Amount Of Biochar Research Articles

Sustainable and mechanical properties of Engineered Cementitious Composites with biochar: Integrating micro- and macro-mechanical insight

Engineered Cementitious Composites (ECC) are ductile, strain-hardening cementitious composites with a tightly controlled crack opening profile. A significant concern in the development and application of ECC is its high carbon emissions associated with high cement content consumption. As an emerging green additive, biochar can significantly cut down on the carbon emission of concrete products. However, research that integrates micro- and macro-mechanical insights with biochar incorporation is limited. In this study, micro-mechanical tools indicated that a certain amount of substitution biochar could enhance the tensile properties of ECC. The study assessed various properties including compressive strength, porosity, density, tensile performance, crack pattern, sustainability and cost of ECC with different biochar proportions. The findings showed that incorporating 10 %–20 % biochar effectively increased the tensile strain capacity and decreased the crack opening width in ECC materials. This improvement can be attributed to the introduction of finer biochar particles (≤75 μm) at the fiber/matrix interfacial transition zone, which alters the fiber-bridging force by reducing the chemical and frictional bond strength between the fiber and matrix, as revealed by micro-mechanical tests and microstructural inspection. Moreover, the utilization of biochar contributes to reducing the carbon emission of ECC, enhancing sustainability while maintaining a ∼10 % minimal reduction in compressive strength. Overall, this study introduces a novel approach for reusing low-carbon biomass waste in the production of building materials, offering potential advantages in micro- and macro-mechanical performance, cost-effectiveness, and environmental sustainability.

The Effects of Acid-Modified Biochar and Biomass Power Plant Ash on the Physiochemical Properties and Bacterial Community Structure of Sandy Alkaline Soils in the Ancient Region of the Yellow River

The application of biochar can effectively enhance soil organic matter (SOM) and improve soil structure. Biomass power plant ash (BPPA) is also rich in essential nutrients for plants, with similar carbon content. Considering production cost and agricultural waste recycling, it is beneficial to apply BPPA to improve soil fertility and quality. However, it remains unclear whether its ameliorative effects surpass those of biochar in alkaline soils. In the study, we set up seven pot experiments of faba beans in sandy alkaline soils from the ancient region of the Yellow River, including the controls (CK), different amounts of acid-modified BPPA (A1, A2, A3), and the same amounts of acid-modified biochar (B1, B2, B3), to compare their effects on soil physiochemical properties and bacterial community structure. The results indicate that the application of both biochar and BPPA can improve soil physiochemical properties. At the same dosage, the biochar application outperformed BPPA treatment in terms of soil physical properties such as bulk density (BD), maximum water-holding capacity (FC), and soil capillary porosity (SP2). Conversely, BPPA treatment displayed advantages in chemical properties such as readily oxidizable organic carbon (ROOC), total nitrogen (TN), alkaline nitrogen (AN), available phosphorus (AP), available potassium (AK), and electrical conductivity (EC). All the treatments enhanced the richness and diversity of bacterial communities, increasing the relative abundance of eutrophic groups such as Bacteroidota and Firmicutes while decreasing that of oligotrophic groups like Actinobacteriota. BPPA also increased the relative abundance of Proteobacteria, while the opposite was observed for biochar. Correlation analysis showed that the environmental factors such as soil pH, EC, TN, AK, SOM, and SP2 emerged as primary factors influencing the bacterial community structure of alkaline soils, significantly affecting their diversity and abundance. Among them, SP2 and SOM were the dominant physical and chemical factors, respectively. Overall, the application of both acid-modified BPPA and biochar can enhance the physiochemical properties of sandy alkaline soils, while the application of BPPA is superior for improving soil nutrient content and enhancing bacterial community structure. The study explores the potential mechanisms through which the application of acid-modified BPPA affects soil characteristics and microbial features, providing new insight into developing optimizing fertilization strategies for enhancing soil quality in the ancient region of the Yellow River.

