Biochar Composites Research Articles

Efficacy of anthocyanin, kaolinite and cabbage leaves-derived biochar for simultaneous removal of lead, copper and metoprolol from water

Simultaneous removal of toxic elements and pharmaceutical compounds at environmentally relevant concentrations in aqueous solution is challenging. Modification of biochar using environmental materials has attracted significant attention in wastewater treatment, while pristine biochar has several limitations in the simultaneous removal of Lead (Pb2+), Copper (Cu2+), and metoprolol. We investigated the efficacy of biochar composites using waste cabbage leaves-derived biochar with kaolinite, and anthocyanin for simultaneous removal of Pb2+, Cu2+, and metoprolol from water. Using ball milling, the surface area and functional groups of adsorbents were improved via breaking the biochar grains into ultrafine particles. Ball-milled biochar derived from waste cabbage leaves significantly increased Pb2+, Cu2+, and metoprolol adsorption by 105, 71, and 213%, respectively. Results of Brunauer Emmett Teller surface area, Fourier transform infrared and X-ray photoelectron spectroscopies showed that surface area of non-milled biochar improved nearly ten-fold following ball-milling, while several oxygen containing acidic functional groups also increased. The adsorbents resulted in high removal efficiency for Pb2+ (162.9 mg/g) and Cu2+ (48.5 mg/g) in ball milled-kaolinite composite biochar (BMKB) and 76.3 mg/g (metoprolol), respectively in ball milled-anthocyanin composite biochar (BMAB). The simultaneous sorption of Pb2+, Cu2+, and metoprolol in an aqueous solution to BMAB and BMKB, showed that the adsorption capacity followed the order of Pb2+ >Cu2+ > metoprolol in both types of ball-milled biochars. BMKB achieved a high adsorption capacity for Pb2+ and Cu2+ (59 mg/g and 50 mg/g), respectively, while BMAB exhibited an adsorption capacity 22.3 mg/g for metoprolol. It was postulated that sorption of Pb2+, Cu2+ and metoprolol involved multiple adsorption mechanisms namely surface complexation, π-π interaction, H−bond, pore filling, and ion bridging. The findings of this study revealed that ball milling is a potential technology in producing a highlyefficient adsorbent to remediate multi-contaminants in aqueous solution.

Mitigation of asphalt volatile organic compounds emissions and health hazards using a TiO2-doped biochar composite: Microscopic and physiological insights

This study developed a novel TiO2-biochar composite as a modifier for functional asphalt coatings, achieving dual objectives of reducing VOCs emissions and mitigating cytotoxicity. The composite enhanced the softening point of the asphalt by approximately 6℃, reduced penetration and increased viscosity, thereby improving thermal stability and deformation resistance. Headspace-gas chromatography/mass spectrometry analysis confirmed an over 80 % reduction in VOC emissions, significantly reducing the release of harmful compounds like alkanes, cycloalkanes, and aromatic hydrocarbons, with the TiO2-biochar modified and UV-exposed (TUBC) demonstrating the most pronounced effect. In vitro assays with human bronchial epithelial (BEAS-2B) cells showed the composite's cytotoxicity mitigation, with TUBC maintaining higher cell viability. The composite reduced ROS levels and the expression of cytotoxicity-associated biomarkers, suggesting a decrease in oxidative stress and inflammation. The high adsorption capacity of the composite and its photocatalytic degradation under UV light were identified as the key mechanisms for VOCs reduction. These findings collectively establish the TiO2-biochar composite as a promising solution for asphalt for greener and safer asphalt applications, with potential for global environmental and health benefits. Future work will focus on further optimization and field validation to facilitate the adoption of this technology in infrastructure development worldwide.

