Search results for " intensification"
showing 10 items of 37 documents
Improvement of membrane performances to enhance the yield of vanillin in a pervaporation reactor.
2014
In membrane reactors, the interaction of reaction and membrane separation can be exploited to achieve a “process intensification”, a key objective of sustainable development. In the present work, the properties that the membrane must have to obtain this result in a pervaporation reactor are analyzed and discussed. Then, the methods to enhance these properties are investigated for the photocatalytic synthesis of vanillin, which represents a case where the recovery from the reactor of vanillin by means of pervaporation while it is produced allows a substantial improvement of the yield, since its further oxidation is thus prevented. To this end, the phenomena that control the permeation of bot…
A PERVAPORATION PHOTOCATALYTIC REACTOR FOR THE GREEN SYNTHESIS OF VANILLIN
2012
Abstract Pervaporation is the ideal membrane separation process to be coupled with photocatalysis for the green synthesis of vanillin from ferulic acid. In fact the operative conditions of the two processes are absolutely congruent and the integration is straightforward even operating with separate equipments. The utilization of a highly selective membrane allows the continuous recovery of vanillin by pervaporation from the reacting solution, so that its oxidative degradation is largely avoided and the yield is substantially enhanced. The effects of the main parameters are analyzed resorting to a mathematical model, which is validated by a comparison with the experimental data. In particula…
Pesticide doses, landscape structure and their relative effects on farmland birds
2014
International audience; tAgricultural changes related to the intensification of farming practices and the simplification of land-scape elements often occur simultaneously. Their respective effects on biodiversity are thus difficult todisentangle and are poorly understood. This study assessed the relative contribution of each componentof agricultural intensification on taxonomic and functional bird communities.The bird communities studied were composed of 70 species, both farmland and non-farmland birds,found in 66 fields covering three main cereal departments of France. Herbicide dose was related to mea-surable negative effects on the Community Specialization Index (CSI). Overall, the propo…
Agriculture intensity and landscape configuration influence the spatial use of wildcats across Europe
2023
Land use intensification is increasing worldwide and affects wildlife movements, particularly of specialist car-nivores. Resource availability and anthropogenic activities drive the extent and shape of home range size. Wildlife may respond to decreased resource availability under intensification scenarios by increasing their home ranges; however they may be less affected when inhabiting sustainable agricultural landscapes. We investigate whether agricultural practices and landscape configuration influence the spatial behaviour of wildcats, a medium-sized specialist carnivore inhabiting landscapes with different degrees of agricultural presence across Europe. We focus on the effect of the pr…
System Design Rules for Intensifying the Electrochemical Reduction of CO 2 to CO on Ag Nanoparticles
2020
Electroreduction of CO2 (eCO2RR) is a potentially sustainable approach for carbon-based chemical production. Despite significant progress, performing eCO2RR economically at scale is challenging. Here we report meeting key technoeconomic benchmarks simultaneously through electrolyte engineering and process optimization. A systematic flow electrolysis study - performing eCO2RR to CO on Ag nanoparticles as a function of electrolyte composition (cations, anions), electrolyte concentration, electrolyte flow rate, cathode catalyst loading, and CO2 flow rate - resulted in partial current densities of 417 and 866 mA/cm2 with faradaic efficiencies of 100 and 98 % at cell potentials of −2.5 and −3.0 …
The taint of torture and the brazilian legal system
2019
In Brazil, the practice of torture intertwines deeply with its own history. The literature on the subject has had a greater intensification on its registers during the Dictatorial Regime (1964 to 1985). In spite of the Brazilian Constitution of 1988, Brazil only makes efforts to investigate the crimes of torture of this period to comply with the provisions of the United Nations in 2011. Within this scenario, the NationalTruth Commission (Law 12.528, of November 2011) was created with the purpose of clarifying the facts and circumstances of cases concerning human rights violations, as well as the Law on Access to Information (Law 12.527 of November 2011), which have regulated the constitutio…
The role of sustainable agroforestry practices and food consumption to prevent tropical deforestation and increase ecosystem services
2022
Tropical forests harbor most of global terrestrial biodiversity and provide essential ecosystem services, although they have been largely replaced by agricultural activities. Amazon is the largest tropical forest remaining, and cattle ranching and soybean cultivation are by far the greater drivers of deforestation, that together with other few commodities constitutes the main products responsible for the imported deforestation caused by European countries. Agroforestry systems and sustainable intensification are pointed out as solutions to conciliate food production with environmental conservation, thus reviewing the results of studies comparing these practices against conventional ones are…
Photocatalytic process intensification by coupling with pervaporation
2011
The integration of photocatalysis with a membrane separation process, in particular pervaporation, permits the recovery of valuable intermediate compounds (aromatic aldehydes) while they are produced avoiding their further degradation in the reactive ambient. In this way the yield and the conversion are enhanced. The coupling of the two processes is straightforward and the integration is complete even maintaining pervaporation and photocatalysis in two separate apparatuses provided that the process stream is continuously recycled at a sufficiently high flow rate. Additional advantages are: higher degree of purification of the aldehyde in the powder-free product stream, semicontinuous produc…
Photocatalytic ozonation:Maximization of the reaction rate and control of undesired by-products
2014
In theso-calledphotocatalyticozonation(PO)synergisticeffectsbetweenphotocatalysisandozonation enhance therateofoxidationoforganiccompounds,thereforethisintegratedprocessisverypromising for useinwatertreatment.Inthepresentwork,itisdemonstratedthattheimprovementthatcanbe obtained bytheintegratedprocessincomparisonwiththeuncoupledprocessesdependsontherelative weight between photocatalysis and ozonation. In this respect, it has been found that a relatively low rate of photocatalysis (0.3 times the rate of ozonation)issufficienttogetthehighestsynergyandtomaximize the performancesintheoxidationofformate,theadoptedmodelorganiccompound.Thebenefitsof the couplingofphotocatalysistoozonationarenotlimi…
Electrodialysis with bipolar membranes for the generation of NaOH and HCl solutions from brines: an inter-laboratory evaluation of thin and ultrathin…
2022
The SEArcularMINE project aims to recover critical raw materials (CRMs) from brines from saltworks, thus facing a CRM shortage within Europe. To promote a fully circular scheme, the project valorises concentrated brines using electrodialysis with bipolar membranes (EDBM) to generate the required amounts of reactants (i.e., acids and bases). Regarding the performances of new non-woven cloth ion-exchange membranes (Suez): (i) an ultra-thin non-woven polyester cloth and (ii) a thin polypropylene cloth acting as the support structures were assessed. Additionally, the anion layer includes a catalyst to promote the water dissociation reaction. The effect of current density (100, 200, and 300 A m&…