Specific Surface Area Of Biochar Research Articles

Utilization of Charcoal Obtained from Woody Biomass in Metallurgical Processes Based on Solid–Gas Reactions

The high demand for carbon-based products within pyrometallurgy is placing the industry in an increasingly challenging position to meet stringent requirements. To transition away from fossil carbon carriers, biochar emerges as a sustainable and CO2-neutral alternative, presenting a viable solution without necessitating fundamental adjustments to plant technology, unlike hydrogen as an alternative reducing agent. Prior investigations have underscored the potential of woody biomass pyrolysis products for CO2-neutral metallurgy. Nonetheless, it is imperative to recognize that biochar must meet distinct requirements across various metallurgical processes. This paper conducts a comparative analysis between biochar and petroleum coke using thermogravimetric analyses, surface measurements, reactivity assessments, and scanning electron microscopy. Furthermore, the performance in a furnace for simulating the Waelz process, specifically regarding ZnO reduction, is scrutinized. The results illustrate the optical differences between petroleum coke and biochar and the significantly higher reactivity and specific surface area of biochar. When used in solid–gas reactors, it is observed that due to its high reactivity, biochar reacts more vigorously and carbon is completely consumed. However, during the reduction of ZnO, only minor differences were monitored, making biochar comparable to petroleum coke. Therefore, under certain constraints, biochar can be considered a potential substitute for metallurgical solid–gas reactions.

Novel enhanced defluorination of perfluorooctanoic acids by biochar-assisted ultrasound coupling ferrate: Performance and mechanism

An ultrasound (US)/biochar (BC)/ferrate (Fe (VI)) system was firstly proposed to enhance perfluorooctanoic acid (PFOA) defluorination. It achieved 93 % defluorination optimally, higher than the sum of 77 % (28 % and 49 % for US/BC and US/Fe (VI) respectively), implying synergistic effect. Besides, the mechanism study confirmed that, this system can not only increase the specific surface area of BC and the generation of reactive oxidant species (ROS), enriching the active sites and forming new oxygen-containing functional groups, but also promote the formation of intermediate iron species. The PFOA degradation in the US/BC/Fe (VI) was probably an adsorption-degradation process, both ROS and electron transfer promoted the defluorination. Additionally, its sustainability was also demonstrated with 14 % reduced defluorination percentage after five cycles of BC. Overall, the synergistic effect of the US/BC/Fe (VI) and its enhancing mechanism for PFOA defluorination were clarified firstly, which contributes to the development of biochar for assisting polyfluoroalkyl substances degradation.

Influence of microplastics and environmentally persistent free radicals on the ability of biochar components to promote degradation of antibiotics by activated peroxymonosulfate

Microplastics (MPs) in sludge can affect the ability of biochar-activated peroxymonosulfate (PMS) to degrade antibiotics. In this work, biochar was prepared by mixing sludge and polystyrene (PS) through hydrothermal carbonization (HTC) and high-temperature pyrolysis processes. The resulting biochar was used to activate PMS to degrade ofloxacin (OFX), levofloxacin (LEV), and pefloxacin (PFX). The addition of PS significantly enhanced the ability of biochar/PMS to degrade antibiotics and the levels of environmentally persistent free radicals (EPFRs, 4.59 × 1020 spin/g) due to the decomposition of PS. The addition of PS resulted in a slight decrease in the specific surface area of biochar (2–3 m2/g on average), but a significant increase in the concentration of EPFRs increased the removal efficiency. The activation of PMS by biochar is dominated by free radicals, accounting for about 70%, in which SO4•- and •OH contribute the most and O2•- the least. However, 1O2 contributes 15–20% to the degradation of antibiotics in non-free radical processes. Overall, the process of biochar/PMS degradation of antibiotics is mainly dominated by free radicals, and the effect of non-free radicals is not obvious. Both hydrochar and pyrocarbon samples showed good hydrophilicity, and this property should improve the ability of active sites on biochar to degrade antibiotics. In the HTC process, PS can decompose during hydrochar preparation, with a maximum reduction value of 40.09%. The three-dimension excitation emission matrix fluorescence spectroscopy (3D-EEM) and total organic carbon (TOC) results show that the protein content in sludge plays a major role in reducing PS, with little effect of polysaccharide and SiO2. There are six to seven degradation intermediates of quinolone antibiotics, which are eventually degraded into CO2, H2O, and inorganic substances. The regeneration experiment showed good reusability of hydrochar and pyrocarbon, further demonstrating the suitability of biochar for the degradation of antibiotics.

