nZVI particles production for the remediation of soil and water polluted by inorganic Lead

The present study deals with experiments of Pb removal by nano-Zero Valent Iron (nZVI) in aqueous solution and in soil. Synthetic Pb aqueous solutions were treated by nZVI, at a fixed Pb concentration of 100 mg L-1 , varying nanoparticles initial concentration in the range between 27 and 270 mg nZVI L-1 . A kinetic study was carried out: Pb adsorption followed a first order kinetic, and half life times between 11 and 26.66 min were determined. Soil samples were first characterized, and Pb speciation and concentration by sequential extractions was determined. Adsorption tests were then carried out at three selected amounts of nZVI, to allow Pb stabilization in the soil matrix. To evaluate the treatment efficiency, sequential extractions were also performed on the treated samples

Continuous production of KNO3 nanosalts for the fertilization of soil by means of a Spinning Disk Reactor

In this study the production of high soluble material nanoparticles was successfully performed by means of a spinning disk reactor (SDR). This result was possible due to the use of a potassium nitrate saturated solution, which was continuously recycled back to the reactor after removal of the produced solid nanoparticles. Several process configurations were checked. It appears to be mandatory that the recycled saturated solution must be free of residual nanoparticles since their presence would lead to heterogeneous nucleation. In this respect, a small amount of nitric acid was added to the stream to permit the residual nanoparticle dissolution. Moreover, a spiral wounded piping system was developed in order to increase both the contact time and the mixing condition of the saturated solution with the added acid before entering the SD

Hexavalent chromium reduction in manganese-rich soils by ZVI nanoparticles: the influence of natural organic matter and manganese oxides

Hexavalent chromium reduction by nano Zero-Valent Iron (nZVI) has been proved fast and efficient, mainly due to nanoparticles large specific surface area and high chemical reactivity. In this work the influence of natural organic matter and manganese oxide was investigated, through a set of experimental tests carried out on a real polluted soils naturally rich in manganese. Soil samples were characterized in terms of initial concentration of Cr, Cr(VI), Mn, pH, and TOC and three different nZVI solutions were used (120, 360 and 600 mg nZVI L-1 ) for the treatment. At selected interval times (0, 5, 10, 15, 30, 60, 120 min) a slurry sample was filtered and Cr(VI) residual concentration and pH were measured. The same procedure was carried out on an artificial spiked soil, characterized by a similar TOC and poor of Mn. Furthermore the two soils were mixed with different amounts of leonardite, to evaluate the influence of NOM on treatment efficiency

Chromium recovery by membranes for process reuse in the tannery industry

Leather tanning is a wide common industry all over the world. In leather processing, water is one of the most important medium, almost 40-45 L water kg-1 raw-hide or skin is used by tanneries for processing finished leathers. The composition of tannery wastewater presents considerable dissimilarities in the concentration range of pollutants both of inorganic (chlorides, with concentration ranging from several hundred to over 10,000 mg L-1 Cl–; sulphate (VI), ammonium ions and sulphide ions, exhibiting concentration that ranges from tens to several hundred mg L-1) and organic (the COD value is usually several thousand mg L-1 O2). Throughout the years, many conventional processes have been carried out to treat wastewater from tannery industry: unfortunately, in this case, biological treatment methods give rise to an excessive production of sludge, whereas physical and chemical methods are too expensive in terms of energy and reagent costs. In this work, a membrane process based on NF membrane modules was adopted to treat the tannery feedstock after primary conventional treatment. In a first step, the determination of all boundary flux parameters, in order to inhibit severe fouling formation during operation, were performed. After this, experimental work was carried out to validate the approach. The target of water purification was reached, that is the legal discharge to municipal sewer system in Italy of 90% of the initial wastewater stream volume. This allows having an immediate cost saving of 21%. Moreover, the developed process leads to a second benefit, that is the production of 5% of the initial volume as a highly chromium-rich concentrate at no cost suitable to tannery process recycle and reuse. In this case, cost saving rates exceeds 40%. At the end, scale-up of the investigated process will be discussed from technical and economic point of view

About the limits of microfiltration for the purification of wastewaters

In the past, microfiltration was widely used as a pretreatment step for wastewater stream purification purposes. Experiences performed during the last years shows that microfiltration fails to maintain its performances for longer period of times. Many case studies demonstrate that the adoption of microfiltration leads to the failure of the overall process; the severe fouling of the microfiltration membranes leads to high operating costs with the consequence to make the treatment of the wastewater economically unfeasible. The boundary flux concept is a profitable tool to analyze fouling issues in membrane processes. The boundary flux value separates an operating region characterized by reversible fouling formation from irreversible one. Boundary flux values are not content, but function of time, as calculated by the subboundary fouling rate value. The knowledge of both parameters may fully describe the membrane performances in sub-boundary operating regimes. Many times, for wastewater purification purposes, ultrafiltration membranes appear to be suits better to the needs, even they exhibit lower permeate fluxes compared to microfiltration. Key to this choice is that ultrafiltration appears to resist better to fouling issues, with a limited reduction of the performances as a function of time. In other words, it appears that ultrafiltration exhibit higher boundary flux values and lower sub-boundary fouling rates. In this work, after a brief introduction to the boundary flux concept, for many different wastewater streams (more than 20, produced by the most relevant industries in food, agriculture, manufacture, pharmaceutics), the boundary flux and sub-boundary fouling rate values of different microfiltration and ultrafiltration membranes will be discussed and compared. The possibility to successfully use microfiltration as a pretreatment step strongly depends on the feedstock characteristics and, in detail, on the particle size of the suspended matter. In most cases, microfiltration demonstrates to be technically unsuitable for pretreatment purposes of many wastewater streams; as a consequence, the adoption of microfiltration pushes operators to exceed boundary flux conditions, therefore triggering severe fouling, that leads to economic unfeasibility of the process in long terms

