Biomass-based Materials Research Articles

Nanostructured Cellulose-Based Sorbent Materials for Water Decontamination from Organic Dyes.

Nanostructured materials have been recently proposed in the field of environmental remediation. The use of nanomaterials as building blocks for the design of nano-porous micro-dimensional systems is particularly promising since it can overcome the (eco-)toxicological risks associated with the use of nano-sized technologies. Following this approach, we report here the application of a nanostructured cellulose-based material as sorbent for effective removal of organic dyes from water. It consists of a micro- and nano-porous sponge-like system derived by thermal cross-linking among (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPO)-oxidized cellulose nanofibers (TOCNF), branched polyethylenimine 25 kDa (bPEI), and citric acid (CA). The sorbent efficiency was tested for four different organic dyes commonly used for fabric printing (Naphthol Blue Black, Orange II Sodium Salt, Brilliant Blue R, Cibacron Brilliant Yellow), by conducting both thermodynamic and kinetic studies. The material performance was compared with that of an activated carbon, commonly used for this application, in order to highlight the potentialities and limits of this biomass-based new material. The possibility of regeneration and reuse of the sorbent was also investigated.

The Application of Biomass-Based Catalytic Materials in the Synthesis of Cyclic Carbonates from CO2 and Epoxides.

The synthesis of cyclic carbonates from carbon dioxide (CO2) and epoxides is a 100% atom economical reaction and an attractive pathway for CO2 utilisation. Because CO2 is a thermodynamically stable molecule, the use of catalysts is mandatory in reducing the activation energy of the CO2 conversion. Considering environmental compatibility and the high-efficiency catalytic conversion of CO2, there is the strong need to develop green catalysts. Biomass-based catalysts, a type of renewable resource, have attracted considerable attention due to their unique properties—non-toxic, low-cost, pollution-free, etc. In this review, recent advances in the development of biomass-based catalysts for the synthesis of cyclic carbonates by CO2 and epoxides coupling are summarized and discussed in detail. The effect of biomass-based catalysts, functional groups, reaction conditions, and co-catalysts on the catalytic efficiency and selectivity of synthesizing cyclic carbonates process is discussed. We intend to provide a comprehensive understanding of recent experimental and theoretical progress of CO2 and epoxides coupling reaction and pave the way for both CO2 conversion and biomass unitization.

Underlying mechanism of CO2 uptake onto biomass-based porous carbons: Do adsorbents capture CO2 chiefly through narrow micropores?

Biomass-based porous carbon materials, as promising CO2 adsorbents, have demonstrated their superiority and inherent potential. However, most of the previous reports simply attributed the unprecedented CO2 capture of porous carbon to the presence of abundant narrow micropores of less than 0.7 nm. Here, we have successfully prepared microporous carbons with analogous textural properties and oxygen functional groups by KOH activated from hydrothermally treated biomass. Based on the experimental results and theoretical calculations, we have found that the oxygen-containing functional groups on porous carbons are critically sensitive to CO2 uptake, especially with carboxyl and hydroxyl groups. We can roughly estimate that oxygen groups and pore structure of OC700 contribute 37% and 63% respectively to the CO2 capture, which can be elucidated by grand canonical Monte Carlo (GCMC) simulations. The introduction of oxygen functional groups into porous carbon materials firmly grasps CO2 through electrostatic interactions by density function theory (DFT) calculations. These oxygen groups provide new adsorption sites for the efficient CO2 capture. The OC700 achieves an extremely high CO2 adsorption capacity of 8.0 mmol g−1 and 4.8 mmol g−1 at 0° C and 25 °C (1 bar), respectively.

