Search Results (183)

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

Dry Turkish oak (Quercus cerris) sawdust, untreated and treated with three activators, (H₃PO₄, NaOH and H₂O₂) was pyrolyzed under limited-oxygen conditions to obtain biochar samples. The electrochemical properties of these samples were tested and compared to the properties of several commercial carbon blacks. The electrochemical characterization was performed via cyclic voltammetry, analyzing the response toward two commonly used redox probes, [Fe(CN)₆]^3−/−4− and [Ru(NH₃)₆]^2+/3+. The influence of the scan rate on this response was investigated, and the resulting data were used to obtain the values of the heterogenous charge transfer constant, k₀. Higher k₀ values were observed for carbon blacks than for investigated biochar samples. The detection of 4-nitrophenol and heavy metal ions was used to assess the applicability of biochars for electroanalytical purposes. The response of untreated biochar was comparable with the response of Vulcan carbon black, which showed the best response of all analyzed carbon blacks. Full article

Phalaenopsis is a widely cultivated ornamental plant of considerable economic value worldwide. However, traditional growing medium, sphagnum moss, is limited and non-renewable. It also decomposes slowly and is prone to environmental issues. Therefore, there is an urgent need to identify more environmentally friendly and efficient alternatives. Biochar, a sustainable material with excellent physical and chemical properties, has been recognized as an effective promoter of plant growth. In this study, we investigated the influence of biochar derived from three raw materials (corn straw, bamboo, and walnut) mixed1 with coconut shell at ratios of 1:2, 1:10, and 4:1, on the growth of Phalaenopsis ‘Big Chili’. Over a 150-day controlled experiment, we evaluated multiple growth parameters, including plant height, crown width, total root length, total projected area, total surface area, and root volume. Compared to the traditional growing medium, the optimal biochar-coconut shell mixture (maize straw biochar: coconut shell = 1:2) increased plant height and crown width by 7.55% and 6.68%, respectively. Root metrics improved substantially, with total root length increasing by 10.96%, total projected area by 22.82%, total surface area by 22.14%, and root volume by 38.49%. Root biomass in the optimal treatment group increased by 42.47%, while aboveground and belowground dry weights increased by 6.16% and 77.11%, respectively. These improvements were closely associated with favorable substrate characteristics, including low bulk density, high total and water-holding porosity, moderate aeration, and adequate nutrient availability. These findings demonstrate that substrate characteristics critically influence plant performance and that biochar–coconut shell mixtures, particularly at a 1:2 ratio, represent a viable and sustainable alternative to sphagnum moss for commercial cultivation of Phalaenopsis. Full article

In this study, Bacillus amyloliquefaciens SQ-2, previously isolated from a commercial watercress paste, was investigated for its potential in promoting rice growth in Pb/Al-contaminated acidic soil, especially when used in conjunction with corn straw biochar. Firstly, the physiological properties of rice were enhanced, with the activities of catalase and superoxide dismutase increasing by 162.5% and 162.9%, respectively. Additionally, the total phenolic and chlorophyll contents of rice increased by 17.6% and 83.7%, respectively. Secondly, the nutrient content of the rice rhizosphere soil was improved. In particular, nitrate nitrogen, available potassium, and sucrase were enhanced by 9.4%, 45.9%, and 466.8%, respectively. Moreover, SQ-2–biochar was demonstrated to have a notable capacity for removing Pb²⁺ and Al³⁺. The mineralization of Pb²⁺ and Al³⁺ was achieved through the use of SQ-2–biochar, as revealed by SEM-EDS, XRD, XPS, and FT-IR analyses, with the main precipitates being Pb₃(PO₄)₂ and AlPO₄. Functional groups such as C-O-C, C=O, N-H, P-O, and -O-H on the microbial surface were found to be involved in the biosorption process of Pb²⁺ and Al³⁺. In summary, SQ-2–biochar can effectively mineralize Pb²⁺ and Al³⁺, enhance the physiological properties of rice, and improve soil nutrients, thereby augmenting the antioxidant capacity, photosynthesis, and stress resistance of rice and ultimately promoting rice growth. Full article

This study investigates biochar-enriched organic fertilizers made from bagasse, ash, spent wash, and cane tops, assessing their impact on corn growth over 45 days. A randomized complete block design with three replicates was used, testing six formulations with biochar levels at 0%, 10%, and 20%, along with soil-only and commercial fertilizer controls. Treatments T5 (bagasse + ash + spent wash + cane tops), T11 (T5 + 10% biochar), and T17 (T5 + 20% biochar) showed the best results for plant height, leaf development, and biomass production, with T17 performing the best for growth, biomass, and girth. The biochar in T17 had a pH of 9.37 ± 0.16, 18.00 ± 1.25% ash content, and a surface area of 144.58 m²/g. Nutrient analysis of the compost showed 2.85% potassium, 1.12% phosphorus, 1.85% nitrogen, 4.1% calcium, 0.23% magnesium, and 130 mg/kg zinc. The elemental composition was 68.50% carbon, 4.50% hydrogen, 6.00% nitrogen, and 25.30% oxygen, with 85.00% total organic carbon (TOC). This study concludes that T17 is the most effective formulation, offering both environmental and financial benefits, with composting potentially generating $11.16 million in profit, compared to the $19.32 million spent annually on waste management in Sri Lanka’s sugar industry. Full article

