Peanut Shell Biochar Research Articles

Evaluation into the effect of lignocellulosic biochar on the thermal properties of shape stable composite phase change materials

Biochar is suitable for preparing shape stable composite phase change materials (sscPCMs) due to the advantages of cost-effective, environmentally, and sustainability. However, the heat properties of biochar-based sscPCMs were not consistent. To investigate how different types of biochar influence the thermal properties of sscPCMs, three types of sscPCMs were successfully prepared using peanut shell biochar (PSC), poplar wood biochar (PWC), and corn straw biochar (CSC) as framework materials and combined with stearic acid (SA). A comprehensive analysis of the thermal properties of three sscPCMs was performed, taking into account thermal conductivity, phase change latent heat, encapsulation efficiency, crystallization rate, and energy storage efficiency. The study indicated that among the three types of sscPCMs, SA/PWC sscPCMs demonstrated excellent comprehensive performance. The phase change latent heat of SA/PWC reached 100.13 J/g, and the thermal conductivity was 0.38 W/mK. Compared to SA/PSC, the phase change latent heat of SA/PWC increased by 45.96 %, with only a 28.30 % reduction in thermal conductivity. In comparison to SA/CSC, the thermal conductivity of SA/PWC improved by 18.75 %, while the phase change latent heat decreased by only 14.02 %. In addition, the proportions of cellulose, hemicellulose, and lignin played a crucial role in determining the thermal properties of sscPCMs. This study clarified the mechanism by which biochar influences the thermal characteristic of sscPCMs, offering valuable insights for choosing biochar framework materials.

Peanut Shell Biochar as a Conductive Additive for Cement Composites

Peanut Shell Biochar as a Conductive Additive for Cement Composites

Soil organic carbon, carbon fractions, and microbial community under various organic amendments

The impact of various organic amendments on soil organic carbon (SOC) have rarely been reported. To address this, a laboratory experiment was designed to scrutinize the effects of different amendments on soil carbon fractions, microbial communities, and the underlying interactive mechanisms. The experiment encompassed a no-amendment control (CK), as well as treatments with corn straw (CS), tobacco stalks (TS), and peanut shell biochar (PB). Over a 70-day incubation, the SOC in plots amended with CS, TS, and PB displayed significant boosts of 13.9%, 17.5%, and 44.8%, respectively, compared to the CK. For soil carbon fractions, amendments with PB, TS, and CS led to a dramatic rise in particulate organic carbon (POC) of 27.4%, 20.2%, and 105.7%, respectively, in contrast to the CK plots. Mantel analysis and structural Equation Modeling uncovered strong interrelationships among the cbbL, cbbM, Bacteroidota, TOC, and POC. Organic amendments enhance soil carbon fractions, modulating the microbial community by increasing Bacteroidetes abundance and suppressing Acidobacteria richness, thereby influencing the abundance of key carbon cycle genes such as cbbL and cbbM. These results suggest that the addition of peanut shell biochar significantly boosted TOC and key carbon fractions, enhancing carbon content and soil fertility.

Heterogeneous Fenton system driven by magnetic graphene-like biochar for degrading tetracycline

In this study, a novel catalyst with high efficiency and low cost was synthesized from farmland waste peanut shells by one-step pyrolysis modification method via K2FeO4, and employed for the catalytic degradation of tetracycline (TC). The magnetic potassium ferrate modified graphene-like biochar catalyst (PFGB) exhibited a high porosity, a highly graphitized structure, and a large specific surface area (857.09 m2·g-1) which was almost 30 times higher compared with peanut shell biochar, and were found to contain more functional groups. The formation and distribution of Fe3O4 and Fe0 nanoparticles on the surface/pores of PFGB provided more active sites for promoting adsorption and catalytic degradation reactions, and accelerated Fe(II)/Fe(III) recycle. Under the optimal conditions (pH=3.5, catalyst dosage = 0.5g·L-1, H2O2 concentration = 10mmol·L-1), about 98% of TC were degraded within 90min when the initial concentration of TC was 150mg·L-1, and PFGB could perform effectively over a wide pH range of 3-6. Furthermore, PFGB exhibited the advantages of convenient magnetic separation and strong reusability, maintaining a TC removal rate of ~90% after five cycles of experiments. The results of free radical quenching experiment and electron spin resonance analysis revealed that •OH and 1O2 were the main active species in the radical and non-radical pathways, respectively. This study indicated that PFGB, a catalyst developed for heterogeneous Fenton-like systems, possessed high efficiency, stability and reusability, and could be promising for the removal of TC in wastewater and other polluted waters.

