Global Change Biology Bioenergy最新文献

This work assesses pathways towards a net-zero greenhouse gas (GHG) emissions chemical industry sector in Germany until 2050, focusing on the ammonia, methanol, ethylene and adipic acid subsectors and the effect of the recycling of C embedded in chemical end products on the GHG abatement cost and primary resource demand. This was done using a bottom-up mathematical optimization model, including the energy sectors and the chemicals sector, with electricity and biobased options considered. Results show that net-zero GHG emissions for the considered chemicals in 2050 are attainable at a marginal cost of 640–900 €/tCO₂-eq, even with 26%–36% of demand being satisfied by fossil production routes. This is possible because renewable organic chemicals can act as carbon sinks if, at their end of life, C is permanently stored via landfilling or passed on to the next value chain via recycling. Nonetheless, considering the cost implications, the practical deployment of renewable chemicals is a challenge. The considered renewable chemicals cost 1.3–8 times more than their fossil counterparts, resulting in a marginal CO₂ price of 480 €/tCO₂-eq when all primary resources (energy crops, forest residues and renewable electricity) are considered, or 810 €/tCO₂-eq when the availability of arable land is restricted. In the transition to net-zero emissions for the chemicals under study, a circular economy is important not only for reducing demand for primary resources as is typically the case but also reduces GHG abatement costs by 13%–24% through carbon capture and utilization effects.

Biochar is an effective ameliorator for soil quality improvement and nutrient reuse from biomass; however, the effect of biochar application on soil potassium (K) availability, plant K uptake, and the underlying mechanisms have not been well-elucidated. To address this, the variation in the soil K forms, soil aggregate stability, and aggregate-associated K concentration, as well as maize K uptake, were investigated in a field experiment after 9 years of biochar amendment. The treatments included no biochar and NPK fertilizer (CK); NPK fertilizer treatment (F); biochar applied annually at the rate of 2.625 t ha⁻¹ (C₁), and biochar applied annually at rate of 2.625 t ha⁻¹ with NPK fertilizers (C₁F); one-time biochar applied with NPK fertilizers, with biochar rate of 31.5 (C₂F) and 47.25 t ha⁻¹ (C₃F). The results showed that after 9 years of field application, biochar inhibited the downward K migration to the deeper layer, thus increasing water-soluble potassium (WSK), exchangeable potassium (EK), non-exchangeable potassium (NEK), and total potassium (TK) in 0–20 cm soil, with C₁F exhibiting better performance than C₂F and C₃F. Biochar also increased aggregate-associated EK, NEK, and TK pools, mainly due to an increase in the macroaggregate proportion (>0.25 mm). Biochar amendment promoted maize K uptake by an average of 35.69%, the path analysis indicated that the positive effect was an outcome of the synergetic effect of the increase in surface soil WSK content and promoted macroaggregate EK pools, which was primarily attributed to biochar improved soil properties, including soil organic carbon, pH, total nitrogen, total phosphorus, and cation exchange capacity. These factors explained 76% of the variance in maize K uptake. In conclusion, biochar is an effective ameliorator for improving soil K content and availability.

The present work studies the composting effects on the chemical characteristics of bio-oil produced by pyrolysis of sisal residue. Three systems were composted with sisal residue proportions to sisal fiber powder of 100:0, 90:10, and 75:25, respectively. The systems showed reductions of 33%–48% (extractive), 70%–80% (hemicellulose), and 80%–90% (cellulose) after composting. An increase in lignin content was observed in all systems. The pyrolysis of the composted systems was performed at 450°C and 550°C. At both temperatures, this process was selective in producing a large concentration of hydrocarbons (>160% increase), mainly alkanes and alkenes, reducing the concentrations of ketones, aldehydes, and phenolics (>50%) and eliminating esters, furans, and acetic acid to composted biomasses. The higher temperature favored aromatics and cyclic hydrocarbon production from the pyrolysis of composted samples. In addition to these results, composting helped reduce the oxygenated bio-oil species by approximately 44%–75% at the lowest and ~69% at the highest temperatures. These results indicate that composted sisal residue can produce bio-oils that are more suitable for biorefineries since they are rich in aliphatic hydrocarbons and non-oxygenated species.

