Surface Area Of Biochar Research Articles

Surface areas and adsorption energies of biochars estimated from nitrogen and water vapour adsorption isotherms

Nitrogen adsorption isotherms, along with the BET model for interpretation, are recommended for estimating biochar surface area. The frequently measured small surface areas of biochars contrast with their high sorption and cation exchange capacities. We hypothesised that water adsorption provides a better tool for estimating the surface area of biochars. Although adsorption energy also appears to be a valuable surface characteristic, there is a lack of studies on this subject. We studied the surface areas and adsorption energies of three waste deposits – peat, willow dust and biochar prepared from these materials at different temperatures – using nitrogen and water vapour adsorption isotherms. The BET model accurately described all water vapour adsorption isotherms but failed for some nitrogen isotherms. Alternative methods for estimating surface areas and adsorption energies were proposed in cases where the BET model did not apply. Nitrogen adsorption was typically much lower than water vapour adsorption, and the estimated surface areas reflected this. However, nitrogen adsorption energies were significantly higher. Nitrogen surface areas increased with pyrolysis temperature, while water vapour surface areas decreased. The surface area estimated from nitrogen adsorption was generally much lower than needed to accommodate the surface-charged groups responsible for the cation exchange capacity of biochars.

Waste napkin biochar with high-performance designed for antibiotic rapidly removal

In this work, domestic refuse waste napkin (WN) was used as raw material, modified by different dyes and prepared to N-doped biochars via carbonation and activation methods. The results showed that the addition of dyes not only optimized the physicochemical properties of biochars, but also greatly improved the adsorption performances. The specific surface areas of N-doped biochars (BWN-CR, BWN-CV, and BWN-MO) were increased by 5.95–26.6 % compared with that of undoped biochar (BWN, 2173.13 m2/g), similarly, the content of nitrogen atoms in the modified biochars increased by 0.50–2.03 times. In the adsorption experiments using tetracycline hydrochloride as adsorption model, the adsorption capacities of all N-doped biochars (938.71–1159.05 mg/g) were greater than that of most adsorbents including BWN (861.33 mg/g). After 10 cycles of use, both all of the biochars can still maintain more than 65 % of the performance, indicating their stable regeneration ability. This work not only prepared a series of biochars that can be used to efficiently remove antibiotics from water, but more importantly provided a new strategy for the high-value utilization of WN and further released the application potential of secondary resources.

Impact of biochar prepared at different pyrolysis temperatures on the methane production and microbial community structure of food waste anaerobic digestion

Biochars were prepared through the pyrolysis of sawdust at 300 °C, 500 °C, and 700 °C, respectively, under oxygen-limited conditions. The basic physicochemical properties of biochars were explored by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), surface area and porosity analyzer (BET), and Fourier-transform infrared spectrometer (FTIR). The effects of biochar addition on the methane yield and microbial community structure of anaerobic digestion of food waste were also investigated. SEM images showed that biochar had a honeycomb-like pore structure, EDS analysis showed that the C content in the biochar tended to increase, and the O contents tended to decrease with the increasing temperature. The specific surface area of biochars increased from 1.2014 m2/g (300 °C) to 326.8435 m2/g (700 °C). FTIR analysis showed that the number of different surface functional groups decreased with the increasing temperature. The addition of biochar could increase the cumulative methane volume by 11.63%–25.18%. High-throughput sequencing results showed that biochar addition could increase the relative abundance of Bacteroidetes, Chloroflexi, Firmicutes, Proteobacteria, and Spirochaetota, which were associated with the degradation of refractory organic matters. Meanwhile, biochar addition could enrich the relative abundance of methanogens participating in direct electron transfer (Methanosaeta and Methanosarcina), and methanogens producing methane through multiple pathways (Methanobacterium and Methanosarcina). The addition of biochar derived at 700 °C significantly increased the relative abundance of Methanobacterium and Methanosarcina from 1.96% and 0.70% (control group) to 32.68% and 64.69%, respectively and improved methane production by transforming acetoclastic/hydrogenotrophic methanogenic pathways to more metabolically diverse methanogenic pathways.