High-performance biochar from Chlorella pyrenoidosa algal biomass for heavy metals removal in wastewater

In this research, a highly porous sodium bicarbonate modified biochar was produced by the fast pyrolysis of Chlorella pyrenoidosa biomass. The biochar without modification showed non-porous material characteristics based on the results of N2 isotherm adsorption–desorption. The modification with sodium bicarbonate successfully enhanced the BET specific surface area of biochar up to 1282 m2/g at a temperature of 750 °C, with microporous surface area of 871 m2/g and external surface area of 411 m2/g. XRD characterization showed broad peak around 24° which indicates amorphous carbon structure that is favorable for adsorption purposes. FTIR characterization after pyrolysis showed an important functional group that should enhance the adsorption process. Following that, a batch adsorption technique of lead synthetic wastewater is used to conduct more tests on its performance. The maximum adsorption capacity of lead (Pb) based on Langmuir model of modified biochar (qmax) is 159.071 ± 23.4008 mg/g. The heterogeneity factor (hf) based on Freundlich model is 0.4671 ± 0.06394, which mainly indicates the physical adsorption. The separation factor (RL) is nearly zero, indicating irreversible nature. The pseudo second order kinetic model showed that the rate of adsorption (k2) for modified biochar is 0.00931 ± 0.00222 g.mg−1 min−1. Overall, the results demonstrated that in terms of technological feasibility, modified biochar from Chlorella pyrenoidosa met the standards of commercial activated carbon, either based on characterization data or performance results.

Charge Storage and Magnetic Properties Nitrogen-Containing Nanoporous Bio-Carbon

This article presents the technology for the preparation of a nitrogen-containing nanoporous bio-carbon and investigates its properties. It has been shown that the synthesised bio-carbon is characterised by a high degree of homogeneity, which has been confirmed by energy dispersive spectroscopy. The obtained bio-carbon has a micromesoporous structure, which has been confirmed by the results of studies using the method of low-temperature nitrogen adsorption and desorption. It was found that the specific surface area of biochar is 1247 m2/g. The data on nitrogen adsorption and desorption were compared with the data on small-angle X-ray scattering, and it was found that the micropores in the synthesised bio-carbon are open pores, while mesopores remain closed. The energy dispersion analysis showed that the structure of the bio-carbon does not contain ferromagnetic atoms, but due to the addition of nitrogen, the synthesised bio-carbon in a magnetic field has the properties of a ferromagnet with a characteristic hysteresis of the specific magnetisation. It was found that this material has a saturation magnetisation σs of 1.4 A∙m2∙kg−1 and a coercive force Hc of 10 kA/m. Symmetric supercapacitors were fabricated from the synthesised bio-carbon material with 30% aqueous KOH and 1 M Na2SO4 as electrolytes. It was found that for bio-carbon synthesised at 800 °C, the specific capacitance in a 30% aqueous solution of KOH is 180 F/g, and in a 1 M aqueous solution of Na2SO4, it is 124 F/g. The cyclic voltammetry of the fabricated supercapacitors at different rates of potential expansion was investigated and analysed. Impedance studies on these supercapacitors were carried out. The equivalent electrical circuits describing the electrochemical processes in the studied supercapacitors were constructed and characterised.