Biochar is produced by burning biomass under oxygen-limited conditions, and it has been widely used as a soil amendment to improve soil functions such as nutrient retention. However, whether the impact of biochar application on soil nitrogen (N) transformation and N₂O emission varies with the pyrolysis temperature remains unclear, especially in different forest types in subtropical regions. In this study, a 60-day laboratory incubation experiment was conducted to evaluate the impact of biochar with different pyrolysis temperatures (300°C [BC300], 500°C [BC500], and 800°C [BC800]) on net N transformation rates and N₂O emission in soils collected from Castanopsis kawakamii dominated natural forest (NF) and Chinese fir (Cunninghamia lanceolate, CF) plantation in subtropical China. The results showed that the application of biochar significantly increased soil ammonium (NH₄⁺) content (p < 0.001) but reduced nitrate (NO₃⁻) content (p < 0.001) compared with the control. The soil NH₄⁺ content of the BC800 treatment was significantly higher than that of other treatments (p < 0.001). Biochar application significantly reduced soil net N mineralization (NR_min) and nitrification (NR_nit) rate (p < 0.001), but increased net ammonification (NR_amm) rate (p < 0.001). The application of biochar led to a remarkable decrease in cumulative N₂O emission compared to the control (p < 0.001). In particular, soils treated with high-temperature biochar emitted significantly lower N₂O compared to other treatments (p < 0.001). The partial least squares path model demonstrated that biochar influenced N₂O emission through a direct effect in NF soil and an indirect effect in CF soil. This study highlights the distinct role of biochar, particularly that produced under high pyrolysis temperatures as a soil amendment to mitigate N₂O emission and promote N retention in both subtropical natural and planted forests.

Forest management in drained forested peatlands can negatively affect water quality due to the increase in exports of organic matter and nutrients. Therefore, new methods to alleviate this impact are needed. In laboratory conditions, biochar has been shown to be a strong sorbent of organic and inorganic nutrients due to its high surface area and ion-exchange capacity. However, evidence of the adsorption capacity in field conditions is lacking. Here, we studied the water purification performance of two different biochar feedstocks (wood- and garden residue-based) in a 10-day laboratory experiment where we incubated biochar with runoff water collected from drainage ditches in clear-cut peatland forests. We measured changes in pH and concentrations of inorganic phosphorus (PO₄), total dissolved nitrogen (TDN), and dissolved organic carbon (DOC). The biochar with the best adsorbent capacity in the laboratory experiment was then tested in field conditions in a replicated catchment-scale experiment, where both clear-cutting and ditch cleaning were performed. We determined the nutrient concentration of water at the inlet and outlet of biochar filters placed in outflow ditches of four catchments. We found that under laboratory conditions wood-based biochar efficiently adsorbed TDN and DOC, however, it released PO₄. Furthermore, we found that the biochar filters reduced TDN and DOC concentration in field conditions. However, the percentage decrease in concentration was dependent on the initial concentrations of nutrients in the water and could be considered low. Moreover, we found that the biochar in the filters increased in TN content over the course of the experiment. This suggests that a wood-based biochar filter has the potential to be a water protection tool for reducing the export of nutrients from catchments with high nutrient concentration. And that the biochar from the ditches could be applied back to the regenerating forest catchment as a potential soil amendment, closing the nutrient cycle.

Owing to the enormous consumption of petroleum products and their environmental polluting nature, attention has been given to seeking alternative resources for the development of sustainable products. Biomass is a renewable source that can be converted to a variety of fuels and chemicals by different approaches, which are the best replacements for traditional petroleum-derived products. Pyrolysis is a process in which chemical bonds of biomass macromolecules such as cellulose, hemicellulose, and lignin, are fractured into small molecular intermediates under high pressure, and results bio-oil, biochar, and fuel gases as desired products. Of these pyrolysis products, bio-oil is the primary product that usually contains large amounts of oxygen and nitrogen compounds that hinder its application potential. Catalytic pyrolysis is a beneficial method that is reported to alter the constituents and quality of bio-oil and to upgrade them for diverse applications. Catalytic hydropyrolysis and copyrolysis of biomass are an alternative approaches to overcome the drawbacks raised toward product formation in the pyrolysis process. Layered double hydroxides (LDH) and their derived forms are well-known catalytic/catalytic support materials for various chemical reactions due to their superior properties, such as easy preparation, thermal stability, and tuneable acid/base properties. This review summarizes the progress in the utilization of as-synthesized LDH and their modified forms such as mixed metal oxides and functionalized/composite materials as active catalysts for the pyrolysis of various biomass sources.

Switchgrass (Panicum virgatum L.) production for biofuel has the potential to produce reasonable yields on lands not suited for conventional agriculture. We assessed nine switchgrass cultivars representing lowland and upland ecotypes grown for 11 years at a site in the upper Midwest USA for belowground differences in soil carbon and nitrogen stocks, soil organic matter fractions, and standing root biomass to 1 m depth. We also compared potential nitrogen mineralization and carbon substrate use through community-level physiological profiling in surface soils (0–10 cm depth). Average yields and standing root biomass differed among cultivars and between ecotypes, but we found no significant cultivar-related impacts on soil carbon and nitrogen stocks, on the distribution of particulate and mineral-associated soil organic matter fractions, nor on potential nitrogen mineralization or microbial community-level physiological profiles. That these traits did not differ among cultivars suggests that soil carbon and nitrogen gains under switchgrass are likely to be robust with respect to cultivar differences, and to this point not much affected by breeding efforts.

