Search Results (19)

This study aimed to synthesize a magnetic biochar@ZIF-8 composite derived from almond shell biomass for the adsorption of fluoroquinolones (FQs) from aqueous media. The biochar was prepared under different pyrolysis conditions using a central composite design (CCD) based on temperature and residence time, with biochar yield (%) and ofloxacin adsorption capacity selected as the response variables. Subsequently, the composite was obtained by combining KOH-activated biochar with ZIF-8 and magnetic particles, producing a hierarchically porous material with enhanced surface area and functional groups favorable for adsorption. The physicochemical and morphological properties of the composite were characterized by SEM–EDS, FTIR, BET, TGA, and XRD analyses, confirming the successful incorporation of ZIF-8 and magnetic phases onto the biochar surface. The adsorption performance was systematically evaluated by studying the effects of pH and contact time. The kinetic data fitted well to the pseudo-second-order model, suggesting that chemisorption predominates through π–π stacking, hydrogen bonding, and coordination interactions between FQ molecules and the active sites of the composite. Furthermore, the material exhibited high reusability, maintaining over 84% of its adsorption capacity after four cycles, with efficient magnetic recovery without the need for filtration or centrifugation. Overall, the magnetic biochar@ZIF-8 composite demonstrates a sustainable, cost-effective, and magnetically separable adsorbent for water remediation, transforming almond shell waste into a high-value material within the framework of circular economy principles. Full article

The aim of this study is to investigate the potential use of rapidly increasing agricultural wastes in concrete production by substituting them for cement, thereby reducing their environmental impact and producing eco-friendly concrete. For this purpose, concrete samples were produced using a combination of almond shell biomass (ASB) and silica fume (SF). These samples were subjected to standard compressive strength tests as well as ultrasonic pulse velocity (UPV), porosity (P), and maturity (M) tests. In addition, the microstructure of the samples containing ASB and SF was examined using scanning electron microscopy (SEM). The test results show that the combined use of ASB and SF in concrete production significantly improves the strength properties, and the best results were obtained from the ASB6SF10 series. A significant increase of 37.7% was observed in the compressive strength values of the ASB6SF10 series from the early age between 3 and 28 days. UPV and P values were obtained as 4.46 m/s and 10%, respectively. The use of ASB and SF in concrete production has been found to be critically important in terms of the mechanical and physical properties of concrete and environmental benefits. The results of the study show that ASB and SF have potential for use in concrete production and can contribute to more sustainable concrete production, waste management, and the circular economy by reducing the negative environmental impacts arising from this production. Full article

Lead (Pb(II)) contamination in water poses severe environmental and health risks due to its toxicity and persistence. This study compares almond shell-derived biochars produced by slow pyrolysis (SP) and microwave pyrolysis (MW), with and without KOH activation, focusing on structural properties and Pb(II) adsorption performance. Biochars were characterized by proximate and elemental analysis, BET surface area, FTIR spectroscopy, and adsorption experiments including pH dependence, kinetics, and equilibrium isotherms. Non-activated SP exhibited the highest surface area (S_BET = 693 m²·g⁻¹), pronounced mesoporosity (≈73% of total pore volume), and the largest observed equilibrium capacities. KOH activation increased surface hydroxyl content but degraded textural properties; in MW samples, it induced severe pore collapse. Given the very fast uptake, kinetic modeling was treated cautiously: for non-activated biochars, Elovich adequately captured the time-course trend, whereas activated samples returned non-physical kinetic constants (e.g., negative k₂) likely due to high post-adsorption pH (>11) and probable Pb(OH)₂ precipitation. Equilibrium data (fitted over 50–500 mg·L⁻¹) were better captured by the Freundlich and Redlich–Peterson models, indicating a mixed adsorption behaviour with contributions from heterogeneous site distribution and site-specific interactions. Optimal Pb(II) removal occurred at pH 4, with no measurable leaching from the biochar matrix. Overall, non-activated SP biochar is the most effective, sustainable and low-cost option among the tested materials for Pb(II) removal from water, avoiding aggressive chemical activation while maximizing adsorption performance. Full article