Plant performance and soil–plant carbon relationship response to different biochar types

Biochar (BC) applications in soil has positive effects on plant performance, particularly for loose soil in agricultural context. However, how biochar types affect plant performance of non-crop species and soil–plant carbon relationships is not clear. We selected five different BC types and three plant species to investigate the responses of plant performance and the soil–plant carbon relationship to BC effects. The result demonstrated that peanut shell BC led to the death of both R. tomentosa and C. edithiae, due to a reduction in nutrient uptake caused by higher soil electricity conductivity (2001.7 and 976.3 µS cm−1). However, the carbon content of S. arboricola increased by 57% in peanut shell BC-amended soil, suggesting that S. arboricola has a higher tolerance for soil salinity. Wood BC-amended soil led to better stomatal conductance (gs) and leaf area index (LAI) of both R. tomentosa and C. edithiae due to the higher water retention in the soil (22.68% and 20.79%). This illustrated that a higher amount of water retention brought by wood BC with a great amount of pore volume might be the limited factor for plant growth. The relationship between gs and LAI suggested that gs would not increase when LAI reached beyond 3. Moreover, wood and peanut shell BC caused a negative relationship between soil organic carbon and plant carbon content, suggesting that plants consume more carbon from the soil to store it in the plant. Overall, wood BC is recommended for plant growth of R. tomentosa and C. edithiae, and peanut shell BC is suggested for S. arboricola carbon storage.Graphical

Mechanistic studies on bioremediation of dye using Aeromonas veronii immobilized peanut shell biochar

Recalcitrant chemicals in the environment not only present obstacles to living organisms but also contribute to the degradation of natural resources. One contribution to environmental pollution is the discharge of synthetic dyes from the textile sector. This study investigates the combined effect of microbial cells and biochar on eliminating methyl orange (MO) dye. The immobilization of Aeromonas veronii on peanut shell biochar (APSB) was conducted to investigate its efficacy in removing MO dye from water. PSB synthesized by pyrolysis at 300 °C for 120 min showed maximum bacterial immobilization potential. The highest degradation rate of 96.19 % was achieved in APSB within 96 h using MO dye concentration of 100 mg L−1, incubation temperature of 37 °C, pH 7, and biocatalyst dosage of 1g L−1. In comparison, free cells achieved degradation rates of 72.53 % and 61.56 % for PSB. Moreover, the adsorption process was primarily controlled by PSB, with subsequent dye mineralization by A. veronii, as supported by FTIR and LC-MS studies. Moreover, this innovative approach exhibited the reusability of the biocatalyst, giving 76.23 % removal after fifth cycle, suggesting sustainable alternative in dye remediation and potential option for real-time applications.

Enhancement of hydrogen-rich gas production by acetic acid steam reforming: characterization of Ni–Co modified biochar-based catalysts