Prediction of Biochar Yield and Specific Surface Area Based on Integrated Learning Algorithm

Biochar is a biomaterial obtained by pyrolysis with high porosity and high specific surface area (SSA), which is widely used in several fields. The yield of biochar has an important effect on production cost and utilization efficiency, while SSA plays a key role in adsorption, catalysis, and pollutant removal. The preparation of biochar materials with better SSA is currently one of the frontiers in this research field. However, traditional methods are time consuming and laborious, so this paper developed a machine learning model to predict and study the properties of biochar efficiently for engineering through cross-validation and hyper parameter tuning. This paper used 622 data samples to predict the yield and SSA of biochar and selected eXtreme Gradient Boosting (XGBoost) as the model due to its excellent performance in terms of performance (yield correlation coefficient R2 = 0.79 and SSA correlation coefficient R2 = 0.92) and analyzed it using Shapley Additive Explanation. Using the Pearson correlation coefficient matrix revealed the correlations between the input parameters and the biochar yield and SSA. Results showed the important features affecting biochar yield were temperature and biomass feedstock, while the important features affecting SSA were ash and retention time. The XGBoost model developed provides new application scenarios and ideas for predicting biochar yield and SSA in response to the characteristic input parameters of biochar.

Improvement of the specific surface area of biochar by calcium-precipitated nanoparticles synthesized by microbial induction as a template skeleton: Removal mechanism of tetracycline in water

The template method is an effective means to improve the specific surface area and porosity of biochar, but the synthesis of template agents and the way they are integrated with biomass materials still need further development. Therefore, the free Pseudomonas sp. Y1 was used to synthesize calcium-precipitated nanoparticles (CPN) on sludge as a fused template skeleton to enlarge the surface area of sludge biochar facilitating the adsorption of tetracycline (TC) in this work. The modified biochar (FBC) showed excellent specific surface area (448.55 m2 g−1) and porosity (0.0053 cm³ g−1), stable morphological structure, abundant active functional groups, and appreciable adsorption capacity (65.43 mg g−1) based on several characterization and adsorption experiments. Moreover, the adsorption model postulated that the removal of TC is mainly a chemisorption-based heat-trapping, disordered multilayer interaction. In detail, this process involved the joint contribution from electrostatic interactions, ligand exchange, hydrogen bonding, π-π bonding, complexation, and pore filling. Meanwhile, the adaptability and stability of FBC were examined by pH and coexisting substances. This template skeleton induced by microorganisms can provide new insight into the modification of biochar with the template method.

Research on the Effect of Coordinated Remediation of Heavy Metal Pollution in Roadbed Slope Soil by Combining Biochar with Reed

This study investigated the effect of modified activated carbon combined with plants on the coordinated restoration of heavy metal pollution in roadbed slope soil. This study used wheat husks as raw materials, potassium hydroxide and permanganate as modifiers, and aquatic plant reeds to remediate heavy metals in roadbed slope soil. The adsorption amount and removal rate of heavy metals Cu, Pb, and Cr were investigated under adsorbent dosage, adsorbent physical structure parameters, different pH environments, and ternary composite heavy metal body experimental conditions. According to the experimental results, after activation, the total pore volume and total specific surface area of biochar increased significantly, 21.4 and 111.7 times those before activation, respectively. The order of removal rates of heavy metal ions by different adsorbents was Pb > Cr > Cu. When the adsorbent was biochar–reed joint remediation, the maximum adsorption capacity of Cu, Pb, and Cr was 31.25, 136, and 52.3 mg/g. The adsorption capacities of the two adsorbents (biochar and biochar–reed) for Pb were the highest, and the adsorption sensitivity of the adsorbents for Pb was higher than that for Cr and Cu. Under single-component conditions, the adsorption capacity of biochar to heavy metals Cu, Pb, and Cr was ranked as Pb > Cu > Cr. In a ternary solution system, the adsorption capacity of biochar to heavy metals Cu, Pb, and Cr was ranked as Cu > Cr > Pb. Considering the adsorption capacity and removal rate of nutrient-rich substances, as well as the cost and effect of the use of the adsorbent, the recommended amount of the adsorbent was 4–6 g.

Degradation of 2,4-DCP by immobilized laccase on modified biochar carrier.

