During Carbon Fibre Reinforced Polymers (CFRPs) manufacturing, large quantities of scrap are being produced and usually disposed to landfill or incinerated, resulting in a high environmental impact. Furthermore, CFRP parts that have been damaged or reached their end-of-life, follow the same disposal route and because of this, not only the environment is affected, but also high added-value materials, such as carbon fibres (CFs) are lost without further valorisation. Several recycling technologies have been suggested, such as pyrolysis, to retrieve the CF reinforcement from the CFRPs. However, pyrolysis produces CFs that have residual resin and pyrolytic carbon at their surface. In order to retrieve clean long fibres, oxidation treatment in high temperatures is required. The oxidation treatment, however, has a high impact on the mechanical properties of the reclaimed CFs; therefore, an optimised pyrolysis procedure of CFRPs and post-pyrolysis treatment of reclaimed fibres (rCFs) is required. In this study, CFRPs have been subjected to pyrolysis to investigate the reclamation of CF fabrics in their primal form. The temperature of 550 °C was selected as the optimum processing temperature for the investigated composites. A parametric study on the post-pyrolysis treatment was performed in order to remove the residues from the fabrics and at the same time to investigate the CFs reusability, in terms of their mechanical and surface properties.

Biochar is the carbonaceous residue produced from pyrolytic conversion of biomass. Biochar is generally used for agricultural application as soil amendment without exploiting its full potentiality. This brief overview aims to present the use of biochar as filler for the production of reinforced and conductive composites. This study reports an up-to-date description of the most recent achievements reached in the field of both thermosetting and thermoplastic composites.

Since their discovery, carbon dots have attracted a great deal of interest for their perspective biological applications. Nevertheless, the quenching of carbon dots photoluminescence represents an interesting feature for quantitative analysis in very low concentration of many species. A particular approach for the production of carbon dots is the use of biochar, a carbonized biomass, as a precursor. In this work, we overview the main achievements accomplished by using biochar-derived carbon dots for detecting and quantifying inorganic and organic species. We also provide background knowledge of the main properties, production and purification routes of carbon dots.

The global energy transition has started and the mankind actively looking for new way to replace the fossil fuels based technology. This paradigm change is quite hard to accomplished due the many drawbacks related to a complete rethinking of the engines. So, a solid solution could be represented by the use of oil derived analogue fuels produced using renewable sources known as drop-in fuels. In this field, the thermal conversion of fats has played a main role due the easily conversion in hydrocarbon mixture very close to diesel fraction. In this chapter, we overview the use of lipid as feedstock for the production of drop-in fuels through pyrolytic conversions. We overview the main mechanisms behind the cracking of fatty acids and triglycerides, providing a reference point for understanding the process described. We have also reported the most relevant achievement in this field. We included both the early studies and the most recent advancements. A section is also dedicated to catalytic conversions and upgrading to provide a solid background to the reader.

Carbon fibres were synthesized by using cotton-based post-consumer textile waste as precursor in an inert environment of nitrogen at three different temperatures of 400 degrees C, 500 degrees C and 600 degrees C at a heating rate of 5 degrees C/ min. Synthesized carbon fibres were subjected to various analysis such as surface morphology, structural properties and chemical nature using scanning electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy and X-rays photoelectron spectroscopy respectively. Obtained carbon fibres revealed high carbon content and good structural properties especially at 600 degrees C synthesis temperature. The carbon fibres were employed in epoxy composites in five different weight ratios to enhance tensile properties. Maximum strength was exhibited by carbon fibres synthesized at 600 degrees C i.e., 56.77 % by addition of 1 % filler and an increment of 93 % in ultimate tensile strength was recorded at 4 % filler weight when compared to neat epoxy. 400 degrees C carbon fibres-based composites exhibited minimum strength among all composites on comparative basis ranging from 29 % to 63 % at 1 % to 5 % concentrations of filler respectively. While the 500 degrees C carbon fibres-based composites exhibited tensile properties in-between the 400 degrees C and 600 degrees C carbon fibres-based composites. Similar trends were seen in the young modulus, resilience, and tensile toughness analysis.

