Sawdust Biochar Research Articles

Synergistic recycling of biochar from sawdust pyrolysis and waste coke breeze to produce metallurgical quality biocoke with syngas as a by-product

Waste coke breeze and sawdust were synergistically utilized as two solid waste resources to produce a high-quality metallurgical biocoke product and a combustible syngas as a by-product in this study. The experiments of the sawdust pyrolysis were carried out to prepare biochar and bio-syngas. A sawdust biochar with high fixed carbon content (88.23%) and low volatile content (4.98%) was obtained by sawdust pyrolysis at 900 °C for 40 min. Meanwhile, a bio-syngas with 87.7% combustible gases was obtained as a by-product. The carbon valid conversion ratio (to combustible gases and biochar) in sawdust was 89.6%. The obtained biochar was first used as an auxiliary filler for coke breeze(as aggregate) to produce a metallurgical quality formed biocoke product (a metallurgical coke substitute). The cracks and pores inside the formed coke product can be filled with a suitable amount of sawdust biochar powder, improving its internal structure and performance. A formed biocoke product, which met the Chinese secondary metallurgical coke standard, was produced with the mass ratio (biochar to coke breeze) of 2:8 by carbonization under a nitrogen atmosphere for 30 min. This study provides an efficient and high-value-added way of using sawdust and coke breeze resources. And it offers an essential research reference for recycling bioresources and solid waste fuels.

Synergistic effects of biochar derived from different sources on greenhouse gas emissions and microplastics mitigation during sewage sludge composting

This study aimed to investigate the effects of biochar derived from different sources (wheat straw, sawdust and pig manure) on greenhouse gas and microplastics (MPs) mitigation during sewage sludge composting. Compared to the control, all biochar significantly reduced the N2O by 28.91–41.23%, while having no apparent effect on CH4. Sawdust biochar and pig manure biochar significantly reduced the NH3 by 12.53–23.53%. Adding biochar decreased the global warming potential during composting, especially pig manure biochar (177.48 g/kg CO2-eq.). The concentration of MPs significantly increased in the control (43736.86 particles/kg) compared to the initial mixtures, while the addition of biochar promoted the oxidation and degradation of MPs (15896.06–23225.11 particles/kg), with sawdust biochar and manure biochar were more effective. Additionally, biochar significantly reduced the abundance of small-sized (10–100 μm) MPs compared to the control. Moreover, biochar might regulate specific microbes (e.g., Thermobifida, Bacillus and Ureibacillus) to mitigate greenhouse gas emissions and MPs degradation.

Effects of Water Application Rates and Sawdust Biochar on the Physicochemical Properties of Soil and Performance of Five Tree Species Used in Urban Landscaping in Ondo, Nigeria

Effects of Water Application Rates and Sawdust Biochar on the Physicochemical Properties of Soil and Performance of Five Tree Species Used in Urban Landscaping in Ondo, Nigeria

Impact of Biochar Application on Chemical and Microbial Properties of Soil

Biochar is a carbonaceous solid compound formed by high-temperature of organic waste. The quality of biochar produced is determined by pyrolysis conditions and the type of raw materials. This study focused on the evaluation of the impact of biochar application on soil chemical and microbial properties. Four types of biochar from corn cobs, sawdust, mud press, and rice hull were produced and their chemical composition (pH, Organic Matter, Organic Carbon, Total Nitrogen, Carbon: Nitrogen Ratio, Available Phosphorus, and Exchangeable Potassium) was analyzed. A pot experiment with five treatments [T1 - Pure Soil; T2 – Soil + corn cob biochar; T3 – soil + sawdust biochar; T4 – soil + mud press biochar; T5 – soil + rice hull biochar] replicated three times was arranged in a completely randomized design (CRD). An equal amount of soil was placed in pots and mixed with biochar at a ratio of fifty grams (50g) per one-thousand grams (1000g) of soil. A total of fifteen experimental pots were used in the study where each pot contains a soil-biochar mixture of one-thousand five-hundred grams (1500g). Pearson’s correlation coefficients were used to determine how the soils applied with biochar are affected after sixty days of incubation and determine how biochar sources were related. All four biochar from rice hull, corn cobs, mud press, and sawdust are all alkaline and contain comparable amounts of organic matter, organic carbon, pH, soil nitrogen, available phosphorus, and exchangeable potassium. The result of the study showed that biochar application significantly improved soil pH, soil organic matter content, soil organic carbon, and soil nitrogen content. Soils amended with biochar showed comparable amounts of available phosphorus and exchangeable potassium. The application of biochar in soils therefore can be considered a potential solution to enhance soil fertility for sustainable crop production.

