World Congress on Biosensors 2014

World Congress on Biosensors 2014
Biosensors 2014

Wednesday 9 January 2013

Just Published: Journal of Analytical and Applied Pyrolysis


A new issue of this journal has just been published. To see abstracts of the papers it contains (with links through to the full papers) click here:
Journal of Analytical and Applied Pyrolysis
http://rss.sciencedirect.com/publication/science/5247
Selected papers from the latest issue:

Thermal degradation and combustion behavior of reconstituted tobacco sheet treated with ammonium polyphosphate

09 January 2013, 09:22:52
Available online 5 January 2013
Publication year: 2013
Source:Journal of Analytical and Applied Pyrolysis

In this paper, the APP-modified reconstituted tobacco sheet (RTS) was prepared by a paper-making process. Thermogravimetric analysis coupled to Fourier transform infrared spectrometer (TG-FTIR) had been used to investigate the influences of APP on the thermal degradation and the formation of evolved volatile products of RTS. TG-FTIR results illustrated that the incorporation of APP into RTS could retard the thermal degradation of the major components of RTS and meanwhile lead to the formation of more thermally stable char. Moreover, the main gases released during the pyrolysis of RTS and APP-modified RTS were H2O, CO2, CO, NH3, carbonyl compounds, alcohols and alkanes. The presence of APP changed the formation of evolved volatile products of RTS obviously. The effects of APP on the combustion behavior of RTS were studied by micro-scale combustion calorimetry (MCC), cone calorimetry (CCO) and Infrared thermography (IRT). Results demonstrated that the formation of combustible gases was mainly determined by the thermal decomposition stage occurred in the temperature range of 150-600°C. The incorporation of APP into RTS influenced the release of fuel gases and the char formation in the process of the thermal decomposition of RTS, and eventually retarded the flammability of RTS. In addition, it had been found that the maximum firecone temperature of untreated RTS was higher than that of APP-modified RTS.

Highlights

► The APP-modified reconstituted tobacco sheet (RTS) had been prepared successfully by a paper-making process. ► TG-FTIR had been used to investigate the influences of APP on the thermal decomposition and the formation of evolved volatile products of RTS. ► Micro-scale combustion calorimetry (MCC), cone calorimetry (CCO) and Infrared thermography (IRT) were used to evaluate the combustion behavior of RTS and APP-modified RTS.

Properties of spray deposited Cu2ZnSnS4 (CZTS) thin films

09 January 2013, 09:22:52
Available online 5 January 2013
Publication year: 2013
Source:Journal of Analytical and Applied Pyrolysis

A new solar absorber material, Cu2ZnSnS4 (CZTS) in thin film form has been deposited onto glass substrates using spray pyrolysis technique. The thickness dependent (244–754nm) structural, morphological, optical and electrical properties of CZTS films have been studied. The X–ray diffraction studies revealed the formation of polycrystalline CZTS films. The surface morphological studies revealed the formation of smooth, compact and uniform CZTS surface. Absorption coefficient was of the order of 104 cm−1 and depending on film thickness the direct transition was observed with band gap in the range from 1.6 to 1.67eV. The thermoemf measurement revealed that the CZTS films exhibit p–type electrical conductivity.

Highlights

► Detail film formation mechanisms of CZTS thin film. ► Simple and inexpensive method is for the synthesis of CZTS films. ► The Structural, morphological and optical properties. ► In the present manuscript, the work is novel in the context that for the first time, the effect of different film thickness [244-754nm] on physicochemical properties of CZTS thin films.

Fast Pyrolysis of Kraft Lignin - Vapour Cracking Over Various Fixed-Bed Catalysts

09 January 2013, 09:22:52
Available online 5 January 2013
Publication year: 2013
Source:Journal of Analytical and Applied Pyrolysis

Screening of pyrolysis reactions has been carried out with Kraft lignin and various catalysts applying the vTI-mini fast pyrolyzer. Zeolite HZSM-5, FCC and Olivine in a small fixed bed were used as catalyst to investigate their influences on the pyrolysis reaction. The characteristics of catalytic pyrolysis reactions and final products were studied by varying reaction temperature and catalyst type. The vTI-mini fast pyrolyzer is especially suitable to obtain quick mass balances of main products such as char, non-condensable gases and biocrude oil. Their yields were evaluated and the collected biocrude oil was further analysed using GC-MS/FID. Depending on the various catalysts as well as different pyrolysis temperatures, the overall distribution of the three main product categories and the portions of certain chemical compounds were increased or decreased,.To scrutinize the catalytic effect and to highlight the severity of lignin degradation, size exclusion chromatography (SEC) was performed from extracts of the solid residue.

