Direct Observations of Ordered Nanoporosity in Deprotonated 2-(Acetoacetoxy)ethyl Methacrylate (AAEMA-) Polymer: Preliminary Results.

Polymers based on 2-(acetoacetoxy)ethyl methacrylate, charged with iron or sodium, were thermally heated at 150 °C. Both polymers were studied and characterized by SEM, TEM, STEM microscopy and SAEDF techniques. The morphological investigation revealed that, upon heating, both polymers were endowed with microholes, sometimes perfectly ordered, whose dimensions varied from 4-5 nm to approximately 500 nm. In the case of an Fe-containing copolymer, unexpectedly, iron did not fill in the cavities, thus implying that it was "dispersed" in the polymeric matrix. Electronic microdiffraction documented that both polymers exhibited a proto-crystallinity, likely induced by thermal heating.

In vivo functionalization of diatom biosilica with sodium alendronate as osteoactive material.

Bisphosphonates are a class of drugs widely used in the clinical treatment of disorders of bone metabolism, such as osteoporosis, fibrous dysplasia, myeloma and bone metastases. Because of the negative side effects caused by oral administration of bisphosphonates, various silica mesoporous materials have been investigated for a confined and controlled release of these drugs. Here, we propose biosilica from diatoms as suitable substrate for alendronate local activation of bone cells. Following a novel strategy, sodium alendronate can be in vivo incorporated into biosilica shells of cultured Thalassiosira weissflogii diatoms, by feeding the algae with an aqueous solution of the drug. After acid/oxidative treatments for removing organic matter, the resulting bisphosphonate-functionalized mesoporous biosilica was characterized and tested as osteoinductive support. Effects on osteoblast growth and anti-osteoclast activity have been examined by evaluating SaOS-2, BMSC, J774 cell viability on the alendronate-"doped" biosilica. The loading percentage of sodium alendronate into biosilica, estimated as 1.45% w/w via TGA, was able to decrease metabolic activity of J774 osteoclasts-like cells till 5% over glass control. We demonstrated a good osteoconductive ability and activation of a tissue regeneration model together with osteoclasts inhibition of the functionalized biosilica, opening the way to interesting applications for diatom microalgae as a bioinspired mesoporous material for tissue engineering.

Data from in vivo functionalization of diatom mesoporous biosilica with bisphosphonates.

Diatoms are unicellular photosynthetic microalgae that produce a sophisticated mesoporous biosilica shell called frustule. Easy to achieve and extract, diatom frustules represent a low-cost source of mesoporous biocompatible biosilica. In this paper, the possibility to in vivo functionalize the diatom biosilica with bisphosphonates (BPs) was investigated. In particular, two BPs were tested: the amino-containing sodium alendronate (ALE) and the amino-lacking sodium etidronate (ETI). According to first SEM-EDX analysis, the presence of the amino-moiety in ALE structure allowed a better incorporation of this BP into living diatom biosilica, compared to ETI. Then, diatom growth was deeply investigated in presence of ALE. After extraction of functionalized frustules, ALE-biosilica was further characterized by XPS and microscopy, and ALE release was evaluated by ferrochelation assay. Moreover, the bone regeneration performances of ALE-functionalized frustules were preliminarily investigated on bone osteoblast-like cells, via Comassie staining. Data are related to the research article "In vivo functionalization of diatom biosilica with sodium alendronate as osteoactive material".

Sustainable bio-hydrothermal sequencing treatment for asbestos-cement wastes.

In this paper, the treatment of asbestos-cement waste (ACW) has been attempted by a dark fermentation (DF) pre-treatment followed by hydrothermal and anaerobic digestion (AD) treatments. During DF, glucose, employed as a biodegradable substrate, was mainly converted to H2-rich biogas and organic acids (OAs). The latter caused the dissolution of the cement matrix and the partial structural collapse of chrysotile (white asbestos). To complete the chrysotile degradation, hydrothermal treatment of the DF effluents was performed under varying operating conditions (temperature, acid type, and load). After the addition of 5.0 g/L sulfuric acid, a temperature decrease, from 80 °C to 40 °C, slowed down the treatment. Similarly, at 100 °C, a decrease of sulfuric, lactic or malic acid load from 5.0 g/L to 1.0 g/L slowed down the process, regardless of acid type. The acid type did not affect the hydrothermal treatment but influenced the AD of the hydrothermal effluents. Indeed, when malic acid was used, the AD of the hydrothermally treated effluents resulted in the highest production of methane. At the end of the AD treatment, some magnesium ions derived from ACW dissolution participated in the crystallization of struvite, an ecofriendly phosphorous-based fertilizer.

Environmental risk induced by TiO2 dispersions in waters and sediments: a case study.