Characterization and Risk Assessment of Different-Origin Biochars Applied in Agricultural Experiments

This study aimed to assess the impacts of biochar amendments derived from different feedstocks (sewage sludge (SS), olive-mill waste (OMW), compost, and sawdust) in land applications. Tomatoes were used as a test crop in four experiments both under greenhouse and field conditions. SS, OMW, and compost biochar treatments presented 17% to 178.5% higher tomato productivity than control, verifying that biochar behaves as a plant-growth bio-stimulant. This impact is related to the raw material since sawdust biochar did not present results as positive as the other types of biochars. The physicochemical characterization of biochars and their comparison with international and European standards confirmed the safety of their use. A risk-assessment analysis of tomato consumption was conducted in order to explore unfavorable effects on human health. The estimation of cumulative non-carcinogenic risk, found to be between 8.25 × 10−3 and 4.23 × 10−2, and cancer risk for Cr(VI), found to be between 6.56 × 10−6 and 5.2 × 10−5, suggested no risk of potential chronic exposure due to tomato consumption cultivated in biochar-amended soils. This study may be used as a recommendation for farmers and agriculturists for maximizing the yield of agricultural crops in the Mediterranean region, improving soil health, and contributing to the sustainable management of agroecosystems.

Converting sawdust to biochar and its mineral content: A preliminary analysis

In Indonesia, soil degradation is occurring. A strategy to improve soil conditions is by applying biochar as a soil amendment. On the other hand, Indonesia is an agricultural country with many types of biomass that can be converted into biochar. Sawdust of mahogany, teak, and sappan wood from the furniture industry is easy to find and has great potential as raw materials for biochar. This study used X-ray fluorescence spectrometry to determine the mineral content of sawdust biochar from mahogany, teak, and sappan wood sawdust, especially the ash fraction. Biochar was created by burning sawdust woods in a furnace at temperatures ranging from 250°C to 350°C. In general, the main mineral (ash fraction) content of wood sawdust biochar was calcium (CaO) at concentrations ranging from 51 to 72%, with sappan sawdust biochar having the highest concentration at 70–72%. The potassium (K2O) concentration ranged from 9–23%, with mahogany sawdust biochar having the highest concentration (23%). The phosphorus (P2O5) content ranged from 2 to 10%, with teak sawdust biochar having the highest concentration at 7–10%. Moreover, teak sawdust contained 15-20% silica, and sappan sawdust biochar contained 6-8% Fe. The mineral content in biochar ash included alkaline cations; if the biochar is applied to the soil, then a mineralization process may occur and the cations could improve pH conditions through a liming mechanism. This result is only general information; further research is required to produce more comprehensive data.

Poplar Sawdust Biochar Altered Community Composition of Dominant Soil Fungi but Not Bacteria Depending on Pyrolysis Temperature

There is a growing focus on the production of biochar from organic wastes and its forestry use. However, it is unclear how applying biochar pyrolyzed at different temperatures influences both soil bacterial and fungal communities. In this study, two kinds of biochar were pyrolyzed at 350 °C and 600 °C, from poplar sawdust, and then applied as an auxiliary substrate material (15% addition by volume) for the container seedling cultivation of Cyclocarya paliurus, a native timber and medically used tree species, to compare the response of the soil’s microbial traits. The results showed that after 5 months of cultivation, the addition of the biochar application improved the soil’s physical and chemical properties to a certain extent by decreasing its bulk density and increasing its field water-holding capacity, pH and organic carbon content. The soil’s pH and content of organic C, available N and available P were significantly higher in the substrate with the addition of the biochar pyrolyzed at 600 °C (Bioc600) than in that of the substrate with added pyrolyzed biochar at 350 °C (Bioc350). The biochar application also enhanced the soil’s microbial N (MBN) but showed no changes in the MBC/MBN ratio. The biochar application had no effect on the diversity and composition of the soil’s bacterial community, but showed a certain effect on its fungal community composition and had different influences between low and high pyrolysis temperatures. The relative abundance of several of the dominant fungal phyla and genera increased with the addition of biochar due to the increase in the soil’s pH when compared to the CK (no biochar or sawdust addition). When compared with Bioc350, the dominant phylum Basidiomycota and genus Vanrija further increased in abundance with Bioc600. These findings reveal the consistent effects of biochar pyrolysis temperature and demonstrate the different regulatory roles of biochar application in soil bacterial and fungal communities, providing valuable information on how biochar can effectively be used as a substrate for seedling cultivation.