Mechanical and water absorption characterization of rice husk and coconut coir reinforced biochar composites

In this study, four distinct composite samples (Samples A, B, C, and D) were fabricated using varying compositions of biochar, rice bran, coconut coir, and epoxy matrix. Sample A, serving as the baseline with 90% epoxy and 10% biochar, exhibited moderate mechanical properties. Sample B, with 80% epoxy and 20% biochar, demonstrated significantly higher tensile and flexural modulus values, indicative of improved stiffness. Sample C, incorporating 10% rice bran alongside 80% epoxy and 10% biochar, displayed reduced mechanical properties compared to Sample B, potentially due to the lower strength of rice bran particles. Sample D, comprising 80% epoxy, 10% biochar, and 5% coconut coir, demonstrated weaker tensile properties but higher flexural modulus, suggesting enhanced resistance to bending forces. Mechanical testing, water absorption analysis, Fourier Transform Infrared (FTIR) spectroscopy, and SEM imaging provided comprehensive insights into the mechanical and chemical characteristics of the composites, underscoring their potential for diverse applications in sustainable materials development.

Magnetic adsorbents from co‐pyrolysis of non‐woody biomass and red mud for water decontamination

AbstractRed mud (RM) and non‐woody biomass are both underutilized resources for renewable composite materials, which could be used in environmental decontamination processes. This study aims to investigate the efficacy of co‐pyrolyzing non‐woody biomass with RM to produce a magnetic biochar composite. When pyrolyzed, RM is reduced to magnetic iron while the non‐woody biochar is responsible for the adsorption of organic compounds. Ibuprofen, acetaminophen, methyl orange, and methylene blue were used as test compounds to investigate the overall adsorptive capacity of the composite and to determine the possible adsorption mechanisms of biochar produced from RM pyrolyzed with switch grass, phragmites, rice husk, and miscanthus. The composite produced from a 1 to 1 mixture of RM and miscanthus showed the highest adsorption capacity with 13.8 and 8.34 mg/g of ibuprofen and acetaminophen adsorbed, respectively, which is attributed to its greater ‐interactions as a result of lower surface oxygen sites. Different ratios of RM to biomass were also tested for the production of the miscanthus composite, where it was found that the 1:2 ratio showed the best overall adsorption with 25.9 mg/g removal of acetaminophen, surpassing the miscanthus biochar's at 17.9 mg/g.

Heteroatom doped biochar-aluminosilicate composite as a green alternative for the removal of hazardous dyes: Functional characterization and modeling studies

In this work, a novel nitrogen-doped biochar bentonite composite was synthesized by a single-pot co-pyrolysis method. Batch studies were conducted to evaluate the performance of the developed composite in eliminating synthetic dyes from the aqueous matrix. Energy dispersive X-ray spectroscopy analysis and field emission scanning electron microscopy imaging confirmed the N doping and bentonite impregnation into biochar. X-ray photoelectron spectroscopy analysis revealed that the N atoms were doped interstitially into the carbon matrix of biochar in the form of pyridinic and pyrrolic nitrogen. Simultaneous heteroatom doping and bentonite impregnation reduced the specific surface area to 41.721 m2 g−1 but improved the adsorption capacity of biochar for dye adsorption. Further experimental studies depicted that simultaneous bentonite impregnation and N doping into the biochar matrix is beneficial for direct blue-6 (DB-6) and methylene blue (MB) removal and maximum adsorption capacities of 53.17 mg. g−1 and 41.33 mg. g−1 were obtained for MB and DB-6, respectively, at varying conditions. Adsorption energetics of the dyes with the developed composite portrayed the spontaneity of the process through negative ΔG values. The Langmuir and Freundlich isotherm models fitted the best for MB and DB-6 adsorption. The monolayer adsorption capacity and favourability factor for MB and DB-6 adsorption were calculated to be 54.15 mg. g−1 and 0.217, respectively from the best-fitted isotherms. Based on density functional theory calculations and spectroscopic studies, major interactions governing the adsorption were predicted to be charge-based interactions, π-π interactions, H-bonding, and Lewis acid-base interactions.

