After billions of years of evolution, natural materials, such as bamboo, bone, and nacre, show unique mechanical properties, due to their intrinsic hierarchical micro/nanoscale architecture and ...abundant interfacial interactions. This relationship between architecture, interfacial interactions, and mechanical properties of natural materials, supplies the inspiration for constructing high performance lightweight nanocomposites. Graphene's high tensile strength, Young's modulus, and electrical conductivity when compared with other nanomaterials make it an ideal building block for constructing high performance bioinspired nanocomposites. Such nanocomposites demonstrate promise for applications in many fields, including aerospace, aeronautics, submarine devices, car, and flexible electronic devices. In this review, we focus on the bioinspired strategy for preparing graphene-based nanocomposites (GBNs), and discuss the various interfacial interactions. Then the synergistic effects from building blocks and interfacial interactions are discussed in detail, along with the resultant GBNs used in the applications of sensors, actuators, supercapacitors, and nanogenerators, are also illustrated. These GBNs include, for example, one-dimensional (1D) fiber, two-dimensional (2D) film, and three-dimensional (3D) bulk nanocomposites. Finally, we provide our perspective on GBNs, and discuss how to efficiently mimic natural materials for creating new multifunctional bioinspired nanocomposites for practical applications in the near future.
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•The hydrophobicity of lignin was reduced by pre-adsorbing surfactants.•Amphiphilic surfactant weaken adsorption between lignin and cellulase.•Reducing hydrophobicity of substrate ...promoted its enzymatic digestibility.
In this work, amphiphilic surfactant was obtained using dehydroabietic acid from pine rosin and then pre-adsorbed with acid-pretreated bamboo residues (AP-BR) to block the residual lignin adsorption site, which is expected to improve its enzymatic digestibility. Results from cryogenic-transmission electron microscopy (Cryo-TEM) indicated amphiphilic surfactant with PEG with polymerization degree of 34 (D-34) aggregated to form worm-like micelles, which improved enzymatic hydrolysis yield of AP-BR from 24.3% to 71.9% by pre-adsorbing with 0.8 g/L. Amphiphilic surfactants pre-adsorbed on AP-BR could reduce hydrophobicity of AP-BR, adsorption affinity and adsorption capacity of lignin for cellulase from 0.51 L/g to 0.48–0.32 L/g, from 2.9 mL/mg to 1.8–1.4 mL/mg, and from 122.3 mg/g to 101.9–21.4 mg/g, respectively. These changed properties showed compelling positive contributions (R2 > 0.9) for free enzymes in the supernatants and sequently for final enzymatic hydrolysis yield, which was caused by blocking non-productively hydrophobic adsorption between lignin and cellulase.
•ACHC with abundant amino, hydroxyl and carboxylate groups was prepared successfully.•ACHC can remove efficiently and rapidly MB and Cu(II) from aqueous solution.•The surface chelation was mainly ...contribute to Cu(II) adsorption.•π-π interaction, hydrogen bond and electrostatic attraction dominated MB adsorption.
The polyaminocarboxylated modified hydrochar (ACHC) was synthesized to introduce abundant amino, hydroxyl and carboxylate multifunctional groups onto the surface of hydrochar by etherification, amination and carboxylated reaction. The ACHC was systematically characterized and used to evaluate adsorption properties of Cu(II) and methylene blue (MB) by batch sorption tests. The adsorption process toward Cu(II) and MB by ACHC obeyed the pseudo-second-order kinetic model and Langmuir model. Characteristic analysis indicated the surface chelation was mainly contribute to Cu(II) adsorption by large amounts of amino and carboxylate groups while π-π interaction, hydrogen bonding and electrostatic attraction dominated MB adsorption. The maximum adsorption capacities of ACHC were 140.65 and 1238.66 mg·g−1 for Cu(II) and MB at 303 K, respectively. Approximately 97% of the adsorptive uptakes for two pollutants were removed within merely 5 min for kinetic experiment. Competitive adsorption of Cu(II) and MB, and treatment of electroplating wastewater by ACHC were also investigated.
An overview on bamboo culm flattening Fang, Chang-Hua; Jiang, Ze-Hui; Sun, Zheng-Jun ...
