biomass

摘要： Hydrothermal carbonization is highly applicable to high moisture biomass upgrading due to the fact that moist-ure involved can be directly used as reaction media under the subcritical-water region.With this,value-added utilization of hydrochar as solid fuel with high carbon and energy density is one of the important pathways for biomass conversion.In this review,the dewatering properties of hydrochar after the hydrothermal carbonization of biowaste,coalification degree with elemental composition and evolution,pelletization of hydrochar to enhance the mechanical properties and density,coupled with the combustion properties of hydrochar biofuel were discussed with various biomass and carbonization parameters.Potential applications for the co-combustion with coal,cleaner properties and energy balance for biowaste hydrothermal carbonization were presented as well as the challenges.

摘要： Sea ice melt water and circumpolar deep water(CDW)intrusion have important impacts on the ecosystem of the Amundsen Sea.In this study,samples of nutrients and phytoplankton pigments from nine stations in the eastern Amundsen Sea were collected during the austral summer.Based on in-situ hydrological observations,sea ice density data from satellite remote sensing,and chemical taxonomy calculations,the relationships between environmental factors and phytoplankton biomass and community structure were studied.The results showed that with increasing latitude,the contribution of sea ice melt water(MW%)and the stability of the water body increased,and the depth of the mixed layer(MLD)decreased.The integrated concentration of chlorophyll a(Chl-a)ranged from 21.4 mg·m^(−2) to 148.4 mg·m^(−2)(the average value was 35.7±53.4 mg·m^(−2)).Diatoms(diatoms-A[Fragilariopsis spp.,Chaetoceros spp.,and Proboscia spp.]and diatoms-B[Pseudonitzschia spp.])and Phaeocystis antarctica were the two most widely distributed phytoplankton groups and contributed 32%±16%and 28%±11%,respectively,of the total biomass.The contributions of Dinoflagellates,Chlorophytes,Cryptophytes,the high-iron group of P.antarctica,and Diatom group A were approximately 17%±8%,15%±13%,9%±6%,5%±9%,and 3%±7%,respectively.The area with the highest phytoplankton biomass was located near the ice-edge region,with a short time lag(T_(lag))between sampling and complete sea ice melt and a high MW%,while the area with the second-highest Chl-a concentration was located in the area affected by the upwelling of CDW,with thorough water mixing.Vertically,in the area with a short T_(lag) and a shallow MLD,the phytoplankton biomass and proportion of diatoms decreased rapidly with increasing water depth.In contrast,in the region with a long T_(lag) and limited CDW upwelling,the phytoplankton community was dominated by a relatively constant and high proportion of micro phytoplankton,and the phytoplankton biomass was low and relatively stable vertically.Generally,the phytoplankton community structure and biomass in the study area showed high spatial variation and were sensitive to environmental changes.

摘要： Oxygen electrode catalysts are important as inter-conversion of O_(2) and H_(2)O is crucial for energy technologies.However,the sluggish kinetics of oxygen reduction and evolution reactions(ORR and OER)are a hindrance to their scalable production,whereas scarce and costly Pt and Ir/Ru-based catalysts with the highest electrocatalytic activity are commercially unviable.Since good ORR catalysts are not always efficient for OER and vice versa,so bifunctional catalysts on which OER and ORR occurs on the same electrode are very desirable.Alternative catalysts based on heteroatom-doped carbon nanomaterials,though showed good electrocatalytic activity yet their high cost and complex synthesis is not viable for scalable production.To overcome these drawbacks,biomass-derived heteroatom-doped porous carbons have recently emerged as low-cost,earth-abundant,renewable and sustainable environment-friendly materials for bifunctional oxygen catalysts.The tunable morphology,mesoporous structure and high concentration of catalytic active sites of these materials due to heteroatom(N)-doping could further enhance their ORR and OER activity,along with tolerance to methanol crossover and good durability.Thus,biomassderived heteroatom-doped porous carbons with large surface area,rich edge defects,numerous micropores and thin 2 D nanoarchitecture could be suitable as efficient bifunctional oxygen catalysts.In the present article,synthesis,N-doping,ORR/OER mechanism and electrocatalytic performance of biomassderived bifunctional catalysts has been discussed.The selected biomass(chitin,eggs,euonymus japonicas,tobacco,lysine and plant residue)except wood,act as both C and N precursor,resulting in N selfdoping of porous carbons that avoids the use of toxic chemicals,thus making the synthesis a facile and environment-friendly green process.The synthetic strategy could be further optimized to develop future biomass-based N self-doped porous carbons as metal-free high performance bifunctional oxygen catalysts for commercial energy applications.Recent advances and the importance of biomass-based bifunctional oxygen catalysts in metal-air batteries and fuel cells has been highlighted.The material design,perspectives and future directions in this field are also provided.

