Synthesis of magnetite iron pumice composite for heterogeneous Fenton-like oxidation of dyes

Cifci, Deniz Izlen,Meric, Sureyya Techno-Press 2020 Advances in environmental research Vol.9 No.3

The removal of two dyes, namely Methylene Blue (MB) and Reactive Brillant Red (RR) from aqueous solution was investigated using magnetite iron coated pumice (MIP) composite in the Fenton-like oxidation process. A weight ratio of 2.5 g (with the molar ratio of Fe³⁺ to Fe²⁺ to be 2) (5%) of iron to the total pumice (50 g) was enabled during synthesis of catalyst. Surface composition and characteristics of the catalyst were assessed by SEM-EDX, FT-IR, Raman spectral analysis. The effect of the amount of pumice solely used or MIP, H₂O₂ concentration, pH and initial concentration of MB or RR dyes on Fenton-like process efficiency was investigated. EDAX spectrums of pumice and MIP showed that oxygen and silisium are the major elements. The Fe content of MIP increased to 2.24%. SEM, FT-IR and Raman spectrums confirmed the impregnation of Fe on pumice surface. The experimental results revealed that high removal rates of dyes could be obtained using MIP that demonstrated a higher stability for removal of MB dye. pH affected the removal efficiency of both dyes and the degradation of both dyes was sharply dropped when pH was increased above 4. The removal of dyes did not significantly change with increasing H₂O₂ concentration. Degradation rates of both MB and RR dyes increased 3.3 and 2.8 times with the use of MIP compared to pumice alone, respectively. Furthermore, MIP enabled a good removal efficiency at higher dye concentrations. It can be emphasized that MIP composite can be used in the heterogeneous Fenton-like systems considering the economic and easily separation aspects.

Enhancement of Methylene Blue dye adsorption by Fe-Hydroxyapatite composite

Cifci, Deniz Izlen Techno-Press 2016 Advances in environmental research Vol.5 No.4

Synthesized hydroxyapatite (Hyd) and Fe-hydroxyapatite (Fe-Hyd) composite were used for the removal of Methylene Blue (MB) from aqueous solutions in this study. The effect of adsorbent amount, pH and initial MB concentration were carried out to investigate in the aqueous solution. The kinetic study shows that the MB adsorption process with Hyd or Fe-Hyd follow pseudo-second order kinetic model. Experimental results are well fitted to the Langmuir isotherm model. The maximum adsorption capacities of Hyd and Fe-Hyd were obtained as 2.90 mg/g and 5.64 mg/g for MB according to Langmuir Isotherm models, respectively. Fe-Hyd composite increased the adsorption capacity of Hyd by 1.95 times that Hyd. It is concluded that Fe-Hyd composite is promising and economical adsorbent for MB removal in the aqueous solution.

Optimization of methylene blue adsorption by pumice powder

Cifci, Deniz Izlen,Meric, Sureyya Techno-Press 2016 Advances in environmental research Vol.5 No.1

The main objective of this study is to evaluate adsorptive removal of Methylene Blue (MB) dye from aqueous solution using pumice powder. The effects of pH, adsorption time, agitation speed, adsorbent dose, and dye concentrations on dye adsorption were investigated. Process kinetics and isotherm model constants were determined accordingly. The results showed that adsorbent dose, dye concentration and agitation speed are the important parameters on dye adsorption and the removal of MB did not significantly change by varying pH. A total adsorption process time of 60 min was observed to be sufficient to effectively remove 50 mg/L MB concentration. The MB adsorption data obeyed both pseudo first order and second order kinetic models. Adsorption of MB by pumice fitted well both Langmiur and Freundlich isotherms ($R^2{\geq}0.9700$), except for 150 rpm agitation speed that system fitted only Langmiur isotherm. The results of this study emphasize that pumice powder can be used as a low cost and effective adsorbent for dye removal.

Evaluation of Non-invasive Fibrosis Markers in Predicting Esophageal Variceal Bleeding

Sami Cifci,Nergiz Ekmen 대한소화기내시경학회 2021 Clinical Endoscopy Vol.54 No.6

Background/Aims: Esophageal variceal bleeding (EVB) is an important cause of mortality and morbidity in liver cirrhosis. In thisstudy, we aimed to predict the possibility of EVB in patients with cirrhosis using a non-invasive score. Methods: A total of 359 patients with cirrhosis were divided into two groups based on the presence or absence of EVB. Child-Turcotte-Pugh (CTP) score, a model for end-stage liver disease, aspartate aminotransferase to alanine aminotransferase ratio,aspartate aminotransferase to platelet ratio index (APRI), fibrosis-4-index (FIB-4), aspartate aminotransferase to alanineaminotransferase ratio/platelet ratio index (AARPRI), and S-index were measured for all participants. Receiver operatingcharacteristic curves were obtained for all parameters, and the optimal cut-off value was determined in predicting EVB. Results: In patients with EVB, the number of platelets (PLT) were low (p<0.001) and APRI, AARPRI, FIB-4, and S-index weresignificantly higher than those in patients without EBV. APRI, AARPRI, FIB-4, PLT, and S-index were statistically significantpredictors of EVB (p<0.05). Conclusions: FIB-4 and AARPRI, which are non-invasive markers of fibrosis, can be used to predict EVB. In addition, the 66.5 109/Lcut-off value for PLT is important for EVB.