Selective electro-induced reduction using bionic BC@SA-Nafion particle electrodes in 3D systems and phytotoxicity assessment

Three-dimensional electrode technology (3D technology), featuring dispersed particulate electrodes is rapidly advancing in the separation of pollutants. However, in contrast to the electrochemical oxidation performance, the design of particulate electrodes for electrochemical reduction remains relatively underexplored. This study introduced a bionic particle electrode (BC@SA-Nafion) with high reducibility and selectivity, and integrated it into a 3D system. Specifically, the selective electro-induced reduction capacity of BC@SA-Nafion was examined using Cr(Ⅵ) as a model pollutant. The electrochemical reactivity of BC@SA-Nafion was found to be dependent on the amount of biochar (BC) incorporated. Furthermore, the selectivity for Cr(Ⅵ) could be fine-tuned by adjusting the Nafion content, thereby addressing the efficiency decline at lower Cr(Ⅵ) concentrations. In the 3D system, the Cr(Ⅵ) removal rate reached up to 99 % under optimal conditions (pH 2, 2 V cm−1, 30 min). The density functional theory calculations indicated that the selectivity of BC@SA-Nafion for Cr(Ⅵ) was dependent on the presence of fluorine bonds. The reduction of Cr(Ⅵ) mainly relied on direct electron transfer provided, with superoxide (·O- 2) also playing a role. Post-treatment with the 3D technology resulted in negligible phytotoxicity of the wastewater. This study introduced a novel strategy for enhancing the selectivity of particle electrodes, thereby expanding the application of the particle electrode and advancing sustainable water treatment technologies.

Carbon dioxide emission evaluation of biochar based vegetation concrete for ecological restoration projects

Vegetation concrete is increasingly being used for slope stabilization in highways, green roofing in urban developments, and erosion control in coastal areas due to its sustainable solutions for enhancing landscape aesthetics, mitigating pollution, and protecting the environment. However, the environmental and economic impacts of different mix proportions, particularly concerning CO2 emissions, remain insufficiently explored. This study aimed to identify the optimal mix proportions of vegetation concrete through laboratory testing that minimize CO2 emissions while ensuring compatibility with plant growth and cost-effectiveness. The vegetation concrete mix were prepared using different quantities of biochar (5 %, 10 %, and 15 %) and cement content (4 %, 8 %, and 12 %) by weight to evaluate their impact on porosity, unconfined compressive strength (UCS), alkalinity, plant compatibility, cost-effectiveness, and CO2 emissions from raw materials. The results indicate that increasing the biochar content from 0 % to 15 % led to a 16 % reduction in porosity and a 92 % increase in UCS of vegetation concrete. Similarly, increasing the cement content from 0 % to 12 % resulted in an 11 % decrease in porosity and a substantial 200 % increase in the UCS of vegetation concrete. Moreover, the addition of 5 % biochar had a beneficial effect on plant growth, however, increasing the biochar content beyond this level adversely impacted plant development. Based on laboratory test results, the recommended optimal mix for vegetation concrete includes a mix of 5 % biochar, 8 % low-alkaline sulfoaluminate cement, 6 % sawdust, and 6 % ferrous sulfate. The analysis of CO2 emission of the materials studied showed that cement contributed the most to CO2 emissions, followed by biochar, sawdust, water, and soil. Notably, the utilization of sulfoaluminate cement led to a 31.8 % reduction in CO2 emissions compared to Portland cement, while also lowering the overall cost of vegetation concrete by 24.7–33.8 %. This research underscores the necessity of scientifically establishing relationships between the composition of plant-based concretes and their environmental and economic performance. In summary, this study identifies optimal mix proportions for vegetation concrete, leveraging low-alkaline sulfoaluminate cement and biochar to minimize CO2 emissions, enhance landscape aesthetics, and ensure compatibility with plant growth, thus emphasizing its potential as a sustainable and cost-effective construction material.

Effects of different low-temperature pyrolysis treatments on the biotoxicity of biochar derived from tobacco stalks

The pyrolytic treatment of tobacco stalk (TS) waste results in the production of a large amount of biochar, which is usually used for environmental remediation. However, little attention has been given to the effects of different pyrolysis methods on the biotoxicity of TS biochar. This study examined the effects of three different pyrolysis methods at 350 °C (fast pyrolysis, slow pyrolysis, and low-temperature carbonization) on the biotoxicity of TS biochar (Escherichia coli (E. coli) growth and wheat germination). The results revealed that the dissolved organic matter (DOM) of the three types of biochar promoted the growth of E. coli, and the maximum growth of E. coli was ranked as DOM-F350 > DOM-S350 > DOM-350. However, the DOM inhibited the growth of the wheat seeds, with the growth index (below 0.8) of the wheat seeds ranked as DOM-350 > DOM-F350 > DOM-S350. The alkali metal content, pH and humus-like substance content of biochar may be responsible for the biotoxicity of biochar through various mechanisms. In addition, TS-S350 exhibited greater biotoxicity than did TS-F350 because of the greater content of toxic nitrogen-containing organic compounds. These findings can provide reliable theoretical guidance for the effective management and safe utilization of TS waste.