Denitrification-derived nitric oxide modulates biofilm formation in Azospirillum brasilense

Azospirillum brasilense is a rhizobacterium that provides beneficial effects on plants when they colonize roots. The formation of complex bacterial communities known as biofilms begins with the interaction of planktonic cells with surfaces in response to appropriate signals. Nitric oxide (NO) is a signaling molecule implicated in numerous processes in bacteria, including biofilm formation or dispersion, depending on genera and lifestyle. Azospirillum brasilense Sp245 produces NO by denitrification having a role in root growth promotion. We analyzed the role of endogenously produced NO on biofilm formation in A. brasilense Sp245 and in a periplasmic nitrate reductase mutant (napA::Tn5; Faj164) affected in NO production. Cells were statically grown in media with nitrate or ammonium as nitrogen sources and examined for biofilm formation using crystal violet and by confocal laser microscopy. Both strains formed bio- films, but the mutant produced less than half compared with the wild type in nitrate medium showing impaired nitrite production in this condition. NO measurements in biofilm confirmed lower values in the mutant strain. The addition of a NO donor showed that NO influences biofilm formation in a dose-dependent manner and reverses the mutant phenotype, indicating that Nap positively regulates the formation of biofilm in A. brasilense Sp245.Fil: Arruebarrena Di Palma, Andrés. Universidad Nacional de Mar del Plata; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pereyra, Cintia Mariana. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata; ArgentinaFil: Moreno Ramírez, Lizbeth. Benemérita Universidad Autónoma de Puebla; MéxicoFil: Xiqui Vazquez, Maria L.. Benemérita Universidad Autónoma de Puebla; MéxicoFil: Baca, Beatriz E.. Benemérita Universidad Autónoma de Puebla; MéxicoFil: Pereyra, María Alejandra. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lamattina, Lamattina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Biológicas. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biológicas; ArgentinaFil: Creus, Cecilia Mónica. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Analytical Model of Connected Bi-Omega: Robust Particle for the Selective Power Transmission Through Sub-Wavelength Apertures

Cataloged from PDF version of article.In this paper, we present a new analytical model of the connected bi-omega structure consisting of two bi-omega particles connected together through their arms. A single bi-omega particle consists of a pair of regular equal omegas with mirror symmetry. Assuming the individual bi-omega particle electrically small, the equivalent circuit is derived, in order to predict its resonant frequency. Then, two bi-omega particles are connected together, obtaining a symmetric structure that supports two fundamental modes, with even and odd symmetries, respectively. The proposed analytical model, then, is used to develop a procedure allowing the design of the particle for a desired resonant frequency. The effectiveness of the proposed analytical model and design guidelines is confirmed by proper comparisons to full-wave numerical and experimental results. We also demonstrate through a proper set of experiments that the resonant frequencies of the connected bi-omega particle depend only on the geometrical and electrical parameters of the omegas and are rather insensitive to the practical scenario where the particle itself is actually used, e.g. in free-space, rectangular waveguide or across an aperture in a metallic screen

Parental evaluation of a telemonitoring service for children with Type 1 Diabetes

Introduction In the past years, we developed a telemonitoring service for young patients affected by Type 1 Diabetes. That service provides data to the clinical staff and offers an important tool to the parents, that are able to oversee in real time their children. The aim of this work was to analyze the parents' perceived usefulness of the service. Methods The service was tested by the parents of 31 children enrolled in a seven-day clinical trial during a summer camp. To study the parents' perception we proposed and analyzed two questionnaires. A baseline questionnaire focused on the daily management and implications of their children's diabetes, while a post-study one measured the perceived benefits of telemonitoring. Questionnaires also included free text comment spaces. Results Analysis of the baseline questionnaires underlined the parents' suffering and fatigue: 51% of total responses showed a negative tendency and the mean value of the perceived quality of life was 64.13 in a 0-100 scale. In the post-study questionnaires about half of the parents believed in a possible improvement adopting telemonitoring. Moreover, the foreseen improvement in quality of life was significant, increasing from 64.13 to 78.39 ( p-value\u2009=\u20090.0001). The analysis of free text comments highlighted an improvement in mood, and parents' commitment was also proved by their willingness to pay for the service (median\u2009=\u2009200\u2009euro/year). Discussion A high number of parents appreciated the telemonitoring service and were confident that it could improve communication with physicians as well as the family's own peace of mind

In the eye of the storm : the Italian economy and the eurozone crisis

The eurozone crisis had a more significant and longer-lasting impact on Italy than on virtually any other member state, with the effects still visible a decade after. The extent of the shock was surprising in view of progress Italy had apparently made in the 1990s in terms of enhancing its capacity to meet the demands of European Monetary Union. The explanation for this traumatic economic experience lies in Italy’s deep, long-term, structural tensions which were placed under severe pressure during the 1990s and which were cracked open by the 2011 sovereign debt crisis. These have had long-standing economic effects as well as political ramifications in terms of a significant change in the Italy–EU relationship