Search

In this work, a membrane-based separation was investigate for Scenedesmus almeriensis solutions dewatering. A commercial polyvinylidene fluoride (PVDF) membrane, having a pore size of 3 μm was used in order to allow the water passage through it (permeate), retaining, at the same time, algae biomass (retentate). The possibility to reuse the permeate for a second Scenedesmus almeriensis growth step, was also studied. The registered data evidenced the feasibility of the membrane-based dewatering as an alternative competitive technology, even though the recovery of water should need further investigations to be optimized.

The request for natural products such as antioxidant pigments derived from microalgae, i.e. ß-carotene, lutein and astaxanthin, is growing. In this context, astaxanthin, a powerful antioxidant produced by Haematococcus pluvialis, used as an additive in animal feed and as a food supplement, has been extracted by accelerated solvent extraction using acetone and ethanol as green and safe solvents, and hexane and chloroform:methanol (1:1) performing the best operating conditions. The obtained extracts showed not only the recovery of mainly astaxanthin but also other carotenoids, such as lutein and in lesser part of ß-carotene. In addition, the composition of the extracts was analyzed by highlighting the content of other valuable bio-products such as proteins, carbohydrates, lipids and Total Dietary Fibers. The best extraction performance was found using acetone and ethanol as solvent.

The valorisation of microalgae for the production of valuable biomolecules, for their use in several fields, such as cosmetic, pharmaceutical and animal food, by applying technologies able to avoid any kind of alteration of the biomolecule, is becoming a priority research topic. Several techniques can be used, among them Accelerated Solvent Extraction (ASE) with Generally Recognized As Safe (GRAS) solvents is an interesting technology. This paper deals with Accelerated Solvent Extraction investigations for extraction of lutein (C40H56O2, carotenoid belonging to the xanthophylls group) from Haematococcus pluvialis in red phase with a mechanical pre-treatment method to break the cell wall. Experiments were carried out by comparing performance of several solvents both conventional as Chloroform:Methanol (1:1) and Hexane (class 2 according to FDA classification) and solvents normally accepted in the pharmaceuticals and food industry as Acetone and Ethanol (class 3 of FDA classification) by varying extraction conditions (pressure, temperature and time). Copyright © 2018, AIDIC Servizi S.r.l.

29th European Photovoltaic Solar Energy Conference and Exhibition; 3504-3508, The photovoltaic modules are considered to have a negligible environmental impact compared to the fossil energy. However, in the last years the emission of pollutants from photovoltaic life cycles has attracted the attention of scientists. The principal concern regards the presence of heavy metals as Cd in thin film modules or Pb and Cr in crystalline modules. At the end of life of photovoltaic panels, these dangerous substances could be released in the environment, if special requirements for their disposal are not adopted. However, there is still a lack of experimental data about the release of substances in the environment from photovoltaic panels. As part of a study funded by the Italian national consortium for the waste collection and recycling (COBAT), the present work was aimed to analyze experimentally the potential release into the environment of hazardous elements, particularly metals, from photovoltaic waste. For this purpose, leaching and ecotoxicology tests were performed on PV samples produced in the last 30 years.

The purpose of this study is to investigate the current status of contamination due to the heavy metal and organic substances (PAHs, HC >12, organotin compounds, PCB, DDD, DDE, DDT) pollution of the sediments from the coastal area of the Bagnoli brownfield (Naples, Italy) and draw some hypotheses on the origin and trends of industrial and also geogenic contamination. Surface sediments and cores were collected and analysed. The results showed remarkable concentrations of heavy metals, PAHs, and other substances that are significantly higher than the national guideline values of sea sediment quality. Correlation analyses and spatial distribution analyses showed that generally the inorganic and organic pollutants have similar patterns, confirming the common origin from the industrial activity, but also that some of the studied metals have some natural contribution originated from the geologic setting of the area. The distribution of most of the heavy metals (especially Cd, Hg, Pb, Cu, Zn, partially Cr and Ni) and PAHs are similar, and the highest concentrations were recognised between and just off the piers, but a diffuse contamination is widespread up to the external areas of the site perimeter, rising concern on the diffusion of contaminants to the whole Gulf of Pozzuoli.

