Physico-Chemical and Mineralogical Characterizations of Tchiky Clays (Thies, Senegal) for Pharmaceutical Uses

Our study focused on the valuation of Tchiky clays. This work aims to evaluate its properties to explore possible uses in pharmacy. Physico-chemical and mineralogical characterizations were carried out, as well as pharmacopoeial tests and an evaluation of the antioxidant activity. Thus, chemical analysis by X-ray fluorescence spectrometry gave silicon (55.65%), iron (15.73%), aluminum (13.53%), potassium (6.05%), titanium (3.98%), magnesium (2.10%), and calcium (0.82%). X-ray diffraction showed the presence of kaolinite, quartz and illite. This study also revealed that the sample studied was essentially a plastic clay of hard consistency, with average flowability. The evaluation of the antioxidant activity gave a percentage inhibition of 62.97% for a concentration of 7.5 g/l with an IC50 of 5.5 g/l. These results should allow use as an excipient in pharmacy, particularly in liquid, semi-liquid and pasty formulations.

Chemotaxonomic Study of the Covid-Organics of Madagascar Based on the Chemical Composition of Their Essential Oils

The aim of this study was to investigate the chemical composition of the essential oils of “Covid-Organics” of Madagascar (62% Artemisia annua and two other undisclosed medicinal plants) used as curative and preventive treatments of Covid-19, to identify its constituent species. The essential oils isolated by hydro-distillation from two samples (curative and preventive) were analyzed by GC-FID and GC-MS. These essential oils (curative and preventive) were mainly dominated by camphor (17.9% and 11.9%, respectively), spathulenol (4.8% and 11.8%, respectively), α-acorenol (4.3% and 3.7%, respectively), (E)-β-caryophyllene (3.4% and 4.2%, respectively), 1,8-cineole (3.1% and 3.6%, respectively), hexadecanoïc acid (3.8% and 3.2%, respectively) and caryophyllene oxide (3.4% and 2.4%, respectively). From the chemical composition, two species were identified, A. annua characterised by camphor and Cinnamomumcamphora (Ravintsara) characterised by 1,8-cineole and sabinene. However, we were unable to identify the third species.

Review of Research on Li-Ion Batteries Waste Management

Li-ion batteries (Libs) are a mature technology widely used for energy storage in various electronic devices. Nowadays, this technology has become a leading candidate for the portable electronics market and for electric vehicles due to its good performance. As a result, the demand for Libs containing critical metals, rare earth elements and precious metals is increasing day by day with the accelerated upgrades of consumer electronics, which promotes the supply risk of many mining resources. In addition, the problems associated with the production of end-of-life Lib are increasing on a global scale. Used Libs are e-waste containing significant levels of critical raw materials (such as Co, Li, Mn and Ni) along with harmful substances. Without proper management of Lib waste, these precious metals and toxic substances may end up in nature and cause environmental and public health problems. In order to preserve nature, ensure sustainable resource management and stimulate the circular economy, it has become crucial to properly manage and recycle end-of-life Li-ion batteries. By the way, conventional methods focusing on pyrometallurgical treatments combined with hydrometallurgical treatment are widely studied to recover design metals from Libs waste. It is in this context that we have conducted this bibliographic synthesis, focusing on the efficiency of the solvents employed and their competitiveness for a more environmentally friendly economic management. In this manuscript, recent leaching, solvent extraction, electrodeposition and precipitation strategies to recover precious metals from end-of-life Li-ion battery designs are reviewed and the evolution of these processes is discussed.

Chemical Variability and Antibacterial Activity of Eucalyptus camaldulensis Essential Oils from Senegal

1,8-cineole, also known as eucalyptol, is the main constituent and the most important of the leaf oils of many species of the genus Eucalyptus. In present study, the essential oils isolated by hydrodistillation from the leaves of Eucalyptus camaldulensis from six different locations were analyzed by GC-FID and GC-MS. Essential oil yields ranged from 0.33% to 4.35%. In total, 34 constituents were identified, accounting for 94.0% to 99.8% of the total compositions. 1,8-cineole (46.4% - 84.4%) was the main constituent of all the essential oil samples, except for one sample collected in the Fatick region, which had p-cymene (46.4%) and 1,8-cineole (26.0%) as major compounds. The essential oil showed excellent activity against S. aureus, E. coli and E. faecalis (IZ = 25.3 ± 1.2 mm;18.7 ± 0.6 mm;17.8 ± 0.3 mm, respectively) and moderate activity against P. aeruginosa (IZ = 10.8 ± 0.8 mm). They may have potential applications in food and pharmaceutical products.