Vicente Montiel

This work describes a method to create submarine artificial structures based on light metallic structures covered by calcareous layers obtained by electrolysis in sea water, with full environmental safety of the process. For structures based on meshes of cylindrical steel wire, the thickness of the deposited layer increases linearly with time for widths up to 2 mm. In the case of thicker layers, mathematical modelization suggests that the evolution of the deposited layer width might not be linear. Under the experimental conditions of this work, the deposited layers were mainly composed of stable crystalline forms of calcium carbonate. No significant presence of magnesium containing minerals was found in the deposited layers. The composition and texture of the obtained surfaces might be deemed as optimum from the point of view of providing colonization sites for the sessile benthic organisms of interest. These structures may be used as elements that can be included in the design of environmental remediation applications. Regarding their potential applications, once deployed in the marine environment and colonized by sessile benthic filter-feeding species, the structures could contribute to the improvement of sea water quality in commercial ports or marinas, which might be affected by organic pollution.

The objective of the present work is to optimize the simulation of an electrodialysis reactor for the desalination and regeneration of multi-ionic wastewater with high salt contents and conductivities, within the framework in the Sustainable Development Goal 6 (clean water and sanitation) and remarking the Electrodialysis (ED) as a highly energy-efficient and sustainable technology. The mathematical modelling has been carried out by using a semiempirical model that involves an algebraic system of differential equations, including mass and charge balances (taking into account the ions present in the wastewater: Na+, Ca2+, Mg2+, Cl-, SO42-, and HCO3-), and the total electrodialysis stack voltage considering ohmic drops (in the dilute and concentrate compartments), the potential of membrane in each cell pair, and the electrode potentials. In the simulation process, different theoretical and experimental parameters are necessary such as number of cells, membrane working areas, efficiency, diffusion coefficients, molar conductivity at infinite dilution, etc.The experimental parameters have been obtained initially with a specially designed batch reactor printed with 3D technology, to imitate the hydrodynamics and the behavior of the industrial final reactor used. Additionally, to increase the accuracy of the simulation results, same parameters such as the resistance of the membranes (rm), the transport numbers and the mass transfer coefficient (km) can be optimized by using a metaheuristic derivative-free optimizer, specifically a proprietary version of Particle Swarm Optimization (PSO) implemented in MatLab®.The results obtained yield a satisfactory reproduction of the observed experimental behavior, analyzing the evolution over time of the intensity, conductivity, and concentration of the concentrated and diluted currents, respectively. In addition, the evolution of the different contributions of the stack voltage and the membrane resistances are shown, in order to confirm the coherence of the results obtained.

Artificial structures act as points of entry for non-indigenous species (NIS) in port areas and may support higher abundance and richness of them. The studies about NIS are increasing, but studies focusing on the variations in temporal recruitment and ecological mechanisms are still scarce. Thus, the aim of this work was to determine the colonization and development of non-indigenous sessile fouling species over two types of substrates (electrolytic carbonated and steel) during 12 months of immersion in the Alicante harbor. The biofouling communities of both substrates were analyzed in terms of abundance and species richness by status (native, cryptogenic, and NIS), and NIS assemblages of both substrates were studied by means of multivariate analyses. In total, 53 different species were identified, 38 in steel (six NIS and six cryptogenic) and 50 in the carbonated substrate (six NIS and 10 cryptogenic). Most NIS were more abundant and diverse after 9 months of immersion and had a preference for carbonated substrates. Furthermore, most of them were positively correlated in both substrates (mainly in steel) and it is noted that the number of NIS in the port of Alicante is increasing as new records have been detected.

PCN-224 metal–organic framework family is particularly suitable for the electroreduction of molecular nitrogen for the formation of ammonia. The introduction of Ni²⁺ and fluor sites improves both the activity and stability.

The ecological succession has been widely studied by means of biofouling assemblages among different substrates, and mainly targeted in early stages on artificial ones. The present study focuses on biofouling that colonizes carbonated structures, a material similar to the natural substrate produced by the electrolysis of seawater, which is relatively very little studied. We have observed the colonization of sessile macrofouling of the port of Alicante (SE Spain, Western Mediterranean) on two types of substrates (electrolytic carbonated and steel) over 12 months of succession. The assemblages of both substrates have been analyzed by means of diversity indexes and multivariate analysis (PERMANOVA and SIMPER) in order to see the differences over time. The carbonated substrate has presented a community with higher values of biological diversity, structure and complexity, although the differences in species composition between substrates are not evident during all immersion periods. Thus, these results seem to indicate that, even after 12 months of immersion, communities are still in a dynamic successional stage.