Effect of acid gases on the solubility of n-propylmercaptan in 50 wt% methyl-diethanolamine aqueous solution

In this communication, we have measured the solubility and partition coefficient of n-propylmercaptan in 50 wt% MDEA aqueous solution at 366 K in the presence of single and mixed acid gases (CO₂ and H₂S). A static analytic method was used for performing all the measurements. Methane was used to maintain the total pressure of the system in equilibrium cell. The concentration of n-propylmercaptan in aqueous phase was in the 50–1000 ppm (mole) range. The effect of acid gas loadings on the physical and chemical solubility of n-propylmercaptan is discussed.     

An efficient composition of Web services with active network support

Composition of Web services enables collaboration among autonomous business organisations such that they can integrate their services to perform collaborative business activities. It facilitates the development of new services using pre-existing Web services thus reducing development and operational costs. However, the highly distributed, dynamic, and autonomous nature of component Web services gives rise to various issues such as service matchmaking, reliability, availability, security and efficiency. This paper presents a new protocol in order to improve the efficiency of Web services composition. The proposed protocol is based on the peer-to-peer paradigm which exploits the capabilities of underlying networks such that part of the processing is carried out at the network nodes. Efficiency of the proposed protocol is tested through various experiments. Experimental results show that the proposed protocol significantly improves performance by reducing the system response time in the composition of Web services.     

Comparison of electrothermal and hydride generation atomic absorption spectrometry for the determination of total arsenic in broiler chicken

The purpose of this study was to estimate total arsenic concentration in different tissues (leg, breast, liver and heart) of broiler chicken by hydride generation atomic absorption spectrometry (HGAAS) and graphite furnace atomic absorption spectrometry (GFAAS), prior to microwave assisted acid digestion. The accuracy of the techniques was evaluated by using certified reference material DORM-2. The percentage recoveries of total As were observed as 100.6% and 99.4% for HGAAS and GFAAS, respectively. The precision of the techniques, expressed as relative standard deviation, was observed as 1.71% and 4.18% for HGAAS and GFAAS measurements, respectively. The limits of detection for HGAAS and GFAAS were 0.025 μg/g and 0.052 μg/g, respectively. The concentrations of total arsenic in different tissues of broiler chicken were found in the range of 2.19–5.28, 2.15–5.22, 2.97–7.17 and 2.68–6.36 μg/g for leg, breast, liver and heart tissues, respectively. At a mean level of chicken consumption (60 g/person/day), people may ingest in the range of 72.0–85.1 μg arsenic/person/day from chicken alone.     

Second generation bioethanol (SGB) production potential in Turkey

Energy demand is increasing by the years. Population's needs and technological investments bring the new approach about generating energy. It is considered that fossil fuels will not be able to respond to all energy requirements after approximately 150 years. Turkey imports nearly all of its petroleum and so this causes major economic problems. Turkey, as a major cereal producer, has a huge potential to grow energy crops and other cellulosic biomaterials and can obtain plant's residues, which are suitable to produce second generation bioethanol (SGB). With domestic production, bioethanol can reduce the dependence of petroleum for Turkey, and greenhouse gas emissions can be decreased. Taking into account Turkey's situation in fuel–oil consumption, costliness of gasoline and environmentally hazardous specification of fossil fuels, bioethanol gains more importance and increases in value. Especially, SGB production is rising. Foodstuffs are valuable, and producing ethanol from directly those materials can cause a crisis in Turkey because lignocellulosic bioethanol is becoming prominent. In this regard, bioethanol production in Turkey becomes a major alternative to petroleum and may be a key to new and clean energy source. Copyright © 2013 John Wiley & Sons, Ltd.     

Banana peel: an effective biosorbent for aflatoxins

This work reports the application of banana peel as a novel bioadsorbent for in vitro removal of five mycotoxins (aflatoxins (AFB1, AFB2, AFG1, AFG2) and ochratoxin A). The effect of operational parameters including initial pH, adsorbent dose, contact time and temperature were studied in batch adsorption experiments. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and point of zero charge (pH_pzc) analysis were used to characterise the adsorbent material. Aflatoxins’ adsorption equilibrium was achieved in 15 min, with highest adsorption at alkaline pH (6–8), while ochratoxin has not shown any significant adsorption due to surface charge repulsion. The experimental equilibrium data were tested by Langmuir, Freundlich and Hill isotherms. The Langmuir isotherm was found to be the best fitted model for aflatoxins, and the maximum monolayer coverage (Q₀) was determined to be 8.4, 9.5, 0.4 and 1.1 ng mg^?1 for AFB1, AFB2, AFG1 and AFG2 respectively. Thermodynamic parameters including changes in free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) were determined for the four aflatoxins. Free energy change and enthalpy change demonstrated that the adsorption process was exothermic and spontaneous. Adsorption and desorption study at different pH further demonstrated that the sorption of toxins was strong enough to sustain pH changes that would be experienced in the gastrointestinal tract. This study suggests that biosorption of aflatoxins by dried banana peel may be an effective low-cost decontamination method for incorporation in animal feed diets.     

Photoelectrochemical water splitting at nanostructured α-Fe2O3 electrodes

In this study, nanostructured α-Fe₂O₃ thin films were deposited by simple electrodeposition for photoelectrochemical water splitting. Post-annealing temperature was found to have drastic effect on photoactivity of these films. SEM analysis illustrated that size of nanoparticles increases with annealing temperature. The current–potential characteristics showed that the water-splitting photocurrent strongly depends on post-annealing temperature. A maximum photocurrent density of 0.67 mA/cm² was observed at 1.23 V versus reversible hydrogen electrode (RHE) under standard illumination conditions (AM 1.5 G 100 mW/cm²), and the water-splitting current was over 1.0 mA/cm² before the dark current flow starts (at 1.55 V versus RHE). The electrode shows an onset potential as low as 0.8 V (versus RHE) for water photooxidation, which is one of the best results reported for hematite photoanodes. This high photoactivity of electrodes is attributed to the preferential growth of hematite nanostructures along the most conductive plane (001) and incorporation of Sn in film from the substrate at high annealing temperature. The best-performing electrode shows an incident photon conversion efficiency (IPCE) of 12% at 400 nm (in 1 M NaOH at 1.23 V versus RHE), which indicate the improved light-harvesting properties of these nanostructures.