Abstract The development of cost-effective and highly efficient biochar-based catalysts is essential for the catalytic steam reforming process of bio-oil. In this study, pickling peanut shell biochar was used to prepare biochar-supported Ni/Co monometallic catalyst and biochar-supported nickel-Co bimetallic catalyst through the impregnation method. The catalytic effect of these catalysts on acetic acid (a bio-oil model compound) steam reforming was investigated. It was found that Co could enhance the dispersion of metal particles. The catalyst exhibited the best catalytic effect and significantly improved resistance to carbon deposition with a loading of 8 wt% and a Ni-to-Co ratio of 6:2. At the temperature of 600 °C and the S/C ratio of 3, the selectivity of H2 reached 84.48 %, and the conversion of acetic acid reached 95.49 %. A synergistic effect was observed between Ni and Co, leading to increased metal dispersion, enhanced reducibility, and a higher number of active centers. Co facilitates water dissociation and promotes the oxidation of C–H and mobile O, resulting in a faster decarbonization rate. The effective utilization of biochar-based catalysts and the rational utilization of bio-oil contribute to the timely achievement of carbon emission reduction targets.

Effects of peanut shell biochar and fermented cow manure on plant growth and metabolism of tomato

BackgroundThis experimental study used peanut shell biochar and fermented cow manure as the main raw materials forming a substrate for tomato plants.ResultsSubstrates were created from peanut shell biochar, fermented cow manure, slag, and vermiculite mixed in volume ratios of 6:0:1:2, 5:1:1:2, 4:2:1:2, and 3:3:1:2, respectively. Comparisons were made to a control substrate composed of peat, slag, and vermiculite in a volume ratio of 6:1:2, respectively. As the proportion of biochar in the substrate increased, the bulk density showed a downward trend while the total porosity, aeration porosity, and water holding capacity showed upward trends. As the proportion of cow manure increased, the total N, available K, Ca, and Mg in the substrate increased. Tomatoes demonstrated similar or better growth than the control at experimental substrate composition ratios of 6:0:1:2 and 5:1:1:2. This was reflected in seedling strength index, seedling growth, chlorophyll content, root growth, plant carbohydrates, purine metabolism, caffeine metabolism, galactose metabolism, and starch and sucrose metabolism. The results of this study indicate the experimental substrate composition ratios of 6:0:1:2 and 5:1:1:2 were the most beneficial in terms of supporting the growth of tomato plants.ConclusionsThe study confirms biochar in composite substrate promotes plant growth by improving the root environment and plant metabolism. This investigation provides new information to moderate the use of peat and support efforts to achieve carbon neutrality through the creative utilization of agricultural waste.Graphical abstract

Peanut shell biochar for Rhodamine B removal: Efficiency, desorption, and reusability

A high-performance and affordable peanut shell-derived biochar was employed for the efficient removal of Rhodamine B (RhB) from aqueous solutions. The properties of peanut shell biochar (PSB) were investigated through Fourier transform infrared (FTIR) spectroscopy and Brunauer–Emmett–Teller surface area measurements. The FTIR analysis revealed numerous active sites and functional groups for the binding of dye molecules, while the BET surface area was determined to be 351.11 m2g-1. Four different isotherms and kinetic models were applied to determine the equilibrium adsorption of RhB, and the results indicated that the Freundlich isotherm was the most appropriate model. A maximum dye removal rate of 94.0% occurred at a pH of 3 with an adsorbent dose of 0.325 g L−1. The prepared adsorbent showed excellent sorbent behaviour and can be reused multiple times after regeneration, with the surface area decreasing from 351.11 m2g-1 to 140.13 m2g-1 after the third cycle. The negative Gibbs free energy ΔGo at all applied temperatures suggested that spontaneous adsorption occurred and RhB adsorption on the PSB was found exothermic, as evidenced by the negative value of ΔHo. The regenerated PSB can be utilized as an efficient, environmentally friendly, and cost-effective sorbent for the removal of dyes at temperatures lower than ambient temperature, providing both technical and financial advantages for sustainable environmental management.

Efficacy of Agricultural Residue-Derived Biochar for Tackling Cadmium Contamination in an Aqueous Solution.