摘要： A series of Zn_(x)Ni_(y)CrO_(m±δ)catalysts were synthesized via a typical co-precipitation method,in which Zn-Cr layered double hydroxides(LDHs)were found and Ni-Zn intermetallic compound(IMC)was formed after reduction in hydrogen.During auto-thermal reforming(ATR)of acetic acid(HAc),the Ni-Zn IMC was transformed into Ni/(amorphous-ZnO)-ZnCr_(2)O_(4) species with uniformed distribution and appropriate interaction within these Ni-Zn-Cr-O species;besides,the adsorbed oxygen promoted the activation and transfer of oxygen species;therefore,deactivation by oxidation,sintering and coking was inhibited.And the optimized Zn_(2.37)Ni_(0.63)CrO_(4.5±δ)catalyst presented high activity and stability in a 45-h ATR test with HAc conversion near 100%and hydrogen yield at 2.7 mol-H_(2)/mol-HAc,showing potential for hydrogen production via ATR of HAc.

摘要： Potential of green hydrogen producing from biomass, solar and wind in Togo has been performed. The availability of these three resources has been depicted with maps showing them per cantons in Togo, thus, by using the datasets from ESA Biomass Climate Change Initiative, the global solar atlas and the global wind atlas. The conversions rates used were: for solar resource, 3% of land was allocated for the analysis after removing the exclusions with a conversion rate of 52.5 kWh/kg of hydrogen;for biomass hydrogen, the conversion rate of 13.4 kg BS/kg H2 was assumed. Wind resources at 50 m above ground were not sufficient to evaluate the potential as it is lower than class 3 winds. QGIS version 3.6.4 and R version 4.0.4 were used. Results showed that biomass is the leading resource for producing green hydrogen from renewable energy resources;with good impact in these two cantons: Bassar, Gobe/ Eketo/Gbadi N’Kugna. However, this resource is still decreasing and in some cantons it is null.

摘要： The relationships between climate conditions and wood density in tropical forests are still poorly understood.To quantify spatial dependence of wood density in the state of Minas Gerais(MG,Brazil),map spatial distribution of density,and correlate density with climate variables,we extracted data from the Forest Inventory of Minas Gerais for 1988 trees scaled throughout the territory and measured wood density of discs removed from the trees.Environmental variables were extracted from the database of the Ecological-Economic Zoning of Minas Gerais.For spatial analysis,tree densities were measured at 44 georeferenced sampling points.The data were subjected to exploratory analysis,variography,cross-validation,model selection,and ordinary kriging.The relationships between wood density and environmental variables were calculated using dispersion matrices,linear correlation,and regression.Wood density proved to be highly spatially dependent,reaching a correlation of 96%,and was highly continuous over a distance of 228 km.The distribution of wood density followed a continuous gradient of 514-659 kg m^(−3),enabling corre-lation with environment variables.Density was correlated with mean annual precipitation(−0.57),temperature(0.63),and evapotranspiration(0.83).Geostatistical methods proved useful in predicting wood density in native tropical forests with different climate conditions.Our results confirmed the sensitivity of wood density to climate change,which could affect future carbon stock in forests.

摘要： With the world’s fossil fuels being finite in nature,an increasing interest focuses on the application of alternative renewable resources such as biomass.Biomass-derived platform chemicals with abundant functional groups have the potential to replace bulk chemicals for the production of value-added chemicals,fuels,and materials.The upgrading of these platform chemicals relies on the development of efficient catalytic systems.Hydrotalcite,with its wide compositional variety,tuneable anion-exchange capacity,and controlled acidity/basicity sites demonstrates great potential in the catalytic upgrading of biomass and the derived platform chemicals.The past decade has witnessed the emergence of research achievements on the development of efficient and robust hydrotalcite-derived metal catalysts and their applications in the upgrading of biomass or the derived platform chemicals.In this review,we aim to summarize the recent advances on the catalytic upgrading of biomass-derived platform chemicals(e.g.,furfural,5-hydroxymethylfurfural,levulinic acid,and glycerol)via hydrotalcitederived metal catalysts.We also observed that the crucial role of using hydrotalcite-derived catalysts relies on their strong metal–support interactions.As a result,a section focusing on the discussion of the metal–support interactions of hydrotalcitederived catalysts was provided.

