Thiosulfate effluents are generated in the photography and radiography industrial sectors, and in a plant in which thiosulfates are used to recover the gold and silver contained in ores. Similar effluents also containing thiosulfate are those generated from the petrochemical, pharmaceutical and pigment sectors. In the future, the amounts of these effluents may increase, particularly if the cyanides used in the extraction of gold and silver from ores are substituted by thiosulfates, or if the same happens to electronic scrap or in metallic coating processes. This paper reports a study of the oxidation of thiosulfate, with oxygen using copper (II) as a catalyst, at a pH between 4 and 5. The basic idea is to avoid the formation of tetrathionate and polythionate, transforming the thiosulfate into sulfate. The nature of the reaction and a kinetic study of thiosulfate transformation, by reaction with oxygen and Cu2+ at a ppm level, are determined and reported. The best conditions were obtained at 60 °C, pH 5, with an initial concentration of copper of 53 ppm and an oxygen pressure of 1 atm. Under these conditions, the thiosulfate concentration was reduced from 1 g·L−1 to less than 20 ppm in less than three hours.

In scientific and technical degrees, the opinion of the final employers on the given subjects is really important. For this reason, the Quality Committee (CQ) of the Faculty of Chemistry of the University of Barcelona prepared a survey for chemical, engineering and pharmaceutical companies asking about the academic training required by the companies. The survey consists of nine sections including items related to laboratory operations, chemical processes, calculation methods, management systems (quality, environment and safety) or general management information. In addition, at the end of each section, a question inquires the companies about the competences shown by students in the items of the section. The results were compared with those of a similar survey carried out in 2007. The scores obtained were between 2 and 3 for all the items (score: 1, not important; 2, less important; 3, important; 4, very important) and show that companies accept the training given to our students and the competences achieved by them. However, according to their opinion, it is possible to improve this training, especially in the subjects related to management (time, information, environment, quality, safety, etc.). Therefore, surveys are a good tool for the evaluation of the training achieved in our degrees and, consequently, for -80-Journal of Technology and Science Education -https://doi.org/10.3926/jotse.232 improving our teaching task, according to the Quality Management System implemented in the Faculty of Chemistry.