Mahmut Bayramoğlu

• Prof.Dr.
• Professor at Gebze Technical University

In this paper, ceria (CeO2 ) nanorod (NR) supported Ni-Cr2 O3 anode electrocatalysts were synthesized as nonnoble metalbased anode electrocatalysts for ethanol electrooxidation reaction (EOR) in alkaline media. Physicochemical characterization of the electrocatalysts was investigated by XRD, SEM, and TEM techniques. Electrochemical performances of...

One of the most promising, non-toxic, and economical alternative fuels is ethanol and ethanol electrooxidation reaction (EOR) must be completed efficiently to generate energy from ethanol. However, this clean alternative fuel cannot be used commercially because of the slow kinetics of the EOR. In this study, Ni cocatalyzed with CeO2 nanorods (Ni-Ce...

This study presents an easy and quick method for the synthesis of graphene from graphite in a set of solvents, including n-Hexadecane (n-Hexa), dimethylsulfoxide (DMSO), sodium hydrox-ide (NaOH), 1-octanol (OCTA), perchloric acid (PA), N,N-Dimethylformamide (DMF), ethylene gly-col (EG), and ethylene diamine (ED), via microwave (MW) energy. The prop...

In this study, biodiesel production with canola oil and methanol in the presence of dolomite catalyst was examined in a multimode Enhanced Microwave System (EMS) with simultaneous cooling worked under constant, continuous microwave (MW) power and isothermal conditions. The experiments were carried out in the EMS utilizing the "one variable at a tim...

Direct Methanol Fuel Cell (DMFC) system is considered as one of the most important clean and sustainable energy generation system. This system generates energy by electro oxidization of methanol however, this reaction is not fully completed. Consequently, the efficiency of the system is lower than expected. Studies in literature generally assume a...

In this study, calcium carbonate has been produced continuously using synthetic soda ash industry liquid waste with different process variables. The effect of process variables such as gas flow rate (1000 to 4000 ml/min), waste liquid flow rate (80 to 280 ml/min), CO2 concentration (20% to 40%), ultrasonic probe area (2.83 to 4.90 cm²), ultrasonic...

Reusability of two heterogeneous catalysts in ultrasound (US) assisted biodiesel production was investigated in comparison to each other. An ultrasound (US) generator (200 W, 20 kHz) equipped with a horn type probe (19 mm) was used. Regeneration experiments were planned according to second order central composite design (CCD) method. After the eigh...

In this study, Mo2C and MoS2 were used as cocatalyst for a non‐noble metal for the first time for ethanol electro‐oxidation reaction (EOR) in alkaline media. Anode electrocatalysts containing Nickel, Mo compound, and carbon support were synthesized at different weight ratios of Ni and Mo2C (or MoS2) while keeping the carbon support weight constant...

Antibiotic-resistant organisms are crucial problems, which lead to ecological disasters and cause fatal damage such as in aquatic environments and human beings. Thus, researchers have sought an effective way to minimize this issue, and they stated that the photocatalytic reaction is an effective method for degrading antibiotics. In this study, an a...

The liquid-phase exfoliation (LPE) method has been gaining increasing interest by academic and industrial researchers due to its simplicity, low cost, and scalability. High-intensity ultrasound energy was exploited to transform graphite to graphene in the solvents of dimethyl sulfoxide (DMSO), N,N-dimethyl formamide (DMF), and perchloric acid (PA)...

In recent years, a great deal of concentration has addressed the electronic and morphological characteristics of carbonaceous substances. Nowadays, particularly, graphene is one of the most popular materials in condensed-matter physics and materials science. It is used in different fields such as desalination of seawater, smartphones, computers, sa...

Liquid Phase Exfoliation (LPE) method has been gaining increasing interest by academic and industrial researchers due to its simplicity, low-cost, and scalability. High intensity ultrasound energy was exploited to transform graphite to graphene in the solvents of dimethyl sulfoxide (DMSO), N,N-dimethyl formamide (DMF), and perchloric acid (PA) with...

