Metals in biomass

Background, Aim and Scope

Metal ions generally share the ability/tendency of interacting with biological material by forming complexes, except possibly for the heavy alkali metals K, Rb and Cs. This is unrelated to the metals being either essential for sustaining life and its reproduction, apparently insignificant for biology, although perhaps undergoing bioconcentration or even being outright toxic, even at low admission levels. Yet, those different kinds of metal-biomass interactions should in some way depend on properties describing coordination chemistries of these very metals. Nevertheless, both ubiquitously essential metals and others sometimes used in biology should share these properties in numeric terms, since it can be anticipated that they will be distinguished from nonessential and/or toxic ones. These features noted above include bioconcentration, the involvement of metal ions such as Zn, Mg, Cu, Fe, etc. in biocatalysis as crucial components of metalloenzymes and the introduction of a certain set of essential metals common to (almost) all living beings (K, Mg, Mo, Mn, Fe, Cu and Zn), which occurred probably very early in biological evolution by ‘natural selection of the chemical elements’ (more exactly speaking, of the metallomes).

Materials and Methods

The approach is semiempirical and consists of three consecutive steps: 1) derivation of a regression equation which links complex stability data of different complexes containing the same metal ion to electrochemical data pertinent to the (replaced) ligands, thus describing properties of metal ions in complexes, 2) a graphical representation of the properties-two typical numbers c and x for each metal ion-in some map across the c/x-space, which additionally contains information about biological functions of these metal ions, i.e. whether they are essential in general (e.g. Mg, Mn, Zn) or, for a few organisms of various kinds (e.g. Cd, V), not essential (e.g. rare earth element ions) or even generally highly toxic (Hg, U). It is hypothesized that, if coordination properties of metals control their biological ‘feasibility’ in some way, this should show up in the mappings (one each for mono and bidentate-bonding ligands). 3) eventually, the regression equation produced in step 1) is inverted to calculate complex stabilities pertinent to biological systems: 3a) complex stabilities are mapped for ligands delivered to soil (-water) by green plants (e.g. citrate, malate) and fungi and, compared to their unlike selectivities and demands of metal use (photosynthesis taking place or not), 3b) the evolution of the metallome during late chemical evolution is reconstructed.

Results

These maps show some ‘window of essentiality’, a small, contrived range/area of c and x parameters in which essential metal ions gather almost exclusively. c and x thus control the possibility of a metal ion becoming essential by their influencing details of metal-substrate or (in cases of catalytic activities) metal-product interactions. Exceptions are not known to be involved in biocatalysis anyhow.

Discussion

Effects of ligands secreted, e.g. from tree roots or agaric mycelia to the soil on the respective modes (selectivities) of metal bioconcentration can be calculated by the equation giving complex stability constants, with obvious ramifications for a thorough, systematic interpretation of biomonitoring data. Eventually, alterations of C, N and P-compounds during chemical evolution are investigated — which converted CH₄ or CO₂, N₂ and other non-ligands to amino acids, etc., for example, with the latter behaving as efficient chelating ligands: Did they cause metal ions to accumulate in what was going to become biological matter and was there a selectivity, a positive bias in favour of nowessential metals (see above) in this process? Though there was no complete selectivity of this kind, neither a RNA world in which early ribozymes effected most of biocatalysis, nor a paleoatmosphere containing substantial amounts of CO could have paved the way to the present biochemistry and metallomes.

Conclusions

This way of reasoning provides a causal account for abundance distributions described earlier in the Biological System of Elements (BSE; Markert 1994, Fränzle &; Markert 2000, 2002). There is a pronounced change from chemical evolution, where but few transformations depended on metal ion catalysis to biology.

Recommendations and Perspectives

The application of this numerical approach can be used for modified, weighted evaluation of biomonitoring analytical data, likewise for the prediction of bioconcentration hazards due to a manifold of metal ions, including organometallic ones. This is relevant in ecotoxicology and biomonitoring. In combining apoproteins or peptides synthesized from scratch for purposes of catalysing certain transformations, the map and numerical approaches might prove useful for the selection of central ions which are even more efficient than the ‘natural’ ones, like for Co²⁺ in many Zn enzymes.