Effect of pyrolysis temperature on the physical and chemical characteristics of pine wood biochar

Biochar is a useful bioproduct with a wide range of promising applications. The main objective of this study is to investigate the effect of pyrolysis temperatures on the physicochemical properties of biochar produced from pine wood using a slow pyrolysis methodology. Fourier transfer infrared (FTIR) spectroscopy analysis uncovered that the biochar synthesized at the different temperatures selected possessed distinct functional groups. The elemental analysis confirmed that an increase in pyrolysis temperature led to a rise in the carbon (C) concentration, whereas conversely there is a reciprocal decrease in the levels of oxygen (O) and hydrogen (H). Consequently, biochar produced at high temperatures showed low (O/C) and (H/C) fractions. Surface area (gas adsorption) studies indicated that the biochar surface area and pore volume increase at higher pyrolysis temperature. In contrast, the pore size was found to decrease at high temperatures. It was found that increased pyrolysis temperature resulted in reduced biochar yield. Biochar for use in specific applications like as an adsorbent material is ultimately influenced by the pyrolysis temperature. Therefore, it can be concluded that the results of the current study enhances the understanding on the effect of pyrolysis temperature on biochar synthesis and how different parameters can be used to tailor the material characteristics for specific applications.

The effect of biochar in a specialty adsorbent on enhanced PFAS removal from surface water

An enhanced specialty adsorbent, referred to as biochar-based iron and perlite-integrated green environmental media (BIPGEM), was designed to simultaneously remove both long-chain PFAS mainly including perfluorooctanoic acid (PFOA) and Perfluorooctanesulfonic acid (PFOS) from surface water matrices. Batch-scale experiments using BIPGEM revealed that the removal efficiencies for PFOA and PFOS exceeded 98 % when treating a mixture of 3 short-chain PFAS, including perfluorobutanoic acid (PFBA), perfluorobutane sulfonic acid (PFBS), and hexafluoropropylene oxide dimer acid (GenX Chemicals). Additionally, a fixed-bed column study using BIPGEM revealed that the removal efficiencies of PFOA and PFOS were over 85 % within the first 12 h whereas the removal efficiency of PFBA was over 40 % at the fortieth hour. It was confirmed that the critical role of biochar in the removal of long-chain PFAS, particularly PFOA, can be attributed to the following factors: (1) the morphological structure and pore size of biochar restrict PFAS mobility, (2) the extensive specific surface area of biochar, with a positive charge (point of zero charge = 10.7) at the experimental condition, enhances the adsorption likelihood with the negatively charged hydrophilic heads of PFOA and PFOS, and (3) the presence of non-polar aromatic rings with high hydrophobicity in biochar facilitates the removal of PFAS through hydrophobic interactions with the functional groups of PFAS.

Mycelium-Doped Straw Biochars for Antibiotic Control.

Straw, a predominant agricultural residue, represents a significant waste product. Harnessing its potential is of paramount importance both in terms of research and economic value. In this study, chemically pretreated corn straw was infused with distinct microbial fungal mycelium variants and subsequently transformed into a series of biochars through a process involving carbonization and activation. The findings revealed enhancements in the specific surface area and total pore volume of mycelium-doped straw biochars compared to the original corn straw biochar (BCS). Additionally, discernible disparities were observed in their physical and chemical attributes, encompassing functional groups, surface chemistry, and micro-morphology. Notably, in water-based antibiotic removal experiments focusing on tetracycline hydrochloride (TH) and chloramphenicol (CP), the mycelium-doped straw biochars outperformed BCS. Their maximum adsorption capacities for TH and CP surpassed those of alternative adsorbents, including other biochars. Impressively, even after five cycles, the biochar exhibited a removal rate exceeding 80%, attesting to its robust stability. This study successfully emphasized the efficacy of incorporating fungal mycelium to enhance the adsorption properties of straw-based biochar, introducing a new theoretical basis for the development of lignocellulosic materials.

Enhancing biochar production: A technical analysis of the combined influence of chemical activation (KOH and NaOH) and pyrolysis atmospheres (N2/CO2) on yields and properties of rice husk-derived biochar

