Search Results (66)

This study examines the effect of temperature during pyrolysis on the capacity of cedar wood-derived biochar to be employed as a sustainable electrode material for supercapacitors. Cedar wood-derived biochars were produced at different temperatures of 800 °C, 900 °C, 1000 °C and 1100 °C and fully characterized in terms of their structural, physicochemical and electrochemical properties, including specific surface area, hydrophobicity, electrical conductivity, and surface functional groups. The results indicated that the cedar wood biochar obtained through pyrolysis at 900 °C (BC900) provided optimal electrical conductivity, hydrophobicity, and porosity characteristics relative to the other cedar wood biochars produced by pyrolysis at 800 °C to 1100 °C. Specifically, when compared to commercial activated carbon (AC), BC900 provided half the specific capacitance at a current density of 1 A g⁻¹ and indicated that there is more potential for improvement with further activation and doping. The influence of the binder (either polyvinylidene fluoride (PVDF) or chitosan) in combination with conductive carbon black (CB) was also examined. Electrodes fabricated with PVDF binder showed higher specific capacitance, while biochar electrodes made from CB and chitosan (BC900/CB/chitosan) showed better electrical conductivity, wettability, and good electrochemical stability with >95% capacity retention even after 10,000 cycles. Full article

Tetracycline (TC) is widely used in medicine and livestock farming. TC is difficult to degrade and tends to persist and accumulate in aquatic environments, and it has gradually become an emerging pollutant. Biochar (BC) has strong potential for removing TC from water. This potential arises from its excellent surface properties, low-cost raw materials, and renewable nature. However, raw biomass materials are highly diverse, and their preparation conditions vary significantly. Modification methods differ in specificity and the application scenarios are complex. These factors collectively cause unstable TC removal efficiency by biochar. The chemical activation process using KOH/H₃PO₄ significantly enhanced porosity and surface functionality, transforming raw biochar into an activated carbon material with targeted adsorption capacity. Adjusting the application dosage and environmental factors (particularly pH) further enhanced the removal performance. Solution pH critically governs the adsorption efficiency: optimal conditions (pH 5–7) increased removal by 35–40% through strengthened electrostatic attraction, whereas acidic/alkaline extremes disrupted ionizable functional groups. The dominant adsorption mechanisms of biochar involved π–π interactions, pore filling, hydrophobic interactions, hydrogen bonding, electrostatic interactions, and surface complexation. In addition, the main challenges currently hindering the large-scale application of biochar for the removal of TC from water are highlighted: (i) secondary pollution risks of biochar application from heavy metals, persistent free radicals, and toxic organic leaching; (ii) economic–environmental conflicts due to high preparation/modification costs; and (iii) performance gaps between laboratory studies and real water applications. Full article

Biochar, as an emerging biotechnology, has been widely used in the remediation of soil organic pollution, mainly by promoting the abundance of related degrading bacteria in soil. In this study, we explored the influence of sewage sludge biochars pyrolyzed at different temperatures of 300–700 °C (SSB₃₀₀-SSB₇₀₀) and addition rates (1% and 5%) on the atrazine biodegradation in soils. After a 21-day incubation, the application of 5% SSB₃₀₀ significantly increased soil catalase (CAT), urease activity, dissolved organic carbon (DOC), and electrical conductivity (EC). However, biochar amendment exhibited inhibitory effects on atrazine degradation in soils. The atrazine degradation ratio decreased with decreasing pyrolysis temperature and increasing addition rates. Further analysis found that there were two possible reasons for the significant decline of atrazine biodegradation in SSB₃₀₀ groups: (1) SSB₃₀₀ demonstrated higher adsorption capacity for atrazine compared to SSB₅₀₀ and SSB₇₀₀ and reduced atrazine bioavailability due to its stronger hydrophobic nature and more abundant surface functional groups; and (2) the SSB₃₀₀ significantly decreased the abundances of dominant atrazine-degraders (Arthrobacter and Pseudomonas) and atrazine-degrading genes (atzA, atzB, and trzN). Full article