Rape straw was used as the raw material for the biochar in this study, which was then changed using acid, alkali, and magnetic techniques. The laccase was attached using the adsorptions-crosslinking process, and the three modified biochars served as the carriers. The ideal circumstances for laccase immobilization were explored, and both biochar and immobilized laccase's characteristics were examined. The removal of 2,4-dichlorophenol (2,4-DCP) by immobilized laccase from modified biochar and its degradation products were researched. The main conclusions are as follows: the optimal concentration of glutaraldehyde (GLU) was 4%, and the pH was four, and the enzyme dosage was 1.75mg/mL for the immobilized laccase of acid-modified biochar (SBC@LAC). The optimal concentration of GLU was 5%; the pH was four, and the enzyme dosage was 2mg/mL for immobilized laccase from alkali-modified biochar (JBC@LAC). The optimal concentration of GLU was 5%; the pH was four, and the enzyme dosage was 1.75mg/mL for immobilized laccase from magnetically modified biochar (CBC@LAC). SEM images could show the changes in the surface morphology of biochar caused by three modification methods. The BET results demonstrated that acid and magnetic modification increased the specific surface area of biochar, and alkali modification mainly expanded the pore size of biochar. FT-IR and XRD showed that modification and laccase loading had little effect on the structure of biochar. The stability of immobilized laccase was better than that of free laccase in acid-base, heat, and storage. Among the three modified biochar immobilized laccases, JBC@LAC showed the best acid-base stability and thermal stability, and the relative enzyme activity changed the least when pH and temperature conditions changed. The storage stability of SBC@LAC is the best. After 30days of storage, the relative enzyme activity is still 83%. The removal rates of 2,4-DCP were 57, 99, and 63%, respectively, by SBC@LAC, JBC@LAC, and CBC@LAC. After five reuses, the removal rates of 2,4-DCP by SBC@LAC, JBC@LAC and CBC@LAC were 26, 42, and 27%, respectively. The intermediate products of 2,4-DCP degradation by immobilized laccase were p-phenol, p-benzoquinone and maleic acid.

Engineering sulfuric acid-pretreated biochar supporting MnO2 for efficient toxic organic pollutants removal from aqueous solution in a wide pH range

Manganese dioxides (MnO2) and biochar materials are both desirable candidates for environmental remediation of toxic organic pollutants (TOPs) in water due to wide availability and environmental-friendly. In practical application, however, MnO2 suffers from low redox activity owing to deprotonation, while biochar is subject to limited removal capacity. Herein, a difunctional engineering sulfuric acid-pretreated biochar supporting MnO2 composite (MBC-A) was firstly synthesized and optimized to remove various TOPs from aqueous solution. Specifically, sulfuric acid not only served as an active agent to improve the specific surface area of biochar for improvement of adsorption capacity and more MnO2 loading, but also facilitated the introduction of sulfonic acid groups (-SO3H) as an internal proton reservoir to inhibit inactivation of MnO2 due to deprotonation in alkaline. Thanks to adsorption and oxidation, MBC-A showed excellent removal capacity (214.9 mg/g) and fast reaction kinetics (360 min) for tetracycline (TC), exceeding precursor and other materials reported in literature. Importantly, the effective operation pH range of MBC-A was broadened to 1–13 with the help of buffering capacity of –SO3H groups. The dominant driving force of adsorption were π-π interaction and hydrogen bond; while reactive oxidative species were mainly ascribed to singlet oxygen (1O2), hydroxyl radical (·OH) and reactive Mn3+. The possible reactive sites and pathway were investigated by combining experimental results with density functional theory (DFT) calculation. Further, the results of multiple cyclic runs, removal in real river water and toxicity assessment demonstrated well reusability, high environmental security, and excellent practical applicability of MBC-A.

A review of emerged constructed wetlands based on biochar filler: Wastewater purification and carbon sequestration/greenhouse gas reduction

Constructed wetlands (CWs) are a promising ecological wastewater treatment technology. The method of biochar (BC) filler to enhance CWs has been widely researched in the past decade. This article summarizes the applications of BC-added CWs technology and consolidates the various impacts of BC filler on the operation of CWs, which can be divided into two aspects. One is to enhance the wastewater purification performance of CWs ecosystems, and the other is to improve the abilities of CWs to sequester carbon and reduce greenhouse gas (GHG) emissions. These two aspects are precisely among the environmental challenges facing humanity globally. The BC prepared from CWs plants used as CWs filler can solve excess biomass in CWs. Moreover, the large specific surface area of BC, excellent adsorption performance, and good biocompatibility improve the sewage treatment effect of CWs. The BC has a high potential for stimulating the growth of CWs plants, biomass carbon sequestration, inhibition of organic carbon mineralization in CWs substrates, and reducing GHG emissions, which mitigates global climate change. In short, the BC-added CWs is a technology that combines wastewater purification and carbon sequestration/GHG reduction. This study provides solid references for the engineering promotion of CWs based on BC filler.