This study aimed to investigate the efficacy of biochar, produced from different agricultural residues varying in lignin and cellulose content and subjected to different pyrolysis temperatures, in removing cadmium ions (Cd (II)) from an aqueous solution. This removal process is crucial for protecting human health and the environment. Specifically, the study focused on the adsorption behaviors of Cd (II) by the biochars made from rice husk biochar (RHB), maize straw biochar (MSB), peanut shell biochar (PSB), cottonseed shell biochar (CHB), and mulberry leaf biochar (MLB), which were prepared at 300 °C and 600 °C. The results indicated that the type of agricultural residue used to produce biochar significantly influenced the adsorption of Cd (II). Notably, mulberry leaf biochar prepared at 300 °C (MLB-300) demonstrated the highest adsorption efficiency, achieving a maximum adsorption capacity of 42.2 mg g-1. Batch adsorption experiments assessed the impact of various factors, including system pH, NO3- concentration, and adsorption duration. The adsorption kinetics were better described by the pseudo-second-order model than the pseudo-first-order model. Moreover, the study found that the lignin content of the biochar plays a major role in determining the adsorption capacity. The surface characteristics of biochar, influenced by the types of agricultural residues and preparation temperature, directly impact its adsorption mechanism and capacity. While biochar produced at 300 °C showed optimal Cd(II) adsorption, those processed at 600 °C were less effective, likely due to the loss of functional groups at higher temperatures.

Molybdenum disulfide anchored peanut shell biochar composite for efficient adsorption of Pb2+: Performance and mechanism

Heavy metal lead (Pb2+) contamination in water poses a serious threat to human health, and developing some effective strategies for the removal of Pb2+ is urgent. Herein, molybdenum disulfide (MoS2) anchored peanut shell biochar (BC) composite adsorbents were successfully prepared by hydrothermal method and applied for the adsorption of Pb2+. Among these composites, the MoS2/BC-3 composite displayed the best adsorption performance with the adsorption capacity of 232 mg·g−1 at 30 °C. The adsorption procedure followed the pseudo-secondary kinetics and Freundlich adsorption model, indicating that the adsorption process of Pb2+ over MoS2/BC-3 composite was chemical and multilayer adsorption. Moreover, Pb2+ was spontaneously adsorbed by MoS2/BC-3, and the adsorption capacity increased with the enhance of temperature. The main mechanisms involved in the adsorption of Pb2+ by MoS2/BC-3 composite were found to include electrostatic interaction and complexation interaction. In addition, the MoS2/BC-3 composite had a good stability, and the Pb2+ removal rate could still reach more than 80 % after 6 cycles of adsorption experiments. Meanwhile, the adsorbent demonstrated a strong ability to absorb common heavy metals including copper and cadmium, further confirming that the MoS2/BC-3 composite had a potential value.

Biochar Blended with Alkaline Mineral Can Better Inhibit Lead and Cadmium Uptake and Promote the Growth of Vegetables.

Three successive vegetable pot experiments were conducted to assess the effects on the long-term immobilization of heavy metals in soil and crop yield improvement after the addition of peanut shell biochar and an alkaline mineral to an acidic soil contaminated with lead and cadmium. Compared with the CK treatment, the change rates of biomass in the edible parts of the three types of vegetables treated with B0.3, B1, B3, B9, R0.2 and B1R0.2 were -15.43%~123.30%, 35.10%~269.09%, 40.77%~929.31%, -26.08%~711.99%, 44.14%~1067.12% and 53.09%~1139.06%, respectively. The cadmium contents in the edible parts of the three vegetables treated with these six additives reduced by 2.08%~13.21%, 9.56%~24.78%, 9.96%~35.61%, 41.96%~78.42%, -4.19%~57.07% and 12.43%~65.92%, respectively, while the lead contents in the edible parts reduced by -15.70%~59.47%, 6.55%~70.75%, 3.40%~80.10%, 55.26%~89.79%, 11.05%~70.15% and 50.35%~79.25%, respectively. Due to the increases in soil pH, soil cation-exchange capacity and soil organic carbon content, the accumulation of Cd and Pb in the vegetables was most notably reduced with a high dosage of 9% peanut shell biochar alone, followed by the addition of a low dosage of 1% peanut shell biochar blended with 0.2% alkaline mineral. Therefore, the addition of a low dosage of 1% peanut shell biochar blended with 0.2% alkaline mineral was the best additive in increasing the vegetable biomass, whereas the addition of 9% peanut shell biochar alone was the worst. Evidently, the addition of 0.2% alkaline mineral can significantly reduce the amount of peanut shell needed for passivating heavy metals in soil, while it also achieves the effect of increasing the vegetable yield.

