Maria Luisa Almoraima Gil

Universidad de Cádiz | UCA · Department of Physical Chemistry

The main aim of this research is to characterise fresh stone and to highlight how its physical properties change as a result of natural ageing. For this purpose, naturally weathered and freshly cut samples, proceeding from the monument, were analysed. The results obtained allow us to better understand the behaviour of the material in relation to de...

Superhydrophobic coatings have been often used to protect stone surfaces against water. The durability of these coatings has been rarely tested for monumental heritage exposed to outdoor conditions. In this work, a highly effective superhydrophobic nanomaterial has been applied in the archaeological site of Carteia, which is located next to the sea...

In this study, we develop TiO2-SiO2 nanocomposites that can be employed as photoactive coatings to create surfaces with antipollution and self-cleaning properties in urban buildings. In particular, anatase titanium dioxide with a high percentage of {0 0 1} facets, commonly called titania nanosheet (TNS), was used as active phase. This approach allo...

Debido a su escasa conservación, el patrimonio mundial de hormigón del siglo XX, sufre daños de gran magnitud. En este contexto, el proyecto internacional de investigación InnovaConcrete, financiado por el programa Horizonte 2020 de la Unión Europea (UE), ha desarrollado, por un lado, productos y técnicas de conservación para combatir los mecanismo...

In this study, the newly synthesized TiO2 and N doped TiO2 clusters were added to silica sol to synthesize N-TiO2/SiO2 composites via the sol–gel method. Afterwards, the prepared sols were applied by brushing on portland cement. Doping with nitrogen significantly increased the absorption of TiO2 towards the visible region, thus, increasing the phot...

In this study, the newly synthesized TiO 2 and N doped TiO 2 clusters were added to silica sol to synthesize N-TiO 2 /SiO 2 composites via the sol-gel method. Afterwards, the prepared sols were applied by brushing on portland cement. Doping with nitrogen significantly increased the absorption of TiO 2 towards the visible region, thus, increasing th...

A Self-cleaning nanostructured TiO2 coating has demonstrated the capacity to mitigate undesired effects from air pollution. Not only it reduces the deterioration of building materials but may also prevent certain pollution-related human health problems. In this study, mesoporous TiO2/SiO2 photocatalysts were synthesized in order to produce self-cle...

This manuscript presents a 1 year in the laboratory and 3 years In-Situ evaluation of an alkoxysilane-based consolidant containing SiO2 nanoparticles (SiO2NPs) on Ostionera stone, a biocalcarenite traditionally employed in Southwestern Spain. Cádiz Roman Theatre was selected for In-Situ application and testing. In order to safeguard the theatre, pr...

As a consequence of human activities, today, we are exposed to high pollution levels that cause building materials damage and many diseases. The application of TiO2 as coating on building materials has proven the efficiency of self-cleaning and air de-pollution. However, its performance is limited due to its absorption being exclusively located at...

Water and waterborne decay agents (e.g. salts, microorganisms) are commonly associated with undesired alterations and damages on concrete elements. A strategy to mitigate their impact is to decrease water retention in the material either by surface treatments or admixtures. In this work, hydrophobic concretes were developed by the addition of a hyd...

Building materials decay is caused by the combination of chemical, physical and biological aspects. Therefore, the development of innovative multifunctional building materials is an alternative to reduce their impact. This can be achieved by post-treatments or by direct changes in the fabrication of synthetic materials, such as engineered stone. Th...

Magnetic nanoparticles (MNPs) uniquely combine superparamagnetic performance with dimensions that are smaller than or similar size to molecular analytes. Recently, functionalized MNPs are predicted to be a driver for technology and business in this century and hold the promise of high performance materials that will significantly influence all aspe...

Microbial fouling on the surface and water retention are common problems affecting porous ceramic materials (stone, concrete…) that can alter their properties, shorten their service life and even pose a health risk. Though proper maintenance (disinfection, drainage…) can mitigate these issues, it is a time and resource intensive process and prevent...

