Inorganic and organic constituents present in textile effluents have a noticeable effect on the performance of Fenton processes. However, studies have been focused on simple wastewater matrices that do not offer enough information to stakeholders to evaluate their real potential in large-scale facilities. Chemical auxiliaries, commonly present in textile wastewaters (NaCl = 30 g/L, NaCO = 5 g/L, and CHCOONa = 1 g/L), affect both the economic and environmental performance of the process because they increase the treatment time (from 0.5 to 24 h) and the consumption of HSO (657%) and NaOH (148%) during conditioning steps. The life cycle assessment (LCA) performed with the IPCC-2013 method revealed that dyeing auxiliaries increase from 1.06 to 3.73 (252%) the emissions of carbon dioxide equivalent (CO-Eqv/m). Electricity consumption can be considered an environmental hotspot because it represents 60% of the carbon footprint of the Fenton process. Also, the presence of auxiliaries is critical for the process because it results in the increase of the relative impact (between 50 and 80%) in all environmental categories considered by the ReCiPe-2008 method. Chemical auxiliaries increased the costs of the treatment process in 178% (US$2.22/m) due to the higher energy consumption and the additional reagent requirements. It is worthwhile mentioning that the technical simplicity of the Fenton process and its low economic and environmental costs turn this process into an attractive alternative for the treatment of textile effluents in emerging economies.

This study evaluates the technical, economical, and environmental impact of sodium persulfate (NaSO) as an enhancing agent in a photo-Fenton process within a solar-pond type reactor (SPR). Photo-Fenton (PF) and photo-Fenton intensified with the addition of persulfate (PFPS) processes decolorize 97% the azo dye direct blue 71 (DB71) and allow producing a highly biodegradable effluent. Intensification with persulfate allowed reducing treatment time in 33% (from 120 to 80 min) and the consumption of chemical auxiliaries needed for pH adjustment. Energy, reagents, and chemical auxiliaries are still and environmental hotspot for PF and PFPS; however, it is worth mentioning that their environmental footprint is lower than that observed for compound parabolic concentrator (CPC)-type reactors. A life-cycle assessment (LCA) confirms that HO, NaOH, and energy consumption are the variables with the highest impact from an environmental standpoint. The use of persulfate reduced the relative impact in 1.2 to 12% in 12 of the 18 environmental categories studied using the ReCiPe method. The PFPS process emits 1.23 kg CO (CO-Eqv/m treated water). On the other hand, the PF process emits 1.28 kg CO (CO-Eqv/m treated water). Process intensification, chemometric techniques, and the use of SPRs minimize the impact of some barriers (reagent and energy consumption, technical complexity of reactors, pressure drops, dirt on the reflecting surfaces, fragility of reactor materials), limiting the application of advanced oxidation systems at an industrial level, and decrease treatment cost as well as potential environmental impacts associated with energy and reagents consumption. Treatment costs for PF processes (US$0.78/m) and PFPS processes (US$0.63/m) were 20 times lower than those reported for photo-Fenton processes in CPC-type reactors.

Semiconductor materials play a major role in the use of solar energy. ZnO and TiO2-based nanomaterials have been broadly used in photocatalytic applications, such as water splitting and environmental remediation. In order to determine the thermodynamic feasibility in a specific application, it’s important to determine the electronic band structure of these materials. This determination of the energetics in the semiconductor can be conducted from different approaches, usually being determined by the bandgap and conduction band edge first. The bandgap determination is made through well-defined and standardized processes, unlike the conduction band, where the discrepancy is found between the values reported by different authors under the same conditions. In this article a comparison is made between the Mott-Schottky, photocurrent onset potential, and open-circuit potential methods, as techniques of determining the flat band potential, taking as case studies the two semiconductor materials mentioned above. This comparison is followed by a discussion of the difficulties that may arise during experimentation and the possible difference between the values reported by each method.

<p><strong>Introducción</strong>: el sistema nervioso central es uno de los órganos afectados, de manera directa e indirecta, por el VIH; adicionalmente, los trastornos psiquiátricos son más frecuentes en esta población. <strong>Objetivo:</strong> comprender la patogénesis, las manifestaciones clínicas y el manejo de las enfermedades neuropsiquiátricas en la población con VIH. <strong>Métodos</strong>: se realizó una búsqueda en las bases de datos Medline, Embase, SciELO, LILACS y PsychInfo utilizando término libres y MeSH. <strong>Resultados</strong>: los trastornos neuropsiquiátricos generan un impacto negativo en el tratamiento y seguimiento de los pacientes con VIH, lo cual disminuye su adherencia al tratamiento y aumenta las dificultades en su manejo integral. Llamativamente, existe una falta de estudios latinoamericanos en esta área. </p>