A southern Italian area that is characterized by large outcrops of rocks that are rich in titanium oxide (TiO2) phases were investigated to determine the mineralogical risk induced by the natural dispersion of TiO2 minerals. Rock, sediment and surface water samples were collected to determine the physicochemical and mineralogical factors (i.e., size distribution, morphology and alteration) indicative of potential TiO2 toxicity. X-ray diffraction data suggested that titanium oxides were present as rutile and anatase. Scanning electron microscopy images showed elongated TiO2 morphologies; fibres were found as either isolated or embedded/enclosed in flake-like phyllosilicates. The concentration of fibres in stream water ranged from 1.7 to 4.6 million fibres per litre. The highest fibre amounts in the sediments were in the <8-µm fraction, while single fibres were primarily concentrated in the <2-µm fraction. The results indicate that titanium oxide minerals represent a natural source of environmental risk and that the geomineralogical characterization of rich TiO2 areas is indispensable for understanding their geoavailability, dispersion and distribution.

Are conventional statistical techniques exhaustive for defining metal background concentrations in harbour sediments? A case study: The Coastal Area of Bari (Southeast Italy).

Sediment contamination by metals poses significant risks to coastal ecosystems and is considered to be problematic for dredging operations. The determination of the background values of metal and metalloid distribution based on site-specific variability is fundamental in assessing pollution levels in harbour sediments. The novelty of the present work consists of addressing the scope and limitation of analysing port sediments through the use of conventional statistical techniques (such as: linear regression analysis, construction of cumulative frequency curves and the iterative 2σ technique), that are commonly employed for assessing Regional Geochemical Background (RGB) values in coastal sediments. This study ascertained that although the tout court use of such techniques in determining the RGB values in harbour sediments seems appropriate (the chemical-physical parameters of port sediments fit well with statistical equations), it should nevertheless be avoided because it may be misleading and can mask key aspects of the study area that can only be revealed by further investigations, such as mineralogical and multivariate statistical analyses.

Removal of Mn from aqueous solution using fly ash and its hydrothermal synthetic zeolite.

A number of water purification processes have been developed in recent years based on the utilisation of low-cost materials with high pollutant removal efficiency. Among these materials, fly ash and zeolite synthesised from fly ash are two examples of high-efficiency adsorbents. Column absorption tests were performed in order to compare the manganese sorption behaviour of an Italian coal fly ash and zeolite synthesised from it. Different masses of both materials (10-60 g) were exposed to solutions containing a total metal concentration of 10 mg/L. Batch adsorption studies were also conducted to determine the effect of time on the removal on Mn sequestration. The results indicate that both materials are effective for the removal of Mn from aqueous solution by precipitation due to the high pH of the solid/liquid mixtures. However, the leaching tests reveal that the amount of Mn removed from the fly ash was greater than that leached from the zeolite, thereby indicating that the metal is partially sequestrated by zeolite.

Provenance of inorganic aerosol using single-particle analysis: a case study.

A total of 137 samples of airborne particulates with an aerodynamic equivalent diameter of 10 µm or less (PM10) were collected from April 2007 to July 2008 in four different areas (Potenza, Lavello, Viggiano, Matera) of the Basilicata region in southern Italy. A total of approximately 140,000 particles were analysed using a Field Emission Scanning Electron Microscope (FESEM) equipped with an Energy-Dispersive X-ray Spectrometer (EDS). To formulate a hypothesis on the origin of particles, the dataset was numerically reduced using mineralogical criteria. Eight particle groups were established (Silicate, Silica, Carbonate, Sea Salt, Polymineral, Industrial, Sulphur, and Biogenic Particles) among which Silicate, Sulphur and Industrial Particles were found to be the most abundant. Among the Silicate Particles, the alumosilicates were the most commonly occurring particles (mineral and fly ash particles), and the presence of a small metallurgical factory located in the industrial area of Potenza significantly affects the presence of metal particles (mainly Fe-Zn spinels). The anthropogenic pressure exerted by different types of Sulphur-rich (e.g., Na-Ca-Sulphates, S-only) Particles in the other areas is most likely linked to industrial combustion processes, i.e., waste incinerator oil and oil extraction. Significant differences were found in the particulate concentrations and the compositions of samples collected in different seasons as well as during the night and daytime periods. Crustal Particles were the most abundant in spring-summer, and both Sulphur-rich Particles and Industrial Particles increased in autumn-winter. The proportion of latter category of particles increases in the samples collected during the night periods due to weather conditions (atmospheric stability, thermal inversion, etc.). Sulphur-rich Particles were observed to be more abundant during the daytime due to anthropogenic processes (combustion) and solar radiation. In summary, mineralogical and geochemical approaches are fundamental to delineate the human and natural contributions from automated microscopic analyses.

Ultrasonic waves induce rapid zeolite synthesis in a seawater solution.

The synthesis of zeolites from fly ash was performed through a low-temperature hydrothermal process with seawater. Compared with the results obtained using the same hydrothermal method but in the absence of sonication, the application of an ultrasonic pre-treatment to the conventional hydrothermal process with seawater reduces the crystallization temperature below that observed when hydrothermal synthesis is performed using distilled water.