Microwave-assisted extraction (MAE) and solvent-free microwave extraction and Soxhlet extraction were applied to Ray Ruby grapefruit leaves (Citrus paradisi Macf.) to compare extract efficiency. Face centered composite designs were constructed via response surface methodology. Effects of factors of MAE were investigated on total phenolic content (T...

This study represents the experimental assessment of the faradaic, fuel, and energetic efficiency of active direct methanol fuel cell (DMFC). The experimental system was equipped with several sensors, HPLC and UV spectroscopy to make on‐line and off‐line measurements of different components. A polarization study was conducted and an experimental pl...

Green synthesis of graphene from graphite was carried out in molten salt mixture of LiCl-KCl, which is an environmentally friendly alternative to traditional methods using a large number of chemicals. The effect of carbonization temperature on the final properties of graphene products was investigated at a temperature range of 500-800°C. The layer...

In this study, an experimental system irradiated by Microwave (MW) energy was proposed, the main aim being to conduct experimental studies at isothermal conditions and under constant and continuous MW energy supply. For this purpose, a coil-cooled reactor was designed using a MW transparent coolant such as o-xylene circulated between a thermostat b...

This study describes an eloquent and innovative way for synthesizing of graphene through microwave-assisted (MW) exfoliation of graphite. Especially, n-Hexadecane (n-Hexa), dimethylsulfoxide (DMSO), sodium hydroxide (NaOH), 1-octanol (OCTA), perchloric acid (PA), N,N-Dimethyl formamide (DMF), ethylene glycol (EG), and ethylene diamine (ED) were pre...

Graphene is one of the most promising materials discovered in last years. It is usually synthesized by Hummers’ method requiring the usage of many chemicals. As an alternative to traditional methods, in this study a bottom-up synthesis method was developed from various saccharides such as starch, mannose, cellulose, fructose, arabinose, and xylose...

Graphene has created an increasing notice thanks to its appealing properties [1]. In this study, graphene was prepared from graphite by a very simple and easy process. The one-step protocol involves conversion of graphite to graphene by sonication in different types of solvents such dimethyl sulfoxide, N,N-Dimethyl formamide, Perchloric acid. The s...

A process-controlled synergistic solvent extraction (SSX) system consisting Mextral EOL (β-diketone derivative) and Cyanex 923 (mixture of four alkyl phosphine oxides) has been developed for the extraction of lithium from borate and sodium rich wastewaters induced by boron industry. In order to determine regression models and determine optimum cond...

The present study deals with the electrooxidative mineralization of o-tolidine from aqueous solution using various Ti/Pt, mixed metal oxide (MMO) and boron doped diamond (BDD) anodes. The experiments were carried out in two phases. In the first phase, the effect of anode type on the total organic carbon (TOC) removal efficiency was investigated at...

In this study, Poly(l-lactic acid) (PLLA) synthesis was studied using direct melt condensation polymerization (DMP) method in an experimental microwave (MW) system where external cooling was applied to keep both temperature (T) and MW power (P) continuous and constant during the polymerization. T, P, reaction time (t), catalyst type, and catalyst a...

Background: The extraction of phenolic compounds from grapefruit leaves assisted by ultrasound-assisted extraction (UAE) was optimized using a response surface methodology (RSM) by means of D-optimal experimental design and artificial neural network (ANN). For this purpose, five numeric factors were selected: ethanol concentration (0-50 %), extrac...

In this study, the experimental optimization of ultrasound assisted biodiesel production in presence of heterogeneous catalyst was investigated. Three catalysts namely; CaO, calcined dolomite and calcium diglyceroxide (CaDG) were taken into account for comparative purpose. D-optimal experimental plan was applied to obtain regression models which we...

This study deals with the nitration of phenol in a multimode MW reaction system operating under continuous microwave (MW) irradiation. Reactions were carried out with two nitric acid (HNO3)/phenol molar ratios: 1.25 and 1.1, under the following conditions: applied (nominal) MW power, Pnom = 600 W, adsorbed power P = 16.0 kW dm⁻³, reaction temperatu...

