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The catalytic activity of the iron-coated pumice particles used as heterogeneous catalysts in the oxidation of natural organic matter by H2O2
Get PDFWOS: 000379772100004PubMed: 26881482The oxidative removal of natural organic matter (NOM) from waters was investigated by hydrogen peroxide (H2O2) and iron-coated pumice particles in heterogeneous catalytic oxidation process (HCOP). Removal of trihalomethane (THM) precursors, which is formed THM by the reacts with chloride, was performed with the hydroxyl radicals. Coating the original pumice particles with iron oxides significantly enhanced the removal of NOM with peroxide. The studies were carried out in two sections: (1) decomposition of hydrogen peroxide in pure water with iron-coated pumice and (2) oxidation of THM Precursor (NOM) by hydrogen peroxide with iron-coated pumice. The monitored parameters in this study include dissolved organic carbon and trihalomethanes formation potential. The results show that iron-coated pumice catalyst significantly increased the removal efficiency of NOM in the HCOP. The results show that iron-coated pumice catalyst significantly increased the removal efficiency of NOM in the HCOP. Results show that the oxidation of NOM and remaining NOM with H2O2 is improved by the addition of iron-coated pumice particles which activate the H2O2 molecule, leading to the formation of hydroxyl radicals in a Fenton-like process.Environmental Engineering Department of Aksaray UniversityWe would like to thank the Environmental Engineering Department of Aksaray University for funding this paper and support us, and thank Kader Aksu for her work in the deparment laboratory. Thanks are due to a range of people who gave advice, offered comments or helped in other ways during this paper
Development of adaptive neuro-fuzzy inference system model for predict trihalomethane formation potential in distribution network simulation test
Get PDF*Alver, Alper ( Aksaray, Yazar )Trihalomethanes (THMs), which is one of the major classes of DBP known to be highly cytotoxic and genotoxic, were formed and modeled under controlled conditions by laboratory-scale distribution network simulation test. The formation potentials of THM depending on the parameters such as natural organic matter, bromide, chlorine, pH, and contact time were determined. Subsequently, the Adaptive Neuro-Fuzzy Inference System (ANFIS) model was developed using these parameters as inputs and THM formation potentials as output, and the correlation coefficient was 0.9817. In the range of the inputs, the ANFIS model representing the simulation test results were compared with THM formations of an actual distribution network system in dry and wet seasons. As a result, the predictions of the ANFIS model were little affected by the unidentified factors that were not used in model training but are known to affect THM formations in real waters and gave more consistent results than the EPA model
Optimization of landfill leachate oxidation at extreme conditions and determination of micropollutants removal
No full textWOS: 000418401300014The advanced oxidation of macro- and micro-organic pollutants from the landfill leachate using the Fenton reaction was investigated. Central composite design with response surface methodology was applied to evaluate the interaction and relationship between operating variables (i.e., pH, reaction time, ferrous iron and H2O2 dosages) and to develop the optimum operating condition. Based on statistical analysis, quadratic models for the two responses (chemical oxygen demand [COD] and aromatic content [UV254]) proved to be significant with very low probability values (<0.001). The obtained optimum conditions were 1,755 mg/L Fe2+ and 26,422 mg/L H2O2 concentration, pH 3.72 and 99 min reaction time. The results obtained by the predicted model were 70, and 54% removal for COD and UV254, respectively, with optimum conditions. The predicted results fitted well with the results of the laboratory experiment. A wide range of analysis was conducted for micropollutants and some volatile organic compounds, pharmaceuticals, pesticides, plasticizers, polycyclic aromatic hydrocarbons and heavy metals were detected. Removal efficiencies of some micropollutants including bis(2-ethylhexyl)phthalate, anthracene, benzene hexachloride, dieldrin, diuron, chlorpyriphos and diclofenac were between 90% and 99% with Fenton oxidation at the optimum condition. It was also determined that heavy metals decreased as a result of co-precipitation after oxidation.Environmental Engineering Department of Selcuk UniversityWe would like to thank the Environmental Engineering Department of Selcuk University for supporting this paper, and thank Demet Keskin for her work in the department laboratory. Thanks are due to a range of people who gave advice, offered comments or helped in other ways during this paper