Sewage sludge, as a by-product of wastewater treatment, poses severe environmental challenges due to its high moisture, ash, and heavy metal content. Thermochemical conversion technologies, including pyrolysis and gasification, offer promising pathways for transforming sludge into valuable products such as bio-oil, biochar, and syngas. This paper systematically reviews recent advancements in pyrolysis and gasification, focusing on process optimization and catalyst development to enhance product quality and energy recovery. In pyrolysis, factors such as temperature, residence time, and heating rate significantly influence product yields and properties, while catalytic and co-pyrolysis approaches further improve product structure and reduce environmental risks. In gasification, parameters like the equivalence ratio, steam-to-sludge ratio, and catalyst application are key to enhancing syngas yield and quality, with biomass co-gasification offering additional benefits. Despite substantial progress, commercialization remains challenged by high operational costs, catalyst durability, and environmental impacts. Future research should emphasize improving sludge pretreatment, optimizing thermochemical processes, developing efficient and cost-effective catalysts, and addressing critical issues such as bio-oil quality, tar management, and syngas purification to promote the industrial application of these technologies. Full article

Research on using biochar as an adsorbent of contaminants in aqueous matrices has gained significant relevance in recent years due to the surface chemistry and porous structure of biochar, which facilitate the retention of a wide range of pollutants. This study explores the adsorption performance of a novel biochar produced from agave bagasse—a readily available agro-industrial waste in Mexico—through low-temperature pyrolysis. The biochar was evaluated for its capacity to remove conventional water quality parameters (chemical oxygen demand (COD), nitrates (NO₃⁻), total nitrogen (TN), total phosphorus (TP), ammonium (NH₄⁺), turbidity, apparent color, and true color) from water samples collected from the polluted Bustillos Lagoon in Chihuahua, Mexico. Additionally, the removal of emerging pharmaceutical contaminants, specifically acetaminophen (Act) and diclofenac (Dfc), was assessed in synthetic aqueous solutions. Potentiometric titration analyses revealed a significant contribution of surface acidity in the adsorption of pharmaceutical derivatives, highlighting the relevance of functional groups retained during low-temperature pyrolysis. The biochar derived from agave bagasse (BBAF1) was tested in a fixed-bed column system and compared with two commercial activated carbons (CACCF2 and CVCF3). The BBAF1 biochar achieved average removal efficiencies ranging from 50% to 90% for all conventional parameters. In contrast, those of ACT and DFC were between 0.43 and 0.67 mg g⁻¹ (59–85%) and 0.34 and 0.62 mg g⁻¹ (37–79%), respectively, demonstrating their potential as an adsorbent material for improving water quality. This work supports the development of circular economic strategies by valorizing agricultural residues while offering an effective solution to environmental pollution challenges. Full article

Vitamin E is important for ruminants’ health. To increase the rate of vitamin E resorption, the use of a carrier is recommended. One authorised porous feed additive is biochar. Biochar’s adsorption capacity is affected by its pore volume, which is determined, among other factors, by the biomass and the production process applied. For this purpose, the vitamin E adsorption capacity of ten commercial biochars with a varying surface area in the range of 2.6 to 20 nm was investigated. The results of these single-point batch experiments were compared to the theoretical results using a monolayer adsorption model. Our hypothesis was proven, as the theoretical model could predict the experimental adsorption capacity. This generally suggests that the number of trials required to identify optimal adsorbents can be reduced. A high percentage of vitamin E adsorption (>90%) was obtained with a short adsorption time of 10 min using an adsorbent dosage of 15.78 g/L and a vitamin E concentration of 1.70 g/L. The highest correlation of vitamin E adsorption existed for the mesopore class, ranging from 3.22 to 4.03 nm in Barrett–Joyner–Halenda surface area. This indicates the necessity of knowing the size of the adsorptive and the adsorbent in order to optimise sorption kinetics. Full article

