Tomasz Łojewski

Pillared smectite modified with carbon and manganese as catalyst for SCR of NOx with NH3. Part II. Temperature‐programmed studies

Temperature‐programmed desorption (TPD) and surface reaction (TPSR), and additionally FTIR spectroscopy of adsorbed NO molecules were used to characterise surface sites on pillared smectites modified with carbon and manganese. Much higher adsorption of NH3 than NO was found, but acidic pre‐treatment increased NO sorption to comparable values as well as catalytic performance in SCR of NOx. In this case formation of strongly bound NO3− species was recognised, which reacted with NH3 at a temperature 200 °C higher than weaker adsorbed NO.

Size exclusion chromatography and viscometry in paper degradation studies. New Mark-Houwink coefficients for cellulose in cupri-ethylenediamine

The paper deals with the application of size exclusion chromatography (SEC) for the studies of paper degradation phenomena. The goal is to solve some of the technical problems connected with the calibration of multi-detector SEC system and to find the correlation between SEC and viscometric results of degree of polymerization of cellulose. The results gathered for the paper samples degraded by acidic air pollutant (NO(2)) are used as an example of SEC-MALLS application. From the correlation between intrinsic viscosities and absolute value of molecular masses obtained with SEC/MALLS (Multi Angle Laser Light Scattering) technique, Mark-Houwink coefficients for cellulose in cupri-ethylenediamine solution were determined. Thus obtained coefficients were used for the determination of viscometric degree of polymerization (molecular mass) of the aged samples. An excellent correlation was found between the chromatographic values of molecular masses obtained with SEC-UV/VIS detection and the viscometric ones utilizing the improved values of Mark-Houwink coefficients.

Pillared smectite modified with carbon and manganese as catalyst for SCR of NOx with NH3. Part I. General characterization and catalyst screening

Carbon- and manganese-modified zirconia-pillared smectites were prepared, characterized (XRD, BET and pore analysis, XPS) and tested in selective catalytic reduction of NOx with NH3. Both untreated and acidic pretreated smectites were used. The acid pretreatment increased NO conversion and influenced the extent of carbon introduction into the porous system. The carbon deposit improved selectivity of the catalytic reduction to N2.

Spectroscopic characterization of Co3O4 catalyst doped with CeO2 and PdO for methane catalytic combustion

The study deals with the XPS, Raman and EDX characterization of a series of structured catalysts composed of cobalt oxides promoted by palladium and cerium oxides. The aim of the work was to relate the information gathered from spectroscopic analyses with the ones from kinetic tests of methane combustion to establish the basic structure-activity relationships for the catalysts studied. The most active catalyst was the cobalt oxide doped with little amount of palladium and wins a confrontation with pure palladium oxide catalyst which is commercially used in converters for methane. The analyses Raman and XPS analyses showed that this catalyst is composed of a cobalt spinel and palladium oxide. The quantitative approach to the composition of the catalysts by XPS and EDX methods revealed that the surface of palladium doped cobalt catalyst is enriched with palladium oxide which provides a great number of active centres for methane combustion indicated by kinetic parameters.

Effect of water vapour and SO2 addition on stability of zirconia-pillared montmorillonites in selective catalytic reduction of NO with ammonia

Abstract A series of acid-treated zirconia-pillared montmorillonites doped with carbon and manganese was studied in selective catalytic reduction (SCR) of NO with NH3. For selected catalysts, various stability tests were performed. Catalysts M2C and M2CMn14 showed very good stability in long-run tests with the use of a standard reaction mixture. Addition of water vapour caused small decrease in NO conversion but the effect was reversible. SO2 poisoning gave different results depending on the applied method. In the conditions well-simulating DENOX process, i.e. when SO2 was added in the course of catalytic reaction, the activity of the studied catalysts did not change.

