Giorgio Vilardi

Nitrates removal by bimetallic nanoparticles in water

Nitrate contamination of groundwater has become a major environmental concern since nitrates are easily transferred from unsatured zone to the satured one, due to their solubility and low sorptivity on soil particles caused by their negative charge. The effectiveness and rapidity of the reduction of NO3 is strongly dependent on the contact time, the concentration of the reductive agent, the properties and composition of the surrounding medium (pH, dissolved oxygen concentration, heavy metals and organic matter concentration). The aim of this work was to investigate the effectiveness of nZVI and bimetallic nanoparticles of Fe/Cu in the remediation of nitrate-polluted groundwaters. nZVI and Fe/Cu nanoparticles were prepared by sodium borohydride reduction method at room temperature and ambient pressure. Results confirm that the decontamination of nitrate in groundwater via the in-situ remediation by Fe/Cu nanoparticles is environmentally attractive. Batch experiments were conducted on water samples contaminated in laboratory using NaNO3 to fix the initial nitrate concentration to 57.5 mg/L. The Cu/Fe ratio was fixed to 0.05 (w/w) and the parameter investigated was the Fe/NO3 weight ratio (5,10 and 15 w/w). During the tests the aqueous solution was analyzed to measure the evolution of NO3 and pH at 0, 30, 60, 90, 120 and 150 min. The results showed the increasing rate of reduction of nitrate by adding copper to ZVI particles; in fact fixing the Fe/NO3 to 15 the tests without copper resulted in a complete removal within 150 min against the 60 min required by the tests with copper.

The Influence of Heavy Metals and Organic Matter on Hexavalent Chromium Reduction by Nano Zero Valent Iron in Soil

During the last decades great attention has been payed at evaluating the feasibility of Cr(VI) reduction in soil by nano zero valent iron (nZVI). An inhibitory effect on the Cr(VI) reduction by Fe nanoparticles is generally shown in the presence of high level of heavy metals and natural organic matter in soil. Heavy metals in the environment can react with nZVI by redox reactions, precipitation/dissolution reactions, and adsorption/desorption phenomena. As a result of the presence of metals as Ni, Pb, a decrease in the rate of Cr(VI) reduction was observed. Hence, in the present study, experimental tests of Cr(VI) reduction by nZVI in the presence of selected heavy metals, such as nickel and lead, and in the presence of high level of organic matter, are presented and discussed. Results showed a decrease in the rate of Cr(VI) reduction in soil by nZVI (at a x25 stoichiometric excess) from 91% to 78%, 71% and 74% in the presence of Ni, Pb and both metals respectively. As regards the results of Cr(VI) reduction in the presence of organic matter, by using a reducing solution of nZVI (x25 stoichiometric excess) a decrease of Cr(VI) reduction yield from 91% to 12% was observed after 2 hours of treatment in a soil containing 35.71 g/kg of organic matter. Such low efficiency was attributed to the adsorption of organic matter onto Fe nanoparticles surface, thus saturating the active reaction sites of Fe nanoparticles. In addition, a significant reduction of the organic carbon in the treated soil was observed (up to 77.5%) caused by the degradation of organic matter and its dissolution in the liquid phase. A slight decrease of the total metal concentration in treated soil was also observed. Finally, kinetic tests show that Cr(VI) reduction using nZVI in the presence of a high concentration of organic compound obeyed a pseudo-zero-order kinetic model.

Binders alternative to Portland cement and waste management for sustainable construction—part 1:

This review presents “a state of the art” report on sustainability in construction materials. The authors propose different solutions to make the concrete industry more environmentally friendly in order to reduce greenhouse gases emissions and consumption of non-renewable resources. Part 1—the present paper—focuses on the use of binders alternative to Portland cement, including sulfoaluminate cements, alkali-activated materials, and geopolymers. Part 2 will be dedicated to traditional Portland-free binders and waste management and recycling in mortar and concrete production.

Perspectives in nanotechnology based innovative applications for the environment

In this perspective paper, the actual trends in nanotechnology based innovative applications for the environment are analyzed and possible future trends were studied. On the basis of the relevant topics of the NINE congress held in Rome, 2016, a bibliographical search was performed on papers fitting in one or more categories within the last 5 years, that is: 1. Nanosensors and bionanosensors for environmental characterization and monitoring 2. Technologies for the production of Nanomaterials for the environment 3. Nanostructured materials for advanced remediation processes 4. Nano-based water and wastewater treatment processes 5. Membrane processes for the environment 6. Health and safety issues concerning Nanomaterials 7. Education on Environmental Engineering and Nanotechnology. A yearly count of contributions was performed and taken as an indicator of interest of the specific topic within the wide broad scientific community. In a second step, the resulting data was analyzed by regression techniques to estimate the trend in the next future and to evaluate the next challenges within the international research framework.