The production of biochar from biomass has received considerable interest due to its potential in environmental applications; however, optimizing biochar properties remains a major challenge. The objective of the present study was to investigate the synergistic effects of pyrolysis atmospheres (N2 and CO2) and chemical activation (pre- and post-pyrolysis) with NaOH and KOH on the properties of biochar useful for its environmental applications. In this study rice husk and biochar were impregnated with KOH and NaOH before and after pyrolysis, which was carried out at 600 °C under N₂ and CO₂ atmosphere. The pyrolytic yields (biochar, liquid and gas) and detailed characterization of biochar were performed. The results showed that pre-activation with both alkalis under a CO2 atmosphere slightly decreased the biochar yield and carbon contents while increasing oxygen in biochars compared to N2 atmosphere. Alkali pre-activation in the CO2 atmosphere considerably increased the specific surface area and pore volume of biochars compared to the N2 atmosphere, with KOH being more effective than NaOH. The maximum specific surface area (SSA) and pore volume (PV) of biochar obtained were 178.4 m2/g and 0.60 cm3/g for KOH activated biochar under CO2, which were 3.2 times and 30 times higher than the untreated biochar. The post-activation of biochars with both alkalis resulted in moderate improvements in textural properties. Overall, chemical activation under CO2 pyrolysis facilitated a higher level of chemical activation reactions leading to increased formation of oxygen functional groups and contributed to enhanced SSA and PV of the biochar useful for adsorption.

A recyclable and high porosity vinasse-based biochar with enhanced superficial active sites for antibiotics recovery

Antibiotic pollution in water bodies is a global environmental issue. For adsorbing antibiotic residues, biochar produced by direct high temperature pyrolysis faces challenges in balancing adsorption capacity and recyclability due to limited active sites. Thus, a recyclable and high-porosity vinasse-based biochar was developed via co-pyrolysis of K2FeO4 one-pot method. The co-pyrolysis biochar's surface area was augmented by 143 times, from 3.4 m²/g to 490.9 m²/g. The maximum theoretical adsorption capacity of the co-pyrolysis biochar for norfloxacin (NOR) increased from 4.4 mg/g to 364.9 mg/g, an approximate 83-fold enhancement. The surface of the biochar was rich in active groups (C-O, C-Fe, and -OH), which acted as the active sites to enhance the adsorption of NOR. The adsorption mechanism involved a variety of interactions, including pore-filling, hydrogen bond, π-π interactions, surface complexation, and electrostatic interactions. Importantly, the biochar is magnetic and can be recycled attributed to the generation of ferriferous oxides during the carbonization. After three cycles of reuse, the adsorption efficiency of vinasse-based biochar for NOR still exceeded 70 %. Such biochar prepared by this facile and feasible co-pyrolysis method show the potential to enhance active sites for removal of antibiotic from aquatic systems.

Biochar for wastewater treatment: Addressing contaminants and enhancing sustainability: Challenges and solutions

In recent years, biochar has gained interest for its potential use in treating and removing contaminants from domestic, municipal, and industrial wastewater. When applied in fixed filter columns (BFCs), biochar can effectively immobilize, filter, and recover contaminants with high treatment efficiency. On average, COD removal is 80 %, nutrient removal is 71 % for nitrogen-ammonium and 57 % for phosphorus-phosphate, and pathogen reduction averages 2.4 log10 units. These results vary depending on factors such as the biochar's surface area, the conditions under which it was pyrolyzed, and operational parameters like hydraulic loading and retention time. Biochar addresses limitations in traditional wastewater treatment by leveraging adsorption, ion exchange, and biological degradation mechanisms. The larger surface area and functionalized surface of engineered biochar make it particularly effective in treating diverse pollutants, including heavy metals, nutrients, and emerging contaminants, such as antibiotic-resistant bacteria. As the global population and industrial activities increase, there is a pressing need for sustainable wastewater treatment technologies. Biochar addresses this need and serves as a waste valorization tool, contributing to bioenergy production, soil improvement, and other applications. The present review focuses on improving biochar's performance and durability in real-world applications by addressing challenges like physical degradation. It also proposes strategies to enhance biochar's properties and reuse potential.

The influence of amino anchoring position on SnO2/biochar for electroreduction of CO2 to HCOOH

Biochar derived from biomass resources as a carrier to load SnO2 for electroreduction of CO2 not only can benefit carbon emissions, but it also can achieve waste utilization. However, the weak CO2 mass transfer and conductivity ability of SnO2/biochar limits its applications to such eCO2RR processes. This study focused on modifying SnO2/biochar with amino groups and investigated the effects of positioning of amino groups on the catalyst’s physicochemical properties and electrocatalytic behaviors. Elemental analysis revealed that anchoring amino groups on biochar (SnO2/C-NHx) is advantageous for increasing amounts of amino groups attached, thereby enhancing biochar adsorption energy and subsequently increasing the loading of Sn. The CO2 adsorption curve indicated that amino groups anchored on biochar facilitate CO2 adsorption due to high specific surface area of biochar. X-ray photoelectron spectroscopy showed that amino groups anchored on SnO2 (NHx-SnO2/C) resulted in highly electron-rich centers on Sn, which promoted electron transfer between the catalyst and CO2. Electrochemical tests demonstrated the improved performance of amino-modified SnO2/biochar. SnO2/C-NHx exhibited enhanced Faraday efficiency, whereas NHx-SnO2/C showed higher current density. The disparity in electrochemical performance can be mainly attributed to the different selectivity towards rate-controlling steps of electron transfer and mass transfer induced by the various positions of amino groups anchoring.