Nitrogen-rich porous biochar for highly efficient adsorption of perchlorate: Influencing factors and mechanism

Nitrogen-rich porous biochar is produced by direct pyrolysis, combined with K2CO3 or ZnO activation using soybean residue as raw material, their adsorption performance and mechanism for perchlorate are investigated. The results show that the activation process significantly enhances the biochar's adsorption capacity for perchlorate, the saturated adsorption capacities of BK800 and BZ600 increase by 9 and 15 times, respectively. The adsorption process adheres to the Langmuir isotherm model and pseudo-second-order kinetic model, indicating predominant monolayer and chemical adsorption. Pore filling, hydrogen bond and electrostatic interactions play key roles in the adsorption of perchlorate on biochar. The adsorption performance of K2CO3-activated biochar improves with increasing pyrolysis temperature, attributed to the expansion of the biochar's specific surface area (BK800, 1371.7 m2 g−1). Conversely, ZnO-activated biochar exhibits high adsorption performance due to its mesoporous channels and abundant N, O-functional groups (BZ600: 1.86 % N content), despite having a lower specific surface area. Density functional theory (DFT) calculations determine the adsorption energies of perchlorate on various functional groups of biochar, with pyrrole N exhibiting the highest interaction, followed by -OH, -COOH, graphite N, and pyridine N. Acidic conditions promote stronger electrostatic attraction in the functional groups of biochar. Therefore, the adsorption performance of biochar to perchlorate can be improved by targeted modification of its micropore structure, O-functional groups and pyrrole N structures.

Effective Removal of Ammonium from Aqueous Solution by Ball-Milled Biochar Modified with NaOH

The objective of this study was to investigate the feasibility of using modified biochars to enhance removal of ammonium from aqueous solution. The pristine, NaOH-modified, ball-milled, and NaOH-modified ball-milled biochars were prepared from wheat straw at 500 °C. The surface morphology and characteristics of biochar were obviously changed after modification. The NaOH-modification elevated the pH value and ash content of biochar, and the ball-milling treatment promoted the formation of oxygen-containing functional groups. The specific surface area of biochar (20.9 m2/g) increased to 51.4 m2/g and 145.6 m2/g after NaOH-modification and ball-milling treatment, respectively. The modified biochars showed considerable ammonium sorption capacity in a wide pH range (3–7), and the optimal pH of ammonium sorption was around 6. Both NaOH-modification and ball-milling treatment improved ammonium sorption on the biochars. Ammonium sorption of the biochars could be well fitted by the Langmuir and pseudo-second-order model, and the NaOH-modified ball-milled biochar showed the highest ammonium sorption capacity of 8.93 mg g−1. The surface complexation with oxygen-containing functional groups and cation exchange were the dominant mechanisms of ammonium sorption on the biochars. These results indicate that NaOH-modified/ball-milled biochar has a good potential to be used for the ammonium removal from polluted water.

Machine learning models for the prediction of total yield and specific surface area of biochar derived from agricultural biomass by pyrolysis

Machine learning models for the prediction of total yield and specific surface area of biochar derived from agricultural biomass by pyrolysis

The adsorption mechanism of sludge-based biochar toward highly concentrated organic membrane concentrates from landfill leachate.

