Michal Jablonský

The Effect of Acetic and Formic Acid Formation during Accelerated Ageing on Embrittlement of Newsprint Paper

Paper and other lignocellulosic materials undergo deterioration as a result of ageing, influenced by various factors and accelerated by the formation of acids from components used in paper production and ambient species. These acids increase degradation of paper and decrease its mechanical properties. There is a lack of detailed information on the formation of acetic and formic acid in the process of accelerated ageing in the literature. This contributuion presents information on the kinetics of acetic and formic acid formation during accelerated ageing determined by modified ASTM D 6819-02 procedure. Accelerated ageing was performed with newsprint paper at 98°C and 50% RH for 60 days. The ratio of acetic acid to formic acid concentration increases through accelerated ageing by the factor after 10 days and by the factor 5.5 after 60 days. The brittleness index expressed as embrittlement due to paper degradation correlates well with the increase of the carboxylic acids concentration, as well as the molar ratio of concentration of acetic acid to formic acid. Zusammenfassung/résumé at end of article received: 04.04.2011 revised: 27.09.2011

Energy and chemical conversion of five Australian lignocellulosic feedstocks into bio-crude through liquefaction

Thermal liquefaction of five potential feedstocks namely, banana bunch stems (BBS), pineapple tops (PT), Forage sorghum (FS), bagasse (Ba) and Arundo donax (AD) were examined from an energy perspective at a large laboratory scale. Comparison of oil yield and higher heating value (HHV) of feedstock and bio-crude at this scale enabled analysis of the energy efficiency of the liquefaction of feedstock with varying structural compositions under different reaction conditions. Arundo donax was used to investigate degradation behaviour for bio-crude production at temperatures between 250–350 °C and biomass/solvent ratios of 1/10 to 1/25 (wt/wt). Maximum bio-crude yield of 67.3% was observed for AD at 350 °C and biomass/solvent ratio of 1/15. Liquefaction with recycled solvent in the first run improved energy recovery and the heating value of the bio-crude in comparison with fresh solvent. On the basis of the energy conversion, the feedstocks ranked as follows: BBS (105%) > FS (77%) > Ba (57%) > PT (55%) > AD (40%). GCMS results showed that the chemical composition changed in distribution and relative abundance of the oxygenated compounds, varying significantly depending on the type of biomass. Analysis of energy input and output of varying conditions and feedstock showed energy requirements and the HHV varied with the feedstock.

Comparison of Different Methods for Extraction from Lavender: Yield and Chemical Composition

A comparative study of accelerated solvent extraction (ASE) with two conventional volatile isolation methods including traditional steam distillation and Soxhlet extraction was performed on lavender. ASE was carried out by butanol (polar protic solvent) or dichloromethane (nonpolar solvent) and the temperature was 120°C. Separation and identification of the components was carried out by GC/MS. The main components of the analysed samples were Linalool (14.79%), α-Terpineol (4.42%), Linalool oxide (furanoid) (2.92%), cis-linalyl oxide (2.8%), α-Bisabolol (1.86%) and Octacosane (1.56%) for steam distillation; for ASE (dichlormethane): β-Terpineol (2.06%), Linalyl anthranilate (1.82%), Largeracetal (1.82%), Eucalyptol (1.74%), Linalool (1.73%), Coumarine (1.28%) and Caryophylene oxide (1.08%); for ASE (butanol): Lageracetal (8.29%), Octacosane (1.75%), Eucalyptol (1.05%) and Caryophyllene oxide (1.02%) and for Soxhlet (butanol): Largeracetal (11.42%), Linalool (3.36%), Coumarine (0.83%) and Eucalyptol (0.74%). The study has shown that ASE is a fast and environmentally sustainable technique, using butanol and dichloromethane as solvent for the extraction of extractive compounds from lavender.

Composition of fatty acids and tocopherols in peels, seeds and leaves of Sea buckthorn

Abstract Peels, seeds and leaves of the Sea buckthorn were extracted by methanol and chloroform and characterized in terms of the fatty acids (FA) and tocopherol composition. All morphological parts of Sea buckthorn contained these biologically active compounds useful in medicine, pharmacology, human nutrition and cosmetics. The highest amount of α-tocopherol was found in peels (1103 mg kg-1). The lowest content of α-tocopherol was found in leaves (659 mg kg-1). Delta-tocopherol was found in higher amount in peels 1757 mg kg-1. Seeds contained 95 mg kg-1 of delta-tocopherols. Gamma-tocopherol was found in seeds (459 mg kg-1), peels (188 mg kg-1) and in leaves (587 mg kg-1). β-tocopherol was present only in seeds (171 mg kg-1). Unsaturated fatty acids were dominant in all morphological parts of Sea buckthorn. The highest amounts of unsaturated fatty acids (92 rel. %) were determined in seeds. Dominant fatty acids of seeds were linoleic acid (37 %), α-linolenic acid (30 %) and vaccenic acid (20 %). Leaves were rich in α-linolenic acid (51 %). Dominant fatty acids of peels were oleic acid (16 %), palmitic acid (33 %) and palmitoleic acid (29 %).