The wastewater of the munitions industry varies in terms of the recalcitrant compounds depending on the products and the manufacturing process. The most commonly encountered energetic nitro-aromatic compounds in ammunition wastewater are trinitrotoluene (TNT), nitro-heterocyclic hexahydro-trinitrotriazine (RDX), and cyclotetramethylene-tetranitrami...

This study deals with the experimental investigation of compositional changes of various liquid/gas streams during mid-term (3 h) continuous operation of an active direct methanol fuel cell (DMFC). A test system is equipped with various sensors and with sampling ports to collect liquid samples to measure off-line methanol, formaldehyde, and formic...

Lignocellulosic materials are potential sources for low cost bioethanol, a renewable energy source produced through fermentation of sugars. Poplar as a fast growing native tree is suitable for this purpose, in term of energy forestry in Turkey. Dilute sulphuric acid pretreatment at high temperatures is a leading technology for the thermochemical pr...

Ultrasound (US) assisted transesterification of canola oil in presence of heterogeneous catalysts calcined dolomite and CaO was investigated in comparison to each other. An US generator (200 W, 20 kHz) equipped with an horn type probe (19 mm) was used to study the effect of catalyst amount (3-7 wt.% of oil), methanol/oil molar ratio (4/1-15/1), ult...

This paper investigated the effects of extracellular polymeric substances (EPS) on the activated sludge rheology in a submerged membrane bioreactor (sMBR) operated at different sludge retention time (SRT) values and different carbon to nitrogen ratios (C/N) of feed wastewater. The C/N ratios of the feed were adjusted accordingly so that synthetic w...

Despite various studies [1-5] on microwave (MW) assisted polylactic acid (PLLA) synthesis, PLLA has not yet been synthesized under continuous MW irradiation to assess thoroughly the “specific MW effect “ on polymerization. In this study, a multimode MW reaction system irradiated by constant, continuous MW power at 2.45 GHz was set-up where isotherm...

Artificial neural networks and neuro-fuzzy inference systems are well known artificial intelligence techniques used for black-box modelling of complex systems. In this study, Feed-forward artificial neural networks (ANN) and adaptive neuro-fuzzy inference system (ANFIS) are used for modelling the performance of direct methanol fuel cell (DMFC). Cur...

In the literature there are hundreds of research papers for the synthesis of featured membrane to deal with the methanol crossover. Parallel to these experiments, studies focusing on working methanol concentration are continued to obtain the best results in the existing obstacles. Conducted studies reveal that an optimal concentration exists for ea...

Environmental pollution, depletion of fossil fuel reserves and energy needs of a growing world population, are among the important issues concerning the future of energy. In this context, fuel cells are considered as alternative energy sources. In this study, one cell direct methanol fuel cell system, consisting of various sensors and control eleme...

This article contains original experimental data, figures and methods to the study of Microwave-assisted emulsion polymerization of styrene under the frame of "Enhanced Microwave Synthesis" (EMS), has been examined to investigate the advantages of Microwave (MW) power use in emulsion polymerization (Ergan et al., Eur. Polym. J. 69, 2015, 374-384)....

Beneficiation of renewable energy sources is the solution to the growing energy demand for sustainable development all over the world. Ethanol is the one of the most popular renewable energy source produced through fermentation of sugars. Potential sources for low cost ethanol are lignocellulosic materials chosen by considering economical, geograph...

In this work, the effect of the solvent type on microwave (MW)-assisted decomposition of 2,2'-azobis(isobutyronitrile) was investigated by online monitoring of the reaction kinetics in various solvents: n-butanol, dimethyl sulfoxide, dimethylformamide, and n-propanol. The study showed that MW irradiation accelerates the reaction rates, but it does...

In this paper, various physical and chemical characteristics of electro-coagulated (ECC) and chemical-coagulated (CC) aluminum hydroxide flocs were explored comparatively in the context of their impacts on the pollutant removal performance of the processes. First, the sedimentation rate, floc size and zeta potential of the flocs at different pH val...