Preparation of composites of lithium-aluminum layered double hydroxides and biochar and their performance in lithium extraction from aqueous media

Layered lithium aluminum double hydroxides (LiAl-LDH) have significant potential for industrial applications, particularly as adsorbents for lithium extraction from salt lakes. However, their development is constrained by a relatively low adsorption capacity. To address this limitation, a composite material comprising biochar (BC) and lithium aluminum layered double hydroxide (LiAl-LDH@BC) was synthesized via a hydrothermal reaction, using Al(NO3)3·9H2O, LiNO3, urea, and varying amounts of BC as raw materials. This composite demonstrates excellent Li+ adsorption capacity (19.6 mg/g). LiAl-LDH@BC2.5 was characterized using SEM, XRD, XPS, and other analytical methods. The effects of various adsorption conditions—including adsorption temperature, initial Li+ concentration, time, pH, ion interference, and the number of cycles—on the Li+ adsorption performance of LiAl-LDH@BC were investigated. The increased specific surface area and the electrostatic adsorption of surface functional groups after composite formation are the primary reasons for the high adsorption capacity. The mechanism of Li+ adsorption follows pseudo-first-order kinetics and the Langmuir model, involving both physical and chemical adsorption. This study offers a promising adsorbent for the extraction of Li+ from aqueous media.

Endogenous silicon-activated rice husk biochar prepared for the remediation of cadmium-contaminated soils: Performance and mechanism

Biochar is widely used for the remediation of heavy metal-contaminated soils. However, pristine biochar generally has limited active functional groups and adsorption sites, thereby exhibiting low immobilization performance for heavy metals. In addition to carbon (C), silicon (Si) is another common macro-element present in rice husk biochar, but it often exists in the form of amorphous oxide and therefore contributes little to the adsorption performance for heavy metals. The transformation of amorphous Si oxide to dissolved silicate through a precipitation effect can significantly improve its heavy metal immobilization capability. Herein, the amorphous Si oxide in rice husk biochar was activated by sodium hydroxide and then the dissolved silicate was immobilized by calcium salt. The as-synthetized Si-activated biochar was used to remediate cadmium (Cd)-contaminated soils. The results indicated that Si-activated rice husk biochar could reduce Cd migration and environmental risks by the transformation from exchangeable Cd into carbonate-bound and residual Cd. With increasing Ca: Si molar ratio, the content of CaCl2 and H2O-extractable Cd exhibited a decreasing trend. Moreover, a higher addition amount of Si-activated biochar improved the Cd immobilization efficiency. The application of 1.0% Ca/Si molar ratio of 2: 2 Si-activated rice husk biochar decreased the CaCl2-Cd and H2O-Cd concentration by a maximum of 83.7% and 90.5% compared with pristine rice husk biochar, respectively. The present work proposes an approach for highly efficient remediation of Cd-polluted soils by biochar.

Long-term biochar and soil organic carbon stability – Evidence from field experiments in Germany