Eco‐friendly approach to thermal energy storage: Assessing the thermal and chemical properties of coconut biochar‐enhanced phase change material

AbstractPhase change materials (PCMs) can absorb, store, and release substantial latent heat within a specific temperature range during phase transition and have gained huge attention due to environmental concerns and energy crises. However, PCMs have a significant downside in energy storage due to their relatively lower thermal conductivity, leading to inadequate heat transfer (HT) performance. The foremost aim of the research is to synthesize an eco‐friendly coconut shell biochar (CSB) dispersed with organic A46 PCM in the temperature range of 44°C to 46°C to form a green nanocomposite. A two‐step approach is adopted to formulate the nanocomposites with different weight concentrations (0.2% and 0.8%) of green CSB particles. The developed nanocomposite's thermal conductivity and chemical stability were examined using a thermal properties analyzer and a Fourier transforms infrared spectrometer. The developed biochar composites have excellent thermal conductivity (0.39 W/m K) compared with base PCM (0.22 W/m K). Also, the developed nanocomposites were physically mixed together; there were no additional functional groups formed compared to pristine PCM, and the prepared materials were composite. Furthermore, a numerical analysis was performed using two‐dimensional energy modeling software to ascertain the HT rate of A46 composites. These thermally energized green nanocomposites show great promise for thermal energy storage and thermal management applications like battery thermal management, photovoltaic thermal systems, desalination systems, electronic cooling, building applications, and textiles.

Anti-fouling poly(lactic)acid membrane incorporating titanium dioxide‐coated biochar composites for the separation of lipopeptides from Bacillus subtilis fermentation broth

This study focuses on developing anti-fouling membranes composed of poly(lactic)acid (PLA) incorporating titanium dioxide-coated biochar composites, aiming to separate the lipopeptide biosurfactants from clarified Bacillus subtilis fermentation broth efficiently. The surface area of the Ti-biochar composites, incorporated into the PLA membrane, was measured as 191.69 m2/g and the water contact angle of the optimal PLA/Ti-biochar membrane was determined to be 62.3°, indicating its hydrophilic nature. The PLA membrane's pure water flux, containing 1 wt % Ti-biochar was 174.61±0.5 L m–2h–1 with the water content of 86.73±0.8 %, and porosity of 44.72±0.3 %. Then, Bacillus subtilis lipopeptides were separated by the optimal PLA/Ti-biochar membrane, and their characteristics were compared to the crude sample. Additionally, the purified lipopeptides demonstrated enhanced antimicrobial properties, with a significantly lower minimum inhibitory concentration (MIC) of 1.7±0.52 µg/ml against Staphylococcus aureus and 1.5±0.24 µg/ml against Fusarium oxysporum, compared to the crude lipopeptides, which had MIC values of 5.5±0.26 µg/ml and 4.2 ±0.45 µg/ml, respectively. The purified lipopeptides were confirmed by high-performance liquid chromatography and mass spectrometry. These results underscore the antifouling characteristics of the fabricated PLA/Ti-biochar membrane, positioning it as a promising candidate for the separation of biological molecules.

Torrefaction and pyrolysis of agrowaste-derived materials: Properties and quality of products

Huge amounts of agricultural residues or wastes represent an interesting lignocellulosic material which can be used for energy recovery by pyrolysis as an alternative to incineration. Together with the energy production, biochar (solid residue), can be with an advantage used as a soil conditioner or for other applications such as adsorbents, supporting the principles of circular economy. Here we studied the effect of torrefaction and pyrolysis temperature from 250 to 700 °C on the composition and properties of pyrolysis gas and biochar from four types of agrowaste-derived materials: sunflower harvest residues, grain harvest residues, separate from digestion, and extracted sunflower meal. The paper provides dataset on detailed composition of pyrolysis gases, indicating the differences due to different composition of the feedstock materials and describes the main parameters affecting the use of biochar as soil amendment. Torrefaction proved to be unsuitable for the production of soil amendment quality biochar and the temperature higher than 400 °C is recommended in order to produce good quality biochar while transforming most of the energy content of feedstock to primary pyrolysis products.

