Considerable carbon emissions from the cement industry pose a notable challenge to achieving long-term sustainable development and creating an enriched social environment. Biochar (BC) obtained from biomass pyrolysis can be used as a carbon-negative material, and it plays a crucial role in the reduction of global carbon emissions. The development of more efficient and cost-effective technologies to fully realize this potential and reduce the environmental impact of BC production and use remains a formidable challenge. The utilization of BC to prepare sustainable cementitious composites with economically value-added benefits has recently attracted much research interest. Therefore, this review analyzes factors influencing the physicochemical properties of BC and their optimization methods, as well as the impact of BC addition on various cement composites and their potential applications. Besides, recent advances in machine learning for predicting the properties of composites and the environmental-economic implications of material are reviewed. The progress and challenges of BC–cement composites are discussed and potential directions for exploration are provided. Therefore, it is recommended to explore commercialization pathways tailored to local conditions and to develop machine learning models for performance prediction and life-cycle analysis, thereby promoting the widespread application of BC in industry and construction.
The study highlights the critical mechanistic data supporting the ecological restoration advantages of biochar (BC) and its role in sustainable environmental management. Recognizing the substantial influence of specific feedstock sources and pyrolysis parameters on BC efficacy, this research aims to address these gaps through an extensive investigation into the potential benefits of BC application in ecological restoration. The methodology involves a systematic exploration of effects of BC from latest literature on various aspects of agricultural sustainability, including its ability to support crop growth, improve nutrient bioavailability, facilitate co-composting, enhance consumption efficiency, and contribute to water quality restoration. The main results of the study reveal that BC usage results in a net negative carbon (C) footprint, mitigates heavy metal pollution, and enhances soil and ecosystem health. In bioenergy production, BC serves as a versatile resource for generating renewable energy, reducing waste, and facilitating C sequestration. Advanced BC techniques, such as tailored pyrolysis processes and activation methods, further enhance its effectiveness in ecosystem restoration and sustainable resource management. Furthermore, the research identifies deficiencies in current literature and proposes future research directions to advance understanding of BC application. Overall, the study underscores the importance of considering feedstock and pyrolysis variables in BC research and highlights the potential of BC to contribute to ecological sustainability. However, concerns regarding potential health implications for humans in agricultural contexts warrant further investigation and risk assessment to ensure safe and sustainable BC application.
Application of advanced techniques and machine learning (ML) for designing and predicting the properties of engineered hydrochar/biochar is of great agro-environmental concern. Carbon (C) stability and phosphorus (P) availability in hydrochar (HC) are among the key limitations as they cannot be accurately predicted by traditional one-factor tests and might be overcome by engineering the pristine HC. Therefore, the aims of this study were (1) to determine the optimal production conditions of engineered swine manure HC with high C stability and P availability, and (2) to develop the best ML models to predict the properties of HC derived from different feedstocks. Pristine- (HC) and FeCl3 impregnated swine manure-derived HC (HC-Fe) were produced by hydrothermal carbonization under different pH (4, 7, and 10), reaction temperature (180, 220, and 260 ℃), and residence time (60, 120, and 180 min) and characterized using thermo-gravimetric, microscopic, and spectroscopic analyses. Also, different ML algorithms were used to model and predict the hydrochar solid yield, properties, and nutrients content. FeCl3 impregnation increased Fe-phosphate content, while it reduced H/C and O/C ratios and hydroxyapatite P content, and therefore improved C stability and P availability in the HC-Fe as compared to HC, particularly under lower pH (4), temperature of 220 ℃, and at 120 min. The generalized additive ML model outperformed the other models for predicting the HC properties with a correlation coefficient of 0.86. The ML analysis showed that the most influential features on the hydrochar C stability were the H and O contents in the biomass, while P availability in HC was more dependent on the C, N and O contents in biomass. These results provided optimal production conditions for Fe-engineered manure hydrochar and identified the best performing ML model for predicting hydrochar properties. The main implication of this study is that it offers a high potential to improve the utilization of biowastes and produce biowaste-derived engineered hydrochar with high C stability and P availability on a large scale.
Biochar is a promising technology for carbon storage and greenhouse gas (GHG) reduction, but optimizing it is challenging due to the complexity of natural systems. Machine learning (ML) and natural language processing (NLP) offer solutions through enhanced data analysis and pattern recognition, ushering in a new era of biochar research.