CO2 absorption performance of biogas slurry enhanced by biochar as a potential solvent in once-through CO2 chemical absorption process

Carbon capture, utilization, and storage (CCUS), offers a promising avenue for mitigating CO2 emissions, in which the big challenge is the high CO2 capture cost. A novel CCUS technology called once-through CO2 chemical absorption using biogas slurry, could potentially reduce the CO2 capture cost through decreasing the energy consumption greatly during CO2 capture. This technology, however, is constrained by the CO2 absorption capacity of biogas slurry. To enhance the CO2 capture capacity of this innovative technology, we proposed a method to enhance CO2 absorption by integrating biochar into biogas slurry. Results indicated that the CO2 absorption capacity of biogas slurry improved by biochar varied with the type of biochar adopted. Among all the investigated biochar, the wood biochar like sea buckthorn and sand willow exhibited the lowest CO2 capture enhancement, with 0.82±0.19 mmol/g and 0.81±0.30 mmol/g, respectively. Biochar from C4 plants like corn stalks and cobs demonstrated the highest enhancement, with 2.11±0.24 mmol/g and 2.47±0.86 mmol/g, respectively. The enhancement driven by C3 plant biochar like millet stalks and shells was intermediate, with 1.62±0.47 mmol/g and 1.62±0.46 mmol/g, respectively. The primary factor for promoting CO2 absorption in the biochar-based biogas slurry was the increase in pH of biogas slurry. The total pore volume of biochar was the principal material property that enhanced CO2 absorption, followed by the EC and BET surface areas of biochar. Increasing the carbonization temperature of biochar could also enhance the CO2 absorption capacity by biogas slurry. In CO2-rich biochar-based biogas slurry, CO2 primarily existed as HCO3− and carbamate. However, for the influence of the biochar's pore structure, CO2 in the CO2-rich biochar-based biogas slurry was more stable than that in CO2-rich biogas slurry.

Machine learning assisted prediction of specific surface area and nitrogen content of biochar based on biomass type and pyrolysis conditions

Predicting and optimizing the physicochemical properties of biochar is crucial for its applications. The characteristics of biomass and pyrolysis conditions are the main factors influencing these properties. However, the numerous components of biomass and the pyrolysis conditions contribute to the substantial challenge in predicting the physicochemical properties, particularly the specific surface area and the nitrogen content of biochar. In this work, machine learning methods including random forest (RF), gradient boosting decision tree (GBDT) and extreme gradient boosting (XGB) (all with R2 exceeding 0.97) were used to predict and analyze specific surface area of biochar (SSA), N content of biochar (N-char), and yield of biochar (Yield-char). Compositions of biomass and pyrolysis conditions were selected as input variables. The partial dependence plot analysis showed the impact way of each influential factor on the target variable and the interactions among these factors in the pyrolysis process. The feature importance of these models indicated that the influencing factors toward predicting three targets (sorted by importance) were specified as follows: pyrolysis temperature, nitrogen content, and fixed carbon for Yield-char; N and ash for N-char; ash and pyrolysis temperature for SSA. This work provided new insights for understanding pyrolysis process of biomass.

Effect of Three Different Types of Biochar on Bioelectricity Generated from Plant Microbial Fuel Cells under Unsaturated Soil Condition.