Volatile matter characterization of birch biochar produced under pressurized conditions

AbstractThe volatile matter (VM) content and composition of birch biochars produced at 320 °C under elevated pressure (0.1–11 MPa) and constant pressure or constant volume reactor conditions were characterized by thermogravimetry/mass spectrometry (TG/MS) and pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS). Some of the thermal properties of the biochars and the composition of the VMs varied as a function of the maximal pressure applied during carbonization. The samples prepared at higher pressures released more volatiles up to 320 °C, while the maximal rate of thermal decomposition at around 440 °C showed decreasing tendency with the carbonization pressure. In terms of VM composition, the most apparent effect was the significant increase of the amounts of apoallobetulins from biochars prepared at elevated pressures, which were formed by dehydration, ring closure and rearrangement from the betulin content of birch. The change in the ratio of the evolved guaiacol and 4-methylguaiacol as well as that of syringol and 4-methylsyringol as a function of the maximal pressure of carbonization indicated a modification of the lignin decomposition mechanism.

Acetate anions intercalated Fe/Mg-layered double hydroxides modified biochar for efficient adsorption of anionic and cationic heavy metal ions from polluted water

The simultaneous removal of anionic and cationic heavy metals presents a challenge for adsorbents. In this study, acetate (Ac-) was utilized as the intercalating anion for layered double hydroxide (LDH) to prepare a novel biochar composite adsorbent (Ac-LB) designed for the adsorption of Pb(II), Cu(II), and As(V). By utilizing Ac- as the intercalating anion, the interlayer space of the LDH was enlarged from 0.803 nm to 0.869 nm, exposing more adsorption sites for the LDH and enhancing the affinity for heavy metals. The results of the adsorption experiments showed that the adsorption effect of Ac-LB on heavy metals was significantly improved compared to the original FeMg-LDH modified biochar composites (LB), and the maximum adsorption capacity of Pb(II), Cu(II), and As(V) were 402.70, 68.50, and 21.68 mg/g, respectively. Wastewater simulation tests further confirmed the promising application of Ac-LB for heavy metal adsorption. The analysis of the adsorption mechanism revealed that surface complexation, electrostatic adsorption, and chemical deposition were the main mechanisms of action between heavy metals (Pb(II) and Cu(II)) and Ac-LB. Additionally, Cu(II) ions underwent a homogeneous substitution reaction with Ac-LB. The adsorption process of As(V) by Ac-LB mainly relied on complexation and ion-exchange reactions. Lastly, the modification of the LDH structure by Ac− as an intercalating anion, thereby increasing the affinity for heavy metals, was further illustrated using density-functional theory (DFT) calculations.

Effective Co2+ removal from aqueous solution and industrial wastewater using ZIF-7 and MnFe2O4-modified walnut shell biochar composite

