Authors:V. Jedináková, P. Vaňura, J. Žilková, V. Bílek and F. Touati
The synergistic solvent extraction of Eu(III) and some other rare earth elements from nitrate solutions (HNO3+LiNO3) by a mixture of (TBP+D2EHPA) in n-hexane and cyclohexane has been investigated at 22 °C. Antagonism found in europium extraction from 0.1M HNO3 transforms into a synergistic effect. The synergistic effects existing for all investigated metals in extraction from 0.1M HNO3+3M LiNO3 were caused by formation of mixed complexes of the type Ln(D2EHPA)2nH2n–3+1(NO3)1TBPm, where 1=1 or 2. The selectivity of the extraction in a synergistic system is lower for the La–Yb pair than in the case of D2EHPA extraction under the same conditions. On the other hand, the application of the synergistic mixture is more suitable for Eu–Ho separation. Thus the synergistic effect can be used for the separation or refining of some lanthanides.
Authors:N. El Hazzat, M. Artib, J. Touati, M. Chliyeh, K. Selmaoui, A. Ouazzani Touhami, R. Benkirane and A. Douira
The endomycorrhizal fungi diversity in the rhizosphere of chickpea (Cicer arietinum L.) and the evaluation of root mycorrhizal level were studied in six regions of Morocco: Tahla, Sefrou, Souk Larbae, Souk Tlat, Ouazzane and Jarf Melha. All chickpea roots are carrying endomycorrhizal structures. Root mycorrhizal parameters varied from one site to another, and the highest frequency and intensity of mycorrhization was recorded in the roots of chickpea plants at the two sites Tahla and Jarf Melha respectively, 83%, 33% and 25.03%. In addition, the highest arbuscular content was also noted in the roots of plants growing in the site of Tahla (22.18%) while the lowest content was noted at the site of Sefrou (2.07%). However, the vesicles were not observed in all the sites.
The highest numbers of endomycorrhizal spores were recorded in the rhizosphere of plants collected in Jarf Melha and Tahla, respectively, 74 and 41 spores / 100 g soil. All spores found in the studied sites are represented by 22 morphotypes belonging to 7 genera: Glomus (13 species), Acaulospora (4 species), Gigaspora (one species), Radekera (one species), Entrophospora (one species), Pacispora (one species), Dentiscutata (one species).