摘要： The biodiversity quality of ground-layer invertebrates within the cropped area of a plantation of the biomass crop willow short-rotation coppice (SRC) grown within a floodplain was compared to the biodiversity quality of the neighbouring plots of floodplain grassland and a mixed deciduous woodland plantation. Pitfall traps were used to collect ground beetles (Carabidae) and arachnids (Araneae and Opiliones) in the plots over a period of two years. A range of biodiversity indices was used to assess the biodiversity quality of each of the three plots, and the willow SRC was compared to each of the controls using Mann-Whitney tests. The willow SRC transitioned from almost bare ground to young woodland during the two years of the study, which affected comparisons with alternative land uses as the habitat during the second year was very different from the habitat at the start of the study. Compared to plantation woodland, in the first year, the effect was mostly positive, but this declined in the second year. Compared to grassland there was a largely negative effect in both years. However, when in combination with other habitats, willow SRC cultivation on floodplain land may have an overall positive effect on invertebrate biodiversity quality.

摘要： Medicago sativa (lucerne) is a perennial and drought tolerant fodder crop which is widely used as feed for livestock in South Africa. This study evaluated four lucerne cultivars under two water regimes and also determined the effect of soil type on lucerne biomass production. To determine dry matter production per cultivar per treatment, a random grid (quadrant) sampling method was used and all biomass within that radius was cut to 5 cm above the ground level in each plot. All biomass sampling was done just before regrowth commences. Biomass data collection on four lucerne cultivars belonging to different dormancy groupings (WL 711, WL 525 HQ, KKS 9911 and SA Standard) were collected seasonally under different soil types on both irrigated and non-irrigated plots and analysed. Soil type (site) had a significant (P < 0.05) effect on the overall quantity of dry matter produced as more dry matter was produced in site 2 (S2) in comparison to site 1 (S2). Different levels of water application (moisture supplementation) also affected the quantity of dry matter produced in each soil type. The once-a-month irrigation treatment (Ir1) led to the production of superior dry matter yield on SI even though the effect was not significant. In S2 twice a month irrigation treatment (Ir2) produced the highest dry matter, however, this effect was significant (P < 0.05) only in comparison with zero irrigation (Ir0) treatment. Cultivar 3 (KKS 9911) was the least productive cultivar in S1, while the same cultivar was the least productive cultivar in S2. These findings show that both soil type and irrigation levels had a significant (P < 0.05) effect on the total dry matter production of the tested Lucerne cultivars belonging to different dormancy groupings.

摘要： A series of bifunctional Zn Ce@SBA-15 catalysts with different Zn/Ce ratios were prepared by a solid-state grinding strategy and used in the conversion of ethanol to 1,3-butadiene(ETB).For the supported metal oxides,Zn O serves as the active sites for the dehydrogenation of ethanol,and CeO_(2) promotes the aldolcondensation reaction.Based on the results of Py-FTIR and NH_(3)-TPD,it suggests that the yield of 1,3-butadiene is positively correlated with the number of weak Lewis acid sites on the catalyst surface,given their benefit for aldol-condensation reactions.The catalyst with an optimal Zn/Ce ratio of about 1:5 has the highest concentration of weak Lewis acid.Coupling with the Zn O sites,it contributes to a 98.4%conversion of ethanol and a 45.2%selective of 1,3-butadiene under relatively mild reaction conditions(375°C,101.325 k Pa,and 0.54 h^(-1)).

摘要： 本发明涉及用于生物质基合成气制备低碳醇催化剂的制备方法及应用。所述催化剂以低廉废弃的生物质为载体，直接利用生物质结构单元纤维素的多羟基基团与金属离子进行配位，在生物质骨架内部限域金属离子；高温惰性气氛下，生物质自身的热解碳不仅起到载体的功能，还可原位还原生成金属纳米颗粒，得到纳米颗粒在生物质孔道内部限域型催化剂。在生物质基合成气制备低碳醇反应中，本发明的催化剂表现出优良的CO加氢活性和C2+醇的选择性，且催化剂的寿命超过350h。本发明的催化剂制备工艺流程简单可控，以生物质为原料，极大提高催化剂的经济性，并直接用于催化生物质转化反应，可实现生物质全组分的高效利用，在生物质利用上有广泛应用前景。