Highlights

► The screening of pyrolysis reactions was carried out for Kraft lignin with various catalysts. ► The biocrude oil yields were evaluated and the biocrude oil was further analyzed using GC/MS/FID. ► Also, size exclusion chromatography (SEC) was performed for extracts from the solid residue. ► The minimum and maximum yields of biocrude oil were 10.07% and 15.99%, respectively. ► HZSM-5 and FCC show the remarkable catalytic effects on the pyrolysis characteristics.

Effect of zinc borate and wood flour on thermal degradation and fire retardancy of Polyvinyl chloride (PVC) composites

09 January 2013, 09:22:52
Available online 4 January 2013
Publication year: 2013
Source:Journal of Analytical and Applied Pyrolysis

The thermal decomposition, fire retardancy and mechanical properties of wood-flour-polyvinyl chloride composites (WF-PVC) were investigated. Thermogravimetric analysis (TGA) tests showed that the addition of wood flour (WF) and zinc borate (ZB) significantly influenced the thermal degradation behavior of PVC and WF-PVC composite. WF reduced the initiation temperature (Tinitial) for thermal degradation of PVC, while ZB scarcely affected the initial temperature of WF-PVC. WF retarded the thermal decomposition of PVC in the early stage while ZB increased the rapidest decomposition temperature and reduced the decomposition rate of WF-PVC. The mechanism of thermal decomposition of the composite was analyzed by Fourier transform infrared (FTIR) spectroscopy using the attenuated total reflectance (ATR) method. The decrease of C-H bonds and increase of C=C bonds indicated WF and ZB promote the crosslinking and charring reactions of PVC. According to the cone calorimetry (CONE) tests, WF had a positive effect on fire performance of PVC but had little effect on smoke suppression. In contrast, the incorporation of ZB had little effect on flame retardancy of WF-PVC but it was an effective smoke suppressant, decreasing the total smoke produced (TSP) by more than 50%. Mechanical results indicated that ZB had some negative effects on the strength properties of WF-PVC, however the modulus increased compared with the untreated composite.

Highlights

► WF improved the thermal properties of PVC matrix at a lower temperature while ZB presented better thermal properties at a higher temperature. ► The decrease of C-H bonds and increase of C=C bonds indicated WF and ZB promote the crosslinking and charring reactions of PVC. ► WF had little effect on smoke suppression but resulted in a positive effect on other fire performance properties of PVC. ► ZB hardly contributed to the flame retardancy of WF-PVC but it effectively functioned as a smoke suppressant for WF-PVC composite.

Cellulose, Hemicellulose and Lignin Slow Steam Pyrolysis. Thermal Decomposition of Biomass Components Mixtures

09 January 2013, 09:22:52
Available online 4 January 2013
Publication year: 2013
Source:Journal of Analytical and Applied Pyrolysis

Biomass thermochemical decomposition products have been extensively studied as renewable substitutes of fossil fuel. The approach proposed in this work considers vegetal waste as a source of both energy and matter through the production of a vapor phase fuel, highly diluted in steam, suitable to be burned in non-conventional combustion systems and a char with soil amending and fertilizing properties. To demonstrate the feasibility of such a process an experimental set-up has been designed with the aim to investigate the effect of pressure, heating rate and final temperature in proper variation ranges (P=1-5 ×105 Pa, HR=5-40K/min, T=473-973K) on the yields and on the chemical and physical properties of gaseous and solid products. In this paper the effect of temperature at constant pressure (P=5 ×105 Pa) and heating rate (HR=5K/min) has been investigated in order to explore all the stages of the thermochemical degradation from torrefaction to mild gasification passing through devolatilization. For real biomasses a basic study on characterization of biomass components is needed. Knowledge of dependences on feedstock nature and process conditions are crucial for the comprehension of phenomena occurring during steam pyrolysis of real complex biomasses and for the optimization of the process operating variables. This study characterizes steam pyrolysis up to 873K (at pressure P= 5×105 Pa and heating rate HR=5K/min) both of three single biomasses constituents (cellulose, hemicellulose and lignin) and of three binary mixtures in order to evaluate possible interactions between the biomass components. The results obtained highlight the importance of the interactions between components, mainly cellulose and lignin, on the yield and characteristics of solid and gaseous products. In particular, strong components interactions have been detected on the specific surface area of the solid product.

Highlights

► Mechanisms involved in steam pyrolysis of biomass components have been studied. ► Char porosity, vapor phase yield and HHV increases with process final temperature. ► Cellulose with respect to xylan and lignin gives a char with a higher surface area. ► Lignin is fundamental for the production of a vapor phase with a higher HHV. ► Interactions between biomass components affect char surface area.

Transformation of lignocellulosic biomass during torrefaction

09 January 2013, 09:22:52
Available online 3 January 2013
Publication year: 2013
Source:Journal of Analytical and Applied Pyrolysis

In this study, the effect of torrefaction on the chemical and structural transformation of lignocellulosic biomass was investigated using complementary analytical tools. It was observed that the acid-insoluble fraction was increased from approximately 30 to 38% and the methoxyl content was decreased to about half after torrefaction at 330°C for 2.5min. These results highlight the formation of condensed structures along with lignin transformation via demethoxylation. Solid-state NMR spectroscopy indicated that upon torrefaction the aromaticity increased from about 36 to 60%. For the sample torrefied at 330°C, the non-protonated aromatic carbon fraction was found to be about 60% of total aromatic carbons, indicating the formation of large aromatic clusters. The complementary analyses used in this study are proposed as a suitable approach for the elucidation of chemical and structural transformation of biomass during thermal treatment.

Highlights

► Acid-insoluble residue increased to 38.2 from 30.1% in torrefied biomass at 330°C. ► 51% of lignin modified via demethoxylation in torrefied biomass at 330°C. ► Aromaticity increased from 35.8 to 59.6% in torrefied biomass at 330°C. ► Non-protonated aromatic carbon fraction increased during torrefaction.

The structural development of zeolite-templated carbon under pyrolysis

09 January 2013, 09:22:52
Available online 3 January 2013
Publication year: 2013
Source:Journal of Analytical and Applied Pyrolysis

Three activated carbon samples were synthesized via the pyrolysis of furfuryl alcohol (FA) impregnated in the porous framework of zeolite Y. The pyrolysis temperature was set at 900, 1050, and 1150°C, respectively, to investigate its role on structural development. The surface properties of the carbon samples were characterized using XRD, SEM, Raman, and gas adsorption technologies. It is found that a low pyrolysis temperature is in favor of the structural regularity and the formation of small micropores (d<1.0nm), while a high temperature is necessary for the surface area/pore enhancement. However, a too high temperature will result in the collapse of micropores and the formation of mesopores.

Highlights

► Poly(furfuryl alcohol) impregnated into zeolite-Y to form polymer-zeolite composites; ► 3 carbon samples derived at different pyrolytic temperatures; ► Low temperature (900°C) favors structural regularity and small micropores (d<1.0nm); ► High temperature (1050°C) favors micropore and high surface area; ► A too high temperature (1150°C) collapse micropores and form mesopores.

Fractionation of technical lignins as a tool for improvement of their antioxidant properties

09 January 2013, 09:22:52
Available online 3 January 2013
Publication year: 2013
Source:Journal of Analytical and Applied Pyrolysis

The modern biorefinery concept is aimed at the elaboration of sustainable processes with the most profitable utilization of all biomass products obtained at the technological cycle. Lignin separated as by-product in the lignocellulosic chemical processing are recognized as an important component of polymer systems. The presence of sterically hindered phenolic hydroxyl groups in the lignin macromolecule opens the possibility of its application as antioxidant for composites, e.g. polyurethanes (PU), which are considered as one of the most versatile polymeric materials. In the present work, the object of investigations was lignin obtained as a product, so-called BIOLIGNIN TM, of wheat straw organosolv processing for pulp and fuel ethanol production (CIMV pilot plant, France). However, heterogeneity of the lignin obtained negatively influences its applicability that can be overcome by fractionation. Three soluble fractions were isolated from CIMV lignin by a sequential extraction with dichloromethane (A fraction), methanol (B fraction) and mixture of both the solvents (C fraction) and characterised in terms of their composition, functionality and structure using analytical pyrolysis (Py-GC/MS), 31P NMR and Size Exclusion Chromatogrhaphy (SEC) methods. Antioxidant properties of BIOLIGNIN TM fractions were assessed in the tests with free radicals ABTS•+ and DPPH. Application of Py-GC/MS for characterization of the fractions opened an opportunity to found some novel “structure-activity” correlations needed for understanding and tuning of antioxidant properties of lignins. The antioxidant activity of the fractions under investigation was tested by their influence on thermo-oxidative destruction of prepared model PU films. The data of TGA method (oxidative conditions) clearly testified the antioxidant effect of all three fractions with the most prominent activity for C fraction. The shifting of the exothermal maxima connected with oxidizing of volatile products of PU destruction to the higher temperature region by 20-30K and 30-40K was registered. 

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