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- Campalani, Carlotta, et al.
(författare)
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Biobased Carbon Dots: From Fish Scales to Photocatalysis
- 2021
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Ingår i: Nanomaterials. - : MDPI. - 2079-4991. ; 11:2
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Tidskriftsartikel (refereegranskat)abstract
- The synthesis, characterization and photoreduction ability of a new class of carbon dots made from fish scales is here described. Fish scales are a waste material that contains mainly chitin, one of the most abundant natural biopolymers, and collagen. These components make the scales rich, not only in carbon, hydrogen and oxygen, but also in nitrogen. These self-nitrogen-doped carbonaceous nanostructured photocatalyst were synthesized from fish scales by a hydrothermal method in the absence of any other reagents. The morphology, structure and optical properties of these materials were investigated. Their photocatalytic activity was compared with the one of conventional nitrogen-doped carbon dots made from citric acid and diethylenetriamine in the photoreduction reaction of methyl viologen.
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| 5. |
- D'Angelo, Sebastiano C., et al.
(författare)
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Techno-Economic Analysis of a Glycerol Biorefinery
- 2018
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Ingår i: ACS Sustainable Chemistry & Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 6:12, s. 16563-16572
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Tidskriftsartikel (refereegranskat)abstract
- Biodiesel is an environmentally friendly alternative to fossil fuels, which is experiencing a steep growth in market size. Because the most common biodiesel production technology is based on the transesterification of triglycerides, a burgeoning amount of glycerol byproduct is obtained. In order to address this economic and ecologic drawback, several chemocatalytic technologies have been developed to exploit this compound to feed the market with added-value products. Lactic acid, acrylic acid, allyl alcohol, propanediols, and glycerol carbonate have emerged as the most relevant candidates for this purpose. In previous studies, an environmental and economic assessment of a glycerol biorefinery built on these valorization pathways has been performed, taking into account only the operating costs in relation to the economic aspects. This study evaluates for the first time the investment required by these glycerol valorization processes, based on the Guthrie, Taylor, and Aspen capital cost estimation methods, and then assesses the potential of a heat-integrated glycerol biorefinery. Glycerol carbonate stands out as the dominant product to maximize the profitability with respect to the glycerol utilized, while 1,2-propanediol and allyl alcohol are determined as target compounds to be included in the glycerol biorefinery product mix if further reductions of the environmental impact are sought after. This early stage techno-economic analysis provides a sounder basis toward the practical realization of an integrated facility sustainably upgrading waste streams from the processing of renewables into commodities, thus promoting the concept of circular economy.
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| 8. |
- Lari, Giacomo M., et al.
(författare)
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Environmental and economic assessment of glycerol oxidation to dihydroxyacetone over technical iron zeolite catalysts
- 2016
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Ingår i: Reaction Chemistry and Engineering. - : Royal Society of Chemistry (RSC). - 2058-9883. ; 1:1, s. 106-118
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Tidskriftsartikel (refereegranskat)abstract
- The gas-phase oxidation of glycerol over MFI-type iron zeolite catalysts comprises an attractive technology to prepare dihydroxyacetone with a high productivity, in contrast with the currently practiced biocatalytic system. Herein, we address two crucial aspects in view of a prospective industrial application, i.e., the development of the technical iron zeolite-based catalysts and the environmental and economic assessment of the process by life cycle analysis. Regarding the first task, we show that iron silicalite with the desired structural, acidic and catalytic properties can be prepared by hydrothermal synthesis at the kg-scale and using reagents meeting industrial safety, ecological and cost criteria. The design of suitable mm-sized bodies encompassed the use of shaping methods which minimise the introduction of additional acidity as well as iron clustering and migration from the zeolite to the binder phase. In this respect, silica outperforms kaolin as the binder, pelletisation and polyether-assisted extrusion are superior to water-based extrusion and the calcination and steam activation of the as-crystallised zeolite are preferably done after the forming step. The optimal technical catalyst displays equivalent activity, selectivity and stability to lab-scale pure iron silicalite powder in a 72 h test. From a life cycle perspective, all environmental indicators are drastically improved and the operating cost is halved using a chemocatalytic zeolite-based process for the preparation of high-purity dihydroxyacetone compared to the conventional enzymatic route. This is justified by the high atom economy of the transformation which reduces waste and by the minimisation of the energy input via heat integration and the use of less energy-intensive separation units to purify the substantially more concentrated outlet stream. Since the purity demand for the dihydroxyacetone feedstock to produce lactic acid is lower than that required in the cosmetic and polymer industries, a potential glycerol oxidation process for the former application has an even greater advantage in terms of greenness and cost.
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| 9. |
- Lari, Giacomo M., et al.
(författare)
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Environmental and economical perspectives of a glycerol biorefinery
- 2018
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Ingår i: Energy and Environmental Sciences. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 11:5, s. 1012-1029
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Tidskriftsartikel (refereegranskat)abstract
- Glycerol conversion into chemicals and fuel additives is pursued to valorise a burgeoning by-product in the bioenergy sector. To this aim, heterogeneous catalysts have been developed that enable, in many cases, efficient and green transformations. Still, the evaluation of the environmental and economic footprint that would be associated with their large-scale application has often been neglected, limiting their commercial attractiveness. Furthermore, the impact of integrating different glycerol upgrading routes within a biorefinery, which is highly instrumental to determine the effective sustainability and profitability of biodiesel production from vegetable oils, has not been assessed. Here, the manufacture of the most relevant chemical derivatives of glycerol is considered, i.e., lactic acid, acrylic acid, glycerol carbonate, propanediols, epichlorohydrin and allyl alcohol. State-of-the-art catalysts for each upgrading route are briefly reviewed. Based on their performances, processes are rigorously modelled and relevant indicators, the global warming potential, the cumulative energy demand and the operating costs, quantified by life-cycle analysis. Glycerol-based processes are generally found more attractive than the conventional technologies nowadays applied for the production of the same chemicals, among which the paths to lactic acid and glycerol carbonate are particularly promising. In addition, the process variables mostly contributing to the environmental and cost metrics are identified. Accordingly, future studies should target further optimisation mainly in relation to selectivity, solvent volatility, reactants ratio and catalyst stability. Finally, the processes are integrated simulating a prospective glycerol biorefinery and the advantages deriving from the exchange of heat between the different routes quantified. If the glycerol feed is split equally among all routes the CO 2 emissions and energy requirements are decreased by 15 and 32%, respectively, and the profit is increased by 5% as compared to the sum of the individual glycerol-based processes. In order to minimise the ecological impact of the biorefinery, glycerol should be rather divided in an 80:20 mass ratio among 1,2-propanediol and glycerol carbonate production, which are expected to have a significant market size. The innovative approach outlined in this work holds potential to guide both fundamental chemical research and process design in the development of CO 2 and other bio-refineries.
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