Organic soil amendments (OSA) with long residence times, such as biochar, have a high potential for soil organic carbon (SOC) sequestration. The highly aromatic structure of biochar reduces microbial decomposition and explains the slow turnover of biochar, indicating long persistence in soils and thus potential SOC sequestration. However, there is a lack of data on biochar-induced SOC sequestration in the long-term and under field conditions. We sampled two long-term field experiments in Germany, where biochar was applied 12 and 14 years ago. Both locations differ in soil characteristics and in the types and amounts of biochar and other OSA. Amendments containing compost and 31.5 Mg ha−1 of biochar on a loamy soil led to a SOC stock increase of 38 Mg ha−1 after OSA addition. The additional increase is due to non-biochar co-amendments such as compost or biogas digestate. After eleven years, this SOC stock increase was still stable. High biochar amount additions of 40 Mg ha−1 combined with biogas digestate, compost or synthetic fertilizer on a sandy soil led to an increase of SOC stocks of 61 Mg ha−1; 38 Mg ha−1 dissipated in the following four years most likely due to lacking physical protection of the coarse soil material, and after nine years the biochar-amended soils showed only slightly higher SOC stocks (+7 Mg ha−1) than the control. Black carbon stocks on the same soil increased in the short- and mid-term and decreased almost to the original stock levels after nine years. Our results indicate that in most cases the long-term effect on SOC and black carbon stocks is controlled by biochar quality and amount, while non-biochar co-amendments can be neglected. This study proves that SOC sequestration through the use of biochar is possible, especially in loamy soils, while non-biochar OSA cannot sequester SOC in the long term.

Improving mechanical properties of PLA with pinus sylvestris char: exploring thermal stability, interfacial strengthening mechanisms, and applications in 3D printing

In the present study, submicron and micron-sized pinus sylvestris char (PS) was applied for the modification of polylactic acid (PLA) and the effect of the properties of PS on the mechanical, thermo-mechanical, and crystallization kinetics of PLA were investigated. As demonstrated, PS could enhance the toughness of the PS-PLA composites by forming interfacial "bridges" to facilitate stress transfer due to its stable lamellar structure and interaction with the PLA matrix. The tensile strength of PLA-PS composites increased by 98% and the bending strength increased by 25% compared to that of pure PLA. The addition of PS significantly increased the energy storage modulus (increased 22%) and loss modulus (increased 30%) of PLA, but led to a decrease in the crystallinity and thermal stability of the composite. In the practical utilization for 3D printing, PS-PLA composites possess good tensile strengths (41.5 MPa), allowing for smooth printing of complex products. This work provides an efficient strategy to modulate the thermodynamic and mechanical properties of PLA matrices by regulating the viscosity of the composites and modulating the interfacial strength with the addition of proper amounts of biochar.

Remediation of Arsenic and Heavy Metals and Soil Stabilization by Waste Chitosan based Biochar

Objectives : This study aims to evaluate the feasibility of converting waste chitosan adsorbents, laden with microalgae, into biochar for application as a stabilizing agent to remediate heavy metal-contaminated soil and improve soil quality.Methods : Waste chitosan adsorbents were converted into biochar through two processes: dry thermal carbonization at 400°C to produce pyrochar and hydrothermal carbonization at 200°C to produce hydrochar. The elemental compositions, surface functional groups, morphologies of the biochars were evaluated by elemental analyzer, FT-IR spectrometer, and SEM analysis. The arsenic and heavy metal adsorption characteristics of the produced biochars were assessed. Additionally, the produced biochars were applied as stabilizing agents to arsenic and heavy metal-contaminated soil with varying mixing ratios of 2, 5 and 10 wt%. After a one-week soil stabilization experiment, soil properties and TCLP(Toxicity Characteristic Leaching Procedure) leaching tests were conducted.Results and Discussion : The pyrochar produced from waste chitosan exhibited a porous structure with high pH (pH 10) and minimal surface functional groups. The hydrochar consisted of spherical particles with functional groups such as hydroxyl and amine groups on the surface, exhibiting a slightly acidic pH of 5.8. Pyrochar has a higher adsorption capacity for cationic heavy metals compared to hydrochar due to its porous structure and high pH. On the other hand, when applied to soil, hydrochar demonstrated superior stabilization efficiency for arsenic and heavy metals. This is attributed to the diverse surface functional groups containing oxygen on the hydrochar. The stabilization efficiency was influenced by the biochar mixing ratio, with a 5% hydrochar application resulting in 10-64% stabilization efficiency for all elements.Conclusion : This study confirmed that biochar produced from waste chitosan effectively stabilizes arsenic and heavy metals in soils. Additionally, the quantity of biochar used can impact its effectiveness in stabilization.

