Modification of natural zeolite with NaOH for removal of manganese in drinking water

Akgul, Gokcen/0000-0001-6101-7971WOS: 000365363900029Natural zeolite (NZ) obtained from the Manisa-Demirci region of Turkey was modified by NaOH aqueous solutions (0.5-2.0 mol/dm(3)) and the adsorption capacity of natural and modified forms was determined for manganese removal. the characterisations of the zeolites were carried out by XRD, N-2 sorption, FTIR, NH3-TPD and SEM-EDS. Treatment of the NZ with NaOH leads to a significant decrease of its silica content by desilication and an increase of its Na content by formation of hydroxysodalite. It was seen from the NH3-TPD results that NaOH treatment alters the acidity of zeolite. While the number of weak and medium Bronsted/Lewis acid sites decreases, the number of strong acid sites increases through the intraduction of Na+ and the removal of silica. Treatment with NaOH has the effect of multiply by two the manganese adsorption capacity of the natural zeolite. the maximum manganese adsorption capacity was achieved with the zeolite treated with 1.5 M of NaOH. More than this concentration of NaOH leads not only to a decrease in adsorption capacity of natural zeolite for manganese, but also to a significant deformation of the zeolite structure. the Langmuir isotherm model fits well with the results obtained from manganese adsorption on natural zeolite, while the Freundlich isotherm model fits well with the results obtained on NaOH modified zeolites. (C) 2015 Elsevier B.V. All rights reserved.Cumhuriyet UniversityCumhuriyet University [M-492]; Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [113M813]I gratefully acknowledge the financial support given for this study by the research fund of Cumhuriyet University (M-492) and the Scientific and Technological Research Council of Turkey (TUBITAK) (113M813)

Application of biochar derived from industrial tea waste into the fuel cell-a novel approach

Akgul, Gokcen/0000-0001-6101-7971WOS: 000514814600016Fuel cells play an important role in clean and efficient energy technologies. the proton exchange membrane (PEM) fuel cell, which uses hydrogen as fuel and operates at lower temperatures than other types, is important for portable electrical systems. Carbon material is used in the most of the fuel cell parts. in this study, the effect of biomass derived biochar-the carbonized material- on fuel cell efficiency has been investigated as an alternative, clean, inexpensive and sustainable carbon material in the membrane electrode assembly. Especially the sulphated biochar, the use of catalyst was reduced by half, results in higher fuel-cell voltage. A 0.56 V voltage was obtained with a half-catalyzed fuel cell, while a 0.78 V voltage was measured when sulfated biochar was used in the same cell

Optical and electrical properties of refined carbon derived from industrial tea waste

Akgul, Gokcen/0000-0001-6101-7971WOS: 000530461200001The utilization of nano- and well-ordered carbon materials such as graphene especially in carbon-based electrical devices and in energy storage areas is becoming important in terms of developing economical methods and reducing the dimensions of the electrical devices. These applied carbon materials are mostly originated from fossil sources which are diminishing. Hence, renewable carbon resources are gaining importance. Biomass is the single renewable carbon resource and can be refined to highly ordered carbon materials such as graphene by top to down methods. in this work, industrial tea waste biomass was converted to carbonized material by pyrolysis and refined by some further chemical treatments towards the ordered structured carbon. the newly derived refined carbon material was characterized by Raman, TGA, FTIR, SEM and XRD methods, and its optical and electrical properties were determined. the experimental results showed that the band gap energies of refined carbon derived from tea waste and reduced graphene oxide prepared in this study are in the similar level as 2.375 and 2.264 eV, respectively. Furthermore, the electrical conductivities are at the same stage as 3.16 and 3.28 x 10(-4) (1/omega cm) for reduced graphene oxide and refined carbon. the optically active and electrical conductive refined carbon material from biomass could be a proper carbon in energy related applications in terms of renewable and sustainable processing.Recep Tayyip Erdogan University, Scientific Research Projects Coordinator Unit (BAP) [FYL-2018-970]We gratefully acknowledge the financial support provided by Recep Tayyip Erdogan University, Scientific Research Projects Coordinator Unit (BAP) (Project No: FYL-2018-970)

Hydrothermal Liquefaction - Upgrading

Kruse, Andrea/0000-0002-8156-139X; Akgul, Gokcen/0000-0001-6101-7971WOS: 000354819200010[No abstract available

A biochar-modified carbon paste electrode

WOS: 000403692800014The present work examined the use of biochar derived from tea waste as a novel electrode material. For the fabrication of the biochar electrode, suitable amounts of biochar and graphite were mixed with mineral oil for the first time. The electrochemical performance of the biochar-modified carbon paste electrode (BCPE) was measured by various cyclic voltammetric reactions for several redox systems. The factors affecting the electrode kinetics of BCPE surfaces were examined and optimized. The BCPE was applied as transducer in a glucose biosensor. The results reflect the effective properties of composite electrodes and the electrochemical properties of biochar showing that the BCPE could be used for various electrochemical applications.Recep Tayyip Erdogan University, Scientific Research Projects Coordinator Unit (BAP) [RTEU - 2014.29.109.04.01, RTEU - 2015.53008.109.07.01]We gratefully acknowledge the financial support for chemical analyses provided by Recep Tayyip Erdogan University, Scientific Research Projects Coordinator Unit (BAP) (Project No: RTEU - 2014.29.109.04.01 and RTEU - 2015.53008.109.07.01)