Treatment of olive oil processing wastewater by ultrafiltration, nanofiltration, reverse osmosis and biofiltration

Treatment of Olive Oil Processing Wastewater by Ultrafiltration, Nanofiltration, Reverse Osmosis and Biofiltration Marco Stoller*, Gunel Azizova, Aysel Mammadova, Giorgio Vilardi, Luca Di Palma, Angelo Chianese a Department of Chemical Materials Environmental Engineering, ‘La Sapienza’ University of Rome, Rome, Italy b Department of Ecology and Soil Science, Baku State University, Baku, Azerbaijan c Department of Water Economy and Communication Systems Engineering, Azerbaijan University of Architecture and Construction, Baku, Azerbaijan marco.stoller@uniroma1.it

XPS Spectra Analysis of Ti 2+ , Ti 3+ Ions and Dye Photodegradation Evaluation of Titania-Silica Mixed Oxide Nanoparticles

AbstractTiO2-SiO2 mixed oxides have been prepared by the sol–gel technique from tetrabutyl orthotitanate and tetraethyl orthosilicate. The prepared materials were characterized by x-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, nitrogen physisorption, Fourier-transform infrared spectroscopy (FT-IR) and x-ray photoelectron spectroscopy (XPS). The results indicate that the TiO2-SiO2 mixed oxides have a large surface area and a nanoscale size. FT-IR spectra show that Ti atoms are bonded to silica by oxygen bridging atoms in Ti-O-Si bonds. The titanium valence states in TiO2-SiO2 mixed oxides were investigated by XPS, and their spectra report the presence of Ti2+ and Ti3+ cations for high silica concentration, suggesting the formation of oxygen vacancies. The photocatalytic activity of the prepared materials has been evaluated for the photodegradation of methylene blue (MB). The mixed oxides were activated by means of a UV light source, and the concentration of MB was monitored by UV–Vis spectroscopy. The synthesized TiO2-SiO2 shows significantly higher MB removal efficiency in comparison with that of the commercial TiO2 Degussa, P25.Graphical AbstractIn this paper, we observed three valence states of titanium: Ti4+, Ti3+ and Ti2+ in TiO2-SiO2 40%. This issue has not yet been reported. XPS analysis show that the content of Ti2+ and Ti3+ amounts to 25.26 at.% and 13.08 at.%, respectively, while the concentration of Ti4+ is 61.72 at.%, much lower than in the TiO2-SiO2 9% sample. This behavior is explained observing that in TiO2-SiO2 40%, Ti4+ is reduced to Ti3+ and Ti2+ to a larger extent with respect to TiO2-SiO2 9%.

Process intensification techniques for the production of nano- and submicronic particles for food and medical applications

BACKGROUND Nowadays, nanoparticles are of great interest for the industry due to their numerous possible applications in several fields. Research on this topic seeks to develop many procedures to produce nanoparticles, mostly at lab scale, batch-wise and with low yield. These procedures generally do not suit industrial needs of continuous, high capacity production. Moreover, the product characteristics require targeting narrow particle size distributions and high quality, which is difficult to achieve by traditional equipment. METHODS Process intensification techniques aim to minimize plant size of continuous, high yield equipment capable to produce specific sized, high quality nanoparticles, combined with an increase in energy efficiency, safety and cost reduction. DISCUSSION This paper reviews some adopted Process Intensification (PI) techniques for nanoparticles synthesis processes employed in the food and pharmaceutical sector. CONCLUSION By reducing the technology transfer gap, nanotechnologies may become convenient and feasible, allowing both industries to achieve the production of higher quality products with particular characteristics without sensibly increasing additional costs. This will represent in the next future a strategic key feature of industries in the global market.

Kinetic Modeling of Cr(VI) Reduction by nZVI in Soil: The Influence of Organic Matter and Manganese Oxide

The effect of soil composition on the reduction of hexavalent chromium (Cr(VI)) by zero valent iron nanoparticles was studied. A model was proposed, to investigate both the effect of manganese oxide and the simultaneous effect of manganese dioxide and soil organic matter on the kinetic of Cr(VI) reduction. Fe(0) nanoparticles consumption by the reaction with dissolved oxygen, water and soluble Cr(VI) was taken into account. The model was validated through experimental tests performed on soil samples collected at an industrial polluted site, and on artificially contaminated samples from the same site, in the presence of selected amount of leonardite.

Artificial aggregate from non metallic automotive shredder residue

Until 2005 in the European Union (EU) approximately 12 M vehicles were yearly shredded, and 8 or 9 M t/ year of waste was produced. About 14 million tons of End of Life Vehicles (ELVs) are foreseen by 2015. This huge amount of waste must be treated and disposed of in a sustainable way. The most common treatment technologies, involve ELVs shredding to recover iron and steel (70%) and non ferrous metals (5%) from vehicles. The remaining fraction, called Automotive Shredder Residue (ASR), and representing about 25% wt. of each vehicle, is generally landfilled. For more than two thirds, this last residue deals with combustible materials (fibers, polyethylene etc..), suitable to be reused as a fuel, but a substantial amount of soil particles, metals, glasses and plastics residues are also present. Consequently, a new sustainable way to reuse ASR is to separate the organic from the inorganic fraction, and use them in combustion plants, gasification and in the cement industry, respectively. Regarding this second way of recovery, several studies have been already successfully performed with the aim of transforming ASR into aggregates for asphalt or cement mixes, by thermal treatment followed by chemical treatment, or by physical processes, such as granulation. In this work, a selected fraction of non metallic automobile shredder residue was immobilized in granules produced at room temperature in a pilot scale granulator. Granules were obtained by mixing selected amount of ASR with a binder (cement or lime) in the presence of additions (fly ash) and admixtures. The final aim of this work was to investigate the mechanical properties of concrete samples produced using the artificial aggregate obtained through different combinations of ASR, fly ash and binder. Additional freeze and thaw tests were finally performed to assess concrete durability along time.