The development of surface-enhanced Raman spectroscopy (SERS)-based sensors necessitates a deeper understanding of the analyte-nanoparticle interaction. For optimal reliability, factors that may affect the resulting spectra need to be understood. First and foremost, the signal enhancement (and hence the improved sensitivity) offered by these systems highly relies on the localization of molecules or moieties in molecules as close as possible to the nanoparticle surface and decreases the farther a molecule is from the surface. Furthermore, the relative peak intensity, and thus the possibility to rely on a specific peak (or set of peaks) to build a calibration curve, depends on the orientation of the molecule with respect to the metallic surface due to the tensorial nature of the Raman polarizability. As a consequence, a change in analyte orientation on a nanoparticle surface impacts the resulting spectral pattern. Herein, factors that affect analyte orientation on a nanoparticle surface and their effect on the resulting SERS spectra are investigated. To do so, two unique nanostar morphologies and three analytes were selected. SERS spectra were acquired at varying analyte concentrations, and deconvoluted. X-ray photoelectron spectroscopy (XPS) and molecular dynamics (MD) simulations were conducted to confirm the hypothesized adsorbate/nanostars environment. Our study reveals three factors theorized to impact the molecular orientations: (1) analyte concentration, (2) nanoparticle surface properties, and (3) analyte-nanoparticle bond nature. Results herein suggest that when the analyte concentration is sufficiently high, the molecules reorient from parallel to perpendicular or remain perpendicular relative to the nanoparticle surface compared to the situation at low concentration. The way in which the analyte and nanoparticle interact (e.g., physisorb or chemisorb) will determine the preferred analyte orientation at low concentration. If covalently bound, this preliminary orientation is believed to be dictated by the preferred bond angle between surface and bound moiety. If physisorbed, the analyte will be parallel relative to the nanostar surface at low concentrations and then reorient perpendicular at increased concentrations. The work presented here, explaining in detail the concentration-dependent nature of the analyte orientation, will aid in the development of more reliable SERS sensors.

The development of responsive composite materials is among the most interesting challenges in contemporary material science and technology. Nevertheless, the use of highly expensive nanostructured fillers has slowed down the spread of these smart materials in several key productive sectors. Here, we propose a new piezoresistive PVA composite containing a cheap, conductive, waste-derived, cotton biochar. We evaluated the electromagnetic properties of the composites under both AC and DC regimes and as a function of applied pressure, showing promisingly high conductivity values by using over 20 wt.% filler loading. We also measured the conductivity of the waste cotton biochar from 20 K up to 350 K observing, for the first time, hopping charge transport in biochar materials.

We report on the microwave shielding efficiency of non-structural composites, where inclusions of biochar—a cost effective and eco-friendly material—are dispersed in matrices of interest for building construction. We directly measured the complex permittivity of raw materials and composites, in the frequency range 100 MHz–8 GHz. A proper permittivity mixing formula allows obtaining other combinations, to enlarge the case studies. From complex permittivity, finally, we calculated the shielding efficiency, showing that tailoring the content of biochar allows obtaining a desired value of electromagnetic shielding, potentially useful for different applications. This approach represents a quick preliminary evaluation tool to design composites with desired shielding properties starting from physical parameters.

We report on the effects of thermal treatment of biochar embedded in epoxy-based composites on their microwave electrical properties, linking such properties to the material structure investigated by Raman, X-ray photoelectron spectroscopy, and X-ray diffraction. Annealing temperatures in the range 900–1500 °C and biochar concentrations in the epoxy matrix in the range from 5 to 25 wt.% were investigated. The microwave analysis, in the range from 250 MHz to 6 GHz, allowed us to determine the complex permittivity of composites and, through a proper deconvolution technique, to determine the contribution of biochar inclusions alone. High values of real permittivity (up to 220) and conductivity (up to 17 S/m) were evaluated for the biochar particles at 5 GHz, after the 1500 °C thermal treatment. A clear correlation between electrical properties and the biochar microstructure emerged from the dataset, with real permittivity and conductivity increasing as carbon inclusions transform from amorphous to nanocrystalline graphite. Conversely, the percentage of aromatic carbon has a weaker influence on the microwave properties. This study opens to the possibility of tailoring the high-frequency properties of biochar and biochar composites through proper thermal treatments.

