Volume 14, No. 4 (2013)

INFLUENCE OF THE SIZE OF METHYLENE SPACERS ON THE THERMAL BEHAVIOR OF SEVERAL ALIPHATIC-AROMATIC POLYESTERS

NATALIA HURDUC(1), GABRIELA LISA(2*), VIOLETA TOADER(3)

Polyesters have a wide range of technical applications and therefore their processing is of the utmost importance. Since polyesters are usually processed by melting, their thermal stability is an extremely important characteristic for the exact determination of the operational parameters. The thermal analysis was carried out using a MOM-Budapest derivatograph at the 10 C/min heating speed, aluminum oxide the reference material, and the air conditions were static. The study lead to conclusions on the thermal stability and degradation mechanism depending on the number of methylene groups in the spacer. Thermal stability is supported by the increase in the number of methylene groups in the spacer. The degradation mechanism is complex through successive reactions. The spacer size influences the nature of the micromolecules formed by spacer fragmenting and by the number of carbon atoms, respectively.

ANAEROBIC-AEROBIC TREATMENT OF TEXTILE WASTEWATER IN A SEQUENCING BATCH REACTOR

Ibtissam Kanbouchi(1), Salah Souabi(2*), Abdessadek Chtaini(1), Moulay Abdelaziz Aboulhassan(3)

In this work, the treatment of synthetic textile wastewater using sequential batch reactor (SBR) was studied. This in order to predict the effectiveness of biological treatment on wastewater containing dyes while minimizing the aeration cost. Laboratory tests were performed on synthetic wastewater containing filtered urban wastewater (source of bacteria) and dyes solutions. This promotes the biomass development in the mixture, capable of degrading organic matter properly. The results indicate that the increasing of anaerobic phase (16 hours) allows removal of 77 % and 80 % of COD and colour, respectively. The sludge age did not affect markedly dyes biodegradability. However, the biodegradability is strongly influenced by the dyes concentration. Indeed, for the lowest dyes contents, improved biodegradability was observed, while it decreases when the dyes concentration increases.

ANTIMICROBIAL ACTIVITY OF EXTRACTS OF WILD GARLIC (Allium ursinum) FROM ROMANIAN SPONTANEOUS FLORA

Mariana Lupoae(1), Dragomir Coprean(1), Rodica Dinică(2*), Paul Lupoae(3), Gabriela Gurau(4), Gabriela Bahrim(5*)

Wild Romanian spontaneous garlic’s (Allium ursinum) antimicrobial activity was tested in order to establish the inhibition potential of growth of some microorganisms. As test microorganisms were used pure cultures of fungs (Aspergillus glaucus, Geotrichum candidum, Mucor mucedo, Saccharomyces cerevisiae) and bacteria (Bacillus subtilis) isolated from food microbiota. There were also, used microbial strains isolated from different pathological products: wound secretions (Staphylococcus aureus), throat swab (Streptococcus pyogenes), urine (Escherichia coli) and oral mucosa (Candida albicans). The antimicrobial potential of used extracts is highlighted depending on the type of the vegetal tissue (leaves, roots, bulbs) and the nature of the solvent used for extraction. Extracts used in these experiments are recommended to use in food industry to preserve the stability and to improve the organoleptic quality of products.

EFFECTS OF ULTRASOUND ON THE MORPHOLOGY, PARTICLE SIZE, CRYSTALLINITY, AND CRYSTALLITE SIZE OF CELLULOSE

Sumari Sumari(*), Achmad Roesyadi, Sumarno Sumarno

The aim of this study is to optimize ultrasound treatment to produce fragment of cellulose that is low in particles size, crystallite size, and crystallinity. Slurry of 1 % (w/v) the cellulose was sonicated at different time periods and temperatures. An ultrasonic reactor was operated at 300 Watts and 28 kHz to cut down the polymer into smaller particles. We proved that ultrasound damages and fragments the cellulose particles into shorter fibers. The fiber lengths were reduced from in the range of 80-120 µm to 30-50 µm due to an hour ultrasonication and became 20-30 µm after 5 hours. It was also found some signs of erosion on the surface and stringy. The acoustic cavitation also generated a decrease in particle size, crystallinity, and crystallite size of the cellulose along with increasing sonication time but it did not change d-spacing. However, the highest reduction of particle size, crystallite size, and crystallinity of the cellulose occurred within the first hour of ultrasonication, after which the efficiency was decreased. The particle diameter, crystallite size, and crystallinity were decreased from 19.88 µm to 15.96 µm, 5.81 Å to 2.98 Å, and 77.7% to 73.9% respectively due to an hour ultrasound treatment at 40 °C. The treatment that was conducted at 40 °C or 60 °C did not give a different effect significantly. Cellulose with a smaller particle and crystallite size as well as a more amorphous shape is preferred for further study.

COMPARATIVE STUDY ON THE CONSERVATION OF NUTRITIONAL ELEMENTS OF PEAS DURING STORAGE AND FOOD PROCESSING II. SENSORY ANALYSIS

Camelia Vizireanu(*), Felicia Dima, Maria Garnai

The Romanian market has been flooded with a wide range of frozen products or products preserved by sterilization. The quality of these products is reduced or altered by the storage modules, suppliers or customers, product type, and last but not least, by the quality of raw materials subjected to conservation. This study followed the evolution of the nutritional characteristics of three varieties of peas grown in the Galati region subjected to freezing or sterilization, and their behavior during food processing.

SYNTHESIS AND INFRARED STUDY OF SOME NEW IODATO ADDUCTS AND DERIVATIVES

Hassan Allouch (1), Libasse Diop(1*)

Three iodato adducts and one derivative have been synthesized and studied by infrared data. The suggested structures are discrete, the iodate behaving as a mono- or bidentate ligand, or an infinite chain with bridging iodate, the environment around the tin centre being trigonal bipyramidal, tetrahedral or octahedral.

SUBBORIC ACID ADDUCTS R4NOH*2B2(OH)4 (R= Me, Et): SYNTHESIS AND INFRARED CHARACTERIZATION

Aminata Diassé Sarr, Libasse Diop(*)

On allowing Me4NOH as a methanolic solution or Et4NOH as an ethanolic solution to react with BO3H3 in ethanol, R4NOH∙2B2(OH)4 (R = Me, Et) are obtained and characterized by infrared. The subboric acid B2(OH)4 has been obtained in situ. An infinite chain structure has been suggested on the basis of infrared data. When OH.....O hydrogen bonds are considered, supramolecular architectures are obtained.