Synthesis, characterization and thermo-kinetic analysis of sawdust biochar for adsorbent and combustion drives

Biochar is synthesized using two wood species as Dalbergia sissoo wood (DSW) and Mangifera indica wood (MIW), employing pyrolysis of sawdust on a lab-scale. Chemical analysis of these biochars is carried out using elemental analyzer, BET, FTIR, FE-SEM-EDX, and TGA-DTG-DTA analyses. Results showed that high surface area (87.12 and 88.04 m2/g), pore volume (0.0439 and 0.0443 cm3/g), and gross calorific value (28.19 and 28.00 MJ/kg) of DSW and MIW biochar indicate their suitability as sorbent and energy source. Thermogravimetric modeling, based on Coats-Redfern method, is applied on combustion data of biochar samples obtained at 10 and 20 °C/min. Activation energy of DSW- and MIW-biochar are estimated as 2.61–80.49 kJ/mol and 2.58–77.90 kJ/mol, respectively. Statistical analysis of results (R2 > 0.90) indicated the adequacy of proposed kinetic modeling in reproducing the experimental combustion behavior. The propitious outcome of this study account for favoring sawdust-biochar as a good adsorbent and combustion feedstock.

Remediation of lead and cadmium co-contaminated mining soil by phosphate-functionalized biochar: Performance, mechanism, and microbial response

The remediation of heavy metals contaminated soils is of great significance for reducing their risk to human health. Here, pristine pinewood sawdust biochar (BC) and phosphate-functionalized biochar (PBC) were conducted to investigate their immobilization performance towards lead (Pb) and cadmium (Cd) in arable soils severely polluted by Pb (9240.5 mg kg−1) and Cd (10.71 mg kg−1) and microbial response in soils. Compared to pristine BC (2.6–12.1%), PBC was more effective in immobilizing Pb and Cd with an immobilization effectiveness of 45.2–96.2% after incubation of 60 days. Moreover, the labile Pb and Cd in soils were transformed to more stable species after addition of PBC, reducing their bioavailability. The immobilization mechanisms of Pb and Cd by PBC were mainly to facilitate the formation of stable phosphate precipitates e.g., Cd3(PO4)2, Cd5(PO4)3OH, Cd5H2(PO4)4‧4H2O, and pyromorphite-type minerals. Further, PBC increased pH, organic matter, cation exchange capacity, and available nutrients (phosphorus and potassium) in soils. High-throughput sequencing analysis of 16 S rRNA genes indicated that the diversity and composition of bacterial community responded to PBC addition due to PBC-induced changes in soil physicochemical properties, increasing the relative abundance of beneficial bacteria (e.g., Brevundimonas, Bacillus, and norank_f__chitinophagaceae) in the treated soils. What's more, these beneficial bacteria could not only facilitate Pb and Cd immobilization but also alter nutrient biogeochemical transformation (nitrogen and iron) in co-contaminated soils. Overall, PBC could be a promising material for immobilization of Pb and Cd and the simultaneous enhancement of soil quality and available nutrients in co-contaminated mining soils.