Efficient anode material derived from nutshells for bio-energy production in microbial fuel cell

Biochar is a carbonaceous solid that is prepared through thermo-chemical decomposition of biomass under an inert atmosphere. The present study compares the performance of biochar prepared from Peanut shell, coconut shell and walnut shell in dual chamber microbial fuel cell. The physicochemical and electrochemical analysis of biochar reveals that prepared biochar is macroporous, amorphous, biocompatible, and electrochemically conductive. Polarization studies show that Peanut shell biochar (PSB) exhibited a maximum power density of 165 mW/m2 followed by Coconut shell biochar (CSB) Activated Charcoal (AC) and Walnut shell biochar (WSB). Enhanced power density of PSB was attributed to its surface area and suitable pore size distribution which proved conducive for biofilm formation. Furthermore, the high electrical capacitance of PSB improved the electron transfer between microbes and anode.

Exploratory studies on the use of peanut shell biochar as a promising adsorbent for ivermectin removal from aqueous solutions: impact of biomass treatment, pyrolisis temperature and duration

The contamination of environmental matrices by chemical compounds poses a significant challenge for humanity, demanding focused attention from researchers and governments. Within aquatic environments, the emerging contaminants with potential ecotoxicological effects, even at low concentrations, have earned global interest among researchers. The persistence of these contaminants is exacerbated by specific physicochemical characteristics, hindering their natural degradation and removal through conventional water treatment methods. Biochar, a carbonaceous material produced through biomass pyrolysis at high temperatures, exhibits properties that effectively remove emerging contaminants from water. In this study, we investigated the impact of acidic biomass treatment on the removal efficiency of ivermectin from aqueous solutions. The materials were derived from untreated biomass, as well as basic and acidic-treated peanut shell (PS), subjected to pyrolysis at temperatures of 300, 400, 500, and 600 °C for 2, 3, and 4 hours. Characterization was conducted using TGA, ATR-FT-IR, SEM-EDS, and XRD. Quantification of ivermectin removal was performed using HPLC-DAD. The results showed that the removal was enhanced by temperature and time of pyrolysis, while the chemical treatments had different effects. The most effective removal tendency was observed with acidic biochar calcinated at 600 °C, demonstrating an average removal yield of 84.70%.

Management of heavy metals in rice (Oryza sativa) soils by silicon rich biochar materials

Multiple heavy metals have contaminated soils with a combination of ecological consequences that make soil remediation more challenging. An experiment was conducted during 2022–23 at University of Agriculture and Forestry, Hue University, Hue city, Vietnam to evaluate the potential of silicon rich biochar from rice (Oryza sativa L.) husk and peanut shell in the remediation of heavy metals (Cd, Pb, Cu and Zn) present in rice soils of central Vietnam. A total of 20 samples of rice soil were taken from two distinct locations, Quang Tho commune and Thuy Phuong ward, Thua Thien Hue province, Central Vietnam to measure the quantity of heavy metals and evaluate the level of pollution. Silicon is a beneficial element and its external application as fertilizer seems impractical. Therefore, in this study, the effects of different silicon-rich materials [rice husk biochar (RHB) and peanut shell biochar (PSB)] at 6 different rates (0, 1, 2, 3, 4 and 5%) were determined in reducing heavy metal (Cd and Pb). The mean concentrations of Cd, Pb, Cu and Zn in soil samples ranged between 0.56–22.14 mg/kg; 19.48–81.30 mg/kg; 23.26–48.54 mg/kg and 28.47–55.12 mg/kg, respectively. Cd and Pb toxicity in rice soil samples was greater in Thuy Phuong ward than the average shale values. Considering the pollution load index (PLI), a total of 6 sites in Thuy Phuong ward had values >1.0 indicating pollution load in the respective sites, and Cd, Pb were the major contaminants in soils of the study area. The addition of silicon-rich materials decreased the contents of Cd and Pb in rice soils with adsorption efficiency from 22.83–38.54% and 30.69–31.53% in rice husk biochar (RHB); 20.47–29.55% and 26.77–27.87% in peanut shell biochar (PSB), respectively. Thus, RHB could be more effective to remediate soils contaminated with heavy metals when compared to other silicon-rich materials.