Plant microbial fuel cell (PMFC) is an emerging technology, showing promise for environmental biosensors and sustainable energy production. Despite its potential, PMFCs struggle with issues like low power output and limited drought resistance. Recent studies proposed that integrating biochar may enhance PMFC performance due to its physicochemical properties. The influence of different biochar types on PMFC efficiency has been minimally explored. This study aims to fill this gap by evaluating the performance of PMFCs integrated with various biochar types under unsaturated soil conditions. The study found that the addition of biochar types─specifically reed straw biochar (RSB), apple wood biochar (AWB), and corn straw biochar (CSB)─significantly influenced the performance of PMFCs. RSB, with its large surface area and porous structure, notably increased the current output by reducing soil resistance and enhancing electron transfer efficiency in microbial reduction reactions, achieving a peak power density of approximately 1608 mW/m2. AWB, despite its less porous structure, leveraged its high cation exchange capacity and hydrophilic functional groups to foster microbial community growth and diversity, thereby also increasing bioelectricity output. Conversely, CSB, with its large surface area, showed the least improvement in PMFC performance due to its layered structure and lower water retention capacity. Additionally, under drought conditions, PMFCs with added RSB and AWB exhibited better drought resistance due to their ability to improve soil moisture characteristics and enhance soil conductivity. The addition of biochar reduced soil resistance, increasing the bioelectric output of PMFCs and maintaining good performance even under low moisture conditions. This study highlights the critical role of biochar's surface area and functional groups in optimizing PMFC performance. It enhances our understanding of PMFC optimization and might offer a novel power generation method for the future, while also presenting a fresh strategy for soil monitoring.

Study on the properties and components of solid-liquid products by co-pyrolysis of sludge and cotton stalk

The effects of sludge content and pyrolysis temperature on the pyrolysis process and product properties were studied through the co-pyrolysis of sludge and cotton stalk. Multi-objective fuzzy hierarchical analysis was used to analyze the multiphase properties of pyrolysis products, and describe the internal relationship between pyrolysis conditions and product properties. It has been proved using kinetic calculation that the mass ratio of sludge and cotton stalk is higher than 1:2 required the lower pyrolysis activation energy. According to the comparison between experimental and theoretical results, the addition of sludge is beneficial to increase the bio-oil yield. In terms of product performance, the addition of sludge and increase of pyrolysis temperature both can improve the specific surface area, pore volume of biochar and the pH value of bio-oil, reduce the total acid content, increase the total phenol content and optimize calorific value of bio-oil. The specific surface area of biochar, calorific value of bio-oil, total phenol content and pH were evaluated by multi-objective decision analysis method, the optimum process condition of sludge: cotton stalk = 2:1 at 600 ℃. Under the conditions, the specific surface area of biochar is 57.40 m2/g, the pH of the bio-oil is 8.06, the total acid content is 5.94 mg/g, the calorific value is 27.18 KJ/g and the total phenol content is 47.32 mg/g, respectively. Compared to the pyrolysis product of cotton stalks, the specific surface area is increased almost 20 times, the calorific value is increased by 13 %, the total acid content is decreased by 95 %, and the total phenol content is similar. This study proposed a preparation process of bio-oil with high performance, and provided a theoretical basis for the subsequent co-pyrolysis research.

Combined experimental and density functional theory approaches to address different mechanisms of nitrogen and sulfur doping on the enhancement of capacitive performance of hierarchical porous biochars

Activated carbon derived from biomass as hierarchical porous biochars (HPB) has been developed as electrode materials for supercapacitors. Nitrogen is known as the doping element that enhances quantum capacitance, but the mechanisms of sulfur doping on the quantum capacitance enhancement remain ambiguous. In this study, conventional approaches to assess the characteristics and capacitive performance of biochars were combined with density functional theory (DFT) calculations to assess different mechanisms of nitrogen and sulfur doping. The Bbiochar samples were prepared from the pyrolyzed fish bone powder at 800 °C without additional doping possessed a specific capacitance of 240 F g−1 at 1 A/g within 1 M H2SO4. Interestingly, additional nitrogen doping through urea mixing and additional sulfur doping through thiosulfate mixing prior to the pyrolysis enhanced the specific capacitance of biochar samples to exceed 400 F g−1 under the same condition. The urea mixed sample possessed low porosity but high charge transfer resistance, while the thiosulfate mixed sample possessed high porosity but low charge transfer resistance. The different underlying mechanisms were discussed through DFT calculations on graphene models designed based on the x-ray photoelectron spectroscopy (XPS) results. Nitrogen-doped configurations with topological defects mainly stored charge at the dangling atoms and possessed a relatively high quantum capacitance. Meanwhile, doped configurations of oxidized sulfur groups required relatively low formation energy and possessed large bond dipoles, corresponding to larger pore size and surface area of the thiosulfate mixed biochars. Understanding the contrary between effects of nitrogen and sulfur doping could resolve the bottleneck on enhancing the performance of electronic double layer supercapacitors.

