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Öğe Application of simple and low-cost toxicity tests for ecotoxicological assessment of industrial wastewaters(TAYLOR & FRANCIS LTD, 2015) Aydin, Mehmet Emin; Aydin, Senar; Tongur, Sueheyla; Kara, Gulnihal; Kolb, Marit; Bahadir, MuefitThe objective of this study was to identify and to apply appropriate biotests having the advantages of being highly sensitive, easy to run, relatively inexpensive and able to substitute fish toxicity tests due to ethical reasons of animal welfare. To perform an ecotoxicological assessment of industrial wastewaters, different microbiotests were conducted to substitute the fish toxicity test with Lebistes reticulatus through Vibrio fischeri, Thamnocephalus platyurus, Daphnia magna, Lemna minor and Lepidium sativum representing different trophic levels in the aquatic and terrestrial ecosystems. Also, Algaltox F-TM with Pseudokirchneriella subcapitata and Protox F-TM with Tetrahymena thermophila tests were carried out. However, they could not be applied successfully for the wastewater samples. Wastewater samples from seven different industrial zones comprising different industries were subjected to characterization through measuring their physical-chemical parameters and their toxicity versus the above-mentioned organisms. T. platyurus, D. magna and L. reticulatus were the most sensitive test organisms investigated for the wastewaters. Considering toxic unit values, generally wastewater samples were toxic according to Thamnotox F-TM, Daphtox F-TM and fish toxicity tests. As an important outcome, it was concluded that Daphtox F-TM and Thamnotox F-TM could be a good alternative for the fish toxicity test, which is so far the sole toxicity test accepted by the Turkish Water Pollution Control Regulation.Öğe Extraction of carcinogenic aromatic amines from aqueous solution using calix[n]arene derivatives as carrier(ELSEVIER SCIENCE BV, 2009) Erdemir, Serkan; Bahadir, Muefit; Yilmaz, MustafaThe extraction abilities of p-tert-butylcalix[n]arenes (n = 6, 8) and their carboxylic acid and methyl ester derivatives upon some carcinogenic aromatic amines have been investigated. The separation and quantification of aromatic amines were performed by high-performance liquid chromatography with Ace 5 C-18 column and diode array detection. The optimum pH values for aromatic amines sorption were observed at pH 4.0, 7.0 and 8.5 for all calixarene derivatives. In batch sorption experiments of selected carcinogenic aromatic amines, the experimental results show that octacarboxylic acid derivative of p-tert-butylcalix[8]arene exhibited a better affinity than other compounds towards all aromatic amines species at almost all pHs. The sorption of aromatic amines by carboxylic acid derivatives of p-tert-butylcalix[n]arene indicates that carboxyl groups play the major role for the formation of hydrogen bonds and electrostatic interactions between sorbent and aromatic amine. (C) 2009 Elsevier B.V. All rights reserved.Öğe Removal efficiency of a calix[4]arene-based polymer for water-soluble carcinogenic direct azo dyes and aromatic amines(ELSEVIER, 2009) Akceylan, Ezgi; Bahadir, Muefit; Yilmaz, MustafaA Mannich base derivative of 5,11,17,23-tetrakis-[(1,4-dioxa-8-azaspiro-[4,5]decanyl)methyl]-25,26,27,28-tetrahydroxy calix[4]arene 3 was synthesized by the treatment of calix[4]arene with a cyclic secondary amine (1,4-dioxa-8-azaspiro-[4,5]decane) and formaldehyde. The compound 3 was treated with dibromoxylene to obtain a calix[4]arene-based copolymer 4. In batch sorption experiments of selected carcinogenic azo dyes and aromatic amines, the compounds 3 and 4 were found to be a better sorbent for azo dyes than for the aromatic amines. It was observed that the percentage of azo dye removal was 95-99% for compound 3 and 83-97% for 4 when the pH of the dye solution was in the range of 2.0-8.0. The sorption of azo dyes and aromatic amines by calix[4]arenes-based compounds indicates that amino groups play the major role for the formation of hydrogen bonds and electrostatic interactions. (C) 2008 Elsevier B.V. All rights reserved.