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The aim of the paper consist in the synthesis of double substituted carbonated hydroxyapatite using Zn2+ and Mg2+ ions in comparison with the previous obtained Sr-Zn-CHAp. Fourier transform infrared spectroscopy, X-ray diffraction, environmental scanning electron microscope (ESEM) coupled with EDS is used to highlight the presence of the metallic ions into the apatite structure. Both inorganic compounds are tested as consolidants for two types of fir wood, young and 30-years old samples. The consolidation efficiency is demonstrated by colorimetric analysis, mechanical tests and the specific methods for water absorption behavior. Stronger specimens, especially of young wood, with no significant color differences, more hygroscopic and with higher hysteresis index result after treatment. In conclusion, carbonated hydroxyapatite double substituted with zinc, magnesium and strontium ions can be used in wood preservation-conservation techniques.

The aim of the paper consists in assessing the protection of fir wood samples against UV degradation by using polyacrylates and titanium dioxide as absorber. The irradiation was achieved for 648 hours, considered as about 2 years of weathering. Colorimetric, water absorption, and mechanical investigations were performed on samples before and after irradiation. The structural changes were evidenced by FTIR spectroscopy. Small changes in color for coated wood samples are observed after maximum 648 h of UV treatment, with the best results obtained for the specimen covered with Paraloid B72-TiO2. Higher compressive strengths were observed for the polymer-TiO2 coatings, in correlation with a smaller water absorption capacity of the studied samples. FTIR revealed shifted peaks with increased intensities as proof of structural changes produced by irradiation of lignin and polyacrylates. The results highlight that Paraloid B72 and Paraloid B67 mixed with TiO2 can be used as efficient UV protective coatings for fir wood.

The present work aims to study the adsorption processes and the photochemical depollution of the waters contaminated with Direct Orange textile dyes - 26 released into the water. Also, the paper shows the polysulfone (PSf) membranes, used for adsorption processes of the textile dyes azo - direct-orange-26, presenting the kinetics and experimental adsorption conditions for such processes. Advanced oxidation processes (AOP) processes used in photochemical depollution technologies are studied for water contaminated with Direct Orange 26 textile dye, after a preliminary adsorption process, with ZnFe2O4 ferrite photocatalysts.

The aim of this study was to address one of the major challenges of the conservation state of wooden artifacts or artworks namely, the preservation and restoration of wood surfaces. The factors involved in the deterioration of wood are mainly the external factors such as fire, low temperature and microbiological agents, which induce some degradation processes in wood, identified by discoloration, fragility and unsightly appearance. In this study, biodegradable materials based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV) and composites based on PHBHV and particles (zinc oxide (ZnO), carbonated hydroxyapatite (CHAp) and its metallic derivatives with silver (AgCHAp) and strontium (SrCHAp) were applied on firwood specimens in order to investigate their consolidation capacity. Colorimetric measurements have confirmed that the chosen treatments did not change the colour of the natural wood. The hardness test revealed that the consolidation system increases the mechanical properties of the samples. The used treatments confer a strong hydrophobic character which prevents exfoliation of the wood samples, as confirmed by the performed water absorption test.

In this paper, multi-walled carbon nanotubes have been prepared at low synthesis temperatures and without high pressure by a simple chemical route. Fourier transformed infrared spectroscopy, Raman ...

This paper aims with the preparation of Sr2+ and Zn2+ double substituted carbonated hydroxyapatite (Sr-Zn-CHAp) by the nanoemulsion method and to evaluate its consolidation capacity on artificial stone samples. The changes in CHAp lattice parameters were observed by a synergy between the shrinkage and dilatation induced by the two metallic ions, with different ionic radii by comparison with calcium. The changed morphology obtained by calcination was evidenced by SEM analysis. Also, the tendency to agglomerate of the double substituted CHAp as micron- and sub-micron-sized particles with spherical and irregular form was observed. The FTIR, XRD and EDS results confirmed that the CHAp was successfully substituted with Sr2+ and Zn2+ by replacing Ca2+ resulting a AB-type CHAp. The efficacity of Sr-Zn-CHAp as inorganic consolidant for the stone was tested by mechanical strength, resistance at freeze–thaw artificial aging test, thermal shock weathering, colorimetric changes of the artificial stone sample, all the results being correlated with the water absorption test, water repellency, and pore structure changes. By treating the stone with 0.5 g/L Sr-Zn-CHAp led to an improvement of the above-mentioned characteristics, without significant chromatic changes.