Urgently reveal longly hidden toxicant in a familiar fabrication process of biomass-derived environment carbon material

Biomass-derived N-doped carbon (BNC) is an important environmental material and widely used in the fields of water purification and soil remediation. However, the toxicant in the commonly used synthesis process of BNC materials have been largely ignored. Herein, we firstly report the presence of a highly toxic by-product (KCN) in the activation process of BNC materials consequential of the carbothermal reduction reaction. Because this carbothermal reduction reaction also regulates the N-doping and pore development of BNC materials, the KCN content directly relates with the properties of BNC material properties. Accordingly, a high KCN content (∽ 611 mg) can occur in the production process of per g BNC material with high specific surface area (∽ 3600 m2/g). Because the application performance of BNC material is determined by the surface area and available N doping, therefore, production of a BNC material with high performance entails high risk. Undoubtedly, this study proves a completely new risk recognition on a familiar synthesis process of biomass-based material. And, strict protective device should be taken in fabrication process of biomass-derived carbon material.

Efficient Preparation of Spongy-Like Porous-Activated Carbon from Waste Millfeed Towards High Performance Supercapacitors

Biomass-based activated porous carbon (PC) with large porosity and high surface area has been considered as potential electrode material for supercapacitors. The spongy-like porous-activated carbon (SPAC) was prepared from millfeed by one-step carbonization/activation with KOH treatment. It shows three-dimensional (3D) spongy-like structure and high specific surface area (1535[Formula: see text]m2[Formula: see text]g[Formula: see text]). The SPAC electrode exhibits a high specific capacitance (237.9[Formula: see text]F[Formula: see text]g[Formula: see text] at a current density of 0.5[Formula: see text]A[Formula: see text]g[Formula: see text]) and a superior cycle stability (the capacitance retention of 95% after 10[Formula: see text]000 cycles at 2[Formula: see text]A[Formula: see text]g[Formula: see text]) in 2[Formula: see text]M KOH electrolyte, while the SPAC reveals a high specific capacitance of 157[Formula: see text]F[Formula: see text]g[Formula: see text] at 0.5[Formula: see text]A[Formula: see text]g[Formula: see text], good electrochemical stability with 93% capacitance retention after 5000 cycles in ionic liquids. Furthermore, the specific capacitance of SPAC//SPAC supercapacitor reaches 82.1[Formula: see text]F[Formula: see text]g[Formula: see text] at a current density of 0.5[Formula: see text]A[Formula: see text]g[Formula: see text] and achieves a high capacitance retention of 75% when the charging current increases to 10[Formula: see text]A[Formula: see text]g[Formula: see text] in 2[Formula: see text]M KOH electrolyte. The SPAC//SPAC supercapacitor possesses a high specific capacitance of 29.6[Formula: see text]F[Formula: see text]g[Formula: see text] at 0.5[Formula: see text]A[Formula: see text]g[Formula: see text] and a preeminent energy density of 27.8[Formula: see text]Wh[Formula: see text]kg[Formula: see text] (at a power density of 640[Formula: see text]W[Formula: see text]kg[Formula: see text]) in ionic liquids. This paper provides a convenient approach to synthesize low-cost biomass-based carbon material for supercapacitor applications.

Hydrothermal synthesis and applications of advanced carbonaceous materials from biomass: a review

Hydrothermal carbonization (HTC) is a novel method to produce carbonaceous materials, which has been extensively concerned because of its environmentally benign and simple process. This review aims to introduce the approaches and mechanisms of carbonaceous materials prepared by hydrothermal carbonization from biomass in recent years, and discuss the applications of the functional materials transformed from carbonaceous materials. Specifically, the utilizations of various biomass raw materials, including carbohydrates, lignocellulose, and other biomass waste for the production of biochar are discussed. The significant parameter influence and mechanistic aspects of the hydrochar are critically analyzed to better understand the hydrochar formation process. More importantly, recent advances in hydrochar utilization techniques are summarized. Finally, we envision that the ideal designs of the biomass-based functional carbonaceous materials will open up a novel family of functional carbon materials with various applications towards a green and sustainable future.