Surface-modified Ag/TiO2 photocatalysts with enhanced activity under visible light and biocidal properties have been produced through a two-stage method involving the functionalization of TiO2 nanoparticles(NPs) with –SH or –NH terminated alkoxysilanes and deposition of AgNPs. The functionalization process increased the yield of the Ag deposition a...

The biosynthesis of ultra-small gold nanoparticles (AuNPs) with very narrow size distribution and stable dispersion through an aqueous drago (Dracaena draco L) aged leaf extract used as a non-toxic reducing and stabilizing agent has been achieved. The gold nanoparticles obtained in this way, have a size in the range 0.9–2.8 nm and an average size o...

The alarming increase of pollution has significantly increased buildings maintenance. Nowadays, the economic figures associated to repairing activities are even more relevant than those corresponding to new construction works, especially on heritage buildings. Since the degradation of building materials is the result of a complex combination of phy...

Colonization by phototrophic microorganisms causes a range of problems for building façades, The combination of biological physical and chemical agents accelerates the decay of materials. For this reason, in recent years there has been a growing interest in the application of multifunctional treatments that combine consolidant and biocidal action....

En este artículo se investigan las percepciones del profesorado de ciencias sobre el efecto de las pruebas de acceso a la universidad, en la metodología docente y en las prácticas de evaluación. En el estudio participaron 120 profesores/as con experiencia docente en asignaturas de ciencias de segundo curso de bachillerato. Como instrumentos de reco...

An effective procedure has been developed to consolidate and hydrophobize decayed monumental stones by a simple sol-gel process. The sol contains silica oligomer, silica nanoparticles and a surfactant, preventing gel cracking. The effectiveness of the process on biocalcareous stone samples from an 18th century cathedral has been evaluated, and it w...

The high pollution levels in our cities are producing a significant increase of dust on buildings. An application of photoactive coatings on building materials can produce buildings with self-cleaning surfaces. In this study, we have developed a simple sol-gel route for producing Au-TiO2/SiO2 photocatalysts with application on buildings. The gold n...

The objective of this work was to ascertain the nature of the components responsible for the reducing and stabilizing properties of Zostera noltii extracts that lead to gold nanoparticle formation using chemical techniques of analysis. In order to achieve this aim, we try the synthesis of AuNPs with three different extracts from plants collected in...

The decay of building materials is generally caused by the combination of chemical, physical and biological agents. Therefore, the development of products that combine multiple protection mechanisms is desirable. We have developed, via a sol-gel route, CuO/SiO2 nanocomposites with application as a multifunctional protective treatment for building s...

Se analizan las percepciones de alumnos y profesores del último curso de bachillerato sobre el efecto de las pruebas de acceso a la universidad en asignaturas de ciencias en la inclusión de contenidos CTS en el currículo. Se emplearon cuestionarios tipo Likert, entrevistas semiestructuradas y cuestionarios abiertos, como instrumento de recopilación...

Se estudia la tipología de preguntas formuladas en las pruebas de Química de acceso a la universidad en la Comunidad Autónoma Andaluza. Se analizaron 576 preguntas según los temas del currículum implicados y de acuerdo al sistema de categorías propuesto por Smith, Nakhleh y Bretz (2010) para exámenes de Química. Los temas más frecuentes fueron los...

The study reported here was conducted to investigate the perceptions of high school students on the use of educational games as a tool for teaching the periodic table of elements in a chemistry class in Spain. The 127 students who participated in this study came from six different classes in grade 10 (15-16 years old). The students' perceptions of...

The work reported here involved a comparative study regarding the understanding that high school students (16-18 years) have of the concept of chemical elements and their periodic classification. More specifically, the level of knowledge on this topic was compared before and after the completion of baccalaureate studies in a sample of Spanish stude...

ABSTRACT: The super-fragile materials existing in underwater archaeological sites are an invaluable source of historical information that can rarely be documented because of their poor condition. The natural fiber ropes used in rigging historic vessels are a key to understanding the evolution of nautical architecture in antiquity. A new method of m...

Super-fragile materials existing in underwater archaeological sites are an invaluable source of historical information which are rarely documented due to their poor condition. Natural fiber ropes used for rigging historic vessels are a key to understanding the evolution of nautical architecture in antiquity. A new method of molding adapted to super...