The Potential Significance of Microwave-Assisted Catalytic Pyrolysis for Valuable Bio-Products Driven from Albizia Tree

The objective of this study is to investigate the feasibility of Na2CO3 and ZSM-5 as catalysts in the microwave pyrolysis of Albizia branches. An evaluation was conducted to determine the influence of power applied, experimental time, particle size, and catalysis type and ratio on the quality and quantity of pyrolysis products. Established methods such as GC-MS, FTIR, HHV, SEM, EDX, and BET were used to characterize the properties of bio-oil and biochar produced. The results demonstrated that using both catalyst types led to a substantial enhancement in biogas production. The improvement ranged from 5% to 41% with Na2CO3 and reached 45% with ZSM-5. At a lower power level of 300 W, the bio-oil yield augmented from 28% to 40% and 53% when using ZSM-5 and Na2CO3, respectively. The GC-MS analysis revealed that the utilizing of catalysts enhanced the levels of aromatic compounds, esters, and alcohols in bio-oil, along with an increase in the higher heating value (HHV) from 19.5 MJ/kg to 22 MJ/kg and 24.2 MJ/kg using Na2CO3 and ZSM-5, respectively. Moreover, the biochar's surface area and pore volume experienced a considerable rise, going from 0.5512 m2/g and 0.00011 cm3/g to a higher value of 115.2073 m2/g and 0.0774 cm3/g when treated with Na2CO3. The data indicated that both catalyst types enhanced the generation of CH4, and CO2 was lower with ZSM-5. The utilization of catalysts improves the quality of the biofuel produced and promotes the efficiency of the process in terms of energy consumption and processing time.

Efficacy of anthocyanin, kaolinite and cabbage leaves-derived biochar for simultaneous removal of lead, copper and metoprolol from water

Simultaneous removal of toxic elements and pharmaceutical compounds at environmentally relevant concentrations in aqueous solution is challenging. Modification of biochar using environmental materials has attracted significant attention in wastewater treatment, while pristine biochar has several limitations in the simultaneous removal of Lead (Pb2+), Copper (Cu2+), and metoprolol. We investigated the efficacy of biochar composites using waste cabbage leaves-derived biochar with kaolinite, and anthocyanin for simultaneous removal of Pb2+, Cu2+, and metoprolol from water. Using ball milling, the surface area and functional groups of adsorbents were improved via breaking the biochar grains into ultrafine particles. Ball-milled biochar derived from waste cabbage leaves significantly increased Pb2+, Cu2+, and metoprolol adsorption by 105, 71, and 213%, respectively. Results of Brunauer Emmett Teller surface area, Fourier transform infrared and X-ray photoelectron spectroscopies showed that surface area of non-milled biochar improved nearly ten-fold following ball-milling, while several oxygen containing acidic functional groups also increased. The adsorbents resulted in high removal efficiency for Pb2+ (162.9 mg/g) and Cu2+ (48.5 mg/g) in ball milled-kaolinite composite biochar (BMKB) and 76.3 mg/g (metoprolol), respectively in ball milled-anthocyanin composite biochar (BMAB). The simultaneous sorption of Pb2+, Cu2+, and metoprolol in an aqueous solution to BMAB and BMKB, showed that the adsorption capacity followed the order of Pb2+ >Cu2+ > metoprolol in both types of ball-milled biochars. BMKB achieved a high adsorption capacity for Pb2+ and Cu2+ (59 mg/g and 50 mg/g), respectively, while BMAB exhibited an adsorption capacity 22.3 mg/g for metoprolol. It was postulated that sorption of Pb2+, Cu2+ and metoprolol involved multiple adsorption mechanisms namely surface complexation, π-π interaction, H−bond, pore filling, and ion bridging. The findings of this study revealed that ball milling is a potential technology in producing a highlyefficient adsorbent to remediate multi-contaminants in aqueous solution.