Effect of Silicon based Fertilizer and Biochar from Crop Residues on Dry Matter Accumulation and Si Uptake by Rice Crop in Central Vietnam

Background: Silicon (Si) has been considered a beneficial element for many plants. Si-rich biochar (Sichars) from rice husk or peanut shell have been suggested to be a potential source of bioavailable Si for Si-accumulator plants. Our study aimed to assess the Si-fertilization efficiency from chemical fertilizer and rice husk and peanut shell biochars on rice dry matter and shoot Si uptake. Methods: Pot trials were conducted in two crop seasons in 2023 (from February to April - spring season and from May to July- summer season) in the close net house. Treatments included 1 treatment with pure soil (control), 4 treatments with Si and N–P–K fertilizers and 6 treatments with biochar amendments and N-P–K fertilizers. These pot experiments were designed in the randomized complete block (RCBD) with 4 replications. Result: Shoot dry matter increased from 35.6 to 66.7% compared with control in different rates of Si fertilizer application and was also found the highest values in RHB and PSB at 15 g/kg soil application. Different Si and biochar application rates had a significant effect (P less than 0.05) on Si uptake by rice shoot. Therefore, Si-rich biochar considers as potential material for providing available Si to maintain the required level of available Si in soil and plant for healthy and high crop production.

Biochar loaded with root exudates of hyperaccumulator Leersia hexandra Swartz facilitated Cr(VI) reduction by shaping soil functional microbial communities

Cr(VI) contamination is widely recognized as one of the major environmental hazards. To address the problem of remediation of soil Cr(VI) contamination and utilization of waste peanut shells, this study comprehensively investigated the effects of peanut shell-derived biochar loaded with root exudates of hyperaccumulator Leersia hexandra Swartz on Cr(VI) reduction and microbial community succession in soil. This study confirmed that root exudate-loaded peanut shell biochar reduced soil pH while simultaneously increasing DOC, sulfide, and Fe(II) concentrations, thereby facilitating the reduction of Cr(VI), achieving a reduction efficiency of 81.8%. Based on XPS and SEM elemental mapping analyses, Cr(VI) reduction occurred concurrently with the Fe and S redox cycles. Furthermore, the microbial diversity, abundance of the functional genera (Geobacter, Arthrobacter, and Desulfococcus) and the metabolic functions associated with Cr(VI) reduction were enhanced by root exudate-loaded biochar. Root exudate-loaded biochar can promote both direct Cr(VI) reduction mediated by the Cr(VI)-reducing bacteria Arthrobacter, and indirect Cr(VI) reduction through Cr/S/Fe co-transformation mediated by the sulfate-reducing bacteria Desulfococcus and Fe(III)-reducing bacteria Geobacter. This study demonstrates the effectiveness of peanut shell biochar loaded with root exudates of hyperaccumulator Leersia hexandra Swartz to promote soil Cr(VI) reduction, reveals the mechanism how root exudate-loaded biochar shapes functional microbial communities to facilitate Cr(VI) reduction, and proposes a viable strategy for Cr(VI) remediation and utilization of peanut shell.