Performance and mechanism of antibiotic resistance removal by biochar-enhanced sediment microbial fuel cell

This study is the first to explore the performance and mechanism of biochar-impacted sediment microbial fuel cell for removing antibiotic resistance genes (ARGs), and examines the effects of different biochar contents. The addition of 5% biochar produced the highest output voltage and power density, which increased by 100% and 219%, respectively, while simultaneously reducing the abundance and risk of ARGs. Comparatively, the addition of moderate amount of biochar (1–5%) promoted the removal of ARGs, while the opposite was true for excessive (10%) biochar. Biochar affected ARGs through prophages, insertion sequence, and transposons. Biological factors and voltage jointly influenced ARGs variation, with the former accounting for 56%. Further analysis of functional genes indicated that biochar controlled ARGs by regulating the synthesis of genetic material and amino acids to influence metabolism. Overall, findings of this study shed light on the potential removal of ARGs in microbial electrochemical systems.

Impact assessment of Zeolite, Ca-bentonite and Biochar amendments on Cd bioavailability and fractions in polluted calcareous soils

The refining of polluted soils by heavy elements is one of the most important environmental policies in industrialized and developing countries. Using adsorbents is a suitable procedure for the immobilization of heavy metals in polluted soils. This study aimed to assess the immobilization of Cadmium (Cd) in polluted calcareous soil affected by the application of organic and inorganic amendments including Biochar (from grape pruning residues) and natural Zeolite and their interaction under wheat cultivation. The treatments used in this study were two amendments of Zeolite and Biochar (from grape pruning wastes) at three levels (0, 1, and 4%) and three levels of Cd contamination (0, 75, and 150 mg/kg soil). A 16-week incubation period was considered for the homogenization of the amendments in soil and wheat was grown according to the standards procedure. At the end of incubation, different fractions of Cd including residual, exchangeable, bonded to organic matter, bonded to carbonate and bonded to iron and manganese. Also available Cd by DTPA and EDTA methods and 1000-grain weight of wheat were measured. The results showed that the highest amount of Cd bound to organic matter was obtained in 4% Biochar treatment to 15 mg/kg. The highest and lowest amounts of Cd extracted with DTPA were obtained in the control one (92 mg/kg) and the level of 4% Biochar (67 mg/kg), respectively. The results showed that increasing the amount of Biochar and Zeolite amendments increased the weight of 1000 grains of wheat in all treatments. According to the results of the study, the use of Biochar and Zeolite reduced the amount of Cd extracted by DTPA ( 82.436 mg/kg) and EDTA (115.605 mg/kg). Finally, the results showed that the use of Biochar and Zeolite has reduced active Cd and its mobility in the soil due to increasing organic and carbonate fractions. Combining biochar and zeolite in soil remediation efforts can enhance their effectiveness in reducing the concentration and mobility of active Cd. The biochar provides a stable carbon matrix for long-term immobilization of Cd, while the zeolite offers additional adsorption capacity and ion-exchange capabilities. This synergistic effect can lead to improved soil quality and reduced environmental risks associated with Cd contamination.

Study on the optimal water−biochar management mode based on pan evaporation for solar greenhouse tomato (Solanum lycopersicum L.) in Northeast China

Biochar is commonly employed to enhance soil structure. However, the soil structure degradation due to multi-year continuous cropping poses a significant obstacle to the advancement of solar greenhouse agriculture. This study aimed to optimize the water−biochar management mode for seasonal solar greenhouse tomatoes (Solanum lycopersicum L.), which have been continuously cultivated over three years, with irrigation guided by the evaporation of a 20 cm evaporation pan (Ep-20). The experimental design employed a split–plot arrangement with two factors. The primary factor, irrigation amount, was tested at three levels: 0.6 Ep-20 (W1), 0.8 Ep-20 (W2), and 1.0 Ep-20 (W3). The secondary factor, biochar amount, was tested at three levels: 0 (B0), 20 t ha−1 (B1), and 40 t ha−1 (B2). The results revealed that biochar reduced soil bulk density and enhanced field capacity, tomato plant height, and photosynthesis. Increased irrigation improved tomato appearance quality but reduced nutritional quality, whereas higher biochar application improved both aspects. Principal component analysis (PCA) and grey relational analysis (GRA) results identified W2B2 as the optimal mode for the quality of spring tomato and autumn tomato. Compared to the control (W3B0), W2B2 exhibited an average increase of 18.0 % in yield and 47.5 % in irrigation water productivity (WPI) with a 20 % reduction in irrigation amount across two seasons. The technique for order preference by similarity to ideal solution (TOPSIS) comprehensive evaluation determined that the W2B2 mode maximized comprehensive benefits, enhancing both the overall quality of tomato and achieving higher yield and WPI. This study utilized the Ep-20 to characterize the reference crop evapotranspiration (ETo) and the crop evapotranspiration (ETc). The investigation demonstrated the feasibility of utilizing Ep-20 to guide irrigation under biochar application conditions and develop ETc estimation models for water−biochar management modes to optimize solar greenhouse tomato production.