A low-cost lotus leaf-based carbon film for solar-driven steam generation

Solar-driven interfacial evaporation has attracted much attention owing to its potential for addressing the shortage of freshwater. Low-cost and high-efficiency photothermal conversion materials are the key to the application. A low-cost lotus leaf-based carbon film (LLC) for use as a photo-to-heat conversion medium for solar-driven steam generation was prepared by the simple vacuum filtration of LLC obtained at a carbonization temperature of 800 oC using a porous fibrous filter paper. In a laboratory-made solar steam generation real-time test system using commercial polystyrene foam as the insulation layer and the LLC film on porous fibrous filter paper as the water transport path, the LLC film exhibits a solar-driven water evaporation rate of 1.30 kg/m2 h and a solar-vapor conversion efficiency of 77.5%. The LLC film also shows excellent performance in seawater desalination and sewage purification. The work provides a possible route for the use of low-cost and environmentally friendly biomass-based carbon materials in solar-driven steam generation.

Insights into the adsorption of Pb(II) over trimercapto-s-triazine trisodium salt-modified lignin in a wide pH range

A novel fabrication method for modifying alkaline lignin (AL) was reported, in which trimercapto-s-triazine trisodium salt was used as a modifier to tune surface properties of AL. Molecular structure of modified AL (FAL) was determined by 3D-EEM, synchronous fluorescence, FTIR, 13C MAS NMR and XPS. Two-dimensional correlation spectroscopy and electron localization function demonstrated that both of electrostatic and coordinate bonds formed between these functional groups and Pb(II) at higher pH of 3.0 to 6.0 while only coordinate bond at lower pH of 0.2 to 1.2. The higher the solution pH was, the stronger the adsorption capacity of FAL had. The maximum adsorption capacity (qm) of Pb(II) was 20.0, 28.2, 65.1 and 73.7 mg/g at pH of 0.2, 1.2, 3.0 and 6.0 (T = 25 °C), respectively. The adsorption performance of FAL towards Pb(II) was better by comparing with other biomass-based materials via adsorption amount, equilibrium time as well as simplicity of the synthesized steps. These results improve the understanding of FAL-Pb(II) interaction at the molecular level and facilitate a comprehensive evaluation on the treatment efficiency of FAL.

Multi-3D hierarchical biomass-based carbon particles absorber for solar desalination and thermoelectric power generator

To meet challenges of the global energy crisis and the freshwater resources shortage, the interfacial solar-to-steam conversion (ISSC) system was developed quickly in recent years. The photothermal materials play an important role in the ISSC system. We are devoted to developing a unique photothermal material integrating multiple 3D design philosophy both at macroscopic and microscopic levels by employing the cost-effective and widespread resources like straw, rose and coffee grounds, for carbonization as solar absorbers. The biomass-based carbonized particles (CPs) possess three major advantages: (1) wide size-distribution is accessible to form 3D porous rough surface of absorber layer to enhance ability of light absorption; (2) the pristine hierarchical microstructure could absorb nearly all the incident light; (3) the intrinsic vascular bundles with pores on their lumen walls provide a rapid and omnidirectional transport for water and steam escape. A high-efficient solar steam device was fabricated based on the absorber material with its internal 3D micro textures and external 3D architectures. Under the illumination of 1 sun, the photothermal conversion efficiency of straw, rose and coffee CPs can reach 93.4 %, 92.8 % and 76 %, respectively. Simultaneously, a high-efficient solar thermoelectric generator (STEG) is made by coating CPs on a commercial thermoelectric generator and the maximum power of STEG can reach 538.0 μW. Such scalable biomass-based photothermal materials and high-grade thermoelectric conversion capability could be applied to the water purification and the electricity production.

A lignin-based carbon aerogel enhanced by graphene oxide and application in oil/water separation

A lignin-based carbon aerogel enhanced by graphene oxide (LCAGO) is fabricated. As the strong reaction between amine groups from lignin derivates and carboxylic groups from GO and acrylic acid (AA), the compactness and the cross-linkage of the gel are much higher than the samples without lignin derivate and GO. The lignin derivates are used as cross-linkers and GO contributes to reach to superhydrophobicity with a low annealing temperature and improves the mechanical performance after annealing. The carbon aerogel achieves a water contact angle of 150° at 350 °C for 2 h, achieving the energy-saving purpose. The synergistic effect of superhydrophobicity and good mechanical property acquired by lignin derivate and GO ensures the carbon aerogel appropriate for oil/water separation and light oil, heavy oil and emulsified oil are separated respectively by the gel. The oil adsorption ratio is about 32–34 g/g and shows a moderate performance, which is compared with the reported biomass-based materials. The results indicate the material is a highly effective and practicable water-cleaning material. The preparation process is energy-saving and is a pathway for separation and collection oil from water with industry waste.