Effects of ultrasonic treatment on zeolite synthesized from coal fly ash.

The synthesis of zeolites from three samples of fly ash was carried out through a low-temperature (25-60°C) hydrothermal process with a NaOH pre-fusion treatment preceded by sonication. The results were compared with those of conventional hydrothermal syntheses. XRD and SEM investigations demonstrate that the application of ultrasonic treatment facilitates the formation of zeolites at a lower-temperature (25°C) than syntheses not preceded by sonication. No significant difference in type, temperature of crystallization, or amount of zeolites synthesized was noted between the three different samples of fly ash, implying that the chemical composition of fly ash had little influence on the zeolite product within the compositional range of these fly ash precursors. Although there appears to be a correlation between the SiO(2)/Al(2)O(3) ratio of the fly ash and the temperature of zeolite formation by conventional synthesis, no correlation was apparent when ultrasonic pre-treatment was used at low-temperatures.

Immobilization of Ni by synthesising zeolite at low temperatures in a polluted soil.

Over the last few years a great deal of research has been carried out in order to develop remediation methods for reducing environmental risks due to polluting metals. Zeolite formation in contaminated soils mixed with coal fly ash could be a useful method to reduce both the availability and the mobility of metals in contaminated areas. In this study a soil sample--treated with coal fly ash and artificially contaminated with a high concentration of Ni--was used for synthesizing zeolite at low temperatures. The role played by this mineral in the immobilization of heavy metal was investigated. The materials were analysed chemically (sequential extraction) and by XRD and SEM-EDS analyses. The synthesis was carried out both in the laboratory and on a bench-scale for 1 year. Zeolite crystallization readily occurred after a month. The presence of Ni does not exert any influence on zeolite formation. On the other hand newly-formed zeolites reduce the toxicity of the element in the polluted soil. A reduction in heavy metal availability was observed after ammonium acetate extraction. The use of the modified BCR three-step sequential extraction (sequential extraction protocol developed by Community Bureau of Reference of the Commission of the European Communities) suggests that Ni mobilization takes place when zeolite structure collapses after the BCR second step. The Ni thus available was mobilized in the third step.

Synthesis of zeolite from Italian coal fly ash: differences in crystallization temperature using seawater instead of distilled water.

In this study Italian coal fly ash was converted into several types of zeolite in laboratory experiments with temperatures of crystallization ranging from 35 up to 90 degrees C. Distilled and seawater were used during the hydrothermal synthesis process in separate experiments, after a pre-treatment fusion with NaOH. The results indicate that zeolites could be formed from different kind of Italian coal fly ash at low temperature of crystallization using both distilled and seawater. SEM data and the powder patterns of X-ray diffraction analysis show that faujasite, zeolite ZK-5 and sodalite were synthesized when using both distilled and seawater; zeolite A crystallized only using distilled water. In particular the experiments indicate that the synthesis of zeolite X and zeolite ZK-5 takes place at lower temperatures when using seawater (35 and 45 degrees C, respectively). The formation of sodalite is always competitive with zeolite X which shows a metastable behaviour at higher temperatures (70-90 degrees C). The chemical composition of the fly ash source could be responsible of the differences on the starting time of synthesized zeolite with distilled water, in any case our data show that the formation of specific zeolites takes place always at lower temperatures when using seawater.

Assessing the origin and fate of Cr, Ni, Cu, Zn, Pb, and V in industrial polluted soil by combined microspectroscopic techniques and bulk extraction methods.

The major geochemical forms of Cr, Ni, Cu, Zn, Pb, and V in a soil from an industrial polluted site in the south of Italy were determined by means of synchrotron X-ray microanalytical techniques such as coupled micro-X-ray fluorescence/micro-X-ray diffraction and micro-X-ray absorption near edge structure spectroscopy in combination with bulk extraction methods (sequential extraction procedures, EDTA extractions, and toxicity leaching characteristic procedure tests). Cr, Ni, Zn, and Cu were found in spinel-type geochemical forms (chromite, trevorite, franklinite, zincochromite, and cuprospinel) and often in association with magnetite and hematite. Vwas mainly present as V(V) associated with iron-oxides or in the form of volborthite [Cu3(OH)2V2O7.2H2O]. Pb was speciated as minium (Pb3O4), lanarkite [Pb2O(SO4)], and, in association with Cr(VI), as crocoite (PbCrO4). In general, despite a high total concentration, metals appear to be speciated for the most part as rather insoluble geochemical forms. However, particular attention should be paid to Zn, Cu, V, and Pb that show non-negligible mobilizable fractions. On the basis of the geochemical forms identified, among others, two major former industrial activities were tentatively ascribed as being responsible for the observed major pollution: polyvinyl chloride and cement-asbestos productions.