Advanced oxidation processes (AOPs) have known increased application to treat wastewaters containing recalcitrant compounds that are hardly degraded by conventional technologies. AOPs are characterized by the formation of strong oxidants such as hydroxyl radicals, superoxide anions, hydroperoxyl radicals and singlet oxygen, which react with the contaminant, contributing to its degradation. This paper provides an overview of the determination methods of reactive oxygen species, ROS, in the application of AOPs; the methods developed in the available literature for the detection and quantification of ROS are reviewed as a first step in the assessment and detailed description of the mechanisms involved in the oxidation reactions, focusing on the critical analysis of the main strengths and weaknesses presented by the probe molecules employed in the evaluated studies.

This work contributes to the development of electro-oxidation on commercial boron doped diamond (BDD) anodes as an efficient and versatile environmental technology to deal with remediation of tetrahydrofuran (THF) polluted industrial wastewaters.Working with an undivided flow-by electrochemical cell, a systematic experimental study has been carried out to analyze the influence of the following operation variables: i) initial THF concentrations in the range 500-1100 mg/L ii) supporting electrolyte, Na 2 SO 4 and NaCl and iii) current density in the range 300-1200 A/m 2 . The performance of the oxidation process was assessed through the change in the concentration of THF, chemical oxygen demand (COD), and total organic carbon (TOC) being the current density the variable that exerted the most positive kinetic influence; more precisely the reduction of COD after 60 minutes changed from 40 % at j app = 300 A/m 2 to 95.5 % at j app =1200 A/m 2 , whereas the reductions of TOC were typically higher than 95 % for a value of the specific charge of Q=10 A/hL. Besides, THF oxidation products have been analyzed, and the reactions' pathway are proposed.Finally, the formation of chloride by-products, such as perchlorate was assessed observing that it was hindered at low current densities. In the view of these findings, it is concluded that THF oxidation on BDD anodes should be better performed at low current densities, i.e. 300 A/m 2 for the type of wastewaters analyzed in the present work, to reach a compromise between effective degradation and the formation of undesirable chlorinated by-products.

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Hydrogen recovery is at the center of the energy transition guidelines promoted by governments, owing to its applicability as an energy resource, but calls for energetically nonintensive recovery methods. The employment of polymeric membranes in selective gas separations has arisen as a potential alternative, as its established commercial availability demonstrates. However, enhanced features need to be developed to achieve adequate mechanical properties and the membrane performance that allows the obtention of hydrogen with the required industrial purity. Matrimid®, as a polyimide, is an attractive material providing relatively good performance to selectively recover hydrogen. As a consequence, this review aims to study and summarize the main results, mechanisms involved and advances in the use of Matrimid® as a selective material for hydrogen separation to date, delving into membrane fabrication procedures that increase the effectiveness of hydrogen recovery, i.e., the addition of fillers (within which ZIFs have acquired extraordinary importance), chemical crosslinking or polymeric blending, among others.