Case Study of Bacterial Decontamination of an Aromatic and Medicinal Plant: Decontamination of Thymus Satureioides by Gamma Radiation at Low Doses and Impact on Hygienic and Physicochemical Quality

The purpose of our study is to verify the usefulness of gamma irradiation treatment at low doses (0.25, 0.5 and 1 kGy) combined to vacuum packaging on commercial teas of Thymus satureioides deliberately contaminated with Escherichia coli. The efficiency and the influence of the process on contamination level and the shelf life of the product were studied. The phenolic composition and concentration were identified in the unirradiated and irradiated thyme. The total phenolic content (TPC) was assayed by the Folin-Ciocalteu method, the individual phenolic compounds were determined by high liquid chromatography (HPLC) and the essential oil was characterized by gas chromatography coupled to mass spectroscopy (GC-MS). The plant was observed by scanning electrons microscopy and the radioactivity effect was analyzed. The results show a complete decontamination of thyme depending to the dose and the storage time. Privileged hygienic quality was found in the irradiated thyme with the highest concentrations of polyphenols. The process showed the conservation of thyme quality without any alteration of its characteristics or radioactivity effect

Green chemistry for treatment of liquid discharges from a dyeing industry: bio coagulation and flocculation

Textile industry is among the highly polluting industries in water effluent. It consumes large quantities of water and chemicals compounds. These releases can have varying characteristics regarding their volumes and pollutants concentrations. Therefore, adverse effects can be observed as consequence on environment and biodiversity. According to the environmental protection regulations in Morocco, the treatment of this water before discharge is compulsorily to avoid pollution of surface and ground water. The aim of our study is the treatment of these effluents by a physicochemical process using coagulation / flocculation.  Two coagulants of different type and purity are used. The first one “aluminum sulfate” is a pure coagulants used on industrial scale. The second “alum stone” is excerpt from the nature of Moroccan desert. Beside, two flocculants are compared, a natural extract from cactus and a polymer synthesized (polyacrylamide). The comparative study between a pure coagulant and a biocoagulant, with the two flocculants, showed a very good absorbency rate of reduction (ABS), turbidity (T), chemical oxygen demand (DCO), dry matter (DM) and chemical elements (sodium, lithium, nitrogen, phosphorus, boron, and silicon). By the jar test treatment process, the optimal dose of coagulants and flocculants to use in the neutral pH treatment was identified. The optimal dose used gives 85% of abatement efficiency absorbance, 90 % for turbidity and 80% for the chemical oxygen demand. Moreover, the dry matter content is over 25% and over 90% for some chemical elements

Comparative sorption isotherms of conserved Thymus satureioides

Thymus satureioides is an endemic plant of Morocco used for its virtues in traditional medicine. This natural plant in comparison with the preserved one by gamma irradiation and thermal-biochemical treatment using a solar dryer, were investigated at various temperatures and water activity using a saturated salt solution method. Thus, it was necessary to study the effect of preservation processes on the storage conditions. The sorption curves of thyme decreased with the increase in temperature at constant relative humidity and the hysteresis effects were observed. The experimental data of sorption were described by six equations. The Enderby’s model was found to be the most suitable for describing the sorption curves for untreated and irradiated thyme. In opposition, treated thyme was approached by Peleg’s model. Moreover, the optimum water activity of storage was investigated.

Valorisation of cellulosic waste basic cactus to prepare activated carbon

The cellulosic waste is the most abundant material in the earth. It is considered as a renewable polymer of wood cell walls and plant cells. It is used in different fields mainly as sustainable potential precursors and it is useful for the preparing activated carbon.The purpose of this study is the valorisation and production of activated carbon from cellulose waste, old cladodes of Ficus indica cactus optunia, and the residue of prickly pear seeds after oil extraction. Preparation and characterization of activated carbon (AC) from the two wastes by chemical treatment, phosphoric acid H3PO4 at a temperature of 450 °C has shown a very good adsorption of methylene blue and iodine. This treatment illustrated an important surface area of 820 m2/g for waste seeds and more than 470 m2/g for waste cactus cladodes. Analysis by infrared and pH point of zero charge showed a basic character for both carbons active developed. Keywords: Cactus, Activated carbon, Fig tree barbarism, Chemical activatio