Interface optimization of hole-conductor free perovskite solar cells using porous carbon materials derived from biomass soybean dregs as a cathode

Abstract Hole transporting material (HTM)-free carbon-based perovskite solar cells (C–PSCs) have attracted widespread attention for their notable characteristics of excellent long-term stability and low cost. However, the power conversion efficiency (PCE) of C–PSCs is significantly lower than that of HTM-based PSCs. This is mostly due to the unexpected electron recombination happening at the interface of perovskite/carbon. In this study, biomass-based carbon materials were obtained from discarded soybean dregs with sufficient pore size and good conductivity through programmed temperature carbonization and KOH activation processes. Composites of KOH-activated soybean dregs carbon and conductive carbon were used as the counter electrodes (CEs) of C–PSCs, the electrode interface performance was significantly improved and a PCE of 12.05% was obtained, which was 50% higher than that of pure carbon-based C–PSCs. Through long-term stability tests, it was found that the efficiency of the unpackaged cell did not decrease in after 960 h in the air.

Production and closed-loop recycling of biomass-based malleable materials

The search of biomass-based substitutes for fossil-based plastics has become a pressing task due to the severe long-term threats of plastic wastes to the ecosystem. However, the development in this area is strongly impeded by the high cost of biomass separation and the poor processability of unseparated biomass. Herein, we demonstrate, for the first time, an efficient and scalable method to generate greener plastics by directly integrating unseparated biomass waste (i.e., wood powder) with crosslinked covalent adaptable networks. Through a simple compression molding process, the wood biomass and polymer particles can be fused together to form a continuous material, which is endowed with repairability, reprocessibility, and closed-loop full recyclability. The method demonstrated in this work paves the way for largescale industrial production of environmentally friendly biomass- based plastics.

Dual-templated 3D nitrogen-enriched hierarchical porous carbon aerogels with interconnected carbon nanosheets from self-assembly natural biopolymer gel for supercapacitors

This work reports the design and fabrication of nitrogen-enriched hierarchical porous carbon aerogel (NPCA) with high supercapacitance performance derived from self-assembly natural biopolymer gel using a novel dual-template method. The as-obtained NPCA exhibited a honeycomb-like 3D network architecture composed of interconnected carbon nanosheets with hierarchical porous structure, large specific surface area (SSA, large to ∼1438 cm3 g−1) and high content of N element (large to ∼6%). The 3D hierarchical porous structure was designed and tailored to enhance the electron/ion transport ability. NaCl was in favor of the enhancement of SSA/graphitization degree and the support of 3D architecture, while NaOH played an important role in the formation of micropores. The N dopants were introduced to provide the extra pseudocapacitance, which could improve the performance of energy storage. It was also found that the SSA, graphitization degree and N dopants were highly affected by pyrolysis temperature. Among the resultant samples, NPCA-650 displayed the highest specific capacitance (264.3 F g−1 at 0.5 A g−1) attributed to not only the developed pore structure but also the abundant active N dopants. The as-assembled symmetric supercapacitor exhibited a high energy density of 12.4 Wh kg−1 with excellent cycling stability. Overall, this work provides a novel approach for the fabrication of low-cost biomass-based energy storage materials and could be also helpful for the design and tailoring of the hierarchical porous carbon aerogel architecture.