Mechanical and thermal properties of composite carbonized briquettes developed from cassava (Manihot esculenta) rhizomes and groundnut (Arachis hypogea. L.) stalks with jackfruit (Artocarpus heterophyllus) waste as binder

Composite briquettes from agricultural residues are a potential sustainable domestic solid fuel resource. This study aimed to develop and characterize composite briquettes developed from cassava rhizomes and groundnut stalks with jackfruit waste binder as an alternative sustainable fuel for domestic cooking applications. Cassava rhizomes and groundnuts stalks feedstock were carbonized in a step-down kiln under slow pyrolysis conditions at temperatures between 400 and 500 ℃. Thermogravimetric analysis was used to determine the proximate and thermal properties of the developed composite briquettes. Bomb calorimetry was used to determine their heating values. Relaxed density, drop strength and compressive strength results were used to determine the mechanical properties of the developed briquettes. Design of Experiments (Box Behnken design) was used to evaluate the effect of factors (biochar amount, jackfruit waste binder amount, and amount of water) on the mechanical and thermal properties of the developed composite briquettes. The Coats-Redfern kinetic model was used to determine the activation energy for the developed briquettes. Calorific values and drop strength of developed composite briquettes ranged from 18.1 to 24.0 MJ/kg and 92–99%, respectively. Combustion performance results indicated that ignition temperature increased from 155.1 to 184 ∘C\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\\circ{\\rm C}$$\\end{document}, when heating rate was increased from 10 to 15 ∘C\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\\circ{\\rm C}$$\\end{document}/min. However, burnout temperature decreased from 618.1 to 453 ∘C\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\\circ{\\rm C}$$\\end{document}/min with a similar corresponding increase in heating rate. Optimum biochar amount, amount of water, and jackfruit waste binder amount for optimal mechanical and thermal properties were 89.3%, 893.0 ml, and 29.5 g, respectively. Composite briquettes developed from cassava rhizomes and groundnut stalks with jackfruit waste as binder are suitable potential domestic cooking fuels.

Pyrolysis assessment of palm kernel shell waste valorization to sulfonated magnetic biochar from techno-economic and energy perspectives

Most agricultural activities generate a significant quantity of biomass waste that has not been fully utilized. This study utilized palm kernel shells as the primary material to produce sulfonated magnetic palm kernel shell biochar. The post-sulfonation magnetic palm kernel shell biochar had a greater particle size of around 137 nm compared to the pre-sulfonation biochar. This increase in size can be attributed to the presence of the − SO3H group. The biochar that underwent post-sulfonation was chosen for a techno-economic evaluation to ascertain its viability in terms of economics and energy efficiency. Soybean straw and coconut shell-derived biochar were chosen for the techno-economic assessment. The energy intake for soybean straws, coconut shells, and palm kernel shells derived from biochar is 48.85 MJ∙kg−1, 23.83 MJ∙kg−1, and 52.44 MJ∙kg−1, respectively. The energy output for soybean straws, coconut shells, and palm kernel shells derived biochar is determined to be 22.54 MJ∙kg−1, 23.68 MJ∙kg−1, and 31.55 MJ∙kg−1, respectively. The ultimate profit-to-cost ratios of soybean straws, coconut shells, and palm kernel shells derived biochar are 0.21, 4.92, and 1.11, respectively. The techno-economic assessment indicates that coconut shell-derived biochar production is favourable, primarily due to its attributes of low net energy balance, high porosity, and lower density. Both coconut shells and palm kernel shells derived biochar productions are economically viable and efficient due to their high profit-to-cost ratio. The microwave-assisted technology is proven efficient and demands less energy to generate an equivalent quantity of biochar compared to traditional furnaces.