In this study, we developed a novel magnetic composite of walnut shell biochar (WSB) and modified it with ZIF-7 for the purpose of removing Co2+ ions. We conducted a comprehensive evaluation of its performance in Co2+ removal, considering various factors such as contact time, temperature, adsorbent dose, pH, and initial Co2+ concentration. Utilizing response surface methodology-central composite design (RSM-CCD), we examined the interactions between these variables. The specific surface area and magnetic saturation value of the WSB/MnFe2O4/ZIF-7 composite were determined as 170.560 m2.g−1 and 23.469 emu.g−1, respectively. ANOVA analysis indicated that our model effectively captures the interactions between variables, with a high R2 value of 0.9982, explaining 99.82 % of the experimental data. Optimal conditions for maximum Co2+ adsorption efficiency (99.05 %) were identified as follows: a contact time of 44.82 min, pH of 6.04, adsorbent dose of 0.947 mg.L-1, temperature of 25.55 °C, and Co2+ concentration of 11.13 mg.g−1. Kinetic studies revealed that the Pseudo 2nd order kinetic model provided the best fit to the experimental data. The negative entropy parameter indicated a decrease in disorderliness during the adsorption process, while the exothermic nature of adsorption was confirmed by enthalpy values of −92.751 and −40.511 kJ.mol−1 for WSB/MnFe2O4/ZIF-7 and WSB, respectively. Furthermore, the Langmuir isotherm model demonstrated excellent fitting to the isotherm results, suggesting the dominance of homogeneous surfaces in adsorption. The maximum adsorption capacities for Co2+ using WSB/MnFe2O4/ZIF-7 and WSB were determined to be 29.26 and 22.39 mg.g−1, respectively. The WSB/MnFe2O4/ZIF-7 magnetic composite demonstrates promising potential for efficiently removing Co2+ from both natural water sources and industrial wastewater, highlighting its versatility and effectiveness in environmental remediation applications.

Iron-based metal organic framework (Fe-MOF)-doped sesame stalk biochar enhances antibiotic degradation: Important role of free radicals and comparison of multiple degradation processes

A novel iron-based metal organic framework-doped sesame stalk biochar (Fe-MOF@SBC) composite was successfully synthesized using sonication and used for the degradation of sulfamethoxazole (SMX), norfloxacin (NOR), erythromycin (ERY) and tetracycline (TC) in aqueous solution. The characterization results indicated that Fe oxide was successfully loaded on the biochar. The Fe-MOF@SBC composite presented a porous structure enriched in micropores and mesopores. Adsorption mechanisms, including pore filling, π–π electron donor–acceptor (EDA) interactions, hydrophobic interactions, hydrogen bonding and electrostatic interactions, and the catalytic effect of the Fe-MOF@SBC composite facilitated antibiotic degradation. Specifically, single-layer and multilayer adsorption occurred, and abundant oxygen-containing functional groups were involved in the degradation of NOR, which might be one reason for the high degradation rate of NOR by the Fe-MOF@SBC composite. Scavenging experiments combined with electron paramagnetic resonance (EPR) analysis indicated that free radicals such as •OH, O2−• and 1O2 played vital roles in the degradation of SMX, NOR, ERY and TC. Furthermore, the proposed degradation pathways and possible intermediates of SMX, NOR, ERY and TC were identified, which indicated that the adsorption properties and free radical (•OH, O2−• and 1O2) activity of the Fe-MOF@SBC composite strongly promoted the removal of SMX, NOR, ERY and TC.

Co-pyrolysis of chicken manure with tree bark for reduced biochar toxicity and enhanced plant growth in Arabidopsis thaliana

Co-pyrolysis of chicken manure with tree bark was investigated to mitigate salinity and potentially toxic element (PTE) concentrations of chicken manure-derived biochar. The effect of tree bark addition (0, 25, 50, 75 and 100 wt%) on the biochar composition, surface functional groups, PTEs and polycyclic aromatic hydrocarbons (PAH) concentration in the biochar was evaluated. Biochar-induced toxicity was assessed using an in-house plant growth assay with Arabidopsis thaliana. This study shows that PTE concentrations can be controlled through co-pyrolysis. More than 50 wt% of tree bark must be added to chicken manure to reduce the concentrations below the European Biochar Certificate-AGRO (EBC-AGRO) threshold. However, the amount of PAH does not show a trend with tree bark addition. Furthermore, co-pyrolysis biochar promotes plant growth at different application concentrations, whereas pure application of 100 wt% tree bark or chicken manure biochar results in decreased growth compared to the reference. In addition, increased plant stress was observed for 100 wt% chicken manure biochar. These data indicate that co-pyrolysis of chicken manure and tree bark produces EBC-AGRO-compliant biochar with the potential to stimulate plant growth. Further studies need to assess the effect of these biochars in long-term growth experiments.