Physicochemical and thermal analysis of argan fruit residues (AFRs) as a new local biomass for bioenergy production

A detailed investigation of the physicochemical properties and thermal characteristics of argan fruit residues (AFRs) was carried out to identify their potential application as biofuels. This experimental study covered the four main by-products of argan fruit: argan pulp (AP), argan nut shell (ANS), argan oilcake (AOC) and argan deoiled cake (ADC). Physicochemical analysis was performed to characterize biomass-based materials. Thermogravimetric techniques (TG, DTG and DTA) were applied to assess structural decomposition, biomass reactivity and combustion parameters. Lastly, thermal conductivity and diffusivity between 25 and 100 °C were measured using the transient plane source technique (TPS). The study shows that heating values were in the range of 17–22.5 MJ kg−1, which is comparable to those of wood pellets and lignite coal. The maximum ash content was found in AP and the minimum in ANS. The residual oil of AOC was found to affect the drying process and calorific value. Thermal analysis showed that ANS has the highest ignition temperature and thermal conductivity values and therefore appears to be the most reactive material. Our data show that ANS has a good potential to produce heat through direct combustion. A pretreatment appears to be necessary to improve the characteristics of AP and AOC in order to make them suitable biofuels in the near future.

Engineering flexible 3D printed triboelectric nanogenerator to self-power electro-Fenton degradation of pollutants

Abstract By harvesting the ambient mechanical energy using a 3D printed elastic triboelectric nanogenerator (PE-TENG), a self-powered electro-Fenton (EF) system is integrated to sustainably remove methylene blue (MB) with the biomass-based carbon materials as cathode catalysts featuring distinct vesicle-like structure, high surface area, good superhydrophilicity and large defect degree. Here, the PE-TENG characteristic of resource efficiency, time saving, and design flexibility produces maximum power density of 1.95 W m−2 and short-circuit current of 375 μA, qualifying itself as a portable power to drive the EF system. With the continuous electricity generated by PE-TENG, the MB removal efficiency can reach up to 97.0% within 140 min. With a collection of compelling features, such as flexible design of PE-TENG, high removal efficiency for MB, wide availability of biomass-derived cathode catalyst, the present work provides various accesses to other 3D-printed self-powered EF system with flexible, shape-adaptive, energy-/cost-saving integration to restore green hills and blue waters.

Biomass Straw Based Activated Porous Carbon Materials for High-Performance Supercapacitors

Biomass straws are often regarding as agricultural waste, usually burned off in rural areas, which results in severe resource waste and air pollution. In this work, biomass-based porous carbon material with a lamellar microstructure is obtained via simple hydrothermal and subsequent KOH activation, the optimum activate process is determined by the proportion of activator. Scanning electron microscopy (SEM) and nitrogen adsorption techniques are conducted to investigate the physical properties of the materials. Cyclic voltammetry and constant current discharge/charge in the three-electrode system and symmetrical double-layer capacitors results indicate the best electrochemical performance of SCA-1.5 electrode material, with a capacity of 250.0 F g-1 at 1.0 A g-1. And notably, high recycling stability at a high cycling rate of 1.0 A g-1 after 18,000 cycles.

Experimental research on an innovative sawdust biomass-based insulation material for buildings

Sawdust wastes, having high production in China, can be utilized as raw materials of insulation materials to increase their application value and save resources, while the geopolymer will be a good adhesive because of its unique characteristics and low CO2 emissions during the production process. Therefore, a novel biomass-based composite material, which can be used for building insulation, was fabricated with geopolymers as adhesives and sawdust wastes as aggregates. In addition, the influence of three main variables was studied to determine the material’s optimal proportion by testing its thermal and mechanical properties, water resistance and microstructure. The three variables were wetting water to biomass mass ratio (WW/B ratio), H2O2 to adhesive mass ratio (H/A ratio) and biomass to adhesive mass ratio (B/A ratio), respectively. The results indicated that the composite materials with the WW/B ratios of 1–2, H/A ratios of 0.012–0.015, and B/A ratio of 0.12 were the optimum ones with heat conductivity of 0.112–0.125 W/(m·K) and compression strength of 0.76–1.71 MPa. This new biomass-based insulation material with good physical performances can contribute to building energy conservation, cleaner production, and sustainable development.