Evaluating degradation of silk’s fibroin by attenuated total reflectance infrared spectroscopy: Case study of ancient banners from Polish collections

In this study a part of research where artificially aged model samples were used as a guideline to the mechanism of degradation is presented. In previous work Bombyx Mori silk samples were exposed to various environments such as different oxygen, water vapour and volatile organic products content, all at the temperature of 150 °C [11]. Based on those results gathered with by Attenuated Total Reflectance/Fourier Transform Infrared Spectroscopy (ATR-FTIR) the degradation estimators were proposed and classified as follows: (1) Primary functional groups estimators EAmideI/II - intensity ratios of Amide I C=O stretching vibration to Amide II N-H in-plane bending and C-N stretching vibrations A1620/A1514. ECOOH - band 1318 cm(-1) integral to band integral of CH3 bending vibration band located at 1442 cm(-1)P1318/P1442. (2) Secondary conformational estimators EcC=O2 - intensity ratios within Amide I C=O stretching vibration of parallel β-sheet to antiparallel β-sheet A1620/A1699. In this work estimators were verified against estimators calculated from spectra of silk samples from 8 museum objects: 3 from 19th, 2 from 18th, 1 from 17th and 2 from 16th century including 3 banners from the storage resources of the Wawel Royal Castle in Cracow, Poland.

Note: Light ageing with simultaneous colorimetry via fibre optics reflection spectrometry

In this article, the design and characteristics of a micro-fadeometer is presented. The technique allows for a non-(micro-) destructive evaluation of the light fastness of colorants on various materials and can be used to directly assess valuable materials, such as heritage objects, and develop safer display strategies to promote their preservation. The presented instrument has several benefits over standard light ageing methods--low operating cost, non-damaging, real time measurement of induced changes for kinetics studies, and automated high throughput screening of materials. A selection of data is presented to demonstrate the flexibility of the presented instrument and illustrate how it can be used to evaluate museum lighting and oxygen-free display of heritage objects.

AN EXPERIMENTAL STUDY OF THE PRESSURE DROP IN FLUID FLOWS THROUGH WIRE GAUZES

Catalytic wire gauzes have been used for many years for ammonia oxidation. The flow and transfer properties of stacked gauzes, however, have not been sufficiently examined in the literature. This study presents an experimental program designed to characterize the pressure drops observed across stacked woven and knitted wire gauzes. This work generated an extensive database of measurements and reveals that each gauze requires its own correlation equation. Furthermore, previously published general models were not able to describe all four cases with high accuracy. After surveying the literature, we present some modifications to the models based on our collected experimental results.

Application of metal oxidation and oxide reduction to determine superficial phases containing active centres in redox catalysts

Temperature-programmed reduction (TPRed) and oxidation (TPOx) have been applied to distinguish various redox states of the metal present in the superficial phases of cobalt hydrogenation catalysts undergoing different redox pretreatment. The results were the bases for determination and titration of the active centres, performed by TPRed and pulse reoxidation, and for kinetic modelling.

Hyperspectral imaging coupled with chemometric analysis for non-invasive differentiation of black pens

Abstract Differentiation of the written text can be performed with a non-invasive and non-contact tool that connects conventional imaging methods with spectroscopy. Hyperspectral imaging (HSI) is a relatively new and rapid analytical technique that can be applied in forensic science disciplines. It allows an image of the sample to be acquired, with full spectral information within every pixel. For this paper, HSI and three statistical methods (hierarchical cluster analysis, principal component analysis, and spectral angle mapper) were used to distinguish between traces of modern black gel pen inks. Non-invasiveness and high efficiency are among the unquestionable advantages of ink differentiation using HSI. It is also less time-consuming than traditional methods such as chromatography. In this study, a set of 45 modern gel pen ink marks deposited on a paper sheet were registered. The spectral characteristics embodied in every pixel were extracted from an image and analysed using statistical methods, externally and directly on the hypercube. As a result, different black gel inks deposited on paper can be distinguished and classified into several groups, in a non-invasive manner.