A rapid in situ biosynthesis of gold nanoparticles (AuNPs) is proposed in which a geranium (Pelargonium zonale) leaf extract was used as a non-toxic reducing and stabilizing agent in a sonocatalysis process based on high-power ultrasound. The synthesis process took only 3.5min in aqueous solution under ambient conditions. The stability of the nanop...

The main objective of this study consists of comparing the electrocatalytic activity of different types of gold nanoparticles (AuNPs) obtained from two different synthetic routes (thermal and ultrasonic methods) deposited on the surface of a Sonogel-Carbon (SNGC) matrix and the application of the sensing devices built with them to the determination...

An easy, cheap and green synthetic route, using high-power ultrasounds and sodium citrate dihydrate as non-toxic reducing and stabilizer agent, produces gold nanoparticles in aqueous solution, and at ambient conditions. The time required for the synthesis is 5.5 min. The spherical nanoparticles obtained by this route show a homogeneous size distrib...

With the purpose of optimising a suitable methodology for the conservation of an archaeological object of iron, a low current intensities electrolytic treatment has been applied, to a piece of cast iron, proving to be effective in the extraction of chloride ions from the structure of akaganeite, principal corrosion product of iron in the marine med...

With the purpose of optimising a suitable methodology for the conservation of an archaeological object of iron, a low current intensities electrolytic treatment has been applied, to a piece of cast iron, proving to be effective in the extraction of chloride ions from the structure of akaganeite, principal corrosion product of iron in the marine med...

This article describes the design of a photochemical reactor intended to carry out experiments illustrating the fundamentals of heterogeneous photochemistry. The photodegradation kinetics of brilliant green (C27H33N2•HSO4) in a TiO2 dispersion under near-UV radiation is presented as a simple experimental example of the use of this reactor, intended...

Electrolytic treatment at low currents intensities has been applied to a piece of cast iron, with the object of optimising a suitable methodology for the conservation of archaeological objects of iron. This technique has proved to be effective in the extraction of chloride from the structure of akaganeite (β-FeOOH(Clx)), the principal corrosion pro...

Electrochemical evidence shows that the oxidation of thiols on mercury is characterized by an extensive adsorption of the oxidized products on the electrode surface, and by the formation of dimeric R-S-Hg-S-R organometallic complexes as the final oxidation products. The orthogonal collocation technique has been used in this work to solve the simple...

La conservación de las piezas metálicas extraídas de fondos marinos exige seguir un tratamiento de estabilización para impedir el desarrollo de la corrosión cíclica debida a los cloruros depositados en el metal por el agua del mar. Cuando la pieza es extraída y secada, es posible que la corrosión continúe por la presencia de especies cloradas higro...

The formation and reductive desorption of self-assembled monolayers of 6-mercaptohexanol on mercury has been studied by using cathodic stripping voltammetry and capacitative transients, including the possibility of expanding or contracting the electrode area at the end of the preconcentration step. Experimental evidence shows the existence of three...

The theory for surface redox processes perturbed by a father–son reaction under linear voltammetric conditions, and in the absence of mass transport complications, has been extended to remove the kinetic restrictions of previous treatments. The solution of the initial value problem, when reactants and products remain in the adsorbed state, is shown...

The influence of analyte adsorption and of a follow-up surface dimerization reaction on desorptive stripping voltammograms has been investigated. A modified version of the spline orthogonal collocation technique has been developed to compute the voltammetric response under Langmuirian reversible conditions. Simple analytical expressions derived for...

The influence of reactant adsorption/diffusion coupling on the voltammetric behavior of redox processes that lead to the formation of a passivating product monolayer was investigated. The orthogonal collocation technique was used to compute cyclic voltammetric waves under reversible Langmuirian conditions. Systematic analysis of the peak parameter...

The theory for surface dimerization reactions under linear voltammetric conditions, and in the absence of mass transport complications, has been extended to remove the kinetic constraints of previous treatments. The solution of the initial value problem is shown to be identical when reactant and products remain in the adsorbed state and when the ad...