Unique multifunctional coatings, comprising a 3D superhydrophobic agent and two nanostructured photocatalysts (solar-light sensitive 50/50 and 10/90 TiO 2 -ZnO nanoheterostructures), compatible with the inorganic substrates of the Built Heritage, have been designed.The synthesized nanoparticles showed an enhanced photocatalytic activity (tested by NO degradation) as compared with the raw TiO 2 and ZnO materials.Dispersing agents were used to optimize the coatings, avoiding agglomeration of the photocatalytic nanoparticles and increasing the stability of the suspensions. Four distinct dispersions were optimized and applied as coatings onto stony materials used in the Built Heritage, such as sandstone, lime mortar, granite and limestone. Their effectiveness was assessed by assessing hydrophobicity of the surfaces (static water contact angle), photocatalytic activity and self-cleaning as well as water vapour permeability of the treated specimens. These transparent coatings demonstrated high compatibility with the construction materials of the Architectural Heritage and showed a synergistic effect rendering a minimized water absorption, self-cleaning ability evidenced by the reduced adsorption of soiling deposits and a reasonable degradation of any trace that might be adsorbed, as well as a protecting hydrophobic environment for the photocatalyst.

A new range of grouts prepared by air lime and metakaolin (MK) as a pozzolanic admixture has been obtained by using as dispersing agents two polymers, namely poly-naphthalene sulfonate (PNS) and lignosulfonate (LS), with the aim of improving the fluidity of the fresh grouts. Fluidity and setting times of the grouts were assessed. Differences in the molecular architecture and in the anionic charge density explained the different adsorption of the polymers and the different performance. The higher anionic charge of PNS and its linear shape explained its better adsorption and effectiveness. The pozzolanic reaction was favoured in grouts with PNS, achieving the highest values of compressive strength (4.8 MPa after 182 curing days). The addition of PNS on lime grouts slightly decreased the frost resistance of the grouts (from 24 freeze-thaw cycles for the polymer-free samples to 19 or 20 cycles with 0.5 or 1 wt % of PNS). After the magnesium sulphate attack, grouts were altered by decalcification of hydrated phases and by formation of hexahydrite and gypsum. A protective role of portlandite against magnesium sulphate attack was clearly identified. Accordingly, the polymer LS, which preserves a significant amount of Ca(OH)2, could be an alternative for the obtaining of grouts requiring high sulphate attack resistance.

This paper presents the experimental procedure to develop air lime-based injection grouts, including polymeric superplasticizers, a water repellent agent and pozzolanic agents as additives. Our research focuses on the development of grouts to improve various characteristics simultaneously by combining different additions and admixtures. Aiming to improve the injectability of the grouts, in this study, different polymeric superplasticizers were added, namely polycarboxylated-ether derivative (PCE), polynaphthalene sulfonate (PNS) and condensate of melamine-formaldehyde sulfonate (SMFC). As a water-repellent agent, sodium oleate was used to reduce the water absorption. The enhancement of the strength and setting time was intended by using microsilica and metakaolin as pozzolanic mineral additions. Compatibility between the different admixtures and action mechanism of the different polymers were studied by means of zeta potential and adsorption isotherms measurements. Diverse grout mixtures were produced and investigated by assessing their injectability, fluidity, stability, compressive strength, hydrophobicity and durability. This research led to several suitable mixtures produced by using more than one component, to enhance efficiency and to provide better performance of grouts. According to the results, the grout composed of air lime, metakaolin, sodium oleate and PCE was found to be the most effective composition, improving the mechanical strength, injectability and hydrophobicity.

Mining is one of the principal economic activities in Mexico, which in addition to bringing benefits to the population, causes health and environmental problems. This activity produces a lot of wastes, but the main one is tailings. In Mexico, these wastes are disposed of in the open air, and there is no control over them, so the particles of these wastes are dispersed by wind currents to the surrounding population. In this research, tailings were characterized, finding in them particles smaller than 100 microns; in this way, tailings can enter into the respiratory system and hence can cause diseases. Furthermore, it is important to identify the toxic components. The present work does not have previous research in Mexico, and it shows a qualitative characterization of the tailings from an active mine using different analytical techniques. In addition to the data obtained from the characterization of the tailings, as well as the concentration of the toxic elements found, which were Pb and As, a dispersal model was generated and used to estimate the concentration of particles in the wind generated at the studied area. The air quality model used in this research is AERMOD, where it uses emission factors and available databases provided by Environmental Protection Agency (USEPA); Moreover, the model was coupled with meteorological information from the latest generation WRF model. The modeling results estimated that the dispersion of particles from the tailings dam can contribute up to 10.15 µg/m3 of PM10 to the air quality of the site, which, according to the characterization of the samples obtained, could be dangerous for human health and can be estimated up to a concentration of 0.04 µg/m3 of Pb and 10.90 ng/m3 of As. It is very important to make this kind of research to know the risk which people around this disposal sites are exposed to.

ampliamente (plata, plomo y cobre) desde la época del virreinato hasta su cierre; por consiguiente, se acumularon grandes cantidades de jales o relaves, producto del procesamiento metalúrgico. Estos jales pueden producir drenaje ácido de mina debido a las reacciones de oxidación e hidrólisis. Con el objetivo de predecir si los jales son generadores de drenaje ácido, se realizó la caracterización de las muestras de jales y la determinación de la posibilidad de generar acidez. Los valores de pH hallados fueron ligeramente alcalinos (7.8-8.4). Por otro lado, los sulfatos y el azufre total se determinaron mediante los métodos turbidimétrico e infrarrojo, respectivamente. Cabe mencionar que la concentración de azufre total estuvo por debajo del límite de detección del equipo Leco S-144DR y las concentraciones de azufre en forma de sulfatos fueron mínimas. La caracterización mineralógica mostró que sólo en tres muestras se encontró pirita, y en bajos porcentajes. Los minerales calcita y dolomita presentes en el yacimiento tipo skarn intervienen en la neutralización del drenaje ácido de la mina y disminuyen la movilidad de la mayoría de los metales y metaloides tóxicos.