Deep Eutectic Solvents as Medium for Pretreatment of Biomass

In the field of green chemistry is the study of new solvent systems the great challenge. Deep eutectic solvents (DESs) represent the principles of green chemistry. Currently are preferred these new types of chemicals suitable for the selective removal of extractives, lignin or polysaccharides from biomass. Biomass is selectively treated to the individual fractions, of which is possible with following purification to obtain products in higher yields and purity. In this work are describes various deep eutectic solvents, which can be used for pretreatment of biomass.

Extraction of value-added components from food industry based and agro-forest biowastes by deep eutectic solvents

The scientific community, experts in technology and marketing have been seeking cost-competitive and green solvents with good dissolving capacity for the valorisation of biomass and biowaste. Along with traditional solvents and techniques, deep eutectic solvents (DESs) and their bio-analogues, natural deep eutectic solvents (NADESs) are currently emerging as a new class of promising liquid media. In this review, a comprehensive summary of recent contribution of DESs to the processing and valorisation of various kinds of plant and animal based biomass and biowaste is provided. In the field of food industry based and agro-forest waste valorisation, through treatment of the waste, by-products, and natural materials by DESs, several types of compounds, such as flavonoids and other plant phenolics, phenolic acids, stilbenes, tannins, lignans, and lignin were obtained. Extraction of algae by DESs led to isolation mainly of proteins, carbohydrates, lipids and nucleic acids. Vegetable oils, spent oils, residues and by-products of their processing are a rich source of phenolic compounds such as phenolic acids and phenolic alcohols, secoiridoid derivatives (aglycone and ligstroside), lignans (pino and acetoxypinoresinol), flavones (luteolin and apigein), tocopherols and tocotrienols. Dietary fibre serves as a source of lignin, pectic substances, gums, resistant starch, inulin, as well as non-carbohydrate components, e.g., polyphenols, waxes, saponins, cutin, phytates, resistant proteins. Valorisation of wastes originated from animal processing by DESs means obtaining high-value chemicals including amino acids, proteins, bioactive peptides, collagen peptides, albumin etc. Through the valorisation of the mentioned waste types value-added products with potential applications in the pharmaceutical, food and cosmetic industries are produced. The paper gathered data on the used DESs, treated substances and obtained products, together with treatment conditions and the products yields. The evaluation of the state-of-the-art in the field of biowaste valorisation using DESs and NADESs led to conclusions and indication of future prospects and predicted development in this field.

Antibacterial and antifungal activity of phytosterols and methyl dehydroabietate of Norway spruce bark extracts

The current study focuses on the analysis of in vitro biological activity of extract from bark of Norway spruce (Picea Abies), which can find potential application in food and cosmetic industry and pharmacology. Milled bark was subjected to Soxhlet extraction and supercritical fluid extraction to obtain two ethanol extracts. These extracts were further used to obtain their pre-extracts to n-hexane. It was investigated whether beta-sitosterol exhibits bacteriostatic activity necessary to observe antimicrobial and antifungal activity of methyl dehydroabiatate. This synergic effect and bacteriostatic activity of beta-sitosterol have not been previously reported. The greatest inhibition zone of n-hexane pre-extracts was confirmed in bacterium Pseudomonas aeruginosa (0,9 - 1,5 cm) and yeast Alternaria alternata (0,7 - 1,6 cm). It is novel, the antioxidant, antimicrobial and antifungal activity of spruce bark extracts assessed in terms of food and cosmetic fortification.

Stability of the Lignins and their Potential in Production of Bioplastics

Chemical industry includes a biobased materials (sector) in which some oil-derived plastics and chemicals are replaced by new or alternative products derived, at least partially, from biomass. One of these biobased products is here today - lignin, but to fulfil its societal potential it is necessary to improve their market share while making valuable contributions to climate change mitigation. Great source of lignin is by-product (waste) from paper making industry. Lignin isolated from black liquors has a big potential to be used as a component for new bioplastic compositions. Lignosulphonates and lignin are polydispersions of different large fragments from natural tree dimensional lignin present in the wood. The kraft lignin consists of large amount of sulphur which is bonded in functional groups. Content of lignin in black liquor is in range 30 - 45% what brings potential of its isolation. In this paper we characterised and precipitated lignin with two inorganic and one organic acid (nitric, hydrochloric and tartaric acid).