Chemical composition and in vitro antimicrobial and antioxidant activities of Citrus aurantium l. flowers essential oil (Neroli oil).

Neroli essential oil is extracted from the fragrant blossoms of the bitter orange tree. It is one of the most widely used floral oils in perfumery. In this study chemical composition and in vitro antimicrobial and antioxidant activities of neroli oil are investigated. The essential oil of fresh Citrus aurantium L. Flowers (Neroli oil) cultivated in North East of Tunisia (Nabeul) were analyzed by GC-FID and GC-MS. About 33 compounds were identified, representing 99% of the total oil. Limonene (27.5%) was the main component followed by (E)-nerolidol (17.5%), alpha-terpineol (14%), alpha-terpinyl acetate (11.7%) and (E, E)-farnesol (8%). Antimicrobial activity was determined by Agar-well-diffusion method against 6 bacteria (3 Gram-positive and 3 Gram-negative), 2 yeasts and 3 fungi. Neroli oil exhibited a marked antibacterial activity especially against Pseudomonas aeruginosa. Moreover, Neroli oil exhibited a very strong antifungal activity compared with the standard antibiotic (Nystatin) as evidenced by their inhibition zones. Antioxidant activity determined by ABTS assay showed IC50 values of 672 mg L(-1). Finally, this study may be considered as the first report on the biological properties of this essential oil. The results of this study have provided a starting point for the investigations to exploit new natural substances present in the essential oil of C. aurantium L. flowers.

Use of a transient model to simulate fluidized bed incineration of sewage sludge.

This paper presents a mathematical model dedicated to fluidized bed incineration of sludge. The main assumptions as well as the principal equations of the model are presented. Basically, this model relies on instantaneous pyrolysis of sludge and on a five zones description of the hydrodynamics into the incinerator. Its originality is essentially due to the introduction of a two-dimensional buffer zone between the bubble and the emulsion phase. The chemistry of the gaseous system is described by chemical equilibrium. Results of a start up procedure have been presented in order to illustrate the ability of the model to describe transient behavior. To validate the model from an energetic point of view, different types of sludge (primary, activated and digested) have been computed and compared to industrial data and to results obtained from a simple calculation. The lower dryness limit corresponds to self incineration of the sludge. The higher one corresponds to maximal thermal level that should not be exceeded within the furnace.