Electrocoagulation (EC) has long been considered a phase separation process, well suited for industrial wastewater treatment since it causes a quick, drastic decay of organic matter content. This research demonstrates that EC also behaves, at least for some molecules like the industrial preservative bronopol, as an effective transformation technology able to yield several breakdown products. This finding has relevant environmental implications, pointing to EC as a greener process than described in literature. A thorough optimization of EC was performed with solutions of bronopol in a simulated water matrix, yielding the complete disappearance of the parent molecule within 20 min at 200 mA (∼20 mA/cm(2)), using Fe as the anode and cathode. A 25% of total organic carbon (TOC) abatement was attained as maximum, with bronopol being converted into bromonitromethane, bromochloromethane, formaldehyde and formic acid. N atoms were accumulated as NO3(-), whereas Br(-) was stable once released. This suggests that mediated oxidation by active chlorine, as well as by hydroxyl radicals resulting from its reaction with iron ions, is the main transformation mechanism. Aiming to enhance the mineralization, a sequential combination of EC with electro-Fenton (EF) as post-treatment process was proposed. EF with boron-doped diamond (BDD) anode ensured the gradual TOC removal under the action of (•)OH and BDD((•)OH), also transforming Br(-) into BrO3(-).

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BACKGROUND: Electro-Fenton technology has demonstrated great potential for the degradation of recalcitrant organic contaminants in polluted wastewaters. In this technology, the decomposition of hydrogen peroxide is catalysed by the presence of iron, and powerful oxidants, hydroxyl radicals, are generated. However, there is concern over the reduction of iron released in the treated effluent. Therefore, retention of catalyst is required, and advances in electro-Fenton heterogeneous catalysis are necessary. In this study, the use of polyacrylamide hydrogel was evaluated as a support for the iron, and the performance of the catalyst (Fe-PH) developed was assayed in the electro-Fenton degradation of two dyes, Reactive Black 5 and Blue Sella Solid. RESULTS: First, the synthesis of Fe-PH catalyst was studied. The results showed that the loaded hydrogel with a mixture of Fe(II) and Fe(III) in 1:2 molar ratio reached the highest decolourization efficiency. The performance of the optimized Fe-PH catalyst was evaluated in the decolourization of the selected dyes. These studies demonstrated the satisfactory performance of electro-Fenton using Fe-PH catalyst as well as its reusability. CONCLUSION: In summary, the Fe-PH catalyst developed gives the promise of wastewater treatment by means of an electro-Fenton process.

Proper Orthogonal Decomposition and Statistical Analysis of 2D Confined Impinging Jets Chaotic Flow The Proper Orthogonal Decomposition (POD) is shown to be a statistical operation that identifies the main characteristics of chaotic flows and separates them into few modes. The dynamic chaotic flow is obtained from 2D Computational Fluid Dynamics (CFD) simulations, for different Reynolds numbers, of a Confined Impinging Jets mixer (CIJ). The POD enables a reconstruction of the dynamic flow from a few modes that are related with coherent flow structures. The POD flow reconstruction enables a large compression of the flow data set. The decomposition of the flow field in orthogonal modes related to coherent structures, provides a direct insight into the mixing dynamics and scales, which are not accessible from flow dynamics statistic quantities that were introduced in the context of turbulence and are here applied to a chaotic flow.

This article analyses three of the Sustainable Development Goals (SDGs) gathered by the 2030 Agenda and adopted by the United Nations, and how online educational models may help to reach these goals. Specifically, the three goals discussed through this article are: i) Ensure inclusive and equitable quality education and promote lifelong learning opportunities for all (Goal 4); ii) reduce inequality within and among countries (Goal 10); and iii) take urgent action to combat climate change and its impacts (Goal 13). This work delves fundamentally into aspects related to online engineering education, such as the impact of the carbon footprint in online education, the reduction of geographical barriers and the social gap, and the complete online accessibility to the educational environment. Finally, this article presents the case of the International University of La Rioja with its 100% online methodology, and approximately 42,000 students distributed throughout the world. This institution is supported by tools that facilitate engineering training for people with reduced mobility and who are geographically dispersed, reducing the carbon footprint through remote training.