Construction & building materials,
05/2018, Volume:
171
Journal Article
Peer reviewed
•Flattening technologies offer a novel way to better use bamboo resource.•The main difficulties for bamboo culm flattening are explained.•The possible solutions for overcoming the difficulties are ...analyzed.•Some examples of bamboo culm flattening process are introduced.
Bamboo is an abundant, sustainable resource in the tropics and subtropics. Owing to faster growth, shorter rotation and higher mechanical strength compared with other species, bamboo, as a supplement to timber, has gained increasing attention for its economic and environmental values over the last three decades. Due to the hollow cylindrical shape of bamboo culms, it is not possible to get large flat surface board directly by sawing or cutting. Research and many novel technologies on bamboo culm flattening have been reported and attempted during the last decades. This paper synthesizes the knowledge and gives an overview on bamboo culm flattening in an effort to inspire researchers and entrepreneurs to further improve and spread the technologies for better using this abundant biomass resource.
•Micro-sized residue with high cellulose content was first produced from bamboo by microwave liquefaction.•The cellulose enriched residues could be readily purified by subsequent chemical ...treatments.•Cellulose nanofibers were isolated from chemically purified residues by gave to high-intensity ultrasonic nanofibrillation.•The cellulose nanofibers have high thermal stability for thermally stable composites.
Cellulose nanofibers were successfully isolated from bamboo using microwave liquefaction combined with chemical treatment and ultrasonic nanofibrillation processes. The microwave liquefaction could eliminate almost all the lignin in bamboo, resulting in high cellulose content residues within 7min, and the cellulose enriched residues could be readily purified by subsequent chemical treatments with lower chemical charging and quickly. The results of wet chemistry analyses, SEM images, and FTIR and X-ray spectra indicated the combination of microwave liquefaction and chemical treatment was significantly efficient in removing non-cellulosic compounds. Ultrasonication was used to separate the nanofibrils from the purified residues to extract nanofibers. The TEM images confirmed the presence of elementary fibrils, nano-sized fibril bundles, and aggregated fibril bundles. As evidenced by the TGA analysis, cellulose nanofibers isolated by this novel technique had high thermal stability indicating that the isolated nanofibers could possibly be applied as reinforcing elements in biomaterials.
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•Bamboo biochar (BB) is an attractive material for environmental remediation.•Fe3O4–BB activated the accelerated formation of SO4− in persulfate oxidation.•Fe3O4–BB exhibited high ...polycyclic aromatic hydrocarbon (PAH) removal efficiency.•Fe3O4–BB-activated persulfate oxidation can treat PAH-contaminated sediment.
This study developed a new and cost-effective method for the remediation of marine sediments contaminated with PAHs. Fe3O4 particles were synthesized as the active component, supported on bamboo biochar (BB) to form a composite catalyst (Fe3O4–BB). The effects of critical parameters, including the initial pH, sodium persulfate (PS) concentration, and dose of catalyst were investigated. The concentration of high-molecular-weight PAHs in sediments was much higher than that of low-molecular-weight PAHs; pyrene was an especially prominent marker of PAH contamination in sediments. Fe3O4–BB/PS exhibited a substantial improvement in PAH degradation efficiency (degradation rate: Fe3O4–BB/PS, 86%; PS, 14%) at a PS concentration of 1.7×10−5M, catalyst concentration of 3.33g/L, and pH of 3.0. The results of this study demonstrate that possible activation mechanisms include Fe2+–Fe3+ redox coupling and electron shuttling that mediates electron transfer of the BB oxygen functional groups, promoting the generation of SO4− in the Fe3O4–BB/PS system.
•Microwave and heating jacket series technology was developed.•The catalyst is separated from the material rather than mix with material.•The optimal catalyst parameters and bamboo/polypropylene ...ratio were determined.•The optimal catalytic parameters were determined.•The yield of naphthenic hydrocarbons in bio-oil achieved 70.92%.
The ex-catalytic co-pyrolysis of bamboo and polypropylene (PP) with HZSM-5 was investigated with microwave assistance. The influences of catalytic temperature, feedstock/catalyst ratio, and bamboo/PP ratio on the product yields and chemical components of bio-oil from the co-pyrolysis were studied. When the catalytic temperature, feedstock/catalyst ratio, and bamboo/PP ratio were 250 °C, 1:2, and 2:1, respectively, the bio-oil yield reached its maximum value at 61.62 wt%. The oxygenate proportion compounds decreased with increasing catalyst content. The PP addition improved the proportions of aromatics and naphthenic hydrocarbons. The bio-oil was upgraded significantly from the jet fuel perspective. A synergistic effect also existed between bamboo and PP.
