this paper reports the experimental results of an on-going project running at lab-scale and aimed at the valorization of roasted hazelnut cuticles through both chemical (i.e., solvent extraction) and thermochemical treatment (i.e., torrefaction) routes. In particular, the potential of using water as a green solvent for the extraction of bioactive compounds (i.e., substances of chemical-food-pharmaceutical interest, such as the polyphenols) contained in residues originated by industrial processing of hazelnuts has been investigated, applying the conventional laboratory Soxhlet extraction procedure. A subsequent valorization stage has been explored for the spent post-extraction residues versus the “as collected” ones; they lend themselves to become “renewable” solid fuels thanks to torrefaction, which is a “mild” thermochemical conversion process. The obtained results are first presented in terms of theoretical yields of the bioactive compounds of interest with respect to the original mass of hazelnut residue; in addition, the findings on torrefaction are discussed in terms of performance indexes with respect to the torrefied fuel and quantitatively expressed as correlations as a function of temperature.

Polyvinyl alcohol is the most commercially water-soluble biodegradable polymer, and it is in use for a wide range of applications. It shows good compatibility with most inorganic/organic fillers, and enhanced composites may be prepared without the need to introduce coupling agents and interfacial modifiers. The patented high amorphous polyvinyl alcohol (HAVOH), commercialized with the trade name G-Polymer, can be easily dispersed in water and melt processed. HAVOH is particularly suitable for extrusion and can be used as a matrix to disperse nanocomposites with different properties. In this work, the optimization of the synthesis and characterization of HAVOH/reduced graphene oxide (rGO) nanocomposite obtained by the solution blending process of HAVOH and Graphene Oxide (GO) water solutions and ‘in situ’ reduction of GO is studied. The produced nanocomposite presents a low percolation threshold (~1.7 wt%) and high electrical conductivity (up to 11 S/m) due to the uniform dispersion in the polymer matrix as a result of the solution blending process and the good reduction level of GO. In consideration of HAVOH processability, the conductivity obtained by using rGO as filler, and the low percolation threshold, the nanocomposite presented here is a good candidate for the 3D printing of a conductive structure.

In the last years, the European Commission has been funding numerous projects regarding the valorization of food wastes. Tomato by-products received great attention especially in Spain, Italy, Greece, and Portugal due to high volumes and high concentration of valuable compounds. Among 40 funded projects about the management of tomato wastes in general, 14 projects are strictly connected to the valorization and exploitation of the tomato residues/by-products after processing and are of great interest for their scientific, technical, and economical outcomes. They received an overall budget of around 37 M€ over 35 years, involving 20 European and 4 non-European countries, with project coordinators located in Germany, the Netherlands, and Italy in most of the cases. This chapter delivers general information about these projects, assessing and reporting scientific and technical results. Moreover, the interconnection is highlighted among them by focusing on the contribution they gave to the European know-how, the management of the by-products and the progress they reached in waste minimization and valorization. Finally, the industrial and environmental outcomes of these projects have been reported by highlighting issues and problems that are still to be overcome.

This work aims to model the extraction process of lycopene from tomato peels using a conventional or a "green" solvent, which could be more environment-friendly, and its subsequent encapsulation. The Aspen Plus® software is used to this end. Different cases considering alternative extracting solvents, as well as the recycling of recovered solvent streams and water are evaluated and compared. The raw materials to be considered in an inventory analysis are tomato peels from local industries, solvents, drying agents and soft capsules. Based on literature data and using MS Excel® worksheets, the process mass and energy balances are set up and, hence, the extraction yield is evaluated, while the solvent recovery stage is simulated and optimized in Aspen Plus®. The economic potential of these cases is calculated by considering the cost of utilities, product and by-product sales, wastewater treatment, and raw material costs. Results show that tomato peels can be appealing for lycopene extraction and valorization. The productivity of lycopene-containing tablets is appreciably large: 12000 pz/h of lycopene-containing tablets after extraction with ethyl acetate and 3500 pz/h in the case of limonene were obtained. Moreover, the predicted gross profit is reasonably attractive, with 39 M€/year for the conventional process and 11 M€/year for the "green" alternative.

This contribution is a piece of work within a more comprehensive research program dedicated to a thorough exploitation of industrial tomato by-products, which should be technically feasible, economically convenient and environmentally friendly. In this respect, the proposed paper focuses three aspects of newer and broader interest: lycopene extraction, cutin separation and compost production. The investigated case study refers to the tomato industry in the Campania region (IT). The lycopene extraction from peels is usually carried out by a solventor supercritical CO2-assisted operation; the separation of cutin is performed in two process steps: alkaline hydrolysis and acidification. The solid residual, after cutin separation, is proposed to be used as feedstock for composting, not alone, but mixed with other suitable biomass to adjust both the final moisture content and C/N ratio. To this end, two scenarios according to the “biorefinery cascade approach” were developed that differ in the extraction technology for lycopene, i.e., 1) an optimized organic solvent; 2) CO2 as a supercritical fluid. The proposed process block diagram takes into account the upstream separation of peels from seeds and the downstream composting of seeds and residual solids (i.e., after lycopene and cutin extraction) in both scenarios, which were set up and quantitatively evaluated, under both viewpoints of process feasibility and economic sustainability. The mass and energy balances were written for all the involved process steps; the balance equations and the mathematical calculations were implemented and solved in MS EXCEL®.