Poly(lactic acid) (PLA) is a biodegradable thermoplastic polymer used in various applications, including food packaging, 3D printing, textiles, and biomedical devices. Nevertheless, it presents several limitations, such as high hydrophobicity, low gas barrier properties, UV sensitivity, and brittleness. To overcome this issue, in this study, biochar (BC) produced through pyrolysis of bio-mass waste was incorporated (1 wt.%, 2wt.%, and 3 wt.%—PLA 1, PLA 2, and PLA 3) to enhance thermal and mechanical properties of PLA composites. The impact of pyrolysis temperature on the kinetic parameters, physicochemical characteristics, and structural properties of banana and orange peels for use as biochar added to PLA was investigated. The biomass waste such as banana and orange peels were characterized by proximal analysis and thermogravimetric analysis (TGA); meanwhile, the PLA composites were characterized by tensile straight, TGA, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The results indicated that the presence of biochar improved hygroscopic characteristics and Tg temperature from 62.98 °C for 1 wt.% to 80.29 °C for 3 wt.%. Additionally, it was found that the tensile strength of the composites increased by almost 30% for PLA 3 compared with PLA 1. The Young’s modulus also increased from 194.334 MPa for PLA1 to 388.314 MPa for PLA3. However, the elongation decreased from 14.179 (PLA 1) to 7.240 mm (PLA3), and the maximum thermal degradation temperature shifted to lower temperatures ranging from 366 °C for PLA-1 to 345 °C for PLA-3 samples, respectively. From surface analysis, it was observed that the surface of these samples was relatively smooth, but small microcluster BC aggregates were visible, especially for the PLA 3 composite. In conclusion, the incorporation of biochar into PLA is a promising method for enhancing material performance while maintaining environmental sustainability by recycling biomass waste. Full article

The use of biodegradable active materials is being explored as a strategy to reduce food loss and waste. The aim is to extend the shelf life of food and to ensure biodegradation when these materials are discarded. The utilization of biodegradable polymers remains limited due to their inherent properties and cost-effectiveness. An alternative approach involves the fabrication of bionanocomposites, which offer a potential solution to address these challenges. Therefore, this study investigates the production of a polyhydroxybutyrate/biochar/clay/essential oil (Tepa:Eugenol) bionanocomposite with antioxidant and antimicrobial properties. The morphological, physicochemical, and antioxidant properties of the materials were evaluated in comparison to those of the original PHB. The materials obtained showed a porous surface with cavities, associated with the presence of biochar. It was also determined that it presented an intercalated–exfoliated morphology by XRD. Thermal properties showed minor improvements over those of PHB, indicating that the components did not substantially influence properties such as crystallization temperature, decomposition temperature, or degree of crystallinity; the melting temperature decreased up to 11%. In addition, the PHB/biochar_7/MMT-OM_3/EO_3 bionanocomposites showed a tendency toward hydrophobicity and the highest elastic modulus with respect to PHB. Finally, all essential-oil-loaded bionanocomposites exhibited excellent antioxidant properties against DPPH and ABTS radicals. The results highlight the potential of these bionanocomposites for the development of antioxidant active packaging. Full article

Lignocellulosic waste biomass, a versatile natural resource derived from plants, has gained significant attention for its potential in the sustainable production of biobased chemicals. Furfural (FAL), xylo-oligosaccharides (XOSs), and reducing sugars are important platform chemicals, which can be obtained through the valorization of lignocellulosic solid biomass in a green and sustainable way. Waste yellow bamboo (YB) is one kind of abundant, inexpensive, and renewable lignocellulosic biomass resource. In order to improve the high-value utilization rate of raw YB, biochar-based solid acid catalyst (AT-Sn-YB) was utilized to assist the hydrothermal pretreatment for the valorization of YB in water. Under the optimal reaction conditions (200 °C, 60 min, and AT-Sn-YB dosage of 5.4 wt%), the FAL yield reached 60.8%, and 2.5 g/L of XOSs was obtained in the pretreatment system. It was observed that the surface structure of YB became rough and loose, exposing a significant number of pores. The accessibility increased from 101.8 mg/g to 352.6 mg/g after combined treatment. The surface area and hydrophobicity of lignin were 70.7 m²/g and 2.5 L/g, respectively, which were significantly lower than those of untreated YB (195.4 m²/g and 4.1 L/g, respectively). The YB solid residues obtained after treatment were subjected to enzymatic saccharification, achieving an enzymatic hydrolysis efficiency of 47.9%. Therefore, the hydrothermal pretreatment assisted by the AT-Sn-YB catalyst shows potential application value in FAL production and bamboo utilization, providing important references for other biomass materials. Full article