Synergistic fermentation of coal and corn straw is an effective tool to increase biomethane production. However, a large gap exists between the biomethane production conditions of corn straw filling coal mine goafs and laboratory experiments. In order to determine the effect of the field environment on synergistic biomethane production, biomethane production experiments with coal and corn straw were carried out under different conditions to find the key factors restricting the potential of biomethane production. The obtained results showed that various bacterial sources had significant influences on the biomethane production of coal and corn straw, and domesticated bacterial sources provided fermentation systems with more efficient biomethane production capacities than mine water sources. Biomethane production of coal and corn straw was relatively high under mixed conditions, but it was also promoted under unmixed conditions. Different inorganic minerals had different effects on synergistic biomethane production, which varied. For example, calcite, montmorillonite, and kaolin are common minerals in coal-bearing strata that significantly enhance synergistic biomethane production of coal and corn straw. However, pyrite was found to significantly inhibit the synergistic biomethane production effect of coal and corn straw. Highly metamorphosed anthracite coal also presented biomethane production potential when stimulated by corn straw as a carbon source. The obtained results revealed the influences of different field conditions on the biomethane production of coal and corn straw and provided a reference for the field application of corn straw filling in coal mine goafs.

Invasive alien plant species (IAPS) are a global problem, representing a threat to ecosystem functioning, biodiversity, and human health. Legislation requires the management and eradication of IAPS populations; yet, management practices are costly, require several interventions, and produce large amounts of waste biomass. However, the biomass of eradicated IAPS can become a resource by being used as feedstock for biochar production and, at the same time, implementing the management of IAPS. Here we carried out an in-depth characterization of biochar produced at 550°C derived from 10 (five woody and five herbaceous) widespread IAPS in the central-southern Alps region to determine their potential applications for soil amendment, soil remediation, and carbon storage. Biochar was produced at a laboratory scale, where its physicochemical characteristics, micromorphological features, and lead adsorption from aqueous solutions were measured. To investigate any possible trade-offs among the potential biochar applications, a principal component analysis was performed. IAPS-derived biochars exhibited relevant properties in different fields of application, suggesting that IAPS biomass can be exploited in a circular economy framework. We found coordinated variation and trade-offs from biochars with high stability to biochars with high soil amendment potential (PC1), while the biochar soil remediation potential represents an independent axis of variation (PC2). Specifically, IAPS-derived biochar had species-specific characteristics, with differences between the woody and herbaceous IAPS, the latter being more suitable for soil amendment due to their greater pH, macronutrient content, and macropore area. Biochar derived from woody IAPS showed a greater surface area, smaller pores, and had higher lead adsorption potentials from aqueous solutions, hinting at their higher potential for heavy metal pollution remediation. Moreover, biochar derived from woody IAPS had a higher fixed carbon content, indicating higher carbon stability, and suggesting that their biochar is preferable for carbon sequestration in the view of climate change mitigation.

Bioenergy with carbon capture and geological storage (BECCS) is considered one of the top options for both offsetting CO₂ emissions and removing atmospheric CO₂. BECCS requires using limited land resources efficiently while ensuring minimal adverse impacts on the delicate food-energy-water nexus. Perennial C4 biomass crops are productive on marginal land under low-input conditions avoiding conflict with food and feed crops. The eastern half of the contiguous U.S. contains a large amount of marginal land, which is not economically viable for food production and liable to wind and water erosion under annual cultivation. However, this land is suitable for geological CO₂ storage and perennial crop growth. Given the climate variation across the region, three perennials are major contenders for planting. The yield potential and stability of Miscanthus, switchgrass, and energycane across the region were compared to select which would perform best under the recent (2000–2014) and future (2036–2050) climates. Miscanthus performed best in the Midwest, switchgrass in the Northeast and energycane in the Southeast. On average, Miscanthus yield decreased from present 19.1 t/ha to future 16.8 t/ha; switchgrass yield from 3.5 to 2.4 t/ha; and energycane yield increased from 14 to 15 t/ha. Future yield stability decreased in the region with higher predicted drought stress. Combined, these crops could produce 0.6–0.62 billion tonnes biomass per year for the present and future. Using the biomass for power generation with CCS would capture 703–726 million tonnes of atmospheric CO₂ per year, which would offset about 11% of current total U.S. emission. Further, this biomass approximates the net primary CO₂ productivity of two times the current baseline productivity of existing vegetation, suggesting a huge potential for BECCS. Beyond BECCS, C4 perennial grasses could also increase soil carbon and provide biomass for emerging industries developing replacements for non-renewable products including plastics and building materials.