The aim of this work is to model a more environmental-friendly production of biodiesel from tomato seed oil to assess the feasibility of using an alternative catalyst. The AspenPlus® software is used to this end. Different cases are evaluated and compared, by changing the catalyst and by considering the additional production of high purity glycerol and potassium phosphate. Tomato seed oil obtained from tomato pomace coming from local industries, methanol and catalyst are considered as raw materials. Based on literature data, a methylesters yield formulation is developed and the catalytic transesterification reaction implemented in a simulated reactor, while methanol is recovered by distillation and recycled to the reactor. The necessary distillation towers are designed. All the mass and energy balances were set up for the whole process. The energy return of investment (EROI) was determined by considering the energy for harvesting and that for producing biodiesel. Results show that tomato seed oil can be a feasible alternative for biodiesel production.

The industrial processing of tomato leads to substantial amounts of residues, typically known as tomato pomace or by-products, which can represent as much as 10% by weight of fresh tomatoes. At present, these residues are either used as feedstock for animals or, in the worst case, disposed of in landfills. This represents a significant waste because tomato pomace contains high-value compounds like lycopene, a powerful antioxidant, cutin, which can be used as a starting material for biopolymers, and pectin, a gelling agent. This article presents an overview of technologies that valorize tomato by-products by recovering added-value compounds as well as generating fuel for energy production. These technologies include operations for extraction, separation, and exploitation of lycopene, cutin and pectin, as well as the processes for conversion of the solid residues to fuels. Data collected from the review has been used to develop a biorefinery scheme with the related mass flow balance, for a scenario involving the tomato supply chain of Regione Campania in Italy, using tomato by-products as feedstock.

The aim of this work is to model the extraction of pectin from tomato peels using different acids that could be more environmentally friendly. The AspenPlus® software is used to this end. Several cases, such as considering different extracting acids, the recycle of water and washing solvent streams are evaluated and compared. Tomato peels seasonally generated by factories in a local district, were considered as raw materials, as well as methanol and catalyst. Based on literature data and using Excel® worksheet, the mass and energy balances were set up for the extraction reactor and, hence, a pectin extraction yields up to 25 % and 17 %, for two different scenarios, was determined, while the washing and purification stages were simulated and optimized in AspenPlus®. The distillation tower for solvent recover was designed. The economic potential of these cases was calculated by considering utilities cost, product and by-product sales, wastewater treatment as well as raw material costs. Results show that tomato peels can be a feasible alternative for pectin production. Moreover, this work could be a basis for the development and design of a multi-product biorefinery based on tomato by-products produced by cannery industries in the frame of a circular economy approach.

The growth of single-layer graphene (SLG) by chemical vapor deposition (CVD) on copper surfaces is very popular because of the self-limiting effect that, in principle, prevents the growth of few-layer graphene (FLG). However, the reproducibility of the CVD growth of homogeneous SLG remains a major challenge, especially if one wants to avoid heavy surface treatments, monocrystalline substrates and expensive equipment to control the atmosphere inside the growth system. We demonstrate here that backside tungsten coating of copper foils allows for the exclusive growth of SLG with full coverage by atmospheric pressure CVD implemented in a vacuum-free furnace. We show that the absence of FLG patches is related to the suppression of carbon diffusion through copper. In the perspective of large-scale production of graphene, this approach constitutes a significant improvement to the traditional CVD growth process since (1) a tight control of the hydrocarbon flow is no longer required to avoid FLG formation and, consequently, (2) the growth duration necessary to reach full coverage can be drastically shortened.

Poly(lactic acid)/graphene and poly(lactic acid)/carbon nanotube nanocomposites were prepared by an easy and low-cost method of melt blending of preliminary grinded poly(lactic acid) (PLA) with nanosized carbon fillers used as powder. Morphological, structural and mechanical properties were investigated to reveal the influence of carbon nanofiller on the PLA–based composite. The dependence of tensile strength on nanocomposite loading was defined by a series of experiments over extruded filaments using a universal mechanical testing instrument. The applying the XRD technique disclosed that compounds crystallinity significantly changed upon addition of multi walled carbon nanotubes. We demonstrated that Raman spectroscopy can be used as a quick and unambiguous method to determine the homogeneity of the nanocomposites in terms of carbon filler dispersion in a polymer matrix.