Disinfection by-products formation potential along the Melendiz River, Turkey; associated water quality P parameters and non-linear prediction model
No full textWOS: 000448672400013Organic matters in raw water have a potential to generate harmful disinfection byproducts such as trihalomethanes (THMs) and haloacetic acid (HAA) during the chlorination process. The aim of this study was to investigate the trihalomethane formation potential (THMFP) and haloacetic acid formation potential (HAAFP) in Melendiz River and to determine the effect of several factors including water quality parameters, distance, and seasonal variation. Water samples (n= 93) were collected at Melendiz River during December 2015-November 2016. The range of THMFP and HAAFP was 47.28-3348.73 mu g/L and 41.42-4952.68 mu g/L, respectively. ANOVA analysis was performed to understand the impact of the seasonal and/or distance changes on DBPs formation. It was found that the seasonal variations (sig. 0.80) at Melendiz River. Finally, a non-linear statistical model was developed based on Multiple Stepwise Regression Analysis using highly correlated water quality parameters with TTHM and THAA 5 in Pearson Correlation Analysis. According to the results, among all factors, flow, dissolved organic carbon (DOC), UV254, UV272 , bromide, temperature, and additional chlorine dose have a remarkable effect on THMFP and HAAFP. Especially, the Pearson correlation (P) values for the DOC and the Chlorine dosages are 0.583, 0.786 and 0.994 and 0.865 for THMFP and HAAFP models, respectively. In addition to this, the high R-2 (0.95) values were obtained when compared to other predictive models. The local model development should be utilized because each water source has different organic characterization. For this reason, the development of local models for each water source is important for achieving more consistent results.Environmental Engineering Department of Aksaray UniversityWe would like to thank the Environmental Engineering Department of Aksaray University for funding this paper and the Aksaray Municipality for helping to gather the samples in the field work. Thanks are due to a range of people who gave advice, offered comments or help in other ways during this paper
Catalytic ozonation by iron coated pumice for the degradation of natural organic matters
Get PDFWOS: 000435191500048The use of iron-coated pumice (ICP) in heterogeneous catalytic ozonation significantly enhanced the removal efficiency of natural organic matters (NOMs) in water, due to the synergistic effect of hybrid processes when compared to sole ozonation and adsorption. Multiple characterization analyses (BET, TEM, XRD, DLS, FT-IR, and pH(PZC)) were employed for a systematic investigation of the catalyst surface properties. This analysis indicated that the ICP crystal structure was alpha-FeOOH, the surface hydroxyl group of ICP was significantly increased after coating, the particle size of ICP was about 200-250 nm, the BET surface area of ICP was about 10.56 m(2) g(-1), the pH(PZC) value of ICP was about 7.13, and that enhancement by iron loading was observed in the FT-IR spectra. The contribution of surface adsorption, hydroxyl radicals, and sole ozonation to catalytic ozonation was determined as 21.29%, 66.22%, and 12.49%, respectively. The reaction kinetic analysis with tert-Butyl alcohol (TBA) was used as a radical scavenger, confirming that surface ferrous iron loading promoted the role of the hydroxyl radicals. The phosphate was used as an inorganic probe, and significantly inhibited the removal efficiency of catalytic NOM ozonation. This is an indication that the reactions which occur are more dominant in the solution phase.Environmental Engineering Department of Aksaray University; Scientific Research Projects Coordination Unit of Aksaray University [2015-050]We would like to thank the Environmental Engineering Department of Aksaray University for funding this paper and support us. The authors thank Emine BASTURK for her technical assistance in the lab work. Thanks are due to a range of people who gave advice, offered comments or help in other ways during this paper. This work was supported by Scientific Research Projects Coordination Unit of Aksaray University. The project number is 2015-050
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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