•Carbon yield of biochar decreased from 71.72% to 38.48% as the temperature increased.•The chemical oxidation stability of biochar was determined using the K2Cr2O7 method.•The aromatization degree of ...biochar increased with increasing pyrolysis temperature.•Carbon loss proportion decreased from 16.52% to 6.69% with increasing temperature.•Biochar showed better stability at a higher temperature in the range 300–700°C.
Biochar produced by biomass pyrolysis has the advantage of carbon sequestration. However, some of the carbon atoms in biochar are not very stable. In this study, the effect of pyrolysis temperature on the chemical oxidation stability of bamboo biochar was investigated using the atomic ratios of H/C and O/C, Fourier transform infrared spectroscopy, and potassium dichromate (K2Cr2O7) oxidation spectrophotometric method. The results show that the carbon yield and ratios of H/C and O/C decreased from 71.72%, 0.71, and 0.32 to 38.48%, 0.22, and 0.06, respectively, as the temperature was increased from 300°C to 700°C. Moreover, the main oxygen-containing functional groups gradually decreased, while the degree of aromatization increased accordingly. The biochar showed a better stability at a higher pyrolysis temperature. The proportion of carbon loss, i.e., the amount of oxidized carbon with respect to the total carbon of the biochar, decreased from 16.52% to 6.69% with increasing temperature.
•Lignin-phenol-formaldehyde (LPF) resin was a promising wood adhesive.•Organosolv lignins from bamboo were ideal materials for LPF resin synthesis.•The synthesis of LPF resin was disturbed by ...long-chain hydrocarbon derivatives.•The performance of a LPF resin was affected by various factors.
The synthesis and performance of a lignin-phenol-formaldehyde resin are significantly related to the properties of the lignin used. In an effort to provide a fundamental understanding of lignin structure-property relations for lignin-phenol-formaldehyde resin synthesis and application, two distinct technical lignins were examined as-obtained from an acidic (L1) and an alkaline (L2) organosolv pulping of bamboo. These samples were thoroughly characterized and the structural and compositional features of them were charted. The content of β-O-4′ linkages in L1 were 23.83 per 100Ar, followed by some β-β′ linkages (1.27 per 100Ar). However, almost all the side-chain linkages in L2 were cleaved. The purities of the two lignins both exceeded 81.0%, but significantly more extractives were found to be present in L2. Subsequently, two lignin-phenol-formaldehyde resins were successfully synthesized using L1 and purified L2 at a substitution rate of 50% to phenol. The high content of extractives contaminating L2, especially long-chain hydrocarbon derivatives, severely affected the synthesis of lignin-phenol-formaldehyde resin. The successful removal of this fraction was necessary before the material could be put to use.
•Slow pyrolysis of bamboo was conducted at pyrolysis temperature of 400–600 °C.•Biochar at 600 °C had good physiochemical properties than biochar at 400 and 500 °C.•Biochar yield was predicted based ...on carbonization index of biomass components.•Pathways of cellulose, hemicellulose and lignin to biochar was established.
Slow pyrolysis of bamboo was conducted at 400–600 °C and pyrolysis products were characterized with FTIR, BET, XRD, SEM, EDS and GC to establish a pyrolysis product yield prediction model and biochar formation mechanism. Pyrolysis biochar yield was predicted based on content of cellulose, hemicellulose and lignin in biomass with their carbonization index of 0.20, 0.35 and 0.45. The formation mechanism of porous structure in pyrolysis biochar was established based on its physicochemical property evolution and emission characteristics of pyrolysis gas. The main components (cellulose, hemicellulose and lignin) had different pyrolysis or chemical reaction pathways to biochar. Lignin had higher aromatic structure, which resulted higher biochar yield. It was the main biochar precursor during biomass pyrolysis. Cellulose was likely to improve porous structure of pyrolysis biochar due to its high mass loss percentage. Higher pyrolysis temperatures (600 °C) promoted inter- and intra-molecular condensation reactions and aromaticity in biochar.
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