Tropical acidic soils exhibit inherently low fertility and reduced microbial activity, driven by low pH and accelerated organic matter mineralization, phosphorus (P) fixation, and aluminum (Al³⁺) and iron (Fe³⁺) toxicity. These constraints limit agricultural productivity, necessitating sustainable and low-cost soil amendments essential for improving the soil fertility in such regions. This study investigated the effects of biochar, kitchen stove ash (KSA), and their combined application on the soil chemical properties, nutrient dynamics, and microbial functions in a tropical acidic soil. The treatment included the unamended control and two doses of 0.25% w/w (B₁₀) and 0.5% w/w (B₂₀) corncob biochar, 0.03% w/w kitchen stove ash (A_sh), and 0.027% w/w commercial-grade calcium carbonate (L_ime). Each biochar dose was added alone or in combination with either ash (A_sh + B₁₀ and A_sh + B₂₀) or calcium carbonate (L_ime + B₁₀ and L_ime + B₂₀). After eight weeks of laboratory incubation at 20 °C, the soil pH, N and P bioavailability, microbial biomass, and extracellular enzyme activities were measured. The combined application of 0.5% w/w biochar with 0.03% w/w KSA (A_sh + B₂₀) resulted in the most significant improvements in all of the examined soil fertility indicators than the individual amendments. Specifically, the soil pH was increased by 40% (+1.9 pH units) compared with the unamended control. Available phosphorus, mineral nitrogen, and total potassium were increased by 49%, 22%, and 36%, respectively, compared with the unamended control. Regarding the microbial parameters, the A_sh + B₂₀-treated soil showed the highest microbial respiration (+56%), microbial biomass (+45%), and extracellular C- and N-cycling enzyme activities compared with the unamended soil. The ash supplied minerals (P, K, and Mg) provided a more beneficial effect on the soil’s nutrient content and microbial functions than the calcium carbonate. The study demonstrated that underutilized kitchen ash may supplement biochar’s liming and nutrient supply potentials, even at a lower application rate, to improve the fertility of weathered acidic soil. Full article

Dewatering anaerobic digested sludge leaves a liquid fraction known as reject water, a liquid organic fertilizer containing high amounts of ammonium nitrogen (NH₄-N). However, its concentration should be enhanced to produce commercial fertilizer. Thus, reject water nitrification for stabilization as well as for nitrate capture in biochar to be used as a slow-release fertilizer is proposed. This study attempted to accomplish enhanced nitrification by tuning the operating parameters in two lab-scale sequential-batch reactors (SBRs), which were fed reject water (containing 520 ± 55 mg NH₄-N/L). Sufficient alkalinity as per stoichiometric value was needed to maintain the pH and free nitrous acid (FNA) within the optimum range. A nitrogen loading rate (NLR) of 0.14 ± 0.01 kg/m³·d and 3.34 days hydraulic retention time (HRT) helped to achieved complete 100% nitrification in reactor 1 (R₁) on day 61 and in reactor 2 (R₂) on day 82. After a well-developed bacterial biomass, increasing the NH₄-N concentration up to 750 ± 85 mg/L and NLR to 0.23 ± 0.03 kg/m³·d did not affect the nitrification process. Moreover, a feeding sequence once a day provided adequate contact time between nitrifying sludge and reject water, resulting in complete nitrification. It can be concluded that enhanced stable nitrification of reject water can be achieved with quick adjustment of loading, alkalinity, and HRT in SBRs. Full article

The dissipation pattern and mobility of applied pesticides in the soil represent a crucial process for pesticide safety and subsequent groundwater contamination. In this study, two distinct experiments were conducted to explore the environmental fate, dissipation, and mobility of two pesticides, phorate and boscalid, in greenhouse conditions and laboratory soil column studies, respectively. The role of organic matter and growing conditions was evaluated during dissipation and mobility studies. In the first study, commercial formulations of phorate (10 G) and boscalid (20% SC) were sprayed in the designated greenhouse for Korean cabbage following the recommended dosage. A sequential collection of plant samples (e.g., 0, 7, 14, 21 days) was performed. On the other hand, three sets of packing columns were prepared (control, biochar-amended, and H₂O₂ treated). The effect of organic matter addition or removal during the leaching of pesticides was explored. A 14-day interval after the last spray was suggested for safe spraying. After 30 days of leachate collection, no pesticide residue was detected in the leaching water, indicating the immobility of the studied pesticides. However, the metabolic transformation of phorate was evident during this column study, with slight mobility within soil columns. In particular, phorate sulfoxide and sulfone were mostly detected in the top soil layer (vadose zone) of the soil column. In summary, phorate and boscalid were considered immobile pesticides with moderate persistence in the soils. The safe pre-harvest interval should be maintained to reduce the health risk of pesticides. Full article