Öğe Removal of arsenic (V) from aqueous medium using manganese oxide coated lignocellulose/silica adsorbents(TAYLOR & FRANCIS LTD, 2016) Ouedraogo, Igor W. K.; Pehlivan, Erol; Tran, Hien T.; Pare, Samuel; Bonzi-Coulibaly, Yvonne L.; Zachmann, Dieter; Bahadir, MuefitArsenic (V) adsorption on manganese oxide coated rice wastes was investigated in this study. The modified adsorbents were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, and pH measurements to determine the point of zero charge. Batch adsorption equilibrium experiments were conducted to study the effects of pH, contact time, and initial concentration on arsenic removal efficiency. The adsorption capacity of rice waste was significantly improved after modification with permanganate. The Langmuir isotherm model fitted the equilibrium data better than the Freundlich model which confirms surface homogeneity of the adsorbent. Maxima adsorption capacities are determined as 10 and 12 mg/g at pH 3 for manganese oxide coated rice husk and straw, respectively. The adsorption energy indicates that the adsorption process may be dominated by chemisorption. Pseudo-second-order rate equation described the kinetics sorption of arsenic with good correlation coefficients, better than a pseudo-first-order equation. Manganese oxide coated rice husk and straw appear to be promising low cost adsorbents for removing arsenic from water.Öğe Removal of carcinogenic direct azo dyes from aqueous solutions using calix[n]arene derivatives(WILEY, 2007) Ozmen, Elif Yilmaz; Erdemir, Serkan; Yilmaz, Mustafa; Bahadir, MuefitCalix[n]arenes having different internal cavities sizes were synthesized. The ability of these sorbents to extract carcinogenic direct azo dyes from water by a solid-liquid extraction process was studied and compared to results obtained with the unsubstituted calix[n]arene. The carboxylic acid derivative of calix[6,8]arene showed the highest affinity towards the azo dyes. The sorption capacity of dyes on the calix[n]arenes was dependent on the presence of sulfonate groups on the anionic dyes. The optimum pH value for dye sorption was observed at pH 3.5 to 8.5 for all calixarene derivatives. The proposed sorption mechanism involves several kinds of interactions: electrostatic repulsion between carboxylic acid groups of calix[n]arenes and sulfonate groups of azo dyes, hydrogen bonding and formation of an inclusion complex through host-guest interactions.Öğe Synthesis of iron oxyhydroxide-coated rice straw (IOC-RS) and its application in arsenic(V) removal from water(IWA PUBLISHING, 2015) Ouedraogo, Igor W. K.; Pehlivan, Erol; Tran, Hien T.; Bonzi-Coulibaly, Yvonne L.; Zachmann, Dieter; Bahadir, MuefitBecause of the recognition that arsenic (As) at low concentrations in drinking water causes severe health effects, the technologies of As removal have become increasingly important. In this study, a simplified and effective method was used to immobilize iron oxyhydroxide onto a pretreated naturally occurring rice straw (RS). The modified RS adsorbent was characterized, using scanning electron microscope, Fourier transform infrared spectroscopy, thermogravimetric analyzer, and surface area analyzer. Experimental batch data of As(V) adsorption were modeled by the isotherms and kinetics models. Although all isotherms, the Langmuir model fitted the equilibrium data better than Freundlich and Dubinin-Radushkevich models and confirmed the surface homogeneity of adsorbent. The iron oxyhydroxide-coated rice straw (IOC-RS) was found to be effective for the removal of As(V) with 98.5% sorption efficiency at a concentration of <50 mg/L of As(V) solution, and thus maximum uptake capacity is similar to 22 and 20 mg As(V)/g of IOC-RS at pH 4 and 6, respectively. The present study might provide new avenues to achieve the As concentrations required for drinking water recommended by the World Health Organization.Öğe TOXICITY ASSESSMENT OF LANDFILL LEACHATES WITH A BATTERY OF BIOASSAYS(PARLAR SCIENTIFIC PUBLICATIONS (P S P), 2015) Aydin, Mehmet Emin; Aydin, Senar; Bahadir, Muefit; Kolb, Marit; Tongur, Suheyla; Kara, GulnihalIn this study, the toxicity of the leachate from the municipal landfill was evaluated and assigned to its chemical composition. Leachate samples were collected considering different seasons and assessed for their toxicity by using Thamnotox with Thamnocephalus platyurus, Daphtox with Daphnia magna, Vibrio fischeri, Lemna minor, and Lepidium sativum. Leachate samples were also characterized measuring their physical and chemical parameters. Relationships between the chemical composition and the toxicity of leachate samples were established. EC50, values for Thamnotox, Lemna minor, and Lepidium sativum were negatively correlated with the COD content. There were significant correlations between the TOC with EC50 values of Vibrio fischeri and Lemna minor tests. Vibrio fischeri wasthe most sensitive test organism investigated for the landfill leachate. Considering toxic unit values, leachate samples were highly to very highly acute toxic, according to all the tests carried out.