The amount of waste generated by society is constantly increasing. Consequently, there is a need to develop new and better methods of treating it. A significant part of municipal waste is biowaste, which can be treated as a source of valuable resources such as nutrients, organic matter, and energy. The present work aims to determine the properties of the tested household biowaste and the possibility of using it as feedstock in slow pyrolysis to obtain biochar. The slow pyrolysis process of the biowaste was carried out in an electrically heated Horizontal Tube Furnace (HTF) at temperatures of 400 °C, 500 °C, and 600 °C in a nitrogen atmosphere. The analysis showed that depending on the type and composition of the biowaste, its properties are different. All the biowaste tested has a high moisture content (between 63.51% and 81.53%), which means that the biowaste needs to be dried before the slow pyrolysis process. The characteristics of kitchen biowaste are similar to those of food waste studied by other researchers in different regions of the world. In addition, the properties of kitchen biowaste are similar to those of the typical biomasses used to produce biochar via slow pyrolysis, such as wood, almond shells, and rice husks. Both kinds of garden biowaste tested may have been contaminated (soil, rocks) during collection, which affected the high ash content of spring (17.75%) and autumn (43.83%) biowaste. This, in turn, affected all the properties of the garden biowaste, which differed significantly from both the literature data of other garden wastes and from the properties of typical biomass feedstocks used to produce biochar in slow pyrolysis. For all biowaste tested, it was shown that as the pyrolysis temperature increases, the yield of biochar decreases. The maximum mass yield of biochar for kitchen, spring garden, and autumn garden biowaste was 36.64%, 66.53%, and 66.99%, respectively. Comparing the characteristics of biowaste before slow pyrolysis, biochar obtained from kitchen biowaste had a high carbon content, fixed carbon, and a higher HHV. In contrast, biochar obtained from garden biowaste had a lower carbon content and a lower HHV. Full article

This study investigates the potential of biochars derived from agricultural waste biomass for the removal of heavy metal ions from aqueous solutions. Biochars were produced via slow pyrolysis at 793 K using almond shells (AS), walnut shells (WS), pistachio shells (PS), and rice husks (RH) as feedstocks. The physicochemical properties and adsorption performance of the resulting materials were evaluated with respect to Cd(II), Mn(II), Co(II), Ni(II), Zn(II), total Iron (Fe_tot), total Arsenic (As_tot), and total Chromium (Cr_tot) in model solutions. Surface morphology, porosity, and surface chemistry of the biochars were characterized by scanning electron microscopy (SEM), nitrogen adsorption at 77 K (for specific surface area and pore structure), Fourier-transform infrared spectroscopy (FTIR), and determination of the point of zero charge (pH_pzc). Based on their textural properties, biochars derived from WS, PS, and AS were classified as predominantly microporous, while RH-derived biochar exhibited mesoporous characteristics. The highest Brunauer–Emmett–Teller (S_BET) surface area was recorded for PS biochar, while RH biochar showed the lowest. The pistachio shell biochar exhibited the highest specific surface area (440 m²/g), while the rice husk biochar was predominantly mesoporous. Batch adsorption experiments were conducted at 25 °C, with an adsorbent dose of 3 g/L and a contact time of 24 h. The experiments in multicomponent systems revealed removal efficiencies exceeding 87% for all tested metals, with maximum values reaching 99.9% for Cd(II) and 97.5% for Fe_tot. The study highlights strong correlations between physicochemical properties and sorption performance, demonstrating the suitability of these biochars as low-cost sorbents for complex water treatment applications. Full article

This study investigated the phytotoxicity of agro-industrial wastes (almond, walnut, pistachio and peanut shells, asparagus spears, and brewer’s spent grain) and their biochar through germination bioassays in several horticultural species: green pea, lettuce, radish, and arugula. Biowaste was pyrolyzed under controlled conditions to produce biochar, and both biowaste and biochar were characterized. Germination bioassay was conducted using seeds exposed to different dilutions of aqueous extract of biowaste and their biochar (0, 50, and 100%). Germination percentage, seed vigor, germination index, and root and aerial lengths were evaluated. The results showed that the phytotoxicity of the biowaste was significantly different to that of its biochar. The biochar obtained demonstrated changing effects on germination and seedling growth. In particular, biochar extracts from spent brewers grains, walnut shells, and pistachio shells showed 5–14% increases in seed vigor and root and aerial length. Furthermore, the response of different species to both agro-industrial waste and biochar revealed species-specific sensitivity. Seeds of lettuce and arugula species were more sensitive to aqueous extracts than radish and green peas. This knowledge not only elucidates the behavior of agro-industrial waste-based biochar in the early stage of plant development but also provides valuable insights regarding phytotoxicity, seed sensitivity, and the variables involved in germination. Full article