Lignin is the largest renewable source of aromatic biopolymers on Earth, and it is commercially available as by-product of biorefineries and pulp/paper industries. It is mainly burned for heat and power, but pyrolysis can provide high-value-added products. In this study, the pyrolysis characteristics of alkali lignin pellets are investigated using a packed-bed reactor at a laboratory scale for heating temperatures of 800–900 K. Conversion dynamics are analyzed by means of the thermal field and the rates of gaseous species release, which is a very innovative aspect of the study. The yields of the lumped product classes do not vary significantly in the range of heating temperatures examined (biochar yields around 58–63 wt%, together with gas and liquid yields around 9–12 and 28–30 wt%, respectively). Carbon dioxide is the most abundant gaseous product, followed by methane and carbon monoxide (smaller amounts of C₂ hydrocarbons and hydrogen), while bio-oil is rich in phenolic compounds, especially guaiacols, cresols, and phenol. A comparison with the conversion dynamics of fir, beech, and straw reveals that, mainly as a consequence of softening and melting, the lignin heat- and mass-transfer rates as well as actual reaction temperatures are profoundly different. In fact, the characteristic process size becomes the diameter of the reactor rather than that of the pellets. Full article

The ammonia adsorption capacity of lignin-rich biomass solids was tested for the first time at low partial pressures (<1.5 kPa) and 20 °C. The biomass samples included untreated tree barks, husks, and peats, as well as the biochars produced by their slow pyrolysis. Proximate and ultimate analyses, lignin content, and metal content are also presented. The untreated biosolids had higher VM/FC ratios, molar H/C, and O/C than the treated biosolids (biochars and treated biochars). A novel methodology is described for the safe generation of gaseous ammonia at predictable low partial pressures from tabletop-scale batch reaction experiments of NaOH with (NH₄)₂SO₄ in aqueous solution, leading to the determination of ammonia adsorption capacities from low-cost experiments. Statistically significantly larger NH₃ adsorption capacities were obtained for the untreated biosolids than for their biochars (p < 0.001). In contrast, the biochars were found to be poor NH₃ adsorbers without further treatment. The NH₃ adsorption capacities from this study’s biosolids were compared with those of common adsorbent types in the same conditions using the existing literature through equilibrium model interpolation (Dubinin–Astakhov, Toth, and Freundlich) or cubic spline fit from graphical isotherms. Controls consisting of commercially sourced activated carbons (AC) had low adsorption capacities, close to those derived from the literature in the same conditions for similar materials, confirming the methodology’s robustness. The untreated biosolids’ NH₃ adsorption capacities were in the same range as those reported for silica, gamma-alumina, and some of the treated or doped ACs. They also performed better than the undoped, untreated ACs. The work suggests lignin-rich untreated biosolids such as barks and peats are competent low-cost ammonia adsorbents. Full article

Modern society relies heavily on energy, driving global research into sustainable energy storage and conversion technologies. Concurrently, the increasing volume of waste generated by industrial and commercial activities emphasizes the need for effective waste management strategies. Carbonization emerges as a promising solution, converting waste into energy and valuable end products such as biochar. This study explores an approach for valorizing bone-based food waste, presenting innovative pathways for managing the escalating issue of food waste. We investigate carbon derived from cattle bone waste, carbonized at 800 °C (CBW8), to design sustainable full-cell lithium-ion batteries (FLIBs). FLIBs featuring CBW8 as the anode material and LiFePO₄ as the cathode exhibit exceptional cycling life, even at high current rates. The cell demonstrates a high specific capacity of 165 mAh g⁻¹ at 0.5 C, maintaining stable performance over 1800 cycles at various C-rates. This work not only advances the field of sustainable energy and waste management, but also opens new avenues for eco-friendly technological applications. Full article

Plant growth-promoting bacteria (PGPB) are an effective tool for improving nutrients in agricultural systems; however, their efficacy depends on successful colonization in soils. To address this challenge, biochar has been identified as an effective material for enhancing soil ecosystem services and can serve as a protective for PGPB. However, the impact of biochar and PGPB on soil health indicators and plant growth remains poorly understood. This study aimed to evaluate the effects of biochar and PGPB on soil chemical and biological properties in cowpea. We used biochar from bean husk (BHB) and grape fermentation residue (GFB) and Bradyrhizobium elkanii USDA 76 (BRA), Burkholderia cepacia ATCC 25416 (PRB), or Rhizobium altiplani BR10423 (RHI). BHB and PRB stimulated cowpea growth, while GFB and PRB promoted soil phosphatase activity. Overall, different combinations of biochar and PGPR increased soil pH, phosphorus, potassium, organic carbon content, and urease activity, but did not affect microbial biomass carbon and β-glucosidase activities. The biochars inoculated with the BRA showed the highest productivity. For example, plants subjected to the BRA + GFB treatment exhibited a 3.85-fold increase in productivity compared to the additional treatment that involved the use of commercial peat. The study demonstrated a positive effect of biochar and PGPB on soil enzymatic activity, nutrient content, and cowpea growth suggesting a sustainable alternative to chemical fertilizers, especially in poor soils. These findings highlight the potential of biochar as an environmentally sustainable carrier of PGPB while addressing the issue of agricultural waste reuse. Full article