Biochar Amendments and Phytoremediation: A Combined Approach for Effective Lead Removal in Shooting Range Soils.

The increasing contamination of soil with heavy metals poses a problem to environmental sustainability. Among these pollutants, lead is particularly concerning due to its persistence in the environment, with harmful effects on human health and ecosystems. Various strategies that combine phytoremediation techniques with soil amendments have emerged to mitigate lead contamination. In this context, biochar has gained significant attention for its potential to enhance soil quality and remediate metal-contaminated environments. This study aims to investigate the combined effect of biochar amendments on the phytoremediation of lead-contaminated shooting range soils. A series of experiments were conducted to determine the impact of the amount and distribution of biochar on lead removal from soil. Soil samples were incubated with biochar for one week, after which two types of seeds (Brassica rapa and Lolium perenne) were planted. Plant and root lengths, as well as the number of germinated seeds, were measured, and a statistical analysis was conducted to determine the influence of the amendments. After one month, the Pb concentration decreased by more than 70%. Our results demonstrate that seed germination and plant growth were significantly better in soil samples where biochar was mixed rather than applied superficially, with the optimal performance observed at a 10% wt. biochar amendment. Additionally, the combined use of biochar and phytoremediation proved highly effective in immobilizing lead and reducing its bioavailability. These findings suggest that the combination of biochar, particularly when mixed at appropriate concentrations, and Brassica rapa significantly improved lead removal efficiency.

Study on the Effect of Magnesium Chloride-Modified Straw Waste Biochar on Acidic Soil Properties.

Soil biochar is a kind of organic matter rich in carbon, which is of great significance in soil fertility improvement, fertilizer type innovation and greenhouse gas emission reduction. In this paper, Mg-modified biochar was prepared by thermal cracking using rice straw and corn straw as raw materials. The Mg-modified biochar and unmodified biochar were fully mixed with prepared soil samples at the addition amounts of 0.5% (w/w), 1% (w/w) and 2% (w/w), respectively, and then simulated indoor soil cultivation experiments were carried out. The effects of magnesium ion-modified biochar and non-modified biochar on soil chemical properties and the effects of different amounts of biochar on soil properties were studied. The results showed that the yield of Mg-modified biochar from rice straw and corn straw, prepared by pyrolysis, was 65%, and the ash content was large. The pH of MG-modified corn stalk biochar (MCBC) is weakly basic (8.55), while the pH of MG-modified rice stalk biochar (MRBC) is basic (10.1), and their internal structures are slightly different. After the application of biochar prepared from rice straw and maize stover, soil indicators were determined. Compared to the control, the chemical properties of the treated soil samples were significantly improved, with an increase in soil pH, an increase in the content of effective nutrients, such as fast-acting potassium, fast-acting phosphorus and alkaline dissolved nitrogen, and an increase in the content of the total phosphorus and total nitrogen, as well as an increase in the content of organic matter. The Mg-modified biochar was generally superior to the unmodified biochar in improving soil fertility, at the same addition level. It was also found that the rice-straw biochar performed better than the corn-stover biochar and had a more obvious effect on soil improvement in terms of fast-acting potassium, ammonium nitrogen, nitrate nitrogen, total phosphorus and total nitrogen contents.

Utilizing Date Palm Leaf Biochar for Simultaneous Adsorption of Pb(II) and Iodine from Aqueous Solutions