     

Characterization and valorization of biomass ashes

In India, farming is the primary source of income for many families. Following each harvest, a huge amount of biomass is generated. These are generally discarded as “agrowaste,” but recent reports have indicated several beneficial uses for these biomasses and their ashes. However, before the utilization of biomass ashes (BMAs), their chemical and physical properties need to be investigated (characterized) so as to utilize their potential benefit to the fullest. In this paper, eight different biomass ashes (soybean plant ash, mustard plant ash, maize ash, groundnut plant ash, cotton plant ash, wheat plant ash, pigeon peas ash, and groundnut shell ash) were characterized, and their chemical properties are discussed. Surface chemical composition analysis, proximate analysis, and ultimate analysis were performed on all BMA samples, and properties such as porosity, particle density, bulk density, point of zero charge, BET surface area, water-absorption capacity, and bulk parameters such as surface pH and surface charges were determined. BMAs were characterized by SEM and FTIR. The surface areas of biomass ashes vary from 1.9 to 46 m²/g, and point of zero charge for all BMAs exceed 9.8, which confirmed the alkaline nature of these samples. Based on the chemical composition, BMAs are categorized into four types (S, C, K, and CK), and their utilization is proposed based on the type. BMAs find applications in agriculture and construction industries; glass, rubber, and zeolite manufacturing; and in adsorption (as a source of silica/zeolites). The paper also discusses the research challenges and opportunities in utilization of BMAs.     

Preparation of gasification feedstock from leafy biomass

Dried leaves are a potential source of energy although these are not commonly used beside to satisfy daily energy demands in rural areas. This paper aims at preparing a leafy biomass feedstock in the form of briquettes which can be directly used for combustion or to extract the combustible gas using a gasifier. Teak (Tectona grandis) and rubber (Hevea brasiliensis) leaves are considered for the present study. A binder-assisted briquetting technique with tapioca starch as binder is adopted. Properties of these leafy biomass briquettes such as moisture content, calorific value, compressive strength, and shatter index are determined. From the study, briquettes with biomass-to-binder ratio of 3:5 are found to be stable. Higher mass percentage of binder is considered for preparation of briquettes due to the fact that leafy biomasses do not adhere well on densification with lower binder content. Ultimate analysis test is conducted to analyze the gasification potential of the briquettes. Results show that the leafy biomass prepared from teak and rubber leaves has calorific values of 17.5 and 17.8 MJ/kg, respectively, which are comparable with those of existing biomass feedstock made of sawdust, rice husk, and rice straw.     

Feasible conditions for Japanese woody biomass utilization

Environmental Science and Pollution Research - There is an abundance of woody biomass in Japan. However, its economic feasibility is limited. There have been several discussions on whether...     

生物质气化过程催化剂应用研究进展

生物质气化技术已在国内外得到广泛的开发和运用,但由于燃气品位较差,焦油较多,限制了生物质气化气的进一步利用。在生物质气化过程中应用催化剂是一种有效的提升燃气质量和催化裂解焦油的方法,近年来已引起了国内外的广泛注意。本文对国内外生物质催化气化及相关研究进展进行了综合评述,分析了催化剂对减少生物质气化焦油的生成和改进燃料气品质的作用结果, 提出了进一步的研究方向。     

Woody biomass phytoremediation of contaminated brownfield land

Economic and environmental regeneration of post-industrial landscapes frequently involves some element of re-afforestation or tree planting. We report field trials that evaluate whether woody biomass production is compatible with managing residual trace element contamination in brownfield soils. Large-scale mapping of contamination showed a heterogenous dispersion of metals and arsenic, and highly localised within-site hotspots. Yields of Salix, Populus and Alnus were economically viable, showing that short-rotation coppice has a potentially valuable role in community forestry. Mass balance modelling demonstrated that phytoextraction potentially could reduce contamination hotspots of more mobile elements (Cd and Zn) within a 25-30-year life cycle of the crops. Cd and Zn in stems and foliage of Salix were 4-13 times higher than EDTA-extractable soil concentrations. Lability of other trace elements (As, Pb, Cu, Ni) was not increased 3 years after planting the coppice; woody biomass may provide an effective reduction of exposure (phyto-stabilization) to these less mobile contaminants.     

