Biochar based silicon composites for sensors applications (original) (raw)
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Development and characterization of a novel activated biochar-based polymer composite for biosensors
The aim of this study is to develop and characterize an activated biocharbased polymer composite for biosensors in smart food packaging. Biochar was made from corn stover and activated using the steam-activation method. The activated biochar (ABC) was synthesized with polylactic acid (PLA) by a solvent casting method. While ABC ranged from 85% to 50%, PLA content varied from 15% to 50% (w/w) in the polymer composite. The electrical conductivity of the developed ABC/PLA composite was measured through differential plus voltammetry (DPV) and cyclic voltammetry (CV) using a potentiostat. It was found that the current increased from 0.3 to 2.31 mA for CV and 0.16 to 1.02 mA for DPV when ABC contents changed from 50% to 85%. The tensile strength (TS) and Young 's modulus of the ABC/PLA composite film increased from 0.81 to 3.04 MPa and 56.31 to 102.69 MPa respectively when PLA contents increased from 15% to 50%. The biosensor was fabricated with 85% ABC/PLA-based composite using a drop-casting method. The resistance of the fabricated biosensor increased as the concentration of NH 3 increased over the range of 80 to 170 ppm.
Biochars as Innovative Humidity Sensing Materials
Chemosensors
In this work, biochar-based humidity sensors were prepared by drop-coating technique. Polyvinylpyrrolidone (PVP) was added as an organic binder to improve the adhesion of the sensing material onto ceramic substrates having platinum electrodes. Two biochars obtained from different precursors were used. The sensors were tested toward relative humidity (RH) at room temperature and showed a response starting around 5 RH%, varying the impedance of 2 orders of magnitude after exposure to almost 100% relative humidity. In both cases, biochar materials are behaving as p-type semiconductors under low amounts of humidity. On the contrary, for higher RH values, the impedance decreased due to water molecules adsorption. When PVP is added to SWP700 biochar, n-p heterojunctions are formed between the two semiconductors, leading to a higher sensitivity at low RH values for the sensors SWP700-10% PVP and SWP700-20% PVP with respect to pure SWP700 sensor. Finally, response and recovery times were both reasonably fast (in the order of 1 min). Chemosensors 2017, 5, 35 2 of 16
Rice husk derived biochar as smart material loading nano nutrients and microorganisms
Rice husk derived biochar as smart material loading nano nutrients and microorganisms, 2020
Hassan, A. Z. A., Mahmoud, A. W. M., Turky, G. M. & Safwat, G. (2020). Rice husk derived biochar as smart material loading nano nutrients and microorganisms. Bulg. J. Agric. Sci., 26 (2), 309-322 Present exploration aspired to produce biochar from rice husk basic nano particles using slow pyrolysis technique. The physio-chemical characteristics, phases and surface morphology of biochar were studied by different visual techniques. The obtained result confirmed that rice husk derive biochar is considered as a novel carrier of nano nutrients and advantageous microorganisms. The recorded values of mean radius, nearest distance between particles, perimeter of particles, the surface area of biochar basic nano particles, cation and anion exchange capacity were examined. The image of surface topography showed that biochar enrich by nano-particles with "sponge" shaped structures and nano-particles were imbedded into macro, meso, and micro pores of biochar. The spacemen atoms of pure elements composition of biochar followed the descending order of oxygen > silicon > sodium > potassium > carbon > magnesium > calcium > alumina. The stability and fertility of biochar basic nano particles might be used as safety soil amendment, climate changes mitigation, source of fertilizer and eco-friendly. The determined conductivity of the prepared biochar is found in the range of semiconductors which make it suitable and promising material to be used as filler in polymer composites and nano composites for many electric and electronic applications.
Analysis of biochar with different pyrolysis temperatures used as filler in epoxy resin composites
Biomass & Bioenergy, 2019
Biocomposites are composite materials formed by a matrix and a filler derived from natural biomass. The use of biomasses and other biogenic wastes in composites represent an eco-friendly way to use these natural fillers. Biochar is a solid material generated by pyrolysis of biomasses. It is characterized by high carbon content, and for this reason it can be considered a possible substitute for more expensive and/or less environment friendly carbon fillers in composites. Biochars produced at different pyrolysis temperatures are investigated in this work (Miscanthus). They were characterized as produced (morphology, elemental analysis, graphitization grade, DC electrical conductivity) and subsequently used as fillers in epoxy resin. The complex permittivity of composites was then investigated. The aim of this work is to predict the final electrical properties of the composite by an evaluation of biochars characteristics. Results on biochar characterization, in particular DC electrical conductivity, are in agreement with the electrical performances on final composites.