The aim of the present work is to demonstrate the practical importance of a multidisciplinary approach and weighted criteria to synthesize and integrate different typologies of data (or lines of evidence, LOEs), including chemical levels in marine sediments, their bioavailability to specific indicator species, ecotoxicological effects measured through subcellular biomarkers and batteries of bioassays, and potential impacts of pollution on local benthic communities. The area of Bagnoli (Gulf of Naples, Southern Italy) was selected as a model case-study, as it is a coastal area chronically impacted by massive industrial contamination (trace metals and hydrocarbons), and dismissed decades ago without any subsequent remediation or habitat restoration. The results of each LOE were elaborated to provide specific hazard indices before their overall integration in a weight of evidence (WOE) evaluation. Levels of some trace metals and PAHs revealed a severe contamination in the entire study area. Bioavailability of hydrocarbons was evident particularly for high molecular weight PAHs, which also caused significant variations of cellular biomarkers, such as cytochrome P450 metabolization in fish, lysosomal membrane destabilization in mussels, genotoxic effects both in fish and molluscs. The results of a battery of bioassays indicated less marked responses compared to those obtained from chemical and biomarkers analyses, with acute toxicity still present in sediments close to the source of contamination. The analysis of benthic assemblages showed limited evidence of impact in the whole area, indicating a good functioning of local ecosystems at chronic contamination. Overall, the results of this study confirm the need of combining chemical and biological data, the quantitative characterization of various typologies of hazard and the importance of assessing an integrated environmental WOE risk, to orientate specific and scientifically-supported management options in industrialized areas.

The aim of the paper is to evaluate the bioenergy and bio-based material recovery from fruit scraps through an innovative process, e.g., supercritical water gasification, which presents several advantages in comparison to the traditional processes for energy and matter recovery. In particular, experimental tests of peach scraps were carried out using bench-scale plant plug flow reactor type, in which the selected liquid matter can be pumped until 300 bar and heated until 600°C to achieve the supercritical water condition of the water. The main results showed that, in the range of the feed flow rate of 5-30 mL/min and at fixed operative conditions of T and P (T = 550°C, and P = 250 bar), it is possible to obtain tar-free syngas with a higher heating value of 14-16 MJ/kgdry basis. The influence of the residence time was studied for the gaseous and liquid phases. For each one of them, it was possible to highlight a specific trend. In the liquid phase, the main components were acetic acid, hydroquinone, and syringaldehyde that are intermediates for the chemical synthesis of interesting bio-based chemicals and biochemicals. © 2016 American Chemical Society.

Solvent Extraction was tested to extract astaxanthin from Haematococcus pluvialis in red phase (HPR), by investigating effects of solvents, extraction pressure and temperature. Astaxanthin isomers were identified and quantified in the extract. The performances of acetone and ethanol, Generally Recognized As Safe (GRAS) solvents, were explored. Negligible effect of pressure was found, while with increasing extraction temperature astaxanthin recovery increased till a maximum value, beyond which thermal degradation seemed to be greater than the positive effect of temperature on extraction. Furthermore, to maximize the extraction yield of astaxanthin, mechanical pre-treatment of HPR biomass was carried out and several extraction runs were consecutively performed. Experimental results showed that after the mechanical pre-treatment the astaxanthin recovery strongly increased while a single extraction run of 20 min was sufficient to extract more than 99% of total astaxanthin extracted. After pre-treatment, maximum recovery of about 87% was found for acetone (pressure = 100 bar; temperature = 40 °C; total time = 60 min).