In this paper, the effects of ultrasonic (US) power, pulse ratio, probe area and recipe composition were investigated on two process responses namely, monomer (methyl methacrylate, MMA) conversion and electrical energy consumption per mass of product polymer (PMMA). Pulsed mode US is more suitable than continuous mode US for emulsion polymerization...

In this study, the ceramic powders of Ce1−xGdxO2−x/2 and Ce1−xNdxO2−x/2 (x=0.05, 0.10, 0.15, 0.20 and 0.25) were synthesized by ultrasound assisted co-precipitation method. The ionic conductivity was studied as a function of dopant concentration over the temperature range of 300–800 °C in air, using the impedance spectroscopy. The maximum ionic con...

The effects of microwave power and solvent–reactant dielectric properties on the kinetics of the decomposition of AIBN in n-butanol were investigated. According to the kinetic data, k increases with increasing microwave power, the dependence becomes stronger at high temperature. The Arrhenius parameters (Ea,mw, k0,mw) were higher than thermal count...

In this study, the synthesis of Ce(0.8)Sm(0.2)O(1.9) (SDC) solid electrolyte by the ultrasound assisted co-precipitation method was accomplished to explore the effects of ultrasound power, ultrasound pulse ratio and probe type upon the ionic conductivity of SDC as well as the lattice parameter, the microstructure and the density. Fine powders of un...

Optimal design of shell and tube heat exchangers (STHE) has a crucial role in terms of the energy efficiency of plants. Therefore, it is currently one of the research topics of interest. In this study, a rigorous STHE design model strictly following TEMA standards and including various crucial constraints was established. Ten design variables of va...

The catalytic electro-oxidation of methanol in direct methanol fuel cell (DMFC) has a complex mechanism involving various radical species, as well as stable intermediates, e.g., formaldehyde and formic acid, which are usually omitted in the operational analysis and modeling of DMFC. The compositions of various points the system is in direct contact...

In this work, the specific effect of microwave (MW) energy on chemical reactions was investigated by online monitoring of the decomposition kinetics of potassium persulfate (K2S2O8). Experiments conducted at constant temperature and constant MW power revealed that the rate constant was about 1.1–1.8 times higher than the rate constant of the therma...

Experimental and simulation studies were conducted to design a multiregional fuzzy logic controller (FLC) for a lab-scale pH process system. Scaled coefficients of the controller were optimized offline to obtain the best controller performance in terms of cost function and function evaluation number using two widely used global optimization methods...

In the present investigation, treatment of metal cutting wastewater (MCW) using electrocoagulation (EC) process is designed and analyzed using response surface methodology (RSM). RSM is applied to optimize the operating variables viz. initial pH, current density, and operating time on the treatment of MCW in a batch mode by EC process using iron an...

BACKGROUND: Owing to difficulties in catalyst recovery from slurries the deposition of a catalyst on suitable supports has been investigated extensively in recent years. The support material and the method of coating influence the activity. Photocatalytic decolorization of methyl orange (MO) and Rem Red F3B (RRF3B) was conducted in various reactor...

The recovery of photocatalyst particles constitutes a serious drawback of slurry reactors. Therefore, depositing the catalyst mass on a suitable support without loss of photocatalytic activity is of practical importance. In this study, a chemical deposition method was applied to coat the inner surface of quartz tubes of various diameters with thin...

In the present study, Fenton's oxidation of a chromium complex disazo dye (Acid Blue 193) synthesis wastewater was evaluated, modeled and optimized by employing Central Composite Design. Within this context, the individual and interactive effects of critical process parameters such as Fe(2 + ), H(2)O(2) concentrations, initial chemical oxygen deman...

Effluent iron concentration is an important water quality criterion used for the assessment of the performance of rapid sand filters, in addition to other criteria. This study deals with the prediction of effluent iron concentrations by adaptive neuro-fuzzy (ANFIS) model with input parameters including filter hydraulic loading rate, influent iron c...