Remediation of neonicotinoid-contaminated soils using peanut shell biochar and composted chicken manure: Transformation mechanisms of geochemical fractions

Soil remediation techniques are promising approaches to relieve the adverse environmental impacts in soils caused by neonicotinoids application. This study systematically investigated the remediation mechanisms for peanut shell biochar (PSB) and composted chicken manure (CCM) on neonicotinoid-contaminated soils from the perspective of transformation of geochemical fractions by combining a 3-step sequential extraction procedure and non-steady state model. The neonicotinoid geochemical fractions were divided into labile, moderate-adsorbed, stable-adsorbed, bound, and degradable fractions. The PSB and CCM addition stimulated the neonicotinoid transformation in soils from labile fraction to moderate-adsorbed and stable-adsorbed fractions. Compared with unamended soils, the labile fractions decreased from 47.6% ± 11.8% of the initial concentrations to 12.1 ± 9.3% in PSB-amended soils, and 7.1 ± 4.9% in PSB and CCM-amended soils, while the proportions of moderate-adsorbed and stable-adsorbed fractions correspondingly increased by 1.8–2.4 times and 2.3–4.8 times, respectively. A small proportion (<4.8%) in bound fractions suggested there were rather limited bound-residues after 48 days incubation. The PSB stimulated the -NO2-containing neonicotinoid-degraders, which promoted the degradable fractions of corresponding neonicotinoids by 8.2 ± 6.3%. Degradable fraction of neonicotinoids was the dominant fate in soils, which accounted for 58.3 ± 16.7%. The findings made beneficial theoretical supplements and provided valuable empirical evidence for the remediation of neonicotinoid-contaminated soils.

Three-year field study on grass growth and soil hydrological properties in biochar-amended soil

Field monitoring was conducted to investigate and quantify the long-term effects of peanut shell biochar on soil-grass interaction over three years. Three 10 m × 5 m grassed plots were constructed in completely decomposed granitic soil. Two of them were amended, respectively, with 5% and 10% biochar contents (m3/m3) for grass growth, while the third was without biochar amendment. During the three-year monitoring, plant characteristics, saturated water permeability (ks) of grassed soil and soil suction were measured. The monitored results show that the grass leaf area index (LAI) and root length density (RLD) with biochar amendment were improved by 38% and 200%, respectively. In the grassed plot without biochar, a threshold RLD existed with a value of 1.7 cm/cm3, beyond which ks raised pronouncedly. The threshold RLD increased by 52% when biochar content increased from 0% to 10%. This implies that biochar may restrict the increase in ks of grassed soil due to the rise in the threshold RLD. The presence of biochar and grass can retain over 100% higher suction after heavy rainfalls, while 54% lower peak suction under evapotranspiration (ET) compared with the non-amended plot. Biochar can alleviate the negative effects on hydraulic properties caused by plant growth and reduce ET-induced excessive water loss. A 5% peanut shell biochar content is recommended for the long-term management of vegetated earthen infrastructures.

Unraveling the role of alkali metal in the biochar for enhancing the chemical looping ammonia generation efficiency

Chemical looping ammonia generation (CLAG), efficiently converting C-based material, N2 and H2O into NH3 and CO, is considered to be one of the promising NH3 production technologies. Using biochar as the C-based material is supposed to further improve the “green” level of NH3 but there is rare report about that. This paper was desired to fill this gap. Peanut shell biochar, lotus shell biochar and corncob biochar were used to study the chemical looping ammonia generation performances of the N-support. It was found that metals contained in the biochar significantly affected the nitridation process; alkali metals were simulative while alkaline-earth metals were inhibitory, which indicated that the corncob biochar exhibit the best nitriding properties. In addition, K, with the best positive effect for nitridation, was found to be with negligible negative effect for ammoniation. Furthermore, the carbon conversion efficiency and NH3 production could be still improved by 8.46 % and 9.23 % if the corncob biochar was modified with 2 wt% K (simulating 120 cycles of nitridation/ammoniation reaction). The obtained results indicated that the biochar is a promising carbon source for CLAG.