Preparation and hydrogen storage performance of poplar sawdust biochar with high specific surface area

In the hydrogen storage system, the use of carbon adsorption materials is of great significance, leading to increasing interest in cost-effective biomass activated carbon materials. This study focuses on the use of industrial waste poplar wood chips as raw materials, which can improve the added value of the resulting product, and thus plays an important role in the development of new energy sources and environmental protection. Meanwhile, the activation conditions were investigated and a biomass carbon with a high specific surface area of up to 1486.2 m2 g−1 and a significant micropore volume of 0.767 cm3 g−1 was obtained. The poplar sawdust biochar had a hydrogen storage capacity of 3.03 wt% under normal pressure, showing good reversibility. Based on the results, the poplar wood chip biochar exhibits great potential as a hydrogen storage material.

Valorization of sewage sludge via air/steam gasification using activated carbon and biochar as catalysts

The catalytic gasification of sewage sludge was explored using different catalyst particle sizes, bed temperatures, and gasifying agents. Activated carbon and sawdust biochar were used as catalysts in this study. The effects of the porosity of activated carbon on tar adsorption and cracking, and biochar containing alkali and alkaline earth metallic species (AAEMs), which can enhance gasification reactions, were investigated under different conditions. A catalyst bed temperature of 800 °C and particle size of 0.5–1.7 mm showed optimum conditions for increasing H2 and CO content and decrease CO2 fraction; however, a higher solid residue (∼38 wt%) was also observed due to the high ash content in sewage sludge. Furthermore, the introduction of steam had a positive effect on the H2 increment, owing to the presence of inherent AAEMs in the biochar, promoting water gas shift and hydrocarbon steam reforming reactions. The results of this study provide effective measures for using activated carbon and affordable biochar to enhance H2 production with a parametric effect on the catalyst bed.

Immediate effects of atrazine application on soil organic carbon and selected macronutrients and amelioration by sawdust biochar pretreatment

Abstract Increasing use of herbicides has contributed immensely to current soil and water degradation in the tropics. Published works on effects of herbicides on soil organic carbon (SOC) – a major indicator for soil health and macronutrients and their enhancement by biochar are scarce for soils in Africa despite heavy herbicide applications every cropping season. This incubation trial evaluated immediate effects of atrazine application on SOC and selected soil macronutrients. The potential of sawdust (SD) biochar to mitigate associated SOC and macronutrients depletion was also assessed. A total of 950 g soil was placed in each leaching column (20 cm length and 7 cm diameter). The experiment was a factorial combination of four SD biochar types: SD + poultry manure (PM) pyrolyzed at 350 °C, SD-PM at 350 °C, SD + PM at 450 °C and SD-PM at 450 °C applied at two rates of 5 and 10 t/ha equivalent to 2.38 and 4.76 g/950 g soil, respectively. Atrazine alone and absolute control (AC) that received neither biochar nor atrazine were included for comparison. The treatments were replicated thrice in completely randomized design. Appropriate biochar was applied within 5 cm soil depth, moistened to field capacity, and left to equilibrate for 2 weeks. Thereafter, 20 mL atrazine solution was applied at 2.5 kg a.i/ha (achieved through 6.75 g atrazine powder/l of distilled water). Basal NPK 15:15:15 fertilizer mixed with urea at 0.1 and 0.03 g/900 g soil, respectively, was applied to mimic farmers’ practice on atrazine treated fields. Maize seeds were thereafter sown in the treated soils and nurtured for 2 weeks. Data taken on soil pH, SOC, exchangeable bases, available phosphorus, and dry biomass weight (DBW) of maize seedlings at the expiration of the trial were subjected to two-way analysis of variance using Genstat Statistical Package with means separated using LSD at 5% probability level. There were significant reductions in soil pH (5.8%), SOC (31%), and Ex. Ca (27%) in atrazine alone soil compared to AC. Contrarily, similar atrazine treated soil pretreated with SD biochar had increased soil pH, SOC, exchangeable Ca, available P, and DBW by 5.6 (in SD + PM@450 °C), 73.6 (SD-PM@450 °C), 84 (SD + PM@450 °C), 2,338.4 (SD + PM@450 °C), and 154.8% (SD + PM@350 °C), respectively, dominantly at 10 t/ha compared to AC. Sole atrazine treated soil was, however, higher in soil available P (23.8 mg/kg) and TDBW (0.56 g) against 5.42 mg/kg and 0.42 g from AC, respectively. Biochar pH and organic carbon were the most influential biochar properties contributing significantly to SOC sequestration and macronutrient enrichment in the atrazine treated soil. Pretreatment of soils with sawdust biochar prior to atrazine application is, therefore, recommended for mitigating associated organic carbon and macronutrient depletion in the soils for enhanced maize production.