Cadmium (Cd) contamination in the environment is widespread, making it crucial to reduce Cd accumulation in cereal crops like wheat. However, strategies that not only mitigate Cd pollution but also address other environmental challenges, such as invasive species management, remain unclear. This study introduces an innovative approach combining molybdenum nanoparticles (Mo NPs, 1 µM) and biochar biofilters derived from the invasive plant Mikania micrantha (IPMM), targeting the biochemical and molecular responses of wheat under Cd stress (100 µM). Our findings showed that this novel combination significantly improved wheat physiological characteristics, growth, root architecture, elemental profile, osmoregulation, carotenoid, chlorophyll, gas exchange, and photosynthetic efficiency. Remarkably, simultaneous supply of IPMM biochar biofilters and Mo NPs substantially modulated the Cd translocation, reducing its accumulation in root (30.54%) and shoot (53.59%). Additionally, this strategy not only preserved mesophyll cell structures and the membrane integrity, but also strengthened and activated the oxidative defense systems through the regulation of genetic expressions. This synergistic approach advances the Cd alleviating techniques and offers a sustainable solution for utilizing invasive plants as a potential resource. By addressing both heavy metal pollution and ecological challenges, it provides a promising solution for safer crop production in Cd-contaminated environments.
Electrocatalytic oxidation of more stable 2,5-furanedimethanol (FDM) for 2,5-furanediformic acid (FDCA) generation with concurrent hydrogen production is attractive but still nascent compared to 5-Hydroxymethyl-2-furaldehyde (HMF). The need for effective and stable bifunctional electrocatalysts that are efficient for the FDM cell is thus quite significant. Wood serves as an ideal matrix for boosting the performance of catalysts, since its hierarchical porous structures facilitate mass transport and provide abundant active sites. Unfortunately, it has never been demonstrated for electrochemically organic synthesis. Herein, the effectiveness of Fe-CoP in catalyzing FDM oxidation was demonstrated by density functional theory (DFT) calculations and experiments, and a renewable carbonized porous wood decorated with Fe-doped CoP nanoleaves (Fe-CoP/CW) was constructed for electrocatalytic FDCA and hydrogen generation. The obtained Fe-CoP/CW as an anode in FDM solution afforded a current density of 100 mA cm−2 with a yield of 90% FDCA at a potential no more than 1.50 V vs RHE, which was 90 mV and 350 mV lower than Fe-CoP/carbon cloth (CC) and IrO2. In addition, Fe-CoP/CW showed excellent long-term stability for 108-h FDM oxidation in strong alkaline solution. Remarkably, in stark contrast to Fe-CoP/CC and Pt, the hydrogen evolution performance of Fe-CoP/CW was not impacted by FDM at the cathode, and it required exceptionally low overpotentials of 0.19 V to achieve 100 mA cm−2. As a result, in terms of the overall cell, the hydrogen production rate was 0.756 mmol cm−2 h−1, which was 3.57 times higher than those of commonly used commercial Pt | IrO2 cell, presenting a Faraday efficiency of near 100%. This work will pave the way towards the implementation of highly suited bifunctional electrodes and the possibility of affordable, effective, and environmentally-friendly wood-derived electrocatalysts for electrochemically organic synthesis.
Biocomposite filaments for material extrusion (MEX) additive manufacturing, particularly those derived from agricultural biomass, have attracted significant research and industrial interest. Biochar is a well-documented reinforcement agent that is used in several polymeric matrices. However, systematic research efforts regarding the quality scores of parts built with MEX 3D printing with biochar-based filaments are marginal. Herein, the impact of biochar loading on the quality metrics of the five most popular polymers for MEX 3D printing (ABS, HDPE, PETG, PP, and PLA) is quantitatively examined in depth. Sophisticated and massive Non-Destructive Tests (NDTs) were conducted, and the impact of biochar loading on the critical quality indicators (CQIs), including porosity, dimensional conformity, and surface roughness, was documented. The quality scores for the biochar filler loading, also five in total, were statistically correlated with the corresponding reinforcement metrics for the five polymeric matrices. A statistically significant antagonistic interaction between the tensile strength course and porosity/dimensional deviation metrics, particularly for PETG, was observed. It can be concluded that the lowest porosity and dimensional deviation are associated with the highest strength. The 4 wt% biocomposite exhibited optimal quality performance in most polymers studied.