Since their discovery, carbon dots (CDs) have been a promising nanomaterial in a variety of fields including nanomedicine. Despite their potential in this area, there are many obstacles to overcome for CDs to be approved for biomedical use. One major hindrance to CDs’ approval is related to their poorly defined structure. Herein a structural study of CDs is presented in order to rectify this shortcoming. The properties of three CDs which have significant promise in biomedical applications, black CDs (B-CDs), carbon nitride dots (CNDs), and yellow CDs (Y-CDs), are compared in order to develop a coherent structural model for each nanosystem. Absorption coefficients were measured for each system and this data gave insight on the level of disorder in each system. Furthermore, extensive structural characterization has been performed in order to derive structural information for each system. This data showed that B-CDs and CNDs are functionalized to a greater degree and are also more disordered and amorphous than Y-CDs. These techniques were used to develop a structural model consistent with the obtained data and what is known for carbonic nanostructures. These models can be used to analyze CD emission properties and to better understand the structure-property relationship in CDs.

In this work, we report solid-state synthetized defective Bi2O3 containing Bi(V) sites as effective and recyclable arsenic adsorbent materials. Bi2O3 was extensively characterized, and structure-related adsorption processes are reported. Both As(V) and As(III) species-adsorption processes were investigated in a wide range of concentrations, pH values, and times. The effect of several competing ions was also tested together with the adsorbent recyclability.

In this study, self-standing and flexible Li-ion battery negative electrodes made of interconnected two-dimensional carbonized cotton fibers are developed by using a controlled pyrolysis method, and their electrochemical performance in laboratory-scale lithium-based cells is investigated at ambient temperature. By applying this binder- and current collector-free cotton-based carbon fiber electrode, both the Li+-ion intercalation and capacity decay mechanisms are explored using conventional organic carbonate-based liquid electrolyte. The cotton-based carbon fiber electrode shows excellent cycling performance and delivers a high discharge capacity in the voltage range of 0.02 - 1.2 V. The post cycling analysis of carbon fiber using HR-TEM shows the major SEI layer components formed at the surface of the active fibers during the charge/discharge process. The same electrode is used to assemble a lab-scale Li-ion full cell with high mass loading LiFePO4-based composite electrode, which demonstrates excellent cycling stability, high Coulombic efficiency and remarkable rate capability at ambient temperature. (C) 2020 Elsevier Ltd. All rights reserved.

In this research work, we develop a prototype that is able to convert mechanical strain into an electrical signal. To reach this scope, we evaluated the electrical properties of a thermally annealed biochar-based silicon composite. The great elasticity range of silicon will provide the mechanical properties for the realization of an effective piezoresistive material. For the fulfillment of this aim, we annealed olive biochar at 1500 degrees C in order to achieve a good degree of graphitization and an electrical conductivity close to 10(3) S/m. The electrical conductivity under the mechanical stress of composites was deeply investigated through experiments and simulation to achieve a comprehensive knowledge. Furthermore, a real device based on these composites was designed and realized to demonstrate one of the prospective exploitations of the composite piezoresistive properties.

The global market of carbon-reinforced plastic represents one of the largest economic platforms. This sector is dominated by carbon black (CB) produced from traditional oil industry. Recently, high technological fillers such as carbon fibres or nanostructured carbon (i.e. carbon nanotubes, graphene, graphene oxide) fillers have tried to exploit their potential but without economic success. So, in this chapter we are going to analyse the use of an unconventional carbon filler called biochar. Biochar is the solid residue of pyrolysis and can be a solid and sustainable replacement for traditional and expensive fillers. In this chapter, we will provide overview of the last advancement in the use of biochar as filler for the production of reinforced plastics.