The valorisation of microalgae for the production of valuable biomolecules, for their use in several fields, such as cosmetic, pharmaceutical and animal food, by applying technologies able to avoid any kind of alteration of the biomolecule, is becoming a priority research topic. Several techniques can be used, among them Accelerated Solvent Extraction (ASE) with Generally Recognized As Safe (GRAS) solvents is an interesting technology. This paper deals with Accelerated Solvent Extraction investigations for extraction of lutein (C40H56O2, carotenoid belonging to the xanthophylls group) from Haematococcus pluvialis in red phase with a mechanical pre-treatment method to break the cell wall. Experiments were carried out by comparing performance of several solvents both conventional as Chloroform:Methanol (1:1) and Hexane (class 2 according to FDA classification) and solvents normally accepted in the pharmaceuticals and food industry as Acetone and Ethanol (class 3 of FDA classification) by varying extraction conditions (pressure, temperature and time ).

This work is focused on the production of activated carbon from waste tires by means of a two-steps process: steam gasification of starting material followed by steam activation of char. In particular the evaluation of the most appropriate hold time value for the activation step, in terms of quality and amount of activated carbons produced, and the energy balance of the overall process were performed. The hold time was choose as the best compromise between a high surface area of final product and a not excessively low burn-off value. Investigations were carried out through seven experimental tests on a pilot plant based on a rotary kiln reactor. Studies performed pointed out that, when other process parameters were kept constant (in steam gasification: temperature is 850 °C, steam to feed ratio is 1, mean residence time of material is 6 min, carrier flowrate of N2 is 0.9 Nm3h−1; in steam activation: temperature is 920 °C, steam to char ratio is 2, carrier flowrate of N2 is 1 Nm3h−1), a hold time in activation step set to 3 h is the best choice, resulting in a surface area of 786 m2·g−1 and a burn-off value equal to 78.4%. Moreover, the energy balance of the overall process which goes from waste tires to activated carbon was performed: if 1 kg·h−1 of waste tires are gasified and activated for three hours, an input power of 3.5 kW is requested. After the experimental tests, a theoretical model was developed, based on the Arrhenius equation whose parameters were determined from a sigmoidal regression of the experimental data. The theoretical model showed results in good agreement with the experimental data, especially for hold times greater than 2 h, and can represent a useful tool to make decision choices. © 2017 Elsevier B.V.

Homepage > Generale > Archivio > Archivio completo Surface water – groundwater connectivity implications on nitrate cycling assessed by means of hydrogeologic and isotopic techniques in the Alento river basin (Salerno, Italy): preliminary data Luisa Stellato(a), Brunella Di Rienzo(a), Egidio Di Fusco(a), Mauro Rubino(a), Fabio Marzaioli(a) & Vincenzo Allocca(b) Antonio Salluzzo (c), Juri Rimauro(c), Nunzio Romano(d) & Fulvio Celico(e) (a) Centre for Isotopic Research on Cultural and Environmental heritage (CIRCE), Dip. di Matematica e Fisica, Seconda Università degli Studi di Napoli, Viale Lincoln, 5, 81100 Caserta, Italy. E-mail: luisa.stellato@unina2.it (b) Dipartimento di Scienze della Terra, dell'Ambiente e delle Risorse (DiSTAR), Università di Napoli Federico II,Via Mezzocannone, 8, 80134, Napoli, Italy. (c) ENEA - Research Center of Portici, UTTP-CHIA, Environmental Chemistry Laboratory, Piazzale E. Fermi, 1, 80055 Portici (Napoli), Italy. (d) Dept. of Agriculture, Division of Agricultural, Forest and Biosystems Engineering, Università di Napoli Federico II, Via Università, 100, 80055, Portici (Napoli), Italy. (e) Interdisciplinary Centre for Studies on Water Resources, Department of Physics and Earth Sciences "Macedonio Melloni", University of Parma, Parco Area delle Scienze, 157/A, 43124, Parma, Italy. DOI: 10.3301/ROL.2016.98 Pages: 80-83 Abstract The knowledge of the mechanisms regulating the concentration of nutrients in rivers is of fundamental importance in maintaining the ecological functioning of streams. In particular, in the riverbed sediments, where the biogeochemical activity is enhanced, the study of retention mechanisms becomes crucial in order to determine the restoring capacity of a watercourse. In case of groundwater inflow, hot-spots in the recycling of nutrients within the riparian and hyporheic zones can be observed, influencing the nutrient load transported into the stream depending on retention mechanisms. Hence, the study of biotic and abiotic factors affecting retention and transport of nutrients in a riverine ecosystem at different spatial scales (from reach to catchment) becomes fundamental to understand the mechanisms regulating the concentration of nutrients, and in particular nitrates, in streams. The present work is developed within the framework of the IAEA Coordinated Research Project (CRP) "Environmental Isotopes and Age Dating Methods to Assess Nitrogen Pollution and Other Quality Issues in Rivers". The main scope is to find a reliable methodology to, spatially and temporally, quantify groundwater inflows to a river in order to study nitrates contamination of a groundwater dependent river ecosystem. In particular, the overall objectives of the proposed project are: i) the identification and quantification of spatio-temporal variation of the connectivity between groundwater and surface water; ii) the identification of the nitrate contamination sources of shallow groundwater; iii) the study of the nitrates retention and recycling mechanisms in riverbed sediments in critical effluent river reaches (key sites) in order to determine the importance of hyporheic and riparian zones. Here, the preliminary results of the hydrogeological, chemical and isotopic (222Rn, δ18O, δD) monitoring are presented and discussed.