The aim of this paper is to analyze the construction materials (mortars) of an architectural monument (Deserted Tower (Lilly Tower) from Corvins&rsquo, Castle, Romania). The mortars were characterized following a multidisciplinary approach, combining macroscopic observation with petrographic microscopy, mineralogical analysis (X-ray diffraction) and elemental analysis (X-ray fluorescence), hydric properties, and color of representative samples of the monument. The results revealed the use of gypsum mortars (produced by lumps with higher Fe content), with minor concentrations of crystalline dolomites of the Southern Carpathians, calcite, and quartz. The materials&rsquo, effective porosity and their water absorption capacity were high. A possible solution to consolidate the damaged area with some consolidation products (hydroxyapatite carbonate and its derivatives with Ag and Sr) was investigated, too. The interactions between the mortar&rsquo, s specimens and the effectiveness of the consolidation treatments were evaluated by physico-chemical analyses (molecular structure by X-ray powder diffraction (XRPD), wavelength dispersive X-ray fluorescence (WDXRF), dynamic light scattering (DLS)), morphological characterization by microscopic techniques as SEM-EDS, TEM, and physical and mechanical investigations (peeling test and compressive strength). Results were drawn based on historical, in situ observations, and analytical data, and put into evidence the composition, high weathering degree, and the possibility to surface consolidate with Sr-CHAp.

In recent years, the rapid development of electronic equipment led to millions of tons of waste printed circuit boards (WPCB) generated in the entire world rising important concerns regarding its recycling. Besides the metals recovery, intensively studied, the reuse of the nonmetals is especially difficult. In this study, the non-metallic fraction from the waste of printed circuit boards is used as reinforcing filler of a styrene-butadiene block-copolymer. The composites were characterized by mechanical and dynamo-mechanical analysis and thermo-gravimetry. The study aimed the reintroduction into the economic circuit of WPCB as composites suitable for the production of shoe soles injected directly on the footwear faces and as bitumen modifiers for road coverings.

In this study, multi-walled carbon nanotubes (MWCNTs) were decorated with different types of nanoparticles (NPs) in order to obtain hybrid materials with improved antimicrobial activity. Structural and morphological analysis, such as Fourier transformed infrared spectroscopy, Raman spectroscopy, X-ray diffraction, transmission electron microscopy, environmental scanning electron microscopy/energy-dispersive X-ray spectroscopy and the Brunauer–Emmett–Teller technique were used in order to investigate the decoration of the nanotubes with NPs. Analysis of the decorated nanotubes showed a narrow size distribution of NPs, 7–13 nm for the nanotubes decorated with zinc oxide (ZnO) NPs, 15–33 nm for the nanotubes decorated with silver (Ag) NPs and 20–35 nm for the nanotubes decorated with hydroxyapatite (HAp) NPs, respectively. The dispersion in water of the obtained nanomaterials was improved for all the decorated MWCNTs, as revealed by the relative absorbance variation in time of the water-dispersed nanomaterials. The obtained nanomaterials showed a good antimicrobial activity, however, the presence of the NPs on the surface of MWCNTs improved the nanocomposites’ activity. The presence of ZnO and Ag nanoparticles enhanced the antimicrobial properties of the material, in clinically relevant microbial strains. Our data proves that such composite nanomaterials are efficient antimicrobial agents, suitable for the therapy of severe infection and biofilms.

(1) Background: Due to the precarious situation of many monuments or archeological sites, analytical investigations are necessary to obtain information about the used materials, as well as to identify the most appropriate solutions for their conservation/restoration. This paper addresses the characterization of mural painting fragments collected during the excavation in 2018 in Rapoltu Mare (La vie), Deva. (2) Methods: Specific analytical techniques were used, as follows: X-ray diffractometry (XRD), wavelength dispersive X-ray fluorescence (WDXRF), optical microscopy (OM), zoom microscopy and scanning electron microscopy (SEM), spectroscopic techniques (UV–Vis, FTIR, Raman), porosity and thermal analysis, all of which provide information about the structure, chemical composition, morphology and topography of pigments and their deterioration as well. (3) Results: Up to seven different pigments were identified: Egyptian blue, carbon, calcite, gypsum, hematite, goethite and green earth. Egyptian Blue is identified in all the other color areas, except the white area: in the green zone (as degradation product with beeswax) and in the red zone (in mixture with ochre) too. In addition, carbon and beeswax were highlighted as toner and binder for pigments, respectively. In the presence of the organic beeswax binding environment, the Egyptian blue pigment particles darkened or turned yellow significantly, changing the blue to a greenish color. It is also possible to identify wollastonite (CaSiO3) in the blue pigment, which indicates that the temperature used in the manufacturing of Egyptian blue was higher than 950 °C from thermal analysis. The presence of apatite, hematite and gypsum deposits in the Hunedoara region certifies that these pigments could have been of local origin, as demonstrated by the presence of analytically identified elements (Fe, P, S, Ca). (4) Conclusions: The analytical techniques used for such investigations have highlighted the main pigments used in Roman times for various Roman murals.