In this work, we reported the conversion though carbothermal process of two catalysts produced by pyrolyzing exhausted coffee and waste tires. We tailored the surface with anchored iron nanoparticles through a facile carbothermal route and tested them for catalytic oxidative desulphurization of high sulphur content oil derived from tires pyrolysis. We studied their activity in a biphasic system under different conditions reaching a desulphurization of up to of 60% by using an oil with a sulphur concentration of up to 7139 ppm. The extensive characterization proved the reliability of those materials as promising catalysts for upgrading of sulphur rich drop-in fuels.

Raman spectroscopy is a very powerful tool for material analysis, allowing for exploring the properties of a wide range of different materials. Since its discovery, Raman spectroscopy has been used to investigate several features of materials such carbonaceous and inorganic properties, providing useful information on their phases, functions, and defects. Furthermore, techniques such as surface and tip enhanced Raman spectroscopy have extended the field of application of Raman analysis to biological and analytical fields. Additionally, the robustness and versatility of Raman instrumentations represent a promising solution for performing on-field analysis for a wide range of materials. Recognizing the many hot applications of Raman spectroscopy, we herein overview the main and more recent applications for the investigation of a wide range of materials, such as carbonaceous and biological materials. We also provide a brief but exhaustive theoretical background of Raman spectroscopy, also providing deep insight into the analytical achievements.

ABSTRACTIn this study, we reported the use of cellulose derived microstructured biochars for the production of reinforced plastics. Cellulose nanocrystals and wasted cotton fibers were used as cellulose template structures and converted into carbonaceous materials under pyrolytic conditions. Biochars particles were produced with the shape of deformed spheres or rods and dispersed into an epoxy matrix with a loading ranging from 1 wt % to 10 wt %. Biochar‐based composites showed remarkably elongation properties of up to 8.2% using 2 wt % of carbonized cellulose nanocrystals and a very low friction coefficient of 0.22 using 10 wt % of carbonized cotton fibers. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48896.HIGHLIGHTS Carbon spheres and carbon rods were produced through pyrolytic conversion of cellulose nanocrystals and wasted cotton fibers. Mechanical properties of carbon spheres and carbon rods epoxy composites were studied showing the differences induced by the particle shapes. An ultimate tensile strength improvement of 57% was reached using 5 wt % of carbonized cellulose nanocrystals. A maximum elongation improvement of 100% was reached using 2 wt % of carbonized cellulose nanocrystals. A friction coefficient reduction of 61% was reached using 10 wt % of carbonized cotton fibers.

The aim of this research is to present a method to evaluate the X-ray attenuation coefficient of (nano)particles by uniformly dispersing them in a host polymer, polydimethylsiloxane. The method is described and applied to the case of a material of interest for medical application in X-ray shielding and imaging, namely bismuth oxychloride nanoplates (BiOCl NP). A diagnostic X-ray machine was used to perform X-ray attenuation tests. A certified copper plate was used for calibration purposes and to find the X-ray photon energy. Blank polymer and composites were investigated, and the attenuation coefficient μ and the mass attenuation coefficient μ/ρ of BiOCl NPs were found to be 45 cm−1 and 6 cm2 g−1, respectively. Based on these values, a discussion is presented in which the perspective applications of BiOCl in medicine are discussed with specific focus on (i) X-ray shielding and (ii) X-ray imaging.

Olive pruning is waste from olive cultivation and is generally disposed of through incineration. Olive pruning can, however, be salvaged by pyrolysis, which also produces an interesting carbon-based material known as biochar. Biochar has been proved as a suitable filler which improves the mechanical properties of epoxy composites. Despite this, literature has few studied focused on the relationship between biochar thermal history and the properties it induces in related biochar containing composites. In this work, we report a morphological analysis of biochar produced at different pyrolytic high treatment temperatures (400℃, 600℃, 800℃, and 1000℃) using different heating rates (5℃/min, 15℃/min, and 50℃/min). We investigate the effect of different biochar morphology on the biochar epoxy-related composites, proving the tuneability of the mechanical properties of composites according to the thermal history of the biochar employed.