生物质材料预处理餐饮废水

采用4种廉价的生物质材料（水葫芦、柚子皮、木屑、核桃壳）用于餐饮废水的预处理。通过静态烧杯实验,研究了各生物质材料预处理废水的效果及最佳处理条件。结果表明,生物质材料对废水中COD的去除率均在45％以上,油脂吸附量为4～16mg／g,最优吸附材料为水葫芦,COD去除率达65％,油脂吸附量为16mg／g;水葫芦和柚子皮的最佳处理条件为：粒径〈0．2mm,投加量为20g／L,废水pH为4,处理时间为2h,温度为20℃;木屑和核桃壳的最佳实验条件为：粒径〈0．2mm,投加量为28g／L,pH为2,处理时间为2．5h,温度为20℃。生物质对餐饮废水的预处理,为废水中大量有机物和废弃油脂的去除提供了新思路和途径。     

Performance of bitumen coating sheet using biomass pyrolysis oil

ABSTRACT

The “green” production of bitumen has raised increasing interest in recent years to reduce the environmental, energy-related and petro-based concerns. Bio-oil, prepared by biomass pyrolysis, can be used as a substitute for petro-based bitumen in bitumen or bitumen-based coatings, for its similar properties of good adhesion and anti-corrosion characteristics as bitumen. Although biomass is a renewable and widespread chemical resource, its high-valued utilization is still difficult. Several studies have qualitatively demonstrated the use of bio-bitumen in practical applications. The present study investigates that adding some bio-oil to traditional bitumen to form a bio-bitumen could help improve the properties of traditional bitumen. Bio-bitumen was prepared from biomass pyrolysis oil and applied to self-adhesive and doped hot-melt sheets. Results of physical properties demonstrate that bio-bitumen is a potential substitute in bitumen coating sheet.

Implications: This paper is intended to verify the effect of pyrolyzed bio-oil from wheat straw on the performance of bitumen, as well as the feasibility of application in the coating sheet. Up to now, the research on bio-bitumen is mainly in pavement bitumen. In the present research, bio-bitumen was applied to the coating sheet in different proportions. Interestingly, the prepared coating sheet exhibited higher adhesion. Other performances, such as temperature stability, mechanical strength and temperature flexibility of coating sheet showed improvement in the presence of bio-oil, which indicated the suitability of bio-oil in coating sheet bitumen.     

Regional estimation of current and future forest biomass

The 90,674 wildland fires that burned 2.9 million ha at an estimated suppression cost of $1.6 billion in the United States during the 2000 fire season demonstrated that forest fuel loading has become a hazard to life, property, and ecosystem health as a result of past fire exclusion policies and practices. The fire regime at any given location in these regions is a result of complex interactions between forest biomass, topography, ignitions, and weather. Forest structure and biomass are important aspects in determining current and future fire regimes. Efforts to quantify live and dead forest biomass at the local to regional scale has been hindered by the uncertainty surrounding the measurement and modeling of forest ecosystem processes and fluxes. The interaction of elevated CO2 with climate, soil nutrients, and other forest management factors that affect forest growth and fuel loading will play a major role in determining future forest stand growth and the distribution of species across the southern United States. The use of satellite image analysis has been tested for timely and accurate measurement of spatially explicit land use change and is well suited for use in inventory and monitoring of forest carbon. The incorporation of Landsat Thematic Mapper data coupled with a physiologically based productivity model (PnET), soil water holding capacity, and historic and projected climatic data provides an opportunity to enhance field plot based forest inventory and monitoring methodologies. We use periodic forest inventory data from the USDA Forest Service's Forest Inventory and Analysis (FIA) project to obtain estimates of forest area and type to generate estimates of carbon storage for evergreen, deciduous, and mixed forest classes for use in an assessment of remotely sensed forest cover at the regional scale for the southern United States. The displays of net primary productivity (NPP) generated from the PnET model show areas of high and low forest carbon storage potential and their spatial relationship to other landscape features for the southern United States. At the regional scale, predicted annual NPP in 1992 ranged from 836 to 2181 g/m2/year for evergreen forests and 769-2634 g/m2/year for deciduous forests with a regional mean for all forest land of 1448 g/m2/year. Prediction of annual NPP in 2050 ranged from 913 to 2076 g/m2/year for evergreen forest types to 1214-2376 g/m2/year for deciduous forest types with a regional mean for all forest land of 1659 g/m2/year. The changes in forest productivity from 1992 to 2050 are shown to display potential areas of increased or decreased forest biomass. This methodology addresses the need for spatially quantifying forest carbon in the terrestrial biosphere to assess forest productivity and wildland fire fuels.     