Valorization of Tea-Waste Biochar for Energy Storage

Akgul, Gokcen/0000-0001-6101-7971WOS: 000502504300025Biochar, a carbonaceous material derived from biomass by pyrolysis, stands out as environmentally friendly and low-cost carbon material with specific features that could be exploited for various applications, which range from the safe and long-term storage of carbon in the environment, to soil improvement and energy storage. It can be envisaged that the desired properties of biochar could be fine-tuned by chemical and structural modification for enhanced performance of this sustainable material. in this work, biochar derived from industrial tea waste was valorized by surface functionalization and graphitization to enhance the electrochemical properties and achieve higher capacitance. Several oxidative treatments have been assessed; waste-free UV-generated ozone exposure, nitric acid mediated oxidation, and harsh treatment with sulfonitric acid mixture. Subsequently, metal impregnation was investigated to reveal Fe-mediated catalytic effect on the graphitization process, allowing use of lower temperatures with consequent energy saving. the effects on BC were characterized by transmission electron microscopy (TEM), Fourier-transformed infrared (FT-IR) and Raman spectroscopy, thermogravimetric analysis (TGA) under air or nitrogen gas, physisorption, and electrochemical measurements. the structural design with chemical and physical treatments increased the capacitance from 0.041 to 7.734 F/g at the scan rate of 10 mV/s for pristine and modified biochar, respectively. Graphica

Biochar-iron composites as electromagnetic interference shielding material

Akgul, Gokcen/0000-0001-6101-7971WOS: 000519027600001Electromagnetic waves emitted by electrical and electronic devices constitute interference with each other, which becomes a problem for security devices, space vehicles, ships, electronics or even human beings. Electromagnetic interference (EMI) protective materials are being developed to eliminate such negative effects of electromagnetic waves. Especially carbon-based ones are becoming increasingly important. the carbonized material biochar, derived from biomass, emerges as a sustainable, renewable, environmentally friendly and inexpensive EMI material. in this study EMI protective effect of biochar derived from industrial tea waste biomass and its iron composite was investigated. the effect values of the samples were found to be greater than 10 dB.Tubitak 2209 A-University Students Research Projects Support ProgramTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [1919B011701002]Wewould like acknowledge to Tubitak 2209 A-University Students Research Projects Support Program (Project no. 1919B011701002) and Ramazan Dasbasi at Yildiz Technical University, Faculty of Electrical& Electronics Engineering, Department of Electronics and Communication Engineering for his valuable contributions on the EMI measurements

Hydrothermal gasification of Rosa Damascena residues: Gaseous and aqueous yields

WOS: 000330747200019The gasification of Rosa Damascena residues - by-products of the rose-oil industry - was investigated under hydrothermal conditions at 500 degrees C and 600 degrees C, 35-45 MPa pressure with a reaction time of 1 h. The experiments were performed in the absence and presence of catalysts of K2CO3 and trona in a batch type reactor. The composition of the gaseous and aqueous products was determined by gas chromatography and high performance liquid chromatography, respectively. H-2, CO2 and CH4 are the main gaseous products while carboxylic acids (formic acid, acetic acid, glycolic acid) are the main components found in the aqueous phase followed by furfurals, phenols, aldehyde and ketones. More gaseous products were obtained at the higher temperature of 600 degrees C. Adding catalyst was found to aid the conversion process but the effect was only slight. Rosa Damascena residues have the potential to be a useful source for H-2 production in the future. (C) 2013 Elsevier B.V. All rights reserved.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [106T748]; Ege University-EBILTEMEge University [2008BIL017]We would like to thank EKETIN Rose Oil Company located in Isparta (http://www.ercetin.com). We gratefully acknowledge the financial support provided by The Scientific and Technological Research Council of Turkey (TUBITAK) (Project No: 106T748) and Ege University-EBILTEM (Project No: 2008BIL017). Thanks to Mr. G. Serin for the feed preparation procedure and the mechanical assistance during the experiments

Real-world outcomes of pazopanib in metastatic soft tissue sarcoma: a retrospective Turkish oncology group (TOG) study

AimDescription of patient characteristics, effectiveness and safety in Turkish patients treated with pazopanib for metastatic soft tissue sarcoma (STS).Patients and methodsThis multicenter study is based on retrospective review of hospital medical records of patients (>= 18 years) treated with pazopanib for non-adipocytic metastatic STS at 37 Oncology clinics across Turkey. Objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS) and overall survival (OS) were evaluated with further analysis of data on the three most common histological subtypes (leiomyosarcoma [LMS], undifferentiated pleomorphic sarcoma [UPS], synovial sarcoma [SS]) in the cohort.ResultsData of 552 adults (57.6% women, median age: 52 years) were analyzed. DCR and ORR were 43.1% and 30.8%, respectively. Median PFS was 6.7 months and OS was 13.8 months. For LMS, UPS and SS, median PFSs were 6.1, 5.9 and 7.53 months and median OSs were 15.03, 12.87 and 12.27 months, respectively. ECOG >= 2 was associated with poor PFS and OS. Liver metastasis was only a factor for progression. Second-line use of pazopanib (vs. front-line) was associated with better PFS, its use beyond third line predicted worse OS. Adverse events (AE) occurred in 82.7% of patients. Most common AEs were fatigue (58.3%) and anorexia (52.3%) which were graded as >= 3 in 8.2% and 7.4% of patients, respectively.ConclusionPazopanib is effective and well-tolerated in treatment of non-adipocytic metastatic STS. Its earlier use (at second-line), good performance status may result in better outcomes. Worldwide scientific collaborations are important to gain knowledge on rarer STS subtypes by conducting studies in larger patient populations