Agro-Industrial Waste Biochar Abated Nitrogen Leaching from Tropical Sandy Soils and Boosted Dry Matter Accumulation in Maize

This study was conducted to assess the effects of amending tropical sandy soils with biochar derived from agro-industrial wastes on the leaching and utilization of nitrogen (N) by maize. The experiment was conducted in pots in a greenhouse with two sandy soil types and two different biochars. The biochars used in this experiment were preselected in a preliminary column experiment that assessed the N retention capacities of the different biochars and those that exhibited the best retention capacities chosen for experimentation. The biochars evaluated included saw dust, rice husk and corncob pyrolyzed at 500 °C and the results from the column leaching experiment showed that sawdust biochar had superior retention capacities for both NO3− and NH4+, followed by rice husk biochar. The pot experiment utilized sawdust and rice husk biochars applied at rates of 0, 20 and 40 t/ha to the soil treated with different N sources including cow dung and ammonium sulfate and growing maize on the amendments for two seasons with each season lasting for five weeks. The soils were leached on the 14th and 28th days after planting to determine the amount of leachable N. Biochar amendments reduced the leaching of NO3−N and NH4+N with no significant differences observed between biochar types, but between soil types. The abatement of leaching by biochar amendments consequently enhanced N uptake by maize and dry matter production and thus, agro-industrial waste biochar amendment is recommended for reducing leaching in tropical sandy soils.

Functionalization of pine sawdust biochars with Mg/Al layered double hydroxides to enhance adsorption capacity of synthetic azo dyes: Adsorption mechanisms and reusability

This study determined that the adsorption of azo dyes, Methyl Orange (MO) and Sunset Yellow FCF (SYF), using the pristine pine sawdust biochar (PSB) and post-modified PSB with Mg/Al layered double hydroxides (PSB-LDHMgAl) was examined to offer valuable information into the differences in their adsorption mechanisms. Although a lower specific surface area of PSB-LDHMgAl (147.2 m2 g−1) than PSB (495.7 m2 g−1), LDHMgAl were successfully functionalized on the PSB surface through co-precipitation, which was highly related to the improvements of adsorption capacity of PSB-LDHMgAl toward MO and SYF. The MO and SYF adsorption kinetics by PSB and PSB-LDHMgAl were confirmed to the pseudo-second-order and considered chemisorption. The adsorption capacity of MO and SYF adsorbed onto PSB-LDHMgAl (MO = 21.8 mg g−1, SYF = 23.6 mg g−1) were significantly higher than that of PSB (MO = 2.2 mg g−1, SYF = 1.6 mg g−1). The adsorption isotherms of MO and SYF by PSB were well fitted by Freundlich isotherm, whereas the MO and SYF via PSB-LDHMgAl were by Langmuir isotherm. Even after 3 adsorption-desorption cycles using desorbents, the PSB-LDHMgAl remained excellent reusability (reuse efficiency: >81.2%). These findings suggest that post-modification with LDHMgAl might accelerate the adsorption performance (i.e., electrostatic interaction) of azo dyes to PSB in water.

Alkali Modification: An Approach to Improve Surface Properties of Biochar From Easily Available Feedstocks

Biochar is a stable carbon-rich material whose potentials can be greatly enhanced by modification with simple treatments. Easily available two different biochars such as rice stubble biochar (RSB) and saw dust biochar (SDB) were slowly pyrolyzed (450±50°C) and modified with KOH as RSB-M and SDB-M respectively. Represented biochars were analyzed to know their physicochemical characteristics and nutrient contents. Results revealed that nutrient contents such as total N, P and S of RSB and SDB were found maximum whereas RSB-M and SDB-M showed the lowest nutrient contents. All the biochars possessed pH value higher than 7. In case of organic C, the values of RSB-M (19.97%) and SDBM (17.83%) were the highest and RSB (17.32%) and SDB (14.80%) were the lowest. All the biochars showed very low concentration of heavy metals (such as Cr, Cd, Pb and Ni). Water holding capacity, average particle size and surface area were higher in the RSB-M and SDB-M compared to unmodified RSB and SDB. These findings showed that alkali-modified biochars had better surface properties than unmodified biochars. Dhaka Univ. J. Biol. Sci. 31(2): 213-223, 2022 (July)

Remarkable synergy between sawdust biochar and attapulgite/diatomite after co-ball milling to adsorb methylene blue.