Impacts of Russian biomass burning on UK air quality

Unusually high levels of PM₁₀ were observed in the UK in May 2006 and September 2002. This paper investigates the possible contribution of long-range transport of smoke from widespread agricultural burning and forest fires in western Russia to these air pollution episodes. The Lagrangian dispersion model NAME is run in both forwards and backwards modes to determine the transport and sources of the polluted air masses for the two incidents. Comparison of the model results to satellite data and ground observations from across Europe demonstrates good agreement for both the timing and magnitude of the episodes and suggests that fires in western Russia were the primary cause of both incidents. Secondary contributions to the 2006 episode may have come from European anthropogenic pollution and pollen released in northern Europe. The occurrence and timing of both pollution episodes were strongly controlled by the meteorological situation at the time. Scaling of model results to observations suggests that 0.5–0.7 Mtonnes of biomass per day could have been burnt during periods when winds reaching the UK were from the east. The newly reported 2006 episode means that Russian fires have affected UK air quality at least twice since 2000 and it is suggested that, without changes in current practice, such events are likely to occur again in the future with implications for UK and European air quality.     

水热炭化废弃生物质的研究进展

针对近年来水热炭化技术在废弃生物质处理及资源化利用方面的研究进展,着重讨论水热炭化技术处理废弃生物质的种类、实施方法、炭化物改性及应用,并分析了当前研究需要解决的问题,展望了水热炭化废弃生物质的研究动向。     

钙基吸附剂捕集生物质燃气中的二氧化碳

生物质热解燃气中CO2的捕集,是提高燃气热值和实现碳减排的关键问题之一。为利用生物质热解燃气温度偏高的特点,拟通过化学吸附方法,捕集燃气中高浓度的CO2。为此,利用不同钙基前驱物制备了系列钙基固体吸附剂,系列钙基固体吸附剂对CO2的单次吸附和循环吸附实验结果表明,含钙和镁氧化物混合物的吸附剂具有较稳定的循环吸附特性以及较大的吸附负荷。孔结构特性分析表明,适宜于CO2吸附的有效孔径范围可能为小于4 nm。因此,可以通过对天然白云石的改性获得合适孔径的钙镁基固体吸附剂,达到有效捕集生物质燃气中CO2的目的。     

Utilization of agricultural waste biomass and recycling toward circular bioeconomy

Environmental Science and Pollution Research - The major global concern on energy is focused on conventional fossil resources. The burning of fossil fuels is an origin of greenhouse gas emissions...     

Detection of biomass burning smoke in satellite images using texture analysis

Classification results using texture analysis is presented for forest fire smoke from satellite remote sensing data. Texture analysis is carried out for normalized difference images calculated from visible and thermal infrared images of the Indonesian forest fire in 1997. Smoke regions are identified by assuming threshold values for the resulting texture feature as well as for radiances in the original and difference images. It is found that when the thresholds are chosen appropriately for GMS visible and infrared spin scan radiometer, 94% pixels exhibit agreement between the classification results using the texture analysis and the supervised Euclidean classification. Agreement is found for 96% pixels in mutual verification using the VISSR image and a concurrent NOAA advanced very high resolution radiometer image. A correlation coefficient of 0.91 is obtained between the results from the two sensors in the variation of the number of smoke pixels accumulated for 12 days in September 1997. Additionally, it is confirmed that as the threshold value of the texture feature is increased, the variation range of the aerosol optical thickness is also increased. As a whole, this study indicates that texture analysis provides quite reasonable results in the smoke detection when appropriately combined with the spectral information.     