This study addresses the environmental and health hazards posed by Pb(II) and iodine, two significant contaminants. The objective was to explore the adsorption of these substances from aqueous solutions using biochar derived from the leaf midribs of the date palm through a slow pyrolysis process. The pyrolysis was conducted in two stages within a vacuum furnace: initially at 300 °C for 1 h followed by overnight cooling, and then at 600 °C with a similar cooling process. The resulting biochar was characterized for its microstructural features and functional groups using scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. It exhibited a porous structure with large numbers of pores (20 to 50 μm in size) and functional groups including O-H, C-H, and C=C, which are integral to its adsorption capabilities. For the adsorption studies, a 100 ppm Pb(II) ion solution was treated with varying amounts of biochar (20, 40, 60, and 80 mg) for 24 h. In parallel, iodine adsorption was tested, with biochar quantities ranging from 0.1 to 0.4 g/50 mL. Both treatments were followed by filtration and analysis using atomic absorption spectroscopy to determine the remaining concentrations of Pb(II) and iodine. The study also explored the effect of varying incubation periods (up to 30 h) on iodine adsorption. The results were significant; 100% adsorption of Pb(II) was achieved with the addition of 60 mg of biochar per 10 mL of solution. In contrast, for iodine, a maximum adsorption of 39.7% was observed with 30 mg or 40 mg of biochar per 50 mL. These findings demonstrate the potential of date palm-derived biochar as an effective and sustainable material for the removal of Pb(II) and iodine from contaminated water, offering valuable insights for environmental remediation strategies.

Can Biochar Made from Rice Husk Affect Savanna Soils’ pH, Electrical Conductivity, and Soil Respiration?

Biochar is now gaining awareness as a sustainable tool for soil health improvement, boosting carbon (C) storage and the enhancement of nutrient cycling in agricultural soils. This study assesses the effects of biochar on soil respiration, pH, and electrical conductivity (EC) in savanna soils over a 45-day incubation trail in the laboratory. Four different biochar treatments (0, 2, 4, and 6 t/ha) were used in the study. The treatments were established at 26°C, and after 2, 5, and 10 days, the CO2 levels were recorded. After incubation for 0, 5, 10, and 45 days, the EC and pH were assessed. As the rate of application of biochar increased, the rate of CO2 evolution increased as well. During the first two days of incubation, the CO2 evolution rate rose by a value of 129 at 2 t/ha biochar, 146 at 4 t/ha biochar, and 168 ug CO2/g soil/d at 6 t/ha biochar above the 0 t/ha biochar. Following five days of incubation, the amounts of CO2 evolution that were higher than the control were 99 with 2 t/ha, 116 with 4 t/ha, and 120 ug CO2/g soil/d with 6 t/ha of biochar. The increase in CO2 evolution above the control treatment at 10 days of incubation was 61 with 2 t/ha, 79 with 4 t/ha, and 87 ug CO2/g soil/d with 6 t/ha of biochar. Analogously, rising patterns in CO2 emissions were noted. Throughout the whole incubation period, the biochar treatments' soil EC and pH were greater than those of the control treatment. After applying biochar, there were increases in the evolution of CO2, however after 10 days of incubation, the percentage of C evolved from the addition of biochar decreased as the rates of biochar increased. At two t/ha, four t/ha, and six t/ha, the percentage C developed was 1.74 %, 1.66%, and 0.82% of the applied biochar C, respectively. Although the CO2 evolved ratio to the total amount of biochar C typically reduced with increasing biochar rates, this study shows that the addition of biochar increases soil respiration, EC, and pH.

Palm Oil Mill Effluent Biochar as An Alternative Potassium Source: Effect of Pyrolysis Time and Its Kinetic Release

Palm Oil Mill Effluent (POME) is one of the waste products of palm oil processing that can be processed into a biochar. POME biochar contains high levels of nutrient, such as NPK which can be used an alternative potassium source material. This study aims to produced biochar from POME and the influence of pyrolysis time on the characteristics and its kinetic release. Biochar production from POME was conducted at 300oC with pyrolysis time variation of 1 hour, 3 hours and 5 hours. Biochar characterization was conducted using Fourier Transform Infrared (FTIR) Spectroscopy, Scanning Electron Microscope-Energy Dispersive X-ray (SEM-EDX), Surface Area Analysis (SAA). Study of potassium release was conducted by mixing one gram amount of biochar with 0.01 M CaCl2 as a function of time. The used kinetics modelling in this study are first-order, second-order, pseudo-first order, pseudo-second orde. The results showed that the biochar yield decreased, while the biochar pH value, exchangeable potassium, non-exchangeable potassium and surface area increased with the increasing of pyrolysis time. The pseudo- second order model is the most fitted model to describe the potassium release. The pseudo-second order kinetics model gave K release rates of 0.018; 0.024; 0.020; 0.014 (mg g-1min-1), the qe values are 0.814; 0.839; 0.927; 1.111 (mg g-1), respectively.