Multi-output neural network model for predicting biochar yield and composition

In biomass pyrolysis for biochar production, existing prediction models face computational challenges and limited accuracy. This study curated a comprehensive dataset, revealing pyrolysis parameters' dominance in biochar yield (54.8 % importance). Pyrolysis temperature emerged as pivotal (PCC = −0.75), influencing yield significantly. Artificial Neural Network (ANN) outperformed Random Forest (RF) in testing set predictions (R2 = 0.95, RMSE = 3.6), making it apt for complex multi-output predictions and software development. The trained ANN model, employed in Partial Dependence Analysis, uncovered nonlinear relationships between biomass characteristics and biochar yield. Findings indicated optimization opportunities, correlating low pyrolysis temperatures, elevated nitrogen content, high fixed carbon, and brief residence times with increased biochar yields. A multi-output ANN model demonstrated optimal fit for biochar yield. A user-friendly Graphical User Interface (GUI) for biochar synthesis prediction was developed, exhibiting robust performance with a mere 0.52 % prediction error for biochar yield. This study showcases practical machine learning application in biochar synthesis, offering valuable insights and predictive tools for optimizing biochar production processes.

Predicting Cd(II) adsorption capacity of biochar materials using typical machine learning models for effective remediation of aquatic environments

The screening and design of “green” biochar materials with high adsorption capacity play a pivotal role in promoting the sustainable treatment of Cd(II)-containing wastewater. In this study, six typical machine learning (ML) models, namely Linear Regression, Random Forest, Gradient Boosting Decision Tree, CatBoost, K-Nearest Neighbors, and Backpropagation Neural Network, were employed to accurately predict the adsorption capacity of Cd(II) onto biochars. A large dataset with 1051 data points was generated using 21 input variables obtained from batch adsorption experiments, including preparation conditions for biochar (2 features), physical properties of biochar (4 features), chemical composition of biochar (9 features), and adsorption experiment conditions (6 features). The rigorous evaluation and comparison of the ML models revealed that the CatBoost model exhibited the highest test R2 value (0.971) and the lowest RMSE (20.54 mg/g), significantly outperforming all other models. The feature importance analysis using Shapley Additive Explanations (SHAP) indicated that biochar chemical compositions had the greatest impact on model predictions of adsorption capacity (42.2 %), followed by adsorption conditions (37.57 %), biochar physical characteristics (12.38 %), and preparation conditions (7.85 %). The optimal experimental conditions optimized by partial dependence plots (PDP) are as follows: as high Cd(II) concentration as possible, C(%) of 33 %, N(%) of 0.3 %, adsorption time of 600 min, pyrolysis time of 50 min, biochar dosage of less than 2 g/L, O(%) of 42 %, biochar pH value of 11.2, and DBE of 1.15. This study unveils novel insights into the adsorption of Cd(II) and provides a comprehensive reference for the sustainable engineering of biochars in Cd(II) wastewater treatment.

Simultaneous removal of ammonium, phosphate, and phenol via self-assembled biochar composites CBCZrOFe3O4 and its utilization as soil acidity amelioration