Biochar has been recognized as a promising sustainable adsorbent for removing pollutants from wastewater. In this study, two natural minerals, attapulgite (ATP) and diatomite (DE) were co-ball milled with sawdust biochar (pyrolyzed at 600 °C for 2 h) at ratios of 10-40% (w/w) and examined the ability of methylene blue (MB) to be removed from aqueous solutions by them. All the mineral-biochar composites sorbed more MB than both ball milled biochar (MBC) and ball milled mineral alone, indicating there was a positive synergy in co-ball milling biochar with these minerals. The 10% (w/w) composites of ATP:BC (MABC10%) and DE:BC (MDBC10%) had the greatest MB maximum adsorption capacities (modeled by Langmuir isotherm modeling) and were 2.7 and 2.3 times that of MBC, respectively. The adsorption capacities of MABC10% and MDBA10% were 183.0 mg g-1 and 155.0 mg g-1 at adsorption equilibrium, respectively. These improvements can be owing to the greater content of oxygen-containing functional groups and higher cation exchange capacity of the MABC10% and MDBC10% composites. In addition, the characterization results also reveal that pore filling, π-π stacking interactions, hydrogen bonding of hydrophilic functional groups, and electrostatic adsorption of oxygen-containing functional groups also contribute prominently to the adsorption of MB. This, along with the greater MB adsorption at higher pH and ionic strengths, suggests the roles in MB adsorption was an electrostatic interaction and an ion exchange mechanism. These results demonstrate that mineral-biochar composites prepared by co-ball milling treatment were promising sorbents of ionic contaminants for environmental applications.

Pyrolysis of low-value waste sawdust over low-cost catalysts: physicochemical characterization of pyrolytic oil and value-added biochar

The present work deals with an experimental investigation into the generation and characterization of pyrolytic oil and biochar from Sal wood sawdust (SW). The pyrolysis experiment was performed in a semi-batch reactor at 500 oC and 80 oC/min heating rate with CaO, CuO, and Al2O3 catalysts. Further, the pyrolytic oil and biochar were investigated using different analyses, including proximate analysis, elemental analysis, thermal stability, GC-MS, FTIR, field emission scanning electron microscopy, electrical conductivity analysis, higher heating value (HHV), zeta potential analysis, and ash content analysis. Pyrolysis results revealed that compared to thermal pyrolysis (46.02 wt%), the pyrolytic oil yield was improved by catalytic pyrolysis with CaO and CuO (50.02 and 48.23 wt%, respectively). Further, the characterization of pyrolytic oil revealed that the loading of catalysts considerably improved the oil's properties by lowering its viscosity (69.50 to 22 cSt), ash content (0.26 to 0.11 wt%), and oxygen content (28.32 to16.60 %) while raising its acidity (4.2 to 9.6), heating value (25.66 to 36.09 MJ/kg), and carbon content (61.79 to 74.28%). According to the FTIR analysis, the pyrolytic oil contained hydrocarbons, phenols, aromatics, alcohols, and oxygenated compounds. Additionally, the GC-MS analysis showed that catalysts significantly reduced oxygenated fractions, phenols (20.23 to 15.26%), acids (12.23 to 6.56%), and increased hydrocarbons (12 to 16 wt%). Additionally, the results of the biochar analysis demonstrated that SW biochar was appropriate for a range of industrial applications, including in catalysts, supercapacitors, fuel cells, and bio-composite materials.