Medicines are pharmaceutical substances used to treat, prevent, or relieve symptoms of different diseases in animals and humans. However, their large-scale production and use worldwide cause their release to the environment. Pharmaceutical molecules are currently considered emerging pollutants that enter water bodies due to inadequate management, affecting water quality and generating adverse effects on aquatic organisms. Hence, different alternatives for pharmaceuticals removal from water have been sought; among them, the use of agro-industrial wastes has been proposed, mainly because of its high availability and low cost. This review highlights the adverse ecotoxicological effects related to the presence of different pharmaceuticals on aquatic environments and analyzes 94 investigations, from 2012 to 2024, on the removal of 17 antibiotics, highlighting sulfamethoxazole as the most reported, as well as 6 non-steroidal anti-inflammatory drugs (NSAIDs) such as diclofenac and ibuprofen, and 27 pharmaceutical drugs with different pharmacological activities. The removal of these drugs was evaluated using agro-industrial wastes such as wheat straw, mung bean husk, bagasse, bamboo, olive stones, rice straw, pinewood, rice husk, among others. On average, 60% of the agro-industrial wastes were transformed into biochar to be used as a biosorbents for pharmaceuticals removal. The diversity in experimental conditions among the removal studies makes it difficult to stablish which agro-industrial waste has the greatest removal capacity; therefore, in this review, the drug mass removal rate (DMRR) was calculated, a parameter used with comparative purposes. Almond shell-activated biochar showed the highest removal rate for antibiotics (1940 mg/g·h), while cork powder (CP) (10,420 mg/g·h) showed the highest for NSAIDs. Therefore, scientific evidence demonstrates that agro-industrial waste is a promising alternative for the removal of emerging pollutants such as pharmaceuticals substances. Full article

Five different biomass wastes—orange peel, coffee grounds, cork, almond shell, and peanut shell—were transformed into biochars (BCs) or activated carbons (ACs) to serve as adsorbents and/or ozone catalysts for the removal of recalcitrant water treatment products. Oxalic acid (OXL) was used as a model pollutant due to its known refractory character towards ozone. The obtained materials were characterized by different techniques, namely thermogravimetric analysis, specific surface area measurement by nitrogen adsorption, and elemental analysis. In adsorption experiments, BCs generally outperformed ACs, except for cork-derived materials. Orange peel BC revealed the highest adsorption capacity (Qe = 40 mg g⁻¹), while almond shell BC showed the best cost–benefit ratio at €0.0096 per mg of OXL adsorbed. In terms of catalytic ozonation, only ACs made from cork and coffee grounds presented significant catalytic activity, achieving pollutant removal rates of 72 and 64%, respectively. Among these materials, ACs made from coffee grounds reveal the best cost/benefit ratio with €0.02 per mg of OXL degraded. Despite the cost analysis showing that these materials are not the cheapest options, other aspects rather than the price alone must be considered in the decision-making process for implementation. This study highlights the promising role of biomass wastes as precursors for efficient and eco-friendly water treatment processes, whether as adsorbents following ozone water treatment or as catalysts in the ozonation reaction itself. Full article

Biocharcoal (BioC), a cost-effective, eco-friendly, and sustainable material can be derived from various organic sources including agricultural waste. However, to date, complex chemical treatments using harsh solvents or physical processes at elevated temperatures have been used to activate and enhance the functional groups of biochar. In this paper, we propose a novel easy and cost-effective activation method based on electrochemical cycling in buffer solutions to enhance the electrochemical performance of biocharcoal derived from almond shells (AS-BioC). The novel electrochemical activation method enhanced the functional groups and porosity on the surface of AS-BioC, as confirmed by microscopic, spectroscopic characterizations. Electrochemical characterization indicated an increase in the conductivity and surface area. A modified SPCE with activated AS-BioC (A.AS-BioC/SPCE), shows enhanced electrochemical performance towards oxidation and reduction of nitrite and paraxon ethyl pesticide, respectively. For both target analytes, the activated electrode demonstrates high electrocatalytic activity and achieves a very LOD of 0.38 µM for nitrite and 1.35 nM for ethyl paraxon with a broad linear range. The sensor was validated in real samples for both contaminants. Overall, the research demonstrates an innovative technique to improve the performance of AS-BioC to use as a modifier material for electrochemical sensors. Full article