Carbonated hydroxyapatite (CHAp) is an inorganic compound with various applications that presents better homogeneity and consolidating effect than HAp [1]. [...]

Carbon nanotubes (CNTs) have attracted attention, due to their structures as well as their ability to present multiple walls. [...]

In the last decades, the waste electric and electronic equipment (WEEE) has increased substantially due to an accelerated development of the economy and the lifetime of electronics.

The history portrays the identity of a culture, of people and various civilizations, which has [...]

The color characteristics, vibration spectra, phase and mineral composition, internal structural organization of several fragments of the ancient Roman mosaics from the Roman Mosaic Museum, Constanta, Romania were studied by non-destructive (Chromatic analysis, Neutron Diffraction, Neutron Tomography) and micro-invasive techniques (Optical Microscopy, X-ray Diffraction, Field Emission Scanning Electron Microscopy&ndash, Energy Dispersive X-ray Spectroscopy, Raman Spectroscopy, Wavelength Dispersion X-ray Fluorescence). These investigations were performed in order to characterize the original Roman mosaic fragments. The major and minor phase components of the studied mosaic fragments were determined, the crystal structure of the main phases was analyzed, and their three-dimension spatial arrangement was reconstructed. The similar composition of the major phases of all mosaic fragments can indicate a generic recipe for making mosaic elements, but minor phases were presumably added for coloring of mosaic pieces. Some degradation areas inside the volume of the mosaic fragments were found by means of neutron diffraction and neutron tomography methods. These degradation areas are probably related to the formation of iron hydroxides during chemical interactions of mosaic fragments with the sea and urban polluted atmosphere.

In the last several years, the electronic waste, especially printed circuit boards have significantly increased over the world, generating one of the highest rates of solid waste. The recycling process of the printed circuit boards implies mainly the recovery of metals and glass fibers, while the reuse of the polymeric support has remained largely in the phase of research. In this paper, the non-metallic part of printed circuit boards was used as filler (up to 30%), but also to improve the fire resistance of thermoplastic composites based on recycled polypropylene and diene block-copolymers. The synergy between the elastic effect of elastomers and the reinforcing effect of the waste powder into the thermoplastic matrix was studied by mechanical and dynamo-mechanical analysis, X-ray diffraction, optical microscopy, micro-calorimetry and thermo-gravimetrical analysis. Improved mechanical properties, especially impact strength was observed. The compatibization of components considering the interactions between the ethylene-butylene blocks from the hydrogenated and maleinized styrene-butadiene block-copolymer and recycled polypropylene, respectively between the MA groups and the functionalities of the waste powder, evidenced by FTIR, was highlighted by changes in the X-ray pattern and an increased fire resistance and thermal stability.

The aim of this study was to assess the properties of some concrete samples according to their [...]

Cultural monuments are subject to a degrading phenomenon induced by several factors, such [...]

As the development of the textile industry has progressed, intense concerns have been focusedon the contamination of the environment caused by dye pollutants [...]

The organic part of the waste printed circuit board (WPCB) contains mainly epoxy resin, fiberglass and brominated flame retardants, a composition that makes it quite difficult to reuse [1,2]. [...]

Recently, numerous studies have been carried out on various. [...]

In the last few years, the preservation of cultural heritage has become an important issue globally, due to the fact that artifacts and monuments are continually threatened by degradation. It is thus very important to find adequate consolidators that are capable of saving and maintaining the natural aspect of these objects. This study aims to provide an updated survey of the main nanomaterials used for the conservation and restoration of cultural heritage. In the last few years, besides the classic nanomaterials used in this field, such as metal nanoparticles (copper and silver) and metal oxides (zinc and aluminum), hydroxyapatite and carbonated derivatives, tubular nanomaterials (such as carbon nanotubes) have been used as a potential consolidate material of cultural heritage. Tubular nanomaterials have attracted attention for use in different fields due to their structures, as well as their ability to present multiple walls. These nanotubes have the necessary properties in preserving cultural heritage, such as superior mechanical and elastic strength (even higher than steel), high hydrophobicity (with a contact angle up to 140°), optical properties (high photodegradation protection), large specific surface area (from 50 to 1315 m2/g, depending on the number of walls) for absorption of other nanomaterials and relatively good biocompatibility.