Biochar as a filler in mixed matrix materials: Synthesis, characterization, and applications
Journal of Applied Polymer Science, 2019
ABSTRACTThe use of mixed‐matrix materials (MMM) has become a major topic of research in recent years, due to unique properties achieved in these composites. In this work, biochar from sunflower seed hull pyrolysis and biochar/polysulfone (PSF) MMMs were produced and characterized. The optimal pyrolysis temperature for biochar production was determined to be 500 °C. The resulting biochar properties were an iodine number of 203 mg/g and a pore volume of 0.595 mL/g. In MMM fabrication, the use 4% ethanol as nonsolvent in the wet phase inversion process increased the glass transition temperature by 8 °C, indicating improved biochar/PSF interaction. The presence of biochar was shown to create pores in otherwise dense surfaces. The critical surface energy was also increased by the addition of biochar from 28.6 mN/m in pristine PSF to 35.7 mN/m in biochar/PSF MMMs. We identified and discussed several potential applications based on the determined properties. © 2019 Wiley Periodicals, Inc. ...
Chemical sensors based on polymer composites
Sensor Actuator B Chem, 2005
Developing materials which could be applied as sensors has been attempted. The materials were electrically conductive polymer composites, which matrices were: HDPE, PS, PP, HDPE/PS and HDPE/PP blend. The filler was carbon black of particle size 10–110 nm. Electrical conductivity, mechanical strength, Vicat softening temperature and melt rheology were investigated.The lowest percolation threshold was achieved at 2 wt.% of carbon black, which resulted in electrical resistance of 107 Ω m. Along with the filler volume the Vicat softening temperature increased at every polymer matrix for a few centigrades. At the highest filler content the tensile Young modulus of composites was four times higher, whereas elongation at break decreased substantially if compared to the net polymers. Melt viscosity increased with carbon black content, making composites hardly processable at high filler loadings.
Journal of Composites Science
Biochar obtained from the oxygen-deficient thermochemical processing of organic wastes is considered to be an effective reinforcing agent in biocomposite development. In the present research, biocomposite film was prepared using sugarcane bagasse pyrolyzed biochar and polyvinyl alcohol (PVA), and its electrical and mechanical properties were assessed. The biocomposite films were produced by varying content (5 wt.%, 8 wt.% and 12 wt.%) of the biochar produced at 400 °C, 600 °C, 800 °C and 1000 °C and characterized using X-Ray diffraction, scanning electron microscope, Fourier transform infrared spectroscopy. The experimental findings revealed that biochar produced at a higher pyrolyzing temperature could significantly improve the electrical conductance of the biocomposite film. A maximum electrical conductance of 7.67 × 10−2 S was observed for 12 wt.% addition of biochar produced at 1000 °C. A trend of improvement in the electrical properties of the biocomposite films suggested a thr...
Biocomposites from Organic Solid Wastes Derived Biochars: A Review
Materials, 2020
The replacement of natural fiber with biochars to prepare biocomposites has attracted widespread attention recently. Biochar has unique properties, including the porous structure, large specific surface area, high thermal stability, good conductivity, renewable and abundant feedstock source, and environmental friendliness, which provide excellent properties, environmental benefits, and low production costs for biochar-based composites. Biocomposites from organic solid waste-derived biochars show good prospects worldwide in terms of positive social, environmental, and economic impacts. This paper reviews current biochars, elucidates the effects of biochars on the characteristics and performance of biochar composites, and points out the challenges and future development prospects of biochar composites.
ACS applied electronic materials, 2021
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°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.
Development of Coffee Biochar Filler for the Production of Electrical Conductive Reinforced Plastic
Polymers, 2019
In this work we focused our attention on an innovative use of food residual biomasses. In particular, we produced biochar from coffee waste and used it as filler in epoxy resin composites with the aim to increase their electrical properties. Electrical conductivity was studied for the biochar and biochar-based composite in function of pressure applied. The results obtained were compared with carbon black and carbon black composites. We demonstrated that, even if the coffee biochar had less conductivity compared with carbon black in powder form, it created composites with better conductivity in comparison with carbon black composites. In addition, composite mechanical properties were tested and they generally improved with respect to neat epoxy resin.