At present, direct carbon fuel cells constitute an emerging energy technology that electrochemically converts solid carbon to electricity with high efficiency. The recent trend of DCFCs fueled with biochar from biomass carbonization as green fuel has reinforced the environmental benefits of DCFCs as a clean and sustainable technology. However, there remain new challenges related to some complex unknown kinetic parameters, $\mathrm{X}=({\mathsf{\alpha }}_{\mathrm{a}},{\mathsf{\alpha }}_{\mathrm{c}},{\mathsf{\sigma }}_{\mathrm{g}},{\mathrm{i}}_{0,\mathrm{a}},{\mathrm{i}}_{0,\mathrm{c}},{\mathrm{i}}_{{\mathrm{l}}_{{\mathrm{O}}_2}},{\mathrm{i}}_{{\mathrm{l}}_{{\mathrm{CO}}_2,\mathrm{c}}},{\mathrm{i}}_{{\mathrm{l}}_{{\mathrm{CO}}_2,\mathrm{a}}},{\mathrm{i}}_{{\mathrm{l}}_{\mathrm{CO}}})$, of the electrochemical conversion of biochar in DCFCs and there is a need for intelligent techniques for prediction and optimization, refering to the available experimental data. The differential evolution (DE) algorithm, which ranked as one of the top performers in optimization competitions with competitive accuracy and convergence speed, was used here for providing the optimized values of these parameters by minimizing the root mean squared errors (RMSE). The proposed technique was then applied to DCFCs fueled by activated pure carbon (APC) using CO₂ and CO/CO₂ electrochemical models with RMSE around 10⁻² and 10⁻³, respectively. Then, the CO/CO₂ model was applied to a DCFC fueled with almond shell biochar (ASB), which displayed a slight increase in RMSE (of the order of 10⁻²) due to the complex porous structure of ASB and the content of additional chemical elements that affect the electrochemistry of the DCFC and are not considered in the model. Full article

A homoacetogenic consortium was cultivated from feces from a nursing joey red kangaroo and inoculated into an in vitro ruminal culture. The in vitro ruminal culture was treated with methanogenic inhibitor 2-bromoethanesulfonate (BES), followed by two different homoacetogenic inoculation strategies. Initial observations showed inhibitory effects of BES, with stabilization of the acetic acid concentrations without any increase in concentration, even with the homoacetogenic inoculation. When homoacetogenic bacterial culture was added after the BES addition had ceased, acetic acid production was increased 2.5-fold. Next-generation sequencing showed an increased population of Bacteroidetes after inoculation with the homoacetogenic consortia, along with a slight decrease in diversity. An Almond Shell biochar (AS) addition resulted in a 28% increase in acetic acid concentration if tested directly on the homoacetogenic kangaroo consortia. However, when applied to the rumen culture, it did not enhance acetate production but further promoted other reductive pathways such as methanogenesis and propiogenesis, resulting in increased concentrations of methane and propionic acid, respectively. These findings demonstrate that bioaugmentation with homoacetogenic bacteria can improve acetic acid production of an in vitro rumen culture when methanogenesis has been eliminated. Such advancements can potentially contribute to the optimization of rumen fermentation processes and may have practical implications for improved livestock feed efficiency and methane mitigation strategies. Full article

Phosphorus is one of the main causes of water eutrophication. Hard biochar is considered a promising phosphate adsorbent, but its application is limited by its textural properties and low adsorption capacity. Here, an adhesion approach in a mixed suspension containing egg white is proposed for preparing the hybrid material of Mg/Al-layered double hydroxide (LDH) and almond shell biochar (ASB), named L-A_E or L-A (with or without egg white). Several techniques, including XRD, SEM/EDS, FTIR and N₂ adsorption/desorption, were used to characterize the structure and adsorption behavior of the modified adsorbents. The filament-like material contained nitrogen elements at a noticed level, indicating that egg white was the crosslinker that mediated the formation of the L-A_E hybrid material. The L-A_E had a higher phosphate adsorption rate with a higher equilibrium adsorption capacity than the L-A. The saturation phosphate adsorption capacity of L-A_E was nearly three times higher than that of L-A. Furthermore, the number of surface groups and the density of the positively charged surface sites follow the ASB < L-A < L-A_E order, which is consistent with their phosphate adsorption performance. The study may offer an efficient approach to improving hard biochar’s adsorption performance in wastewater treatment. Full article