Synergistic effect of adsorption and photolysis on methylene blue removal by magnetic biochar derived from lignocellulosic biomass

In this study, magnetic biochar was synthesized by doping Fe3O4 onto the biochar surface followed by analysis of its properties. The efficiency of methylene blue (MB) removal through the combined processes of adsorption and photolysis was assessed. The presence of Fe3O4 on the biochar surface was confirmed using Raman spectroscopy and X-ray photoelectron spectroscopy. The magnetic biochar, after MB adsorption, showed a magnetism of 39.50 emu/g leading to a 97.07 % recovery rate. The specific surface area of biochar was higher (380.68 m2/g) than that of magnetic biochar (234.46 m2/g), and the maximum adsorption capacity of MB was higher in the biochar (0.03 mg/g) than that in magnetic biochar (0.02 mg/g) under the optimal conditions for MB adsorption. The MB adsorption experiments using biochar or magnetic biochar were optimally conducted under 10–20 mg/L MB concentration, 1 g biochar dosage, pH 12, 200 rpm rotation speed, 25 °C temperature, and 30 min duration. Under dark conditions, biochar had a higher MB removal rate, at 83.91 %, compared to magnetic biochar, at 78.30 %. Under visible light (λ > 425 nm), magnetic biochar effectively removed MB within 10 min, highlighting the synergistic effect of adsorption and photolysis. MB is physically and chemically adsorbed by the monolayer on the surface of EB and EMB according to adsorption behavior.

Biochar effects on salt-affected soil properties and plant productivity: A global meta-analysis

Biochar has been recognized as a promising practice for ameliorating degraded soils, yet the consensus on its effects remains largely unknown due to the variability among biochar, soil and plant. This study therefore presents a meta-analysis synthesizing 92 publications containing 987 paired data to scrutinize biochar effects on salt-affected soil properties and plant productivity. Additionally, a random meta-forest approach was employed to identify the key factors of biochar on salt-affected soil and plant productivity. Results showed that biochar led to significant reductions in electrical conductivity (EC), bulk density (BD) and pH by 7.4%, 4.7% and 1.2% compared to the unamended soil, respectively. Soil organic carbon (by 55.1%) and total nitrogen (by 31.3%) increased significantly with biochar addition. Moreover, biochar overall enhanced plant productivity by 31.5%, and more pronounced increases in forage/medicinal with higher salt tolerance than others. The results also identified that the soil salinity and biochar application rate were the most important co-regulators for EC and PP changes. The structural equation model further showed that soil salinity (P < 0.001), biochar pH (P < 0.001) and biochar specific surface area (P < 0.01) had a significant negative effect on soil EC, but it was positively impacted by biochar pyrolysis temperature (P < 0.05). Furthermore, plant productivity was positively affected by biochar pH (P < 0.001) and biochar feedstock (P < 0.01), while negatively influenced by biochar pyrolysis temperature (P < 0.01). This study highlights that woody biochar with 7.6 < pH < 9.0 and pyrolyzed at 400–600 °C under 30–70 t ha−1 application rate in moderately saline coarse soils is a recommendable pattern to enhance forage/medicinal productivity while reducing soil salinity. In conclusion, biochar offers promising avenues for ameliorating degradable soils, but it is imperative to explore largescale applications and field performance across different biochar, soil, and plant types.

Fully upgrade bamboo biomass into three multifunctional products through biphasic γ-valerolactone and aqueous phosphoric acid pretreatment

In this manuscript, three components of lignocellulosic biomass were obtained by deconstructing bamboo with γ-valerolactone-H2O biphasic system, and the delignification rate of 80.92 % was achieved at 120 °C for 90 min. Lignin nanospheres with diameters ranging from 75 nm to 2 um could be customized by varying the self-assembly rate. Furthermore, the lignin nanospheres-poly(vinyl alcohol) film was prepared by cross-linking lignin nanospheres and poly(vinyl alcohol), which can obtain 90 % ultraviolet absorption capacity, while the light transmittance in non-ultraviolet band was almost unchanged. At the same time, due to the strong hydrogen formation between lignin nanospheres and poly(vinyl alcohol) bond network, the tensile properties of the composite film were also improved by 30 %. Besides, the high specific surface area of biomass-derived porous biochar (2056 m2/g) can be obtained after carbonization of solid residues at 850 °C for 2 h, which was almost 8 times the specific surface area of the direct biomass carbonization due to the removal of lignin and hemicellulose. biomass-derived porous biochar can be used as an adsorbent, with a CO2 capture capacity of 4.5 mmol g−1 at normal temperature (25 °C, 1 bar). The filtrate after the reaction contained a large amount of hemicellulose oligomers, which can be reacted with dichloromethane at 170 °C for 1 h to obtain the furfural yield of 74 %. In summary, the proposed biorefinery scheme achieves a full-component upgrade of lignocellulose and can be further applied in various downstream fields.