This work focuses on the removal of perchloroethylene (PCE) from gaseous streams using absorbers connected with electrolyzers. Two types of absorption devices (jet absorber and absorption column) were compared. In addition, it has been evaluated the different by-products generated when a simultaneous electrolysis with diamond anodes is carried out. PCE was not mineralized, but it was transformed into phosgene that mainly derivates into carbon tetrachloride. Trichloroacetic acid was also formed, but in much lower amounts. Results showed a more efficient absorption of PCE in the packed column, which it is associated to the higher gas–liquid contact surface. Jet absorber seems to favor the production of carbon tetrachloride in gaseous phase, whereas the packed column promotes a higher concentration of trichloroacetic acid in liquid. It was also evaluated the scale up of the electrolytic stage of these electro-absorption devices by using a stack with five perforated electrode packages instead of a single cell. Clarification of the effect of the applied current density on the speciation attained after the electrolysis of the absorbent has been attempted. Experiments reveal similar results in terms of PCE removal and a reduced generation of gaseous intermediates at lower current densities.

The development of highly efficient, effective, and low-cost carbon-based catalysts for hydrogen production through water electrolysis represents a significant challenge in sustainable energy conversion. In this work, carbon materials derived from biomass waste, specifically a metal-polluted vegetal species () from a former mining location, were used. Biomass was subjected to hydrothermal carbonization, producing hydrochar. The influence of both thermal and chemical post-treatment was studied in relation to hydrogen production efficiency. The thermal treatment was conducted at 300, 500, and 1000 °C, while the chemical precursors used were KOH and H₃PO₄. Additionally, these waste-derived carbon materials were compared with carbon Vulcan XC-72, a common reference material in these processes originated from fossil sources. Several electrochemical techniques were employed to evaluate and identify the most suitable sample for the hydrogen evolution reaction (HER). Additionally, physicochemical characterization analyses were conducted to gain a comprehensive understanding of the morphology, composition, and surface structure of the biomass-derived carbon materials, as well as to establish correlations with their electrochemical behavior toward the HER. The sample that demonstrated the most favorable performance was the one chemically activated with KOH, which exhibited an outstanding Tafel slope (147 mV/dec) and a low overpotential at 10 mA/cm² (-550 mV vs RHE) surpassing even the commercial Vulcan XC-72 sample. Furthermore, the chronoamperometry test showed a very stable performance for this sample. These results demonstrate that plant biomass waste containing metals presents a viable alternative to carbon blacks, commonly used as electrocatalysts for hydrogen production, also providing an efficient and sustainable method to valorize these wastes.

We report the optical properties of BeCdSe/ZnCdMgSe single quantum well (QW) structures that consist of closely lattice matched ZnCdMgSe barrier layers and a strained BeCdSe QW layer (Δa/a=1.95%) grown on InP substrates. Emission from the red to the green regions of the visible spectrum was obtained from the structures with the QW thickness varying from 95 to 12 Å. Efficient QW emission, dominated by an exciton recombination behavior, was observed. From the Arrhenius plot of the integrated emission intensity as a function of temperature, an activation energy of 61 meV was obtained for a BeCdSe QW structure with a 48 Å thick QW layer. Parameters that describe the temperature dependence of the near band edge emission energy and the broadening of the excitonic emission were evaluated. Our results indicate that the BeCdSe-based QW structures are attractive for application as red light emitters.