BIOCIDES IN METALWORKING FLUIDS Metalworking fluids and coolants are used in various metalworking
Wood ash is a complex mixture of inorganic and organic compounds. It is heterogeneous in composition, which can vary considerably. Ash is mainly disposed of in landfills, which poses a risk for air, soil and groundwater contamination by trace elements. In order for wood biomass ash to be used as a secondary raw material, it is necessary to perform leaching tests, to determine which microelements it contains, and which of them could be released into the environment during the ash disposal. Sequential extraction showed that in the exchangeable and carbonate fraction, the most volatile metals As, Cd, Zn and Pb are released the most from the ash of deciduous trees, while the leaching of ash from coniferous trees is significantly lower. The evaluation of risk assessment code (RAC) for the tested biomass ash samples, indicates that Pb is a high-risk leaching element due to its condensation on the ash particles. By performing TCLP (Toxicity Characteristic Leaching Procedure) and SPLP (Synthetic Precipitation Leaching Procedure) tests, it was established that the released concentrations of tested metals are below the maximum allowable concentration, given by the Regulation. The leaching tests of composites, prepared from wood ash in combination with cement, indicate that the leaching of ash is reduced to a minimum, and that all heavy metals are bound in a cement matrix, which indicates the possibility of using wood ash for construction purposes.
In this paper, the possibilities and effects of using domestic industrially produced zeolite for bleaching crudesunflower oil, compared to imported commercial bleaching earth, were examined.The parameters of the bleaching process in laboratory conditionswere: temperature 95°C, contact time 30 min,and mass fractionsof bleaching agent in oil: 0.2, 1, 2 and 3%.The following methods were used to characterize the bleachingagents: XRD, FTIR, BET and SEM/EDS.The bleaching efficiency parameters were determined by laboratory methods prescribed by the relevant ordinance on edible vegetable oils, and included: soap content, peroxide valueand fatty acid composition.The results of the research showed that the effects of bleaching sunflower oil with synthetic zeolite are similar to the effects of bleaching with imported commercial bleaching earth, with the former showing a slightly higher effectiveness in reducing the peroxide value. KEYWORDS:sunflower oil; oil bleaching; synthetic zeolite; bleaching earth
Different wastes in large quantities are the outcome or the by-product of processes in the tanning industry. The largest part of solid wastes is collagen based and obtained in the reprocessing steps of tanned and non-tanned products. The quality collagen substance obtained from wastes of the leather industry used as a supporting material in many reprocessing industries. Hydrolysis is the basic step of collagen processing, namely the shortening of its polypeptide chain. The main goal of this investigation was to examine the influence of the following parameters on the extent of collagen hydrolysis: type and quantity of reagent used for hydrolysis temperature of hydrolysis, pH, duration of hydrolysis as well as the dimensions of the "shavings" samples. The change of molar mass during hydrolysis was monitored by UV-spectroscopy. Special attention was paid to the dechroming process of the collagen hydrolysate
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