Special Conference Collection Issues

Many natural dyes, for example carminic acid, are soluble in water. We present a simple strategy to naturalize synthetic azadyes through their linkage with lactose to induce their water solubility. The dyeing process of textile fibres then becomes possible in water without additives such as surfactants and mordants, which result in products that are difficult to eliminate. Glyco-azadyes (GADs) we are presenting here are obtained through a diether linker to bond the azadye and the sugar. Tinctorial tests were carried out with fabrics containing wool, polyester, cotton, nylon, and acetate. GADs were found to be multipurpose and capable of dyeing many fabrics efficiently under mild conditions.

The composition and properties of the products of fast pyrolysis of hardwood, obtained in a two-chamber (drying and pyrolytic) ablation type reactor in the temperature range 450-600ºС, were investigated. It has been found that, upon the additional drying of wood at 200ºС and subsequent pyrolysis, the quality of bio-oil is improved owing to the decrease in the amount of water and acids. It has been shown that the increase of the drying temperature to 240ºС decreases the yield of the main product. Optimum parameters of the drying conditions and the temperature of the pyrolysis of wood, at which the bio-oil yield exceeds 60% and its calorific value makes up 17-20 МJ/kg, have been determined.

Oxidation of TMP fibers was compared at 298 K with molecular oxygen, in the presence of either [Co(salen)] in methanol or [Co(sulphosalen)] in water. Electron paramagnetic resonance (EPR) spectroscopy made it possible to reveal and quantify the formation of phenoxy cobalt radicals in the former case and of phenoxy radicals in the latter. These radicals reached the same concentration after 60 min from the onset of reaction. Fiber integrity was more preserved after oxidation in water than in methanol, as assessed by heteronuclear single quantum coherence - nuclear magnetic resonance (2D-HSQC-NMR) spectroscopy, nuclear magnetic resonance spectroscopy of carbon (13C-NMR), and Gel Permeation Chromatography (GPC). These results suggest that efficient radical formation on fibers can be achieved also with water-soluble catalysts. Thus, it is proposed that treatment with molecular oxygen in the presence of [Co(sulphosalen)] in water represents a promising way to approach an environmentally sustainable radicalization of fibers, without heavy modification of the lignin structure.

Butyl and hexyl amides of pectate with various amidation degrees were prepared from citrus pectin by means of alkylamidation of methyl-esterified pectins, followed by the total alkaline pectin methyl esters hydrolysis. These water soluble derivatives were characterized chem-ically as well as by elementary analysis and FT-IR spectroscopy. All prepared pectate amides exhibited the excellent emulsifying efficiency, and pectate hexyl amide also the ability to form stable foam. As the results of the study on the effect of pectin with DE 66% on the function of small intestine in pectin fed rats, the increase of specific activity of alkaline phosphatase, maltase, and aminopeptidase and the decrease of food utilization was demonstrated. The pectin derivatives might serve as emulsifiers and foaming additives in food production and other areas as well as nutraceuticals for obesity treatment.

A humic acid-like substance (cHAL2) isolated from urban green wastes before composting was compared to a humic acid-like substance (cHAL) isolated from a mix of urban organic humid waste fraction and green residues composted for 15 days. cHAL2 was found to contain more aliphatic and O-alkyl C atoms relative to aromatic, phenol, and carboxyl C atoms, and to yield higher critical micellar concentration (cmc = 0.97 g L-1) and surface tension at the cmc (gcmc = 37.8 mN/m) in water than cHAL (cmc = 0.40 g L-1; gcmc = 36.1 mN/m). The results point out that biomass wastes may be an interesting source of biosurfactants with diversified properties that depend on the nature of waste and on its process of treatment.

Agro-industrial residues have become an important source for the production of chemical compounds using biological pathways, contributing to preservation of the environment and making the overall process economically supportable. Vanillin is a very important aromatic compound for the food, beverage, and pharmaceutical industries. The aim of the present study was to evaluate the vanillin production by solid-state fermentation on green coconut residue using the basidiomycete Phanerochaete chrysosporium. Solid-state fermentation was carried on a support of green coconut husk treated in two different ways: sun-dried and mechanical-pressed. A Plackett-Burman experimental design was used to screen the compounds of liquid medium culture of the vanillin production. Nineteen variables were studied to optimize the culture conditions, and eleven of them were significant. The screening improved the production of vanillin from 44.4 mg/g of support to 52.5 mg/g of support in 24 hours of fermentation. Sun-dried coconut husk was found to be superior to mechanical-pressed coconut husk for production of vanillin. HPLC was used for the quantification of vanillin aroma.

Industrially made kraft pulps obtained by a modified cooking process may contain 60-75 mmol/kg of hexenuronic acids (HexAs), which represents 6-7.5 kappa units. HexAs do not react with oxygen and very little of it is actually removed across the oxygen delignification stage, causing low efficiencies in the range of 25-35%. In this study, an economical evaluation of the ECF bleaching processes was carried out, having none and double-stage oxygen delignification, when applied to eucalyptus pulps of kappa varying in the range of 14-21. The bleaching processes included sequences containing specific stages for HexAs removal (Z, A/D and DHT). Results indicated that the use of oxygen delignification was not economically attractive, particularly for HexA-rich low-kappa pulps, but processes without oxygen delignification present significant environmental challenges.

Scale formation in the digester during kraft pulping represents a great problem in pulp mills. Scaling reduces pulping control and efficiency, increasing energy costs and leading to cleaning breakdowns, with subsequent losses in productivity. The kraft process promotes CaCO3 scaling due to high calcium ion and carbonate concentrations, as well as high alkalinity and temperature levels, which increase the speed with which liquors reach a state of supersaturation. This work examines the action of diethylene triamine penta(methylene phosphonic acid) (DTPMPA), either alone or combined with commercial anti-scaling agents, as an inhibitor of calcium carbonate precipitation in the kraft pulping of Pinus taeda. The theoretical amount of calcium deposited in the digester was obtained by mass balance. Soluble calcium was stable throughout cooking when using the phosphonates alone or combined with anti-scaling agents. When adding only DTPMPA, calcium stays in the pulp, rather than forming deposits.

Medium or high charge density cationic polyelectrolytes are frequently used for water treatment. In the papermaking wet-end they are used as retention agents or as flocculating aids. Negative polyelectrolytes that enter the papermaking system increase the demand for cationic polyelectrolytes. Polyelectrolyte concentration can be determined by the colloidal titration method, using either of two options for detecting the endpoint: i) visual observation or spectrophotometric determination of the colour change of an indicator, or ii) streaming current measurement. This work discusses the best conditions for the application of the titration using spectrophotometric measurement for the end point detection. Poly-diallyldimethylammonium chloride was used as the cationic polyelectrolyte, potassium polyvinyl sulphate as the negative polyelectrolyte, and o-toluidine blue as the positive indicator dye. The polyelectrolyte concentration range, interference from the metal ions affecting the indicator color change, the optimal indicator concentration to avoid precipitation problems, and the effect of adding a surfactant to the indicator solution were also considered. Titration curves were analyzed and optimized. Under these conditions the technique provided results with acceptable precision.