Laboratory/In situ Sound Velocities of Shelf Sediments in the South Sea of Korea

김대철,김길영,정자헌,서영교,Roy H. Wilkens,유동근,이광훈,김정창,이희일,Gunay Cifci 한국수산과학회 2008 Fisheries and Aquatic Sciences Vol.11 No.2

Compressional sound velocities of shelf sediments in the South Sea of Korea, were measured in situ and in the laboratory for six cores. In situ sound velocity was measured using the Acoustic Lance (frequency of 7.5-15kHz), while laboratory velocity was measured by the pulse transmission technique (frequency of 1MHz). Physical properties were relatively uniform with sediment depth, suggesting little effect of sediment compaction and/or consolidation. Average in situ velocity at each core site ranged from 1,457 to 1,488 m/s, which was less than the laboratory velocity of 1503 and 1604 m/s. In muddy sediments the laboratory velocity was 39-47 m/s higher than in situ velocity. In sandy sediments, the difference was greater by an average of 116 m/s. Although the velocity data were corrected by the velocity ratio method based on bottom water temperature, the laboratory velocity was still higher than the in situ velocity (11-21 m/s in muddy sediments and 91m/s in sandy sediments). This discrepancy may be caused by sediment disturbance during core collection and/or by the pressure of Acoustic Lance insertion, but wass most likely due to the frequency difference between in situ and laboratory measurement systems. Thus, when correcting laboratory velocity to in situ velocity, it is important to consider both temperature and frequency.

ANN-Incorporated satin bowerbird optimizer for predicting uniaxial compressive strength of concret

Dizi Wu,Shuhua Liu,Hossein Moayedi,Mehmet Akif CIFCI,Binh Nguyen Le 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.45 No.2

Surmounting complexities in analyzing the mechanical parameters of concrete entails selecting an appropriate methodology. This study integrates a novel metaheuristic technique, namely satin bowerbird optimizer (SBO) with artificial neural network (ANN) for predicting uniaxial compressive strength (UCS) of concrete. For this purpose, the created hybrid is trained and tested using a relatively large dataset collected from the published literature. Three other new algorithms, namely Henry gas solubility optimization (HGSO), sunflower optimization (SFO), and vortex search algorithm (VSA) are also used as benchmarks. After attaining a proper population size for all algorithms, the Utilizing various accuracy indicators, it was shown that the proposed ANN-SBO not only can excellently analyze the UCS behavior, but also outperforms all three benchmark hybrids (i.e., ANN-HGSO, ANN-SFO, and ANN-VSA). In the prediction phase, the correlation indices of 0.87394, 0.87936, 0.95329, and 0.95663, as well as mean absolute percentage errors of 15.9719, 15.3845, 9.4970, and 8.0629%, calculated for the ANN-HGSO, ANN-SFO, ANN-VSA, and ANN-SBO, respectively, manifested the best prediction performance for the proposed model. Also, the ANN-VSA achieved reliable results as well. In short, the ANN-SBO can be used by engineers as an efficient non-destructive method for predicting the UCS of concrete.

Characterization of Holocene inner shelf mud deposit the South Sea of Korea

Sung Ho Bae,Dae Choul Kim,Gwang Soo Lee,Gil Young Kim,Young Kyo Seo,Gunay Cifci 대한조선학회 2011 대한조선학회 학술대회자료집 Vol.2011 No.6

Laboratory/In situ Sound Velocities of Shelf Sediments in the South Sea of Korea

Kim, Dae-Choul,Kim, Gil-Young,Jung, Ja-Hun,Seo, Young-Kyo,Wilkens, Roy H.,Yoo, Dong-Geun,Lee, Gwang-Hoon,Kim, Jeong-Chang,Yi, Hi-Il,Cifci, Gunay The Korean Society of Fisheries and Aquatic Scienc 2008 Fisheries and Aquatic Sciences Vol.11 No.2

Compressional sound velocities of shelf sediments in the South Sea of Korea, were measured in situ and in the laboratory for six cores. In situ sound velocity was measured using the Acoustic Lance (frequency of 7.5-15 kHz), while laboratory velocity was measured by the pulse transmission technique (frequency of 1MHz). Physical properties were relatively uniform with sediment depth, suggesting little effect of sediment compaction and/or consolidation. Average in situ velocity at each core site ranged from 1,457 to 1,488 m/s, which was less than the laboratory velocity of 1,503 and 1,604m/s. In muddy sediments the laboratory velocity was 39-47 m/s higher than in situ velocity. In sandy sediments, the difference was greater by an average of 116 m/s. Although the velocity data were corrected by the velocity ratio method based on bottom water temperature, the laboratory velocity was still higher than the in situ velocity (11-21 m/s in muddy sediments and 91 m/s in sandy sediments). This discrepancy may be caused by sediment disturbance during core collection and/or by the pressure of Acoustic Lance insertion, but it was most likely due to the frequency difference between in situ and laboratory measurement systems. Thus, when correcting laboratory velocity to in situ velocity, it is important to consider both temperature and frequency.

여수만 가스함유 퇴적물의 물성 및 음향 특성

김대철(Dae Choul Kim),이광수(Gwang Soo Lee),배성호(Sung Ho Bae),김길영(Gil Young Kim),서영교(Young Kyo Seo),최동림(Dong Lim Choi),Gunay Cifci,Seda Okay,Savas Gurcay 대한지질학회 2012 지질학회지 Vol.48 No.1