Pseudomonas stutzeri Immobilized Sawdust Biochar for Nickel Ion Removal

Nickel ions generated from the electroplating industry and stainless steel and battery manufacturing industries contribute to water pollution, harm human health, and pose environmental risks. A long-term, sustainable, and efficient treatment method should be developed to address this issue. Bioremediation in the presence of biochar and microorganisms is a potential approach for metal ion abatement. This study evaluates the feasibility of Pseudomonas stutzeri immobilized sawdust biochar (PSDB) for Ni2+ removal. Sawdust biochar was prepared by pyrolyzing in a muffle furnace and was characterized using SEM, FTIR, and BET. The influence of biochar preparation parameters such as pyrolysis temperature, time on biochar yield, and impact on cell immobilization was investigated. The effect of various parameters, such as incubation time, pH, temperature, and biocatalyst dosage, was studied. The total Ni2+ in solution was analyzed using inductively coupled plasma optical emission spectrometry. PSDB showed an 83% Ni2+ removal efficiency and reusability up to three cycles. FT-IR analysis revealed that the mechanism of Ni2+ removal by PSDB was the synergistic effect of adsorption by biochar and bioaccumulation by P. stutzeri. This study presents a novel approach for environmental application by utilizing waste biomass-derived biochar as a carrier support for bacteria and an adsorbent for pollutants.

Evaluation of the use of biochar to stabilize polycyclic aromatic hydrocarbons and phthalates in sediment

Three types of biochar (BC) (mulberry biochar (MB), wheat straw biochar, and pine tree sawdust biochar) were prepared and used to stabilize hydrophobic organic compounds (HOCs) in contaminated sediment. The kinetics of HOC adsorption to the BCs had two distinct stages. The second stage adsorption process was longer for MB than the other BCs, presumably because MB contained large pores, mesopores, and micropores. The adsorption isotherms for the three BCs were described well by the Freundlich model. The adsorption capacities of MB, WS and PT for HOCs ranged between 106.7 and 1202 μg/g, 135.1 and 1002 μg/g, and 255.6 and 909 μg/g, respectively. The apparent HOC adsorption coefficients (KBC−w) for the three BCs were determined from the isotherm data and were similar. The HOC logKOW values correlated well with the logKBC−w values. In sediment slurry experiments, HOCs were much more effectively stabilized by MB than wheat straw and pine tree sawdust biochar. This was probably because of the MB pore characteristics that favored adsorption of HOCs of various molecular sizes. The Fourier-transform infrared and Raman spectra indicated that the main binding mechanisms were hydrogen boding, hydrophobic interactions, and π–π interactions. MB was found to be a possible agent for stabilizing HOCs in contaminated sediment. HOCs in sediment slurry continued to become adsorbed to MB for a long time, indicating that relatively long reaction times should be allowed for in situ remediation using MB.

An investigation into biochar, acid-modified biochar, and wood vinegar on the remediation of saline−alkali soil and the growth of strawberries

The salinization of several hundred million hectares of land poses a serious threat to global food security and biodiversity. Biochar and wood vinegar amendment has been suggested as a possible way to promote plant productivity and improve soil qualities, whereas less emphasis has been placed on the application of biochar in saline−alkaline soils to increase plant productivity. Herein, the single and composite application of sawdust biochar, wood vinegar, and acid-modified biochar on the restoration of coastal saline−alkali soil and plant growth of strawberry seedlings was investigated. Proximate and ultimate analyses and different characterization techniques such as FTIR and scanning electron microscopy were applied to study the physicochemical characteristics of raw and modified biochar. A pot experiment was conducted to explore the effects of different soil additives on soil properties and strawberry growth. Our results revealed that acid-modified biochar shows the most significant promoting effect on strawberry growth, which could increase the weight gain rate, root length, root specific surface area, and root volume of strawberry seedlings by 41.2%, 18.9%, 23.0%, and 34.7%, respectively. Moreover, the application of acid-modified biochar can effectively alleviate soil salinization by reducing soil pH (7.65) and CEC (19.5 cmol/kg). Furthermore, the addition of biochar can significantly improve the community structure of microorganisms (Proteobacteria) and increase the content of bacteria related to soil nutrient cycling (Pseudomonadaceae and Sphingomonadaceae). Preliminary findings from this study suggested that acid-modified biochar is a potentially effective means of preventing soil salinization and increasing economic crop yields.