ABSTRACT High concentrations of ammonium, phosphate, and phenol are recognized as water pollutants that contribute to the degradation of soil acidity. In contrast, small quantities of these nutrients are essential for soil nutrient cycling and plant growth. Here, we reported composite materials comprising biochar, chitosan, ZrO, and Fe3O4, which were employed to mitigate ammonium, phosphate, and phenol contamination in water and to lessen soil acidity. Batch adsorption experiments were conducted to assess the efficacy of the adsorbents. Initially, comparative studies on the simultaneous removal of NH4, PO4, and phenol using CB (biochar), CBC (biochar + chitosan), CBCZrO (biochar + chitosan + ZrO), and CBCZrOFe3O4 (biochar + chitosan + ZrO + Fe3O4) were conducted. The results discovered that CBCZrOFe3O4 exhibited the highest removal percentage among the adsorbents (P < 0.05). Adsorption data for CBCZrOFe3O4 were well fitted to the second-order kinetic and Freundlich isotherm models, with maximum adsorption capacities of 112.65 mg/g for NH4, 94.68 mg/g for PO4 and 112.63 mg/g for phenol. Subsequently, the effect of CBCZrOFe3O4-loaded NH4, PO4, and phenol (CBCZrOFe3O4-APP) on soil acidity was studied over a 60-day incubation period. The findings showed no significant changes (P < 0.05) in soil exchangeable acidity, H+, Mg, K, and Na. However, there was a substantial increase in the soil pH, EC, available P, CEC, N-NH4, and N-NO3. A significant reduction was also observed in the available soil exchangeable Al and Fe (P < 0.05). This technique demonstrated multi-functionality in remediating water pollutants and enhancing soil acidity.

CaAl-Layered Double Hydroxides-Modified Biochar Composites Mitigate the Toxic Effects of Cu and Pb in Soil on Pea Seedlings.

Compound contamination of soil with heavy metals copper (Cu) and lead (Pb) triggered by mining development has become a serious problem. To solve this problem, in this paper, corncob kernel, which is widely available and inexpensive, was used as the raw material of biochar and modified by loading CaAl-layered double hydroxides to synthesize biochar-loaded CaAl-layered double hydroxide composites (CaAl-LDH/BC). After soil remediation experiments, either BC or CaAl-LDH/BC can increase soil pH, and the available phosphorus content and available potassium content in soil. Compared with BC, CaAl-LDH/BC significantly reduced the available content of Cu and Pb in the active state (diethylenetriaminepentaacetic acid extractable state) in the soil, and the passivation rate of Cu and Pb by a 2% dosage of CaAl-LDH/BC reached 47.85% and 37.9%, respectively. CaAl-LDH/BC can significantly enhance the relative abundance of beneficial microorganisms such as Actinobacteriota, Gemmatimonadota, and Luteimonas in the soil, which can help to enhance the tolerance and reduce the enrichment ability of plants to heavy metals. In addition, it was demonstrated by pea seedling (Pisum sativum L.) growing experiments that CaAl-LDH/BC increased plant fresh weight, root length, plant height, catalase (CAT) activity, and protein content, which promoted the growth of the plant. Compared with BC, CaAl-LDH/BC significantly reduced the Cu and Pb contents in pea seedlings, in which the Cu and Pb contents in pea seedlings were reduced from 31.97 mg/kg and 74.40 mg/kg to 2.92 mg/kg and 6.67 mg/kg, respectively, after a 2% dosage of CaAl-LDH/BC, which was a reduction of 90.84% and 91.03%, respectively. In conclusion, compared with BC, CaAl-LDH/BC improved soil fertility and thus the plant growth environment, and also more effectively reduced the mobility of heavy metals Cu and Pb in the soil to reduce the enrichment of Cu and Pb by plants.

Influence of agro-wastes derived biochar and their composite on reducing the mobility of toxic heavy metals and their bioavailability in industrial contaminated soils

The agro-waste derived valuable products are prime interest for effective management of toxic heavy metals (THMs). The present study investigated the efficacy of biochars (BCs) on immobilization of THMs (Cr, Zn, Pb, Cu, Ni and Cd), bioaccumulation and health risk. Agro-wastes derived BCs including wheat straw biochar (WSB), orange peel biochar (OPB), rice husk biochar (RHB) and their composite biochar (CB) were applied in industrial contaminated soil (ICS) at 1% and 3% amendments rates. All the BCs significantly decreased the bioavailable THMs and significantly (p < 0.001) reduced bioaccumulation at 3% application with highest efficiency for CB followed by OPB, WSB and RHB as compared to control treatment. The bioaccumulation factor (BAF), concentration index (CI) and ecological risk were decreased with all BCs. The hazard quotient (HQ) and hazard index (HI) of all THMs were <1, except Cd, while carcer risk (CR) and total cancer risk index (TCRI) were decreased through all BCs. The overall results depicted that CB at 3% application rate showed higher efficacy to reduce significantly (p < 0.001) the THMs uptake and reduced health risk. Hence, the present study suggests that the composite of BCs prepared from agro-wastes is eco-friendly amendment to reduce THMs in ICS and minimize its subsequent uptake in vegetables.