In this study, the sludge-based biochar (BC) was prepared by dewatered sludge from a membrane bioreactor to treat the membrane concentrate. Then, the adsorbed and saturated BC was regenerated (RBC) by pyrolysis and deashing treatment to further treat the membrane concentrate. Afterward, the composition of membrane concentrate before and after BC or RBC treatment was detected, and the biochars' surface characteristics were characterized. The results showed that RBC outperformed BC in the abatement of chemical oxygen demand (CODCr), ammonia nitrogen (NH3-N), and total nitrogen (TN), with their removal rates of 60.07%, 51.55%, and 66.00%, respectively, an improvement of 9.49%, 9.00% and 16.50% of the removal rate compare to BC. The specific surface area of BC and RBC was about 109 times as much as the original dewatered sludge, and the pore size of BC and RBC belonged to mesopore which was a benefit for removing small and mediate size pollutants. The increase of the oxygen-containing functional group in RBC and the ash abatement contributed much to the improvement of RBC adsorption performance. In addition, cost analysis showed that BC+RBC had a cost of 0.76$/kg for COD removal, which was a lower cost than other common membrane concentrate treatment technologies.

Experimental and simulation study of peanut shell-derived activated carbon and syngas production via integrated pyrolysis-gasification technique

Carbonaceous materials are among the most appropriate and widely used materials in the field of energy production, conversion, and storage. According to recent studies, biochar-based catalytic supports and adsorbents have shown great potential in the fields of energy production and the adsorption and storage of various gases due to their adjustable surface chemistry and porosity. In the present study, the pyrolysis of peanut shell to produce activated carbon as a precursor for catalyst support was investigated. Acid washing pretreatment was performed on raw biomass before pyrolysis to remove metals and impurities and reduce the ash content of the biomass. Before pyrolysis, thermogravimetric analysis was performed to determine the temperature range of biomass thermal decomposition. Pyrolysis was carried out at temperatures of 300, 400, and 500 °C to study the effect of pyrolysis temperature on biochar yield. KOH-activation on biochar was followed by subsequent pyrolysis at 650 °C to produce activated carbon. To study the effect of pyrolysis temperature and KOH activation on the structural and physiochemical characteristics of biochar, nitrogen adsorption/desorption and FTIR analyses were conducted. The pore size of the activated carbon surface changed from mesoporous to microporous with increasing the pyrolysis temperature and subsequent KOH activation, and the biochar specific surface area increased from 3.5 to 363.1 m2 g-1. In order to evaluate and optimize the operating conditions of the biochar and syngas production processes on larger scales, the integrated pyrolysis and gasification processes were simulated in Aspen Plus software. The effects of temperature, pressure, and air to biomass ratio on biochar production rate and H2/CO ratio were evaluated. A temperature of 650 °C, a pressure of 1 bar and an air to biomass ratio of 0.1 were selected as optimum operating conditions to simultaneously achieve maximum biochar production and maintain the quality of synthetic gas. The findings of the experimental and simulation sections of this study could provide a useful guide for the industrial-scale production of biochar and activated carbon as a catalytic support in various chemical production processes, as well as a water polutant adsorbent and gas adsorbent for various gas purification and storage processes.

The impact of heating rate on the decomposition kinetics and product distribution of algal waste pyrolysis with in-situ weight measurement

Converting algal biomass to clean energy via a thermochemical pathway is an emerging technique for tackling environment and energy issues. Traditional kinetic studies on biomass pyrolysis employ a thermogravimetric analyzer (TGA) which heats the biomass sample at a rate of 0 ∼ 2 K s−1, so TGA could only replicate the thermal behavior of the biomass sample in a fixed bed reactor. However, biomass samples can be heated at a rate over ∼102 K s−1 in industrial reactors, including fluidized beds, spouted beds, or rotary kilns due to the direct contact between biomass samples and the solid heat carriers, thus TGA is incapable to reproduce these thermal behaviors. In view of the limitation of TGA in fast heating cases, this study has developed a fast-heating thermo-balance consisting of wire-mesh and wireless power supply technique to investigate the kinetics of fast pyrolysis. Seaweed is fast-growing and can be considered a promising feedstock for biofuel production. Therefore, this study selected seaweed as representative biomass waste and compared the pyrolysis behaviors under both slow and fast pyrolysis conditions. A key finding was the TGA-derived kinetic parameters were unable to describe the pyrolysis rate under fast pyrolysis conditions with significant overestimation. When compared to slow pyrolysis, fast pyrolysis can increase bio-oil yield by about 3–17%, but the N- and S-containing compounds in the bio-oil increase by about 1.1% and 0.15% respectively at a final temperature of 700 °C. Fast pyrolysis produced about 16–53% more CO2 than slow pyrolysis above a final temperature of 500 °C. The polarity of compounds in biochar was reduced with increasing temperature and the presence of CaO was only found in biochar at a high temperature of 700 °C. The specific surface area of biochar was higher under fast heating pyrolysis (5.534–7.469 m2 g−1) than that under slow heating pyrolysis (4.076–6.414 m2 g−1).