Material selection and production conditions are imperative for determining the functional performances of composite materials. Phase-change composites obtained from phase-change materials (PCMs) and supporting matrices exhibit high thermal energy storage density. They are used to overcome the intermittency issues of wind and solar energy, as well as to reduce waste heat dissipation to the environment. However, the large-scale utilization of composite and pristine materials has severe drawbacks, primarily stemming from the complex fabrication routes of the encapsulating agents, leakage, and inadequate thermal stability. In this study, biochar-based phase-change composites were fabricated using vacuum infiltration techniques, and the effects of biomass feedstock and pyrolysis temperature on the performance of the composite were elucidated using different types of biowastes and temperatures. This approach has several advantages, including facile production techniques, low-cost carbon sources, and environmental friendliness. The PCM adsorption ratio of biochars derived from rice husk (RH) and Miscanthus straw linearly correlated with the pyrolysis temperature (550–700 °C), while RH700 resulted in a composite with a high enthalpy per unit mass of hexadecane (HXD) in RH700/HXD (250.9 J g−1) owing to the high surface area of RH700 (74.66 m2 g−1). The crystalline temperature increased slightly from 10.7 °C in RH550/HXD to 10.9 °C in RH700/HXD, suggesting improved molecular motion and crystal growth of HXD. Wheat straw biomass pyrolyzed at a low temperature (550 °C), displaying a reduced surface area at 700 °C (7.35 m2 g−1) and exhibiting the lowest energy storage density. The latent heat efficiency reached 99.5–100%, where RH700/HXD exhibited 100% efficiency. The composites demonstrated strong leakage resistance at high heating temperatures (60 °C, above the melting temperature of HXD), good chemical compatibility between the biochar and HXD, and high durability after 500 thermal cycles. Therefore, the extent of PCM loading and energy storage density improvements primarily depends on the pyrolysis conditions, feedstock used, and pore size distribution of the biochar samples. This research provides insights into the fabrication of phase-change composites and optimization of the carbonization process of different biomasses used for thermal management applications, such as building energy savings.
Accurate estimation of biochar carbon permanence is essential for assessing its effectiveness as a carbon dioxide removal (CDR) strategy. The widely adopted framework, based on the two-pool carbon exponential decay model, forms the basis of policy guidelines and national CDR accounting. However, our re-analysis of the meta-data used in this model reveals significant deficiencies in its parameterization, leading to two critical issues. First, the current parameterization assigns a disproportionally low percentage of the labile carbon fraction (C1) relative to the recalcitrant fraction (C2), effectively reducing the model to a single-pool approach. Due to the limited duration of incubation experiments, the decay constant of the labile fraction is incorrectly applied to the entire biochar mass, resulting in a considerable overestimation of the biochar decay rate. Second, our analysis reveals a lack of causal correlation between the assigned proportions of C1 and C2 and key carbonization parameters such as production temperature and hydrogen-to-carbon (H/C) ratios, suggesting that the model does not accurately represent the underlying chemistry. This misalignment contradicts the established relationship between increased biochar stability and a higher degree of carbonization. Consequently, the the parameterization of current model may not adequately reflect the carbon sequestration potential of biochar. While a multi-pool decay model is suitable for predicting the permanence of biochar, the primary issue with the current model lies in its parameterization rather than its structure. To address these limitations, we recommend that future research prioritize the development of a revised multi-pool decay model with improved parameterization, supported by empirical decomposition data from a variety of experimental methods, including incubation studies, accelerated aging experiments, and comprehensive physicochemical characterization. This refined approach will improve the accuracy of biochar permanence estimations, strengthening its role in global carbon management strategies.
This study explores a novel approach to biochar modification aimed at increasing persistent free radical (PFR) formation on biochar surfaces, thereby enhancing aniline removal via peroxymonosulfate (PMS) activation. By adjusting pyrolysis temperatures and doping ratios, optimal conditions were established. Spearman's analysis highlighted the importance of C=C bonds, the ID/IG ratio, and pyridinic N in generating PFRs. The modified biochar derived at 500 ℃ (MB500), in conjunction with the PMS system demonstrated impressive efficiency, achieving 92% aniline removal within 30 min. Detailed adsorption tests and active species detection indicated that aniline degradation occurred through both direct oxidation by PFRs and indirect oxidation by reactive species, particularly superoxide radicals (O₂⋅⁻). Furthermore, the synergistic effects of heteroatom nitrogen and Na2CO3 modifications significantly impacted PFR formation and stability. These findings provide valuable insights into the mechanisms of PFR-mediated catalytic oxidation, highlighting the key roles of pyridinic rings, with or without oxygenated groups, in enhancing catalytic performance of biochar. This research advances the understanding of biochar surface chemistry and presents an effective strategy for developing high-performance biochar-based catalysts for environmental remediation, addressing the limitations of unmodified biochar through targeted surface modifications.