Polymer-based composites with nanocarbon fillers are of great interest for the wide application range including the needs of wireless communication and the development of precise measuring means and medical devices. However, the composite properties such as excellent electromagnetic energy dissipation or tailorable conductivity are not enough to solve practical problems in engineering. To be fully applicable, the composite material must be low-cost and suitable for conventional methods of fabrication, for example 3D-printing. In current research the electromagnetic properties of PLA-based composites with graphene nanoplatelets and multiwall carbon nanotubes were investigated in microwave frequency range. The synergistic effect of two fillers was observed, the investigated materials proved to be prospective for 3D-printable composite production for electromagnetic applications such as fabrication of complex geometry microwave shields and antennas.

Highly uniform reduced graphene oxide/silver nanoparticles binary nanocomposites were successfully prepared using a consolidated dopamine-mediated multistep procedure and a novel 'green' one-step solution route mediated itself by graphene oxide. In both nanocomposites, Ag nanoparticles (NPs) with sizes of several nanometers result, anchored on the surface of reduced graphene oxide (rGO) sheets. On the other hand, the one-step procedure allows homogeneously dispersed NPs) on highly exfoliated rGO. The rGO/Ag NP nanocomposites were used as electrode materials for supercapacitors. It was observed that the capacitive performances were markedly affected by the size and dispersion of Ag NPs as well as graphene exfoliation. The one-step synthesized nanocomposite exhibited long stability and specific capacitance as high as 1850 F/g in the voltage range [0 to 1] V and 628 F/g in the voltage range [-0.5 to 0.5] V at a scan rate of 2 mV/s. The excellent capacitive performance can be attributed to the uniform coating of Ag NPs (similar to 8 nm diameter) on rGO nanosheets in close synergy with rGO resulting in a highly conductive (electrical conductivity up to 1.3 x 10(7) S/m) spongy material.

Decoration with silver nanoparticles was obtained by coating graphene with a polydopamine layer, able to induce spontaneous metallic nanoparticles formation without any specific chemical interfacial modifier, neither using complex instrumentation. The choice of dopamine was inspired by the composition of adhesive proteins in mussels, related to their robust attach to solid surfaces. The synthesis procedure started from graphite and involved eco-friendly compounds, such as Vitamin C and glucose as reducing agent and water as reaction medium. Silver decorated graphene was inserted as secondary nanofiller in the formulation of a reference conductive adhesive based on epoxy resin and silver flakes. A wide characterization of the intermediate materials obtained along the step procedure for the adhesive preparation was carried out by several techniques. We have found that the presence of nanofiller yields, in addition to an improvement of the thermal conductivity (up to 7.6 W/m · K), a dramatic enhancement of the electrical conductivity of the adhesive. In particular, starting from 3 · 102 S/cm of the reference adhesive, we obtained a value of 4 · 104 S/cm at a nanofiller concentration of 11.5 wt%. The combined double filler conductivity was evaluated by Zallen's model. The effect of the temperature on the resistivity of the adhesive has been also studied.

Reduced graphene oxide supporting silver nanoparticles, obtained by an efficient, “green” and one step “top- down” solution route, was used for removal from water of chlordane, a known persistent organic pollutants. A two-step mechanism, involving chlordane degradation by Ag nanoparticles and subsequent adsorption of the degraded products: ether bis(2-chloro allyl), 1,10-dichlorodecane and octadecanoid acid were detected, on the reduced graphene oxide surface, leads to a complete removal of chlordane from water solution in only 11 minutes at room temperature.

In this work, we have synthetized a reduced graphene oxide functionalized with silver nanoparticles (G/Ag) by a method developed in our previous study and incorporated it in a hydrogel based on polyvinyl alcohol (PVA) as gelator through a freezing/thawing method. The hydrogel has been tested to catalyze the reduction at room temperature of nitrile group of benzonitrile in water by using glucose as a natural and mild reducing agent.

Here we propose luminescent ZnO QDs synthesized by a simple method in an unusual, powerful and 'green' solvent at low temperature, for the detection of aniline (e.g. 4-nitroanilina) compounds in water environment. To provide aqueous stability, ZnO QDs have been capped by (3-aminopropyl) triethoxysilane (APTES). The synthesized ZnO QDs have been characterized using X-ray diffraction, Transmission Electron Microscopy, Raman, UV-visible, Photoluminescence and Infrared Spectroscopy. This study demonstrates that the as synthesized ZnO QDs are highly luminescent, emitting yellow colour when exposed to UV radiation. Under UV radiation the nanoparticles exhibit high sensitivity to the presence of nitro-compounds in solution when they have a zwitterionic structure, even at very low concentration. In particular, this property makes APTES capped ZnO QDs very effective as sensor for p-nitroaniline.