Effect of biochars with different particle sizes on fates of antibiotics and antibiotic resistance genes during composting of swine manure

The impact of biochars with large particle sizes (LPB, 5–10 mm) and small particle sizes (SPB, <0.074 mm) on fates of antibiotics and antibiotic resistance genes (ARGs) during composting of swine manure with maize straw was explored. The results showed that antibiotics removal efficiencies were 40 %, 50 %, and 76 % for control treatment, control with LPB treatment, and control with SPB treatment after composting, respectively. The introduction of SPB reduced the total ARGs and mobile genetic elements (MGEs) levels by 28 % and 19 % after composting, respectively. The Mantel test results showed that organic matter, moisture content, and NH4+-N contributed the most to changes in antibiotics and ARGs. The significant effects of biochar specific surface area and antibiotics on MGEs further regulated the behavior of ARGs. Therefore, composting with SPB is more conducive to the removal of antibiotics and ARGs during composting of swine manure.

Screening of Rhizosphere Microbes of Salt-Tolerant Plants and Developed Composite Materials of Biochar Micro-Coated Soil Beneficial Microorganisms

To develop composite materials of biochar micro-coated soil beneficial microorganisms, soil samples were collected from the saline-alkali land of the Penghu in Taiwan. After isolation, purification and identification, a total of one Bacillus amyloliquefaciens and two Bacillus megaterium were identified as the source of beneficial microorganisms. The agricultural waste is collected and initially crushed, and then made into biochar through a series of thermal cracking processes. The specific surface area of biochar is more than 100 m2/g, the fixed carbon is more than 80%, the proportion of medium and large pores is more than 30%, the pH after adjustment is 7.3 ± 0.2, and the pore size of beneficial microorganisms grows inward, which is one of the beneficial microorganisms. The biochar micro-coated soil-beneficial microorganism composite material developed in this experiment can indeed help crops to overcome the stress of salt damage to a certain extent, and Bacillus amyloliquefaciens can indeed promote plant growth and help crops effects of over-salting adversity.

Machine learning predicting and engineering the yield, N content, and specific surface area of biochar derived from pyrolysis of biomass

Biochar produced from pyrolysis of biomass has been developed as a platform carbonaceous material that can be used in various applications. The specific surface area (SSA) and functionalities such as N-containing functional groups of biochar are the most significant properties determining the application performance of biochar as a carbon material in various areas, such as removal of pollutants, adsorption of CO2 and H2, catalysis, and energy storage. Producing biochar with preferable SSA and N functional groups is among the frontiers to engineer biochar materials. This study attempted to build machine learning models to predict and optimize specific surface area of biochar (SSA-char), N content of biochar (N-char), and yield of biochar (Yield-char) individually or simultaneously, by using elemental, proximate, and biochemical compositions of biomass and pyrolysis conditions as input variables. The predictions of Yield-char, N-char, and SSA-char were compared by using random forest (RF) and gradient boosting regression (GBR) models. GBR outperformed RF for most predictions. When input parameters included elemental and proximate compositions as well as pyrolysis conditions, the test R2 values for the single-target and multi-target GBR models were 0.90–0.95 except for the two-target prediction of Yield-char and SSA-char which had a test R2 of 0.84 and the three-target prediction model which had a test R2 of 0.81. As indicated by the Pearson correlation coefficient between variables and the feature importance of these GBR models, the top influencing factors toward predicting three targets were specified as follows: pyrolysis temperature, residence time, and fixed carbon for Yield-char; N and ash for N-char; ash and pyrolysis temperature for SSA-char. The effects of these parameters on three targets were different, but the trade-offs of these three were balanced during multi-target ML prediction and optimization. The optimum solutions were then experimentally verified, which opens a new way for designing smart biochar with target properties and oriented application potential.Graphical