Recently the potential environmental hazard of photovoltaic modules together with their management as waste has attracted the attention of scientists. Particular concern is aroused by the several metals contained in photovoltaic panels whose potential release in the environment were scarcely investigated. Here, for the first time, the potential environmental hazard of panels produced in the last 30 years was investigated through the assessment of up to 18 releasable metals. Besides, the corresponding ecotoxicological effects were also evaluated. Experimental data were compared with the current European and Italian law limits for drinking water, discharge on soil and landfill inert disposal in order to understand the actual pollution load. Results showed that less than 3% of the samples respected all law limits and around 21% was not ecotoxic. By considering the technological evolutions in manufacturing, we have shown that during the years crystalline silicon panels have lower tendency to release hazardous metals with respect to thin film panels. In addition, a prediction of the amounts of lead, chromium, cadmium and nickel releasable from next photovoltaic waste was performed. The prevision up to 2050 showed high amounts of lead (30 t) and cadmium (2.9 t) releasable from crystalline and thin film panels respectively. © 2015 Elsevier B.V.

The aim of this study is to investigate at what extent the results of standard nanoparticle (NP) toxicity testing methodologies are affected by the different exposure procedures on soil organisms. In this view, differences in physicochemical properties of ZnO NPs (

The rapid expansion of the photovoltaic (PV) module market in the last years will determine in the near future a remarkable growth of corresponding waste. Then, the hazardous materials contained in the modules, such as Cd, Pb and Cr, could be released in the environment if the waste panels will not be handled adequately. Recycling processes of silicon crystalline panels, finalized to separate PV cells from the glass, involve the removal of the EVA (Ethylene Vinyl Acetate) layer through different methods, as the thermal treatment. During this treatment, some hazardous components can be released due to thermal degradation process. In this paper the metals released in the gas emissions and in the ashes due to the thermal treatment of modules were evaluated. For this purpose, three samples of crystalline panels were heated in furnace up to 600°C and the complete degradation of the EVA was obtained. A mass balance between the sample and its components, before and after treatment, was performed in order to assess the weight loss percentage. Finally, after thermal treatment a qualitative analysis on the separated PV cell surface was performed by SEM-EDS (Scanning Electron Microscope equipped with Energy Dispersive Spectrometer). © 2015 Elsevier Ltd.