Supported ZnO film photocatalysts are prepared on glass and ceramic substrates by zincate method. Prepared ZnO films are seen rather strongly durable. They resist to chemical dissolution in a broad range of pH from 3 to 10. Various physical tests are conducted to measure the relevant characteristics of the films. Band gap of ZnO film is calculated...

The present study provides an electrocoagulation (EC) process for the removal of p-benzoquinone (BQ) from aqueous solution using aluminium as anode and stainless steel as cathode materials. Experiments carried out to investigate the effects of solution pH and conductivity, current density, time, BQ concentration on the removal efficiency of the pro...

Central composite design was used to optimise electrocoagulation of CI Acid Blue 193 production wastewater. By applying a response surface quadratic model, the main process manipulators (effluent chemical oxygen demand, initial pH, electrical current density and treatment time) were optimised to achieve maximum colour, chemical oxygen demand and to...

Breakthrough and terminal head loss are the main parameters that determine the performance of rapid sand filters. Carman‐Kozeny and Ergun equations can be applied to estimate head loss, but can only be applied to clean filter beds. Elaborated models are needed to predict head loss in dirty filters. In this study, a neuro‐fuzzy modeling approach was...

This study focused on the removal of nickel ions from aqueous solution using a surfactant-enhanced (SE) powdered activated carbon (PAC)/microfiltration (MF) hybrid membrane process. The main objective of the research is to investigate the technical performance of the process under the influences of all relevant process variables namely process time...

This study aims at carrying out lipase-catalyzed synthesis of fatty acid methyl esters (biodiesel) from various vegetable oils using lipase immobilized onto a novel microporous polymeric matrix (MPPM) as a low-cost biocatalyst. The research is focused on three aspects of the process: (a) MPPM synthesis (monolithic, bead, and powder forms), (b) micr...

The photocatalytic degradation of a commercial azo-reactive textile dye, Remazol Red F-3B, has been investigated in a batch slurry reactor using semiconductor catalysts like, ZnO and TiO2, and two UV sources emitting mainly at 254 and 365 nm. Non-irradiated catalysts and non-catalyzed UV irradiation have negligible effect on the dye degradation. In...

Electrocoagulation (EC) technique is applied for the treatment of waste metal cutting fluids (WMCFs) characterized by high COD and TOC concentration, discharged from metal manufacturing facilities including automotive engine, transmission, and stamping plants. The effects of initial pH, current density and operating time on the performance of EC ar...

The bench scale of an electrocoagulation (EC) unit requires a detailed study discerning the effects of continuous variables such as pH, current density and operating time, and type variables such as electrode material and connection mode. This paper presents the results of the treatment of a textile wastewater by EC process. Two electrode materials...

This paper presents the comparative results with respect to electrode configurations on the economic performance of treatment of textile wastewaters by electrocoagulation (EC) process. Aluminum and iron electrode materials were used as sacrificial electrode in parallel and serial connection modes. Various direct and indirect cost items including el...

Electrocoagulation (EC) is assessed by a preliminary technical and economic analysis for the treatment of poultry slaughterhouse wastewater (PSW). Chemical oxygen demand (COD) and oil-grease removal efficiencies, and total operating cost have been used for analysis purpose. Various direct and indirect cost items including electrical, sacrificial el...

Surface roughness is one of the most important requirements in machining process. The surface roughness value is a result of the tool wear. When tool wear increase, the surface roughness also increases. The determination of the sufficient cutting parameters is a very important process obtained by means of both minimum surface roughness values and l...

Air pollution is a growing problem arising from domestic heating, high density of vehicle traffic, electricity production, and expanding commercial and industrial activities, all increasing in parallel with urban population. Monitoring and forecasting of air quality parameters in the urban area are important due to health impact. Artificial intelli...

Treatment of poultry slaughterhouse wastewater (PSW) by electrocoagulation (EC) has been investigated batchwise in this paper. Effects of the process variables such as medium pH, electrode material, current density, and operating time are investigated on chemical oxygen demand (COD) and oil-grease removal efficiencies, electrical energy consumption...