生物质催化气化制取富氢燃气的研究

以流化床为反应器 ,探讨了一些主要参数如 :反应器温度 ,水蒸气 ,当量比ER以及催化剂对气体成分、氢产率和潜在氢产率的影响。实验所用催化剂为白云石和镍基催化剂。在实验条件范围内 ,氢产率为 2 2— 83g/kg生物质 (湿基 ) ,潜在氢产率为 115— 2 2 3g/kg生物质 (湿基 )。结果表明 ,较高的反应器温度 ,适当的水蒸气添加量可以有效提高氢的产出 ;白云石和镍基催化剂可使产品气中的氢含量提高 10 %以上。     

Holocene biomass burning and global dynamics of the carbon cycle

Fire regimes have changed during the Holocene due to changes in climate, vegetation, and in human practices. Here, we hypothesise that changes in fire regime may have affected the global CO2 concentration in the atmosphere through the Holocene. Our data are based on quantitative reconstructions of biomass burning deduced from stratified charcoal records from Europe, and South-, Central- and North America, and Oceania to test the fire-carbon release hypothesis. In Europe the significant increase of fire activity is dated approximately 6000 cal. yr ago. In north-eastern North America burning activity was greatest before 7500 years ago, very low between 7500-3000 years, and has been increasing since 3000 years ago. In tropical America, the pattern is more complex and apparently latitudinally zonal. Maximum burning occurred in the southern Amazon basin and in Central America during the middle Holocene, and during the last 2000 years in the northern Amazon basin. In Oceania, biomass burning has decreased since a maximum 5000 years ago. Biomass burning has broadly increased in the Northern and Southern hemispheres throughout the second half of the Holocene associated with changes in climate and human practices. Global fire indices parallel the increase of atmospheric CO2 concentration recorded in Antarctic ice cores. Future issues on carbon dynamics relatively to biomass burning are discussed to improve the quantitative reconstructions.     

活性污泥数学模型中异养菌产率系数的测定

活性污泥数学模型常被用于预测污水处理厂中的生物过程。模型中异养菌产率系数YH对其他组分的测定值有显著的影响。目前．测定YH的主要方法有序批式活性污泥法和序批式呼吸计量法。在序批式呼吸计量法中．起始F／M值的选择十分关键。以醋酸钠为底物．对这两种方法进行了分析比较,序批式呼吸计量法为文章的推荐方法。     

城市生物质废物中温单级厌氧消化中试研究

建立了城市生物质废物中温单级厌氧消化中试反应器,对城市生物质废物厌氧消化过程系统稳定性、产甲烷性能及有机物的去除效果进行解析.反应器稳定运行410 d,共经历2.4、3.6、4.8、6.0 kg VS/(m3·d)4个负荷,反应器pH稳定在7.2 ～7.6之间,有机酸浓度＜500 mg/L.在负荷6.0 kg VS/(m3·d)时反应器平均容积产气率4.25m3/(m3·d),有机物去除率为63.2％;另外,实验结果表明,厌氧消化过程对蛋白质、脂肪、纤维素及多糖类物质的去除效果有明显差异,其中脂肪类物质去除率为98.2％,产沼气贡献率为38.8％.实现了针对我国城市生物质废物的高负荷高效厌氧消化,为我国城市生物质废物厌氧消化规模化处理提供了基础数据.     

改进型生物质阴离子交换纤维制备及吸附性能

用氢氧化钠水溶液预处理,以乙二胺作交联剂,采用环氧氯丙烷和二甲胺对网状植物丝瓜络纤维进行化