Properties and Possibilities of Using Biochar Composites Made on the Basis of Biomass and Waste Residues Ferryferrohydrosol Sorbent.

Biochar enriched with metals has an increased potential for sorption of organic and inorganic pollutants. The aim of the research was to identify the possibility of using biochar composites produced on the basis of waste plant biomass and waste FFH (ferryferrohydrosol) containing iron atoms, after CO2 capture. The composites were produced in a one-stage or two-stage pyrolysis process. Their selected properties were determined as follows: pH, ash content, C, H, N, O, specific surface area, microstructure and the presence of surface functional groups. The produced biochar and composites had different properties resulting from the production method and the additive used. The results of experiments on the removal of methylene blue (MB) from solutions allowed us to rank the adsorbents used according to the maximum dye removal value achieved as follows: BC1 (94.99%), B (84.61%), BC2 (84.09%), BC3 (83.23%) and BC4 (83.23%). In terms of maximum amoxicillin removal efficiency, the ranking is as follows: BC1 (55.49%), BC3 (23.51%), BC2 (18.13%), B (13.50%) and BC4 (5.98%). The maximum efficiency of diclofenac removal was demonstrated by adsorbents BC1 (98.71), BC3 (87.08%), BC4 (74.20%), B (36.70%) and BC2 (30.40%). The most effective removal of metals Zn, Pb and Cd from the solution was demonstrated by BC1 and BC3 composites. The final concentration of the tested metals after sorption using these composites was less than 1% of the initial concentration. The highest increase in biomass on prepared substrates was recorded for the BC5 composite. It was higher by 90% and 54% (for doses of 30 g and 15 g, respectively) in relation to the biomass growth in the soil without additives. The BC1 composite can be used in pollutant sorption processes. However, BC5 has great potential as a soil additive in crop yield and plant growth.

Life Cycle Assessment of a Wood Biomass Gasification Plant and Implications for Syngas and Biochar Utilization

The growing attention regarding the environmental challenges in the energy sectors pushes the industrial system toward the investigation of more sustainable and renewable energy sources to replace fossil ones. Among the promising alternatives, biomass is considered a valid source to convert the system and to reduce the fossil fraction of the national energy mixes, but its multiple potential uses need an environmental evaluation to understand the actual benefit when it is used as an energy resource. For this purpose, life cycle assessment (LCA) is applied to a wood biomass gasification system aimed to produce electricity and heat generated after the combustion of the produced syngas and the management of the biochar. The aim is to provide a quantitative comparison of (i) a baseline scenario where wood biomass is sourced from waste and (ii) a second scenario where wood biomass is drawn from dedicated cultivation. A further evaluation was finally applied to investigate the environmental implications associated with the biochar composition, assuming it was used on land. The proposed strategies resulted in an environmental credit for both the examined scenarios, but the outcomes showed a net preference for the baseline scenario, resulting in better environmental performances for all the examined categories with respect to the second one. It underlines the potentialities of using waste-sourced biomass. However, according to the Climate Change category, if on-site dedicated biomass cultivation is assumed for the second scenario, the baseline is considered preferable only if the biomass transportation distance is &lt;600 km, which is estimated as a theoretical distance for scenarios to break even. Finally, biochar composition proved a particular concern for toxicity-related categories. This study highlights the importance of applying objective and standardized methodologies such as LCA to evaluate energy production systems based on alternative sources and to support decision-making toward achieving sustainability goals.