Özgül Gerçel

Removal of disperse dye from aqueous solution by novel adsorbent prepared from biomass plant material

The adsorption of Disperse Orange 25 (3-[N-ethyl-4-(4-nitrophenylazo) phenylamino] propionitrile) onto activated carbon was investigated in a batch system with respect to contact time, carbon dosage, pH and temperature from aqueous solutions. The Langmuir, Freundlich and Dubinin-Radushkevich (D-R) adsorption models were applied to describe the equilibrium isotherms and the isotherm constants were also determined. The Langmuir isotherm model agrees with the experimental data well. Maximum adsorption capacity (qmax) of Disperse Orange 25 onto adsorbent was 118.93mgg(-1) at 20 degrees C. The first-order, pseudo-second-order kinetic models and the intraparticle diffusion model were used to describe the kinetic data and the rate constants were evaluated as well. The experimental data fitted very well to pseudo-second-order kinetic model. The results show that activated carbon prepared from Euphorbia rigida by sulfuric acid chemical activation could be employed as low-cost material to compare with commercial activated carbon for the removal of disperse dyes from effluents.

Bio-oil Production from an Oilseed By-product: Fixed-bed Pyrolysis of Olive Cake

Abstract A study of pyrolysis of olive cake at the temperature range from 400°C to 700°C has been carried out. The experiments were performed in a laboratory scale tubular reactor under nitrogen atmosphere. The yields of derived gases, liquids, and char were determined in relation to pyrolysis temperature and sweeping gas flow rates, at heating rates of about 300°C min−1. As the pyrolysis temperature was increased, the percentage mass of char decreased whilst gas product increased. The oil products increased to a maximum value of ∼39.4 wt% of dry ash free biomass at a pyrolysis temperature of about 550°C in a nitrogen atmosphere with flow rate of 100 mL min−1 and with a heating rate of 300°C min−1. Results showed that the bio-oil obtained under the optimum conditions is a useful substitute for fossil fuels or chemicals.

Removal of Acid Dyes from Aqueous Solutions using Chemically Activated Carbon

Abstract Textile dyes (Acid Yellow 17 and Acid Orange 7) were removed from its aqueous solution in batch and continuous packed bed adsorption systems by using thermally activated Euphorbia macroclada carbon with respect to contact time, initial dye concentration, and temperature. The activated carbon was prepared using a cheap plant-based material called Euphorbia macroclada, which was chemically modified with K2CO3. Lagergren-first-order and second-order kinetic models were used to fit the experimental data. Equilibrium isotherms were analyzed by Langmuir and Freundlich isotherms. Equilibrium data fitted well the Langmuir model in the studied temperature (25–55°C) ranges. The maximum adsorption capacity of AY17 and AO7 onto activated carbon was found to be 161.29 and 455 mgg−1, respectively by Langmuir isotherm at 55°C. Breakthrough curves for column adsorption have also been studied. The desorption of dyes has been experimentally investigated using NaOH solution of pH 11.

Biosorption of a Basic Dye from Aqueous Solutions by Euphorbia rigida

Abstract In this study, the biosorption of Basic Blue 9 (BB9) dye from aqueous solutions onto a biomass of Euphorbia rigida was examined by means of the initial biosorbate concentration, biosorbent amount, particle size, and pH. Biosorption of BB9 onto E. rigida increases with both the initial biosorbate concentration and biosorbent amount, whereas decreases with the increasing particle size. The experimental data indicated that the biosorption isotherms are well‐described by the Langmuir equilibrium isotherm equation at 20, 30, and 40°C. Maximum biosorption capacity was 3.28×10−4 mol g−1 at 40°C. The biosorption kinetics of BB9 obeys the pseudo‐second‐order kinetic model. The thermodynamic parameters such as ΔG°, ΔH° and ΔS° were calculated to estimate the nature of biosorption. These experimental results have indicated that E. rigida has the potential to act as a biosorbent for the removal of Basic Blue 9 from aqueous solutions.

Capacity of activated carbon derived from peach stones by K2CO3 in the removal of acid, reactive, and direct dyes from aqueous solution.

