING, 2017) Yildiz, SayiterIn the work, adsorption of Cu2+ ions onto almond shell were investigated under different operational conditions. Almond shell was used without any pretreatment prior to the tests. The optimum conditions for adsorption of Cu2+ ions through almond shell were determined to be; pH 5.0, temperature 20 degrees C, shaking rate 125 rpm, sorbent dose 0.3 g and initial Cu2+ ion concentration 50 mg/dm(3). The equilibrium duration of the system was 60 minutes. The sorption capacities of the sorbents were predicted with the aid of equilibrium and kinetic models. The interactions of peanut shell with metal ions were constituted by SEM, EDX, FT-IR, XRD and AFM. The pseudo-first-order, pseudo-second-order, Weber-Morris, Elovich model and Bangham kinetic models were applied to test the experimental data. The Cu+2 ions adsorption onto almond shell was better defined by the pseudo-second-order kinetic model, for initial pH. The equilibrium data were evaluated using Langmuir, Freundlich, Temkin, D-R and Harkins Jura isotherms. The highest R-2 value in isotherm studies was obtained from Langmiur isotherm (R-2 = 0.98) for the inlet concentration.Öğe Photocatalytic degradation of oxytetracycline using ZnO catalyst(Wiley, 2024) Yildiz, Sayiter; Canbaz, Gamze Topal; Mihciokur, HamdiIn the present study, the degradation of oxytetracycline (OTC) under ultraviolet (UV) light in the presence of ZnO catalyst was investigated, and optimum parameters for degradation efficiency were determined. Different pH values, ZnO dosages, reaction times, OTC concentrations, and UV lights were used in this study. The optimum conditions found were as follows: pH 4, ZnO 1 g L-1, reaction time 25 min, and OTC concentration 10 mg L-1. Degradation efficiency was 42.1%, 76%, 70.7%, and 61.7% for ZnO and photocatalytic (for UV-A, UV-B, and UV-C) degradation at optimal conditions, respectively. The resulting products after the photocatalytic oxidation of OTC were determined in the study. To identify the toxicity of degradation products and OTC, the lowest LC 50 (50% lethal concentration) and EC 50 (50% effective concentration) values were found. The resulting ethanamine, 2-(2,6-dimethylphenoxy)-N-methyl- by-products were observed to be more toxic than OTC. Furthermore, it was seen that isopropoxy carbamic acid, ethyl ester by-products were formed, whose presence is environmentally risky for aquatic environments due to their low EC50 values.Öğe Sludge disintegration using UV assisted Sono-Fenton process(Springer Heidelberg, 2021) Olabi, Asaad; Yildiz, SayiterIn this study, the effects of combination of ultrasonic process with UV light and both classical Fenton (CFP) and modified Fenton (MFP) processes on disintegration of waste sludge were investigated. Fe2+ and Fe-0 dosage, hydrogen peroxide dosage, reaction time, pH, and different UV lamps were optimized to achieve a high degree of disintegration (DD). In addition, kinetic study and toxicity analysis were performed under optimum conditions for all processes. For CFP, the best DD 22.85% was found with optimum pH 3, reaction time 60 min, 7 g/kg TS Fe2+, 35 g/kg TS H2O2 doses, and UV-C light, while this value increased to 37.83% with ultrasound (US) application. For MFP; the best DD was achieved as 25.84% with optimum pH 3, reaction time 60 min, 5 g/kg TS Fe-0, 25 g/kg TS H2O2 doses, and UV-C light; however, it rose to 42.32% in the presence of US. The use of US in all processes increased the germination percentage that expresses the sludge toxicity, up to 100%. In the kinetic study, it was found that all processes are in compliance with zeroth-order kinetics. It was concluded with this study that US has an important synergistic effect on Fenton applications and contributes to sludge disintegration.Öğe Suitability of Water Quality for Irrigation Purposes Using GIS-Based Irrigation Water Quality Index(Wiley, 2025) Simsir, Mehmet; Yildiz, Sayiter; Karakus, Can Bulent; Ozbek, Dilara UlgerIn this study, surface water quality was assessed on the basis of irrigation water quality indices and the irrigation water quality index (IWQI) via GIS. The study was carried out on the basis of analyses of samples collected in August (dry) and November (wet) 2023 from 12 designated points along the Y & imath;ld & imath;z River in Sivas. The sodium adsorption ratio (SAR), Kelly index (KI), sodium percentage (Na%), permeability index (PI), residual sodium carbonate (RSC), magnesium hazard (MH) indices and IWQI were calculated to determine the classification of irrigation water quality. Additionally, analyses of Ca2+, Cl-, Fe2+, K+, HCO3-, Mg2+, Mn, Na+, pH and SO42- were conducted on the samples. The spatial distributions of the calculated parameters were mapped via GIS, and irrigation water quality assessment was performed according to the US Salinity Diagram and irrigation water quality standards. The IWQI values ranged from 401 to 61 during the rainy season and from 42 to 67 during the dry season. In the rainy season, two surface water samples were classified as 'poor (MR: moderate restriction, IWQI: 55-70)' and nine as 'very poor (HR: high restriction, IWQI: 40-55)'. In the dry season, three surface water samples were classified as 'poor (MR: moderate restriction)' and nine as 'very poor (HR: high restriction)'. According to the US Salinity Diagram, the majority of surface water samples in both the rainy and dry seasons fell into categories C3S1 (high-salinity hazard-low-sodium hazard) and C2S1 (medium-salinity hazard-low-sodium hazard), respectively. The results highlight the effectiveness of these methodologies in evaluating surface water quality, assisting in the development of informed management strategies for sustainable water resource use in agricultural environments. The IWQI has proven to be a good tool for assessing the quality of irrigation water in the study area and managing water quality and can help decision makers manage water resources more effectively for sustainable agriculture.