The decolorization of the levafix orange textile dye in aqueous solution by electrocoagulation using aluminum sacrificial anode has been investigated. The process performance is analyzed in terms of decolorization efficiency and the important cost-related parameters such as electrode and energy consumptions, as a function of initial pH, conductivit...

This study takes aim at exploring the effectiveness of a surfactant-added powdered activated carbon/microfiltration (PAC/MF) hybrid process in the removal of nickel ions from water and wastewater as a promising technology. For this aim, the influence of system-component variables related to membrane material and pore size, and adsorbent and surfact...

Electrocoagulation (EC) due to some advantages over chemical coagulation is becoming a popular process to be used for wastewater treatment. The aim of this paper is to investigate the effect of initial addition of a chemical coagulant such as polyaluminum chloride (PAC) or alum on the COD removal efficiency of EC treatment of textile wastewaters. T...

The photocatalytic degradation of aqueous solution of a commercial azo-reactive textile dye, Remazol Red F3B, has been investigated in a batch slurry reactor, in the presence of ZnO catalyst using two different UV light sources emitting at 254 nm and 365 nm. The effects of various process variables on degradation performance of the process have bee...

Thiourea leaching of precious metals such as gold and silver from ores has several advantages when compared with conventional cyanidation process. In recent years, the use of ultrasound in leaching processes is becoming increasingly popular in hydrometallurgy. This paper deals with combining these two techniques for silver leaching from solid waste...

The photocatalytic decolorization of aqueous solutions of Remazol Red RR, a commercial azo-reactive textile dye, in the presence of various semiconductor powder suspensions has been investigated in a quartz batch reactor with the use of artificial light sources (UV-C). ZnO and TiO2 have been found the most active photocatalysts; however ZnO indicat...

The photocatalytic decolorization of Remazol Red RR, a commercial azo reactive textile dye, in ZnO suspension, has been investigated in a quartz batch reactor with the use of artificial light source (UV−C). The reaction kinetics are modeled by pseudo-first-order rate law. Regression analysis related pseudo-first-order rate constant, k, to the catal...

Activated carbon was prepared from hazelnut shell with chemical carbonization using concentrated sulphuric acid. The adsorption tests were carried out in an agitated batch system with a fixed initial Cr(VI) ion concentration and varying adsorbent particle sizes and doses. The adsorption of Cr(VI) ions correlated strongly with these two variables. T...

Electrocoagulation (EC) is an efficient method for textile wastewater treatment. Researches are mainly focused on the technical performance of this process, while its economic aspect has been usually neglected. This paper deals with a simplified operating cost analysis for the treatment of a textile wastewater by EC using iron and aluminium electro...

Ultrasound has proven to be a very effective tool for enhancing reaction rates by inducing a number of chemical and mechanical effects on the reaction medium. In this study, the effect of ultrasound power on the sulfuric acid leaching of Ti from red mud has been investigated by statistically designed experiments. The effects of five parameters, ult...

Air pollution continues to be a major problem in many countries. Mathematical models are useful in relating emissions to air quality under a variety of meteorological conditions and source emission concentrations over an urban area. Meanwhile, the forecasting capability of sophisticated models is limited to very large and complex terrains. In this...

Eighteen anthropometric measurements were taken in standing and sitting positions, from 387 subjects between 15 and 17 years old. “Adaptive Neuro-Fuzzy Inference System (ANFIS)” was used to estimate anthropometric measurements as an alternative to stepwise regression analysis. Six outputs (shoulder width, hip width, knee height, buttock-popliteal h...

Treatment of textile wastewaters by electrocoagulation using iron and of aluminum electrode materials has been investigated in this paper. The effects of relevant wastewater characteristics such as conductivity and pH, and important process variables such as current density and operating time on the chemical oxygen demand (COD) and turbidity remova...

The removal of pollutants from effluents by electrocoagulation has become an attractive method in recent years. This paper deals with the batch removal of the reactive textile dye Remazol Red RB 133 from an aqueous medium by the electrocoagulation method using aluminum electrodes. The effects of wastewater conductivity, initial pH, current density,...