The present research deals with the production of activated carbon by chemical activation using peach stones and its adsorption behavior. The prepared activated carbon was used for the adsorption of three kinds of textile dyes, acid, reactive, and direct dyes, from aqueous solution. The results indicated that the overall adsorption process followed the pseudo-second-order kinetic model. The equilibrium data were found to be well represented by the Langmuir adsorption isotherm model. The calculated adsorption capacities for Reactive Orange 16, Acid Yellow 11, and Direct Red 23 onto activated carbon were 667, 539, and 427 mg g−1 at 50°C , respectively. Thermodynamic parameters, such as ΔG° , ΔH° , and ΔS° , were also calculated and indicated that the adsorption of dyes onto activated carbon was spontaneous and endothermic in nature.

Energy Applications of Biomass: Pyrolysis of Apricot Stone

Apricot stone (Prunus armeniaca L.) was pyrolyzed in a directly heated fixed-bed reactor under nitrogen atmosphere. Effects of sweeping gas flow rates and pyrolysis temperature on the pyrolysis of the biomass were also studied. Pyrolysis runs were performed using reactor temperatures between 400°C and 700°C with heating rate of about 300°C min−1. As the pyrolysis temperature was increased, the percentage mass of char decreased while gas product increased. The product yields were significantly influenced by the process conditions. The bio-oil obtained at 550°C, at which the liquid product yield was maximum, was analyzed. It was characterized by Fourier transform infrared spectroscopy (FT-IR). In addition, the solid and liquid products were analyzed to determine their elemental composition and calorific value. Chemical fractionation of bio-oil showed that only low quantities of hydrocarbons were present, while oxygenated and polar fractions dominated.

Removal of textile dye from aqueous solution by electrochemical method

ABSTRACT The use of adsorption and electrochemical treatment technologies for wastewater treatment has significantly increased in recent years. In the present study, carbon prepared from biomass waste can be used as electrode material in the electrochemical process is shown. Given that the electrode material is quite expensive, low-cost manufacturing is gaining more and more importance. Electroadsorption of textile dye (Burdem Orange II) by using activated carbon prepared from waste material, which is cherry stones, was investigated with the variation in the parameters of pH, initial dye concentration, solution flow rate, applied potential, and supporting electrolyte. The removal efficiency of textile dye up to 98% were achieved by electrochemical method.

SULFONATED POLY(ARYLENE ETHER BENZIMIDAZOLE) COPOLYMER MEMBRANE SYNTHESIS AND CHARACTERIZATION

Hidrojenden elektrik enerjisi uretiminde kullanilan yakit hucreleri, gelecegin cevre dostu ve yuksek verimli enerji uretimine alternatif olarak kabul gormektedirler. Nafion gibi perflorosulfonik asit bazli membranlar polimer elektrolit membran yakit hucreleri (PEMHY)’nde siklikla kullanilmaktadirlar. Ancak Nafion membranlarin yuksek sicakliklarda proton iletkenliklerinin dusmesi ve fiyatlarinin yuksek olmasi nedeniyle alternatif polimer elektrolit membran (PEM)’lar uzerine arastirmalar devam etmektedir. Bu calismanin ilk asamasinda, disodyum-3,3’-disulfonat-4,4’-diklorodifenilsulfon (SDCDPS) ve benzimidazol bisfenol (HPBI) monomerlerinin sentezi gerceklestirilmistir. Daha sonra sentezlenen monomerlerden nukleofilik aromatik polikondenzasyon reaksiyonu ile poli(arilen eter benzimidazol) kopolimeri sentezlenmistir. Sentezlenen monomerlerin 1H NMR ve FTIR, kopolimerin ise 1H NMR, FTIR ve termogravimetrik analizleri (TGA) gerceklestirilmistir. Yapilan analizler sonucunda kopolimerin sentezlendigi acikca ortaya konulmustur. TGA egrisi sentezlenen kopolimerin isil kararliliginin yuksek oldugunu (~400 oC) ve yuksek sicaklik uygulamalarinda kullanilabilirligini gostermistir