Mahmut Bayramoglu

Treatment of textile wastewaters by electrocoagulation using iron and aluminum electrodes

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 removal efficiencies have been explored. Furthermore, the electrode and energy consumptions for each electrode have been calculated. The results show that iron is superior to aluminum as sacrificial electrode material, from COD removal efficiency and energy consumption points.

Biodiesel production from sunflower, soybean, and waste cooking oils by transesterification using lipase immobilized onto a novel microporous polymer.

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) microporous polymeric biocatalyst (MPPB) preparation by immobilization of lipase onto MPPM, and (c) biodiesel production by MPPB. Experimental planning of each step of the study was separately carried out in accordance with design of experiment (DoE) based on Taguchi methodology. Microporous polymeric matrix (MPPM) containing aldehyde functional group was synthesized by polyHIPE technique using styrene, divinylbenzene, and polyglutaraldehyde. Thermomyces lanuginosus lipase was covalently attached onto MPPM with 80%, 85%, and 89% immobilization efficiencies using bead, powder, and monolithic forms, respectively. Immobilized enzymes were successfully used for the production of biodiesel using sunflower, soybean, and waste cooking oils. It was shown that immobilized enzymes retain their activities during 10 repeated batch reactions at 25 degrees C, each lasting 24h. Since the developed novel method is simple yet effective, it could have a potential to be used industrially for the production of chemicals requiring immobilized lipases.

A new approach to estimate anthropometric measurements by adaptive neuro-fuzzy inference system

Abstract 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 height, popliteal height, and height) were selected for estimation purpose. The results showed that the number of inputs required estimating outputs varied with sex difference. ANFIS perform better than stepwise regression method for both sex groups, as revealed by the standard deviations averaged over the six outputs: S ANFIS =0.776, S Regression =0.855 for boys and, S ANFIS =0.883, S Regression =1.027 for girls. Relevance to industry More recently, as industry and marketing reach around the globe, body size has become a matter of practical interest to designers and engineers. In ergonomics anthropometric data are widely used to specify the physical dimension of workspaces, equipment, furniture and clothing. This is especially true for school children, which spend most of their time sitting at their chairs and desks and ought to be able to adopt comfortable body postures.

Effect of ultrasound on the dissolution of colemanite in H2SO4

This paper deals with the dissolution of colemanite in sulfuric acid, in the absence and presence of ultrasound. By nonlinear regression analysis, a modified Avrami-typeA equation was fitted to kinetic data and the activation energy was found to be 30 kJ/mol in both cases. The effect of ultrasound is on the pre-exponential factor A in the Arrhenius equation. An empirical relation is also given, which relates the rate constant to ultrasound power.

The effect of process conditions on the treatment of benzoquinone solution by electrocoagulation.

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 process and the adsorption capacity of aluminium hydroxide electrocoagulant flocs. The results show that pH 7.5 seems to be optimum for high removal of BQ near 90% at typical operating conditions such as 20 A/m(2) current density and 20 min operating time. The competing reduction of BQ to hydroquinone (HQ) accompanying the H(+) reduction at the cathode and low removal extent of HQ by electrocoagulant flocs decreases the performance of the EC process.

Statistical modeling and optimization of ultrasound-assisted sulfuric acid leaching of TiO2 from red mud

Abstract 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, ultrasound power, temperature, leaching time, acid concentration and solid to liquid ratio, on the leaching of TiO 2 , Al 2 O 3 and Fe 2 O 3 have been investigated. First-order models have been obtained by using 2 5−1 fractional factorial design. Auxiliary experiments for second-order models have been conducted according to an orthogonal central composite design. These second-order models have been used in a constrained optimization study which showed that both high and selective yields of TiO 2 may be obtained under suitable process conditions. The major factors influencing TiO 2 leaching were acid concentration and temperature, the other variables had comparatively small effects. The use of ultrasound resulted in a 20% increase in TiO 2 leaching compared to identical conditions without ultrasound.

A THERMODYNAMIC MODEL OF A SOLAR ASSISTED HEAT PUMP SYSTEM WITH ENERGY STORAGE

In this study, a thermodynamic model of a solar assisted heat pump system with energy storage was developed. The model consists of thermodynamic correlations concerning the fundamental equipment in the system such as solar collector, energy storage tank, compressor, condenser and evaporator. Some model parameters of the system were calculated by using experimental results obtained from a pilot plant. Simulation studies were performed to assess the importance of some design factors on the system performance and economy.

Effect of ultrasound on the dissolution kinetics of phosphate rock in HNO3

Ultrasound is known to enhance solid/liquid reactions. This paper deals with the investigation of the dissolution of phosphate rock in nitric acid, in the absence and presence of ultrasound. The reaction is first-order with respect to H+ and activation energy equal to 16 kJ/mol in both cases. The effect of ultrasound is on the pre-exponential factor A. An empirical relation is given, which relates rate constant to ultrasound power.

Photocatalytic performance of ZnO coated tubular 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 ZnO film. The method is economical, energy efficient and easy to apply. ZnO film is mechanically durable and resistant to chemical dissolution. Various physical tests were conducted to characterize the film. ZnO thin film exhibits the crystal wurtzite structure with band gap calculated as 3.24 eV. The film exhibits highly hydrophilic behavior. The average ZnO crystallite size is estimated as 72 nm. SEM analysis shows that the ZnO film has granular morphology with uniform particle size of about 300-400 nm. The film thickness is calculated as 1.41 microm after 20 coating cycles and the increase of the thickness of the thin film per cycle was approximately 70 nm. Photochemical activity tests were performed by measuring photo decolorization rate of a commercial azo dye (Rem Red F3B) solution in tubular reactor and as well as in slurry reactor for comparative purpose. First order rate constants were correlated to principal process parameters. The results showed that thin ZnO film has high photocatalytic activity comparable to that of ZnO powder.

Exergy and structural analysis of raw juice production and steam-power units of a sugar production plant

In this paper, exergy analysis successfully assesses the true thermodynamic efficiency of chemical processes. It also indicates the plant irreversibility distribution among plant components, revealing those which contribute most to plant inefficiency. A structural analysis is also performed to determine the effects of some operating parameters on the local irreversibility rates with respect to the overall plant irreversibility rate. This study deals with the application of exergy analysis to raw juice production and the steam-power units of the sugar production plant from sugar beet. The structural bond coefficients of the some operating system parameters are calculated. It is concluded that if the optimal values determined for the operating system parameters in this work were chosen, the total exergy loss of the plant would decrease 4.21%.