Characterization of biomass-based materials for building applications: The case of straw and olive tree waste

Vegetable fibers are more and more frequently used in building materials because of their low carbon footprint and their suitability as hygrothermal panels and acoustic absorbers. In particular, as vegetable materials have high carbon sequestration capacity, any use that prevents their incineration (e.g. the natural end-of-life for most pruning wastes), represents an essential contribution to reduction of CO2 emissions. For the above reasons, several researches promote the revival of sustainable building materials made of biomass. In this study, the hygrothermal and acoustical properties of materials suitable for buildings, made with vegetable fibers, are investigated. Straw fibers and olive tree-pruning residues were mixed with sodium silicate solution binders to create high performance insulating panels. Tests carried out in the laboratory allow a correlation between physical and microstructural properties. They evaluated thermal properties, such as thermal conductivity and thermal diffusivity, as well as the hygric performances of the materials, such as sorption isotherm and water vapor permeability. Moisture diffusivity and moisture buffer value were also estimated. Furthermore, sound absorption measurements were carried out. A final comparison between the new panels and one insulating material (EPS) on the market was discussed based on a numerical simulation using Wufi® software.

Environmental Impact Assessments of Integrated Food and Non-Food Production Systems in Italy and Denmark

Given the environmental footprints of the conventional agriculture, it is imperative to test and validate alternative production systems, with lower environmental impacts to mitigate and adapt our production systems. In this study, we identified six production systems, four in Italy and two in Denmark, to assess the environmental footprint for comparison among the production systems and additionally with conventional production systems. SimaPro 8.4 software was used to carry out the life cycle impact assessment. Among other indicators, three significantly important indicators, namely global warming potential, acidification, and eutrophication, were used as the proxy for life cycle impact assessment. In Italy, the production systems compared were silvopastoral, organic, traditional, and conventional olive production systems, whereas in Denmark, combined food and energy production system was compared with the conventional wheat production system. Among the six production systems, conventional wheat production system in Denmark accounted for highest global warming potential, acidification, and eutrophication. In Italy, global warming potential was highest in traditional agroforestry and lowest in the silvopastoral system whereas acidification and eutrophication were lowest in the traditional production system with high acidification effects from the silvopastoral system. In Italy, machinery use contributed the highest greenhouse gas emissions in silvopastoral and organic production systems, while the large contribution to greenhouse gas emissions from fertilizer was recorded in the traditional and conventional production systems. In Denmark, the combined food and energy system had lower environmental impacts compared to the conventional wheat production system according to the three indicators. For both systems in Denmark, the main contribution to greenhouse gas emission was due to fertilizer and manure application. The study showed that integrated food and non-food systems are more environmentally friendly and less polluting compared to the conventional wheat production system in Denmark with use of chemical fertilizers and irrigation. The study can contribute to informed decision making by the land managers and policy makers for promotion of environmentally friendly food and non-food production practices, to meet the European Union targets of providing biomass-based materials and energy to contribute to the bio-based economy in Europe and beyond.

Power generation from palm kernel shell biochar in a direct carbon fuel cell

The diminishing fossil fuel reserves and energy shortage are serious challenges that have directed the search for alternative fuel sources for energy generation in the twenty-first century. Biomass-based carbon materials are alternative and renewable fuel sources used for contemporary energy conversion and present a promising solution to the above crisis. This study investigates the possibility of power generation from oil palm kernel shell (PKS) biochar through direct carbon fuel cell (DCFC) technology. The objective of the study is to investigate the potential of PKS biochar as a fuel source and consolidate information on the association between the structure of PKS biochar and its electrochemical performance in a DCFC. The effect of acid pre-treatment on the structure of biochar is also investigated. The samples are characterized on the basis of chemical composition (proximate/ultimate analysis) and DCFC performance in terms of open circuit voltage, power densities and electrochemical impedance spectroscopy. The results indicated that carbon, ash and oxygen functional groups on the carbon surface have a major impact on the fuel performance in the DCFC. At DCFC operating temperature of 850 °C, the pre-treated PKS biochar exhibits a maximum power density of 3.3 mW cm−2 which exceeds that of untreated PKS biochar and activated carbon. Besides high carbon and reduced ash in the biochar, the results suggest that the existence of oxygen functional groups in the pre-treated PKS biochar also plays a crucial role in cell performance by providing additional active sites for electrochemical reaction.