The indiscriminate discharge of common dyes, such as malachite green (MG), poses significant risks to water quality and human health. To address this issue, a biochar (MBC) was synthesized from waste Myriophyllum aquaticum biomass (MAB) and further activated with KOH to produce micro-mesoporous biochar (KMBC) with enhanced adsorption efficiency. Characterization results demonstrated that KMBC exhibits a higher specific surface area (1632.7 m²/g) and a larger pore volume (0.759 cm³/g) compared to MBC. Batch adsorption experiments revealed that the adsorption process follows pseudo-second-order kinetics and the Langmuir isotherm model, with the theoretical maximum adsorption capacities of MBC and KMBC reaching 1772.3 mg/g and 2570.7 mg/g, respectively and the adsorption is a spontaneous, endothermic, and entropy-driven process. Key mechanisms involved in the adsorption process include hydrogen bonding, hydrophobic interactions, and surface complexation. Due to electrostatic attraction, selective adsorption experiments confirmed that MBC can effectively separate cationic dyes such as MG from mixed anionic-cationic systems. Dynamic experiments showed that the breakthrough curve data fit well with the Thomas model. In summary, MAB-derived biochar demonstrates significant potential for practical applications in the treatment of MG-contaminated wastewater. Full article

A biochar (BC) generated by the pyrogasification of wood chips from authorized forestry cuts was extensively characterized and evaluated for its efficacy in retaining/releasing two agrochemicals, namely the fungicide penconazole (PEN), the herbicide S-metolachlor (S-MET), and the xenoestrogen bisphenol A (BPA) widely present in industrial effluents. The elemental composition of BC was evaluated using CN elemental analysis and total reflection X-ray fluorescence (TXRF) spectroscopy which showed the abundance of elements typically found in BCs (Ca, K, P) along with essential trace elements such as Fe and Mn. Scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM-EDX) described the surface features of BC along with the major surface elements, while Brunauer–Emmett–Teller (BET) analysis revealed, as expected, a large specific surface area (366 m² g⁻¹). High porosity (0.07 cm³ g⁻¹) was demonstrated by the density functional theory (DFT) method, while Fourier transform infrared (FT-IR) spectroscopy highlighted the presence of a prominent aromatic structure and the abundance of reactive functional groups responsible for the binding of the compounds. The sorption/desorption capacity of BC was studied by means of sorption kinetics and isotherms in batch trials, and by modeling the experimental data with various theoretical equations. All compounds reached sorption equilibrium on BC very rapidly, following preferentially pseudo-second-order kinetics. Freundlich adsorption constants of PEN, S-MET, and BPA were 37.3, 13.2, and 11.6 L g⁻¹, respectively, thus demonstrating the great affinity of BC for hydrophobic pollutants. The adsorption process was hysteretic as only a small fraction of each compound was slowly desorbed from BC. The overall results obtained highlighted the great potential of BC of acting as a biosorbent of contaminants, which is of great importance for the containment of pollution in agricultural soils and for limiting the entry of toxic compounds into the human and animal food chain. Full article

The aim of this study was to develop an innovative material by combining the properties of magnetic biochar derived from orange peels and hydrogel beads (BCA-Mag/AB) and to apply this material for the adsorption of methylene blue dye in water. The BCA-Mag/AB were synthesized using physical crosslinking methods and was characterized using various techniques. The surface functional groups were analyzed using FTIR, the crystal structure was examined through XRD, the surface area was determined by BET, the pore distribution was assessed via BJH, thermal stability was evaluated with TGA, surface morphology was investigated using SEM, and the surface element percentages were analyzed with EDX. The specific surface area obtained through nitrogen adsorption was found to be 455.4 m²/g, and the total pore volume was 0.268 cm³/g. The removal of methylene blue dye on BCA-Mag/AB was investigated concerning three variables using Box–Behnken Design (BBD) as follows: A: BCA-Mag/AB dosage (0.02–0.1 g); B: contact time (20–150 min); and C: initial pH (2–10). Adsorption kinetic and isotherm analyses indicated that the adsorption of methylene blue onto BCA-Mag/AB was governed by pseudo-first-order and Freundlich models. The adsorption mechanisms of methylene blue on the BCA-Mag/AB surface were associated with electrostatic interaction, hydrophobic interaction, and π-π stacking. The results suggest that BCA-Mag/AB could be an effective and locally available candidate adsorbent for the removal of dye pollutants from contaminated industrial wastewater. Full article

