A study of the solvent extraction process of Nd(III) from chloride solutions has been carried out using an ionic liquid (AliOle) prepared from Aliquat 336 (Methyl-tri(octyl/decyl)ammonium chloride) and Oleic Acid. The IL was chosen among other homemade ionic liquids and commercial extractants due to its high Nd(III) extraction ability and good phase separation. Increasing AliOle concentration improves the extraction of Nd(III) as expected. The pH of the aqueous phase strongly influences the extraction process. The appropriate equilibrium pH region has been established in the range 5–6.5. The effect of chloride concentration in the aqueous phase has been investigated. High concentrations of Cl- anion contribute to increasing the extraction yield by promoting neodymium(III) speciation in the aqueous phase. Two extraction models are proposed from experimental data. Chloride concentration in the aqueous phase determines the Nd(III) extraction mechanism. The models consider extraction of Nd3 + species when chloride concentration in the solution is low and NdCl2 + species when chloride concentration is high. Competitive extraction between HCl and the metal ions is also included in the models. They are able to reproduce feasibly the experimental Nd(III) extraction extension.Peer ReviewedPreprin

The renewal of engineering education requires an education that is more affected by students' circumstances which, if known, will help to guide them into the future. It is about channelling the students towards learning, taking into account the factors related to the acquisition of knowledge and how they can share this knowledge with the teachers. The specific aim of the current study was to examine what it means for students to transition from secondary school to university and introduce changes to reduce the failures it generates. The causes of low grades in the initial phase of university are analysed; subsequently some remedies are included. First, to gather information, student surveys and interview activities, led by an expert, were conducted. Subsequently, compensatory actions were organized by experts, for students and teachers. The surveys were designed to provide a self-assessment of new students regarding dedication and performance, and were given to those who failed the first important exam, capturing how they experienced university entrance and their first failure. They point to some personal causes of low performance: time organization deficiencies, impediments to devoting themselves to continuous study, and difficulties to adapt. Half believe their dedication merits better learnings and marks, and stress the difficulties associated with an insufficient level of secondary education and with the types of exams. This study, encompassed within the framework of the activities dedicated to educational improvement at UPC, highlights the need to implement guidance and accompaniment actions devoted to first-year students.