The main aim of this study was to perform a parametric study for treating a model dye containing wastewater (i.e., methylene blue, MB) using locally available biomass wastes in Palestine as the adsorbent. Eight different types of biomasses were investigated in batch adsorption tests, including coffee grains, almond shells, pistachio shells, date pits, jute sticks, sunflower shells, peanut shells, and grapevine sticks. The experiments were conducted on three different phases of processing for these materials: as natural adsorbents, biochar, and activated carbon. The biochar was prepared by pyrolysis, while ZnCl₂ was used to chemically activate the materials for obtaining activated carbon. The influences of pH, initial MB concentration, and adsorbent dosage on the adsorption capacity and kinetics were investigated for activated carbon obtained from sunflower shells. The results indicate that the adsorption efficiency of natural adsorbents and biochar is highly dependent on the biomass type. As a natural adsorbent, peanut hulls demonstrated the maximum efficiency (>95%) for removing MB, whereas date pits showed the lowest efficiency (20%). In terms of biochar, jute sticks provide the highest removal efficiency. After activation with ZnCl₂, a considerable increase in their adsorption efficiency (>95%) was obtained for most of the adsorbents, with sunflower shells being the most efficient adsorbent. The results confirm the technical feasibility of the adsorption technology to treat dye containing wastewater using locally available biomass wastes. Full article

Biomass from specialty crops, including almonds, walnuts, and numerous others, serves as an important resource for energy and materials as agricultural systems evolve towards greater sustainability and circularity in management and operations. Biochar was produced from almond shells in a laboratory furnace at temperatures between 300 and 750 °C for residence times of 30 and 90 min with moisture contents of 5% to 15% wet basis. Response surface methodology was used to optimize the biochar yield. Feedstock and product temperatures were continuously monitored throughout the experiments. In addition, larger batches of biochar were also produced in a fixed-bed pilot-scale pyrolyzer. The yield of biochar was determined as a weight fraction of the amount of oven-dry almond shells used in each experiment. Physical and chemical characteristics of biochars were evaluated. Pyrolysis temperature and time were found to be the significant parameters affecting the biochar yield, with second-order regression models derived to fit yield results. As anticipated, highest biochar yields (65%) were obtained at a pyrolysis temperature of 300 °C and a pyrolysis time of 30 min due to the limited volatilization at this short residence at low temperature affecting torrefaction of the feedstock. The average biochar yield from the fixed-bed pilot-scale experiments was 39.5% and more closely aligned with the fixed carbon from standard proximate analyses. Higher pyrolysis temperatures resulted in higher C:N ratio and pH with the highest C:N ratio of 19:1 and pH of 10.0 obtained at a pyrolysis temperature of 750 °C for 90 min. Particle density increased with the increase of pyrolysis temperature. Results of this study can aid in predicting biochar yields from almond shells under different pyrolysis conditions and determining the amount of biochar required for different applications. Full article

A plastic pot open-air trial was conducted with the Paspalum vaginatum (seashore paspalum) using different rates of biochar or compost addition to sandy loam soil and two water treatments (60% and 20% of the water-holding capacity of the control) during three seasons (winter, spring, and summer). Paspalum growth, physiological characteristics, and physicochemical properties of soil were investigated. The effect of biochar on soil properties was assessed using factor analysis of mixed data (FAMD). Additionally, multiple factorial designs (MFA) were used to examine the impact of three biochars on physiological functions. Peanut hull biochar application increased soil fertility and chlorophyll concentration of paspalum leaves significantly compared to the other biochars. Physiological characteristics were significantly improved with peanut hull biochar under summer compared to winter and spring due to the accumulation of nutrients in the soil by the decomposition of biochar. The application rate of the three biochars reduced the water requirements of paspalum. The best result was obtained by incorporating 6% peanut hull biochar into the soil, which resulted in better soil quality and healthy grass in dryland conditions while using 47.5% less water. These findings can be suitable for golf managers and can serve as a solution for dry zones. Full article