Most organic waste from food production is still not used for energy production. From the perspective of energy production, one option is to valorise the properties of organic waste. The fruit juice industry is growing rapidly and generates large amounts of waste. One of the main wastes in food and fruit juice processing is peach pits and apple peels. The aim of this study was to analyse the influence of torrefaction temperature on the properties of food waste, namely apple peels, peach pits and pea shells, in order to improve their energy value and determine their potential for further use and valorisation as a renewable energy source. The aim was to analyse the influence of different torrefaction temperatures on the heating value (HHV), mass yield (MY) and energy yield (EY) in order to better understand the behavior of the thermal properties of individual selected samples. The torrefaction process was carried out at temperatures of 250 °C, 350 °C and 450 °C. The obtained biomass was compared with dried biomass. For apple peels, HHV after torrefaction was (28 kJ/kg), MY decreased by (66–34%), while EY fell by (97–83%). Peach pits, despite a higher HHV after torrefaction (18 kJ/kg), achieved low MY (38–89%) and EY (59–99%), which reduces their efficiency in biochar production. Pea peels had EY (82–97%) and a lower HHV after torrefaction (11 kJ/kg), but their high ash content limits their wider use. The results confirm that, with increasing temperature, MY and EY for all selected biomasses decrease, which is a consequence of the degradation of hemicellulose and cellulose and the loss of volatile compounds. In most cases, increasing the torrefaction temperature improved the resistance to moisture adsorption, as this is related to the thermal process that causes structural changes. The results showed that the torrefaction process improved the hydrophobic properties of the biomass samples. Temperature was seen to have a great impact on mass energy efficiency. Apple peels generally had the highest mass and energy yield. Full article

Herein, biochars derived from corn stalks, rice husks, and bamboo powder were modified by nitric acid oxidation and sodium hydroxide alkali activation to identify efficient and cost-effective polycyclic aromatic hydrocarbon-adsorbent and microbial-immobilized carriers. The surface characterization and adsorption investigation results suggested that acid/alkali modification promoted the phenanthrene removal ability in an aqueous solution of biochars via facilitating π–π/n–π electron donor–acceptor interactions, electrostatic interactions, hydrogen bonds, and hydrophobic interactions. Subsequently, the degrading bacteria Rhodococcus sp. DG1 was successfully immobilized on the rice husk-derived biochar with nitric acid oxidation (RBO), which exhibited the maximum phenanthrene adsorption efficiency (3818.99 µg·g⁻¹), abundant surface functional groups, and a larger specific surface area (182.6 m²·g⁻¹) and pore volume (0.141 m³·g⁻¹). Degradation studies revealed that the microorganisms immobilized on RBO by the adsorption method yielded a significant phenanthrene removal rate of 80.15% after 30 days, which was 38.78% higher than that of the control. Conversely, the polymer gel network-based microenvironment in the microorganism-immobilized RBO by the combined adsorption–embedding method restricted the migration and diffusion of nutrients and pollutants in the reaction system. This study thus introduces an innovative modified biochar-based microbial immobilization technology characterized by a simple design, convenient operation, and high adsorption efficiency, offering valuable insights into material selection for PAH contamination bioremediation. Full article

The increasing demand for cement, which is being driven by global urbanization and infrastructure expansion, necessitates sustainable alternatives to be used as construction materials. Cement-based composites, a prevalent construction material, are known for their high carbon footprint. Consequently, exploring sustainable alternatives is urgently needed to curb the environmental impact of the construction sector by capturing carbon dioxide (CO₂). Thus, utilizing biochar (BC) in cement-based composites, either as additive or cement, and in aggregate replacement could be a green approach, by producing enhanced composites with the capabilities of CO₂ sequestration. This review investigates the BC-modified cement composites by performing a scientometric assessment of the Scopus database and a thorough manual review. A scientometric assessment of Scopus-indexed publications retrieved from 2010–2024 was conducted to highlight key research trends, including influential authors, frequently cited works, countries, and institutions. The findings provide a comprehensive overview of the current situation of BC research and applications in cement-based composites for sustainable construction. The assessment revealed that the Construction and Building Materials journal was the most prolific source of publications (n = 34), followed by Gupta, with S as the most prolific author (n = 11), and China as the leading country in the field (n = 56). It also highlights the emerging areas for the use of BC in the construction sector for sequestering CO₂ and potential future directions. Additionally, the review discusses BC sources and BC production technologies and characteristics. It also discusses the influence of BC inclusion on the fresh properties, its mechanical properties, durability characteristics, carbon capture capabilities, and the environmental impacts of modified cement-based composites. It has been noted that BC addition to cement-based composites from 1% to 2% can increase its mechanical performance, whereas, beyond a 5% to 6% replacement, they experienced a decline compared to non-modified composites. BC addition has reduced the flow characteristics of the modified composites due to its porous morphology and hydrophobic nature but has shown improved internal curing and reduced shrinkage. It also improved the microstructure of the cement-based composite through pore refinement, due to the filling ability of the BC particles attributed to its specific surface area and size. Additionally, the carbon sequestration potential of BC can be exploited in cement-based composites to create low carbon or carbon-negative building materials with improved mechanical and durability characteristics. The study also highlights the future directions for further studies and implementation strategies of BC as a sustainable construction material at a large scale. Full article

In this research, the biochar-based tin-loaded heterogeneous catalyst Sn-NUS-BH was used for the efficient catalytic conversion of corncob (CC) in a green biphasic system of cyclopentyl methyl ether–water (CPME-H₂O). By optimizing the system conditions (CPME to H₂O ratio, Sn-NUS-BH dosage, reaction time, and reaction temperature), the stubborn structure of corncobs was maximally disrupted. The chemical composition and structural characteristics (accessibility, lignin surface area, and hydrophobicity) of CC before and after treatment were assessed, demonstrating that the natural physical barriers of CC were disrupted and lignin was effectually eliminated. The accessibility was enhanced from 137.5 mg/g to 518.5 mg/g, the lignin surface area declined from 588.0 m²/g to 325.0 m²/g, and the hydrophobicity was changed from 4.7 L/g to 1.3 L/g. Through the treatment at 170 °C for 20 min, furfural (11.7 g/L) and xylooligosaccharides (4.5 g/L) were acquired in pretreatment liquor. The residual CC could be enzymatically saccharified into reducing sugars in a yield of 65.2%. The combination pretreatment with the tin-based biochar chemocatalyst Sn-NUS-BH combined with the green solvent system CPME-H₂O shows great promise in the valorization of biomass. Full article

Plastics are widely used across various industries due to their flexibility, cost-effectiveness, and durability. This extensive use has resulted in significant plastic pollution, with microplastics (MPs) becoming pervasive contaminants in water bodies worldwide, adversely affecting aquatic ecosystems and human health. This review explores the surface characteristics of carbon-based adsorbents, including biochar, activated carbon, carbon nanotubes (CNTs), and graphene, and their influence on MP removal efficiency. Key surface characteristics such as the carbon content, surface area, pore size, and particle size of adsorbents influenced adsorption efficiency. Additionally, hydrophobic interaction, van der Waals forces, π–π interactions and electrostatic interaction were found to be mechanisms by which microplastics are trapped onto adsorbents. Modified biochar and activated carbon demonstrated high adsorption efficiencies, while CNTs and graphene, with their high carbon contents and well-defined mesopores, showed outstanding performance in MP removal. Although a high surface area was generally associated with better adsorption performance, modifications significantly enhanced efficiency regardless of the initial surface area. This review emphasizes the importance of understanding the relationship between surface characteristics and adsorption efficiency to develop optimized adsorbents for MP removal from wastewater. However, challenges such as the lack of standardized testing methods, variability in biochar performance, and the high cost of regenerating carbon adsorbents remain. Future research should focus on developing cost-effective production methods, optimizing biochar production, and exploring advanced modifications to broaden the application of carbon adsorbents. Integrating advanced adsorbents into existing water treatment systems could further enhance MP removal efficiency. Addressing these challenges can improve the effectiveness and scalability of carbon-based adsorbents, significantly contributing to the mitigation of microplastic pollution in wastewater. Full article

Ball milling is a feasible and promising method of biochar modification that can significantly increase its adsorption ability to methylene blue (MB). This study synthesized nine biochars derived from water hyacinth under different pyrolysis temperatures and modified with ball milling and Fe₃O₄. The structural properties of the pristine and ball-milled magnetic biochars were investigated and employed to adsorb MB. The results showed that ball milling significantly enhanced the specific surface area, total pore volume, and C-, N-, and O-containing groups of biochars, especially in low-temperature pyrolysis biochars. The Langmuir isotherm and the pseudo-secondary kinetic model fitted well with the MB adsorption process on biochars. After ball-milled magnetic modification, the adsorption capacity of biochar at 350 °C for MB was increased to 244.6 mg g⁻¹ (8-fold increase), owing to an increase in accessible functional groups. MB removal efficiencies by low-temperature pyrolysis biochars were easily affected by pH, whereas high-temperature pyrolysis biochars could effectively remove MB in a wide pH range. WQM1, with the high adsorption capacity and stability, provided the potential to serve as an adsorbent for MB removal. Based on DFT calculations, the chemisorption and electrostatic interactions were the primary mechanism for enhancing MB removal with ball-milled magnetic biochar at low-temperature pyrolysis, followed by H-bonding, π–π interaction, hydrophobic interaction, and pore filling. Full article