Thermal behavior of native, washed and steam exploded lignocellulosic biomass samples

The aim of this study was to evaluate the chemical changes in the main components (cellulose, hemicellulose and lignin) of various lignocellulosic biomass samples during the steam explosion pretreatment. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and thermogravimetry/mass spectrometry (TG/MS) measurements have been performed on different native, washed and steam exploded woody (willow and spruce) and herbaceous (hemp, wheat straw and sweet sorghum bagasse) biomass samples. The main differences between the thermal decomposition of the samples are interpreted in terms of the altered structure of the biomass samples by the effective steam explosion treatment and the different alkali ion contents which have been determined using inductively coupled plasma-optical emission spectroscopy (ICP-OES) method. In order to separate these two effects, the native biomass samples have been washed with hot water to remove the main parts of the potassium and sodium ions. The concentration of K+ and Na+ has been reduced in the treated biomass samples so the thermal decomposition mechanism has been altered due to the elimination of the catalytic effects. Principal Component Analysis (PCA) has been used to find statistical correlations between the data. The functional group compositions of the lignin molecules have been modified significantly as indicated by the pyrograms and the score plot of the PCA. The amount of hemicellulose has been reduced. On the other hand, the relative amount of the structurally modified cellulose has been increased in the samples by the steam explosion pretreatment step

Magyarországi történelmi téglák eredetének és készítési technológiájának vizsgálata modern analitikai kémiai és fizikai módszerekkel. = Determination of provenance and fabricing technology of old, medieval Hungarian historical bricks with methods of modern analytical chemistry and physical sciences.

Négy évszázadból származó aquincumi bélyeges téglák anyagát vizsgáltuk röntgendiffrakcióval (XRD), valamint meghatároztuk a jellemző geokémiai bélyegeket kézi, hordozható röntgenfluoreszcens elemző készülékkel (XRF). Kimutattuk, hogy a tegulák nyersanyagaként a környező nyersanyaglelőhelyek anyagából azt fejtették, ami a legjobban szolgálta az elérendő technológiai eredményt. Nagyfokú homogenitás jellemzi a tegulák kémiai összetételét. A kiugróan eltérő értékek idegen származásra utalhatnak. A fázisösszetételbeli különbségek az eltérő égetési hőmérsékleteknek, kemencehasználatnak tulajdoníthatók. Megmutattuk, hogy a tegulák anyagvizsgálati eredményei felhasználhatók a korabeli és jelenlegi agyagnyerőhelyek jellemzésére, így az azonos időben keletkezett egyéb kerámia termékek potenciális nyersanyagaként történő értelmezésére, a helyi- és az import termékek megkülönböztetésére. Létrehoztuk egy többfunkciós agyag- és kerámia adatbázis alapjait, amelynek folyamatos bővítésével az archeometriai kutatás új lehetőségeit alapoztuk meg. Az alkalmazott ásvány-kőzettani-geokémiai kutatás megbízható eszköztárát kibővítettük a hordozható XRF készülék lehetőségeinek és korlátainak tesztelésével, pontosságának növelésével. Fontos eredménynek tartjuk továbbá, hogy be tudtuk mutatni az XRF technika (és ezen felül a kémia) szerepének jelentőségét a hazai régészetben, művészettörténetben, restaurálásban, archeometriai kutatásokban. | Numerous historical stamped brick samples representing four centuries A.D. were measured by X-ray diffraction analysis and portable handheld X-ray fluorescence spectrometry as well to determine geochemical features of the matter of bricks. The chemical composition of bricks is very homogeneous. Data which are significantly out of the average composition may suggest an other provenance (non local raw material and/or import products). We showed that results of these examinations (chemical and phase composition) of bricks, tegulas and ceramics can be used for characterization of either ancient and recent clay sources as potential raw material for other sort of ceramic products made in the same time therefore distinguishing between local and import products additionally. We have created the bases of a complex database of ceramics and materials which establishes new possibilities for archaeometric researches via expanding data continuously. By applying, studying and improving our handheld portable XRF analyzer (testing of facilities and limitations) tools of mineralogical-petrological-geochemical researches were enhanced. Very important result of this proposal is that remarkable importance of XRF technique and chemistry itself was proved in archaeology, art history, conservation, restoration and archaeometric researches in Hungary

Transport of Pollutants around a High Building: Integrated Magnetic, Mineralogical and Geochemical Study

We studied the degree and distribution of traffic induced pollution at a 40 m high building at the side of a major road in Budapest by making magnetic, mineralogical and geochemical analysis on settled dust samples collected at different levels and at the front and back sides of the building. We observed strong seasonal dependence of the amounts of anthropogenic pollutants, which were highest during summer. This season was also characterized by strong vertical variation of the amounts of dust, of the magnetic susceptibilities (reflecting best the traffic induced pollution) and of the concentrations of Pb. All these have maximum values at 9 m, on both sides of the building. The pattern of the distribution does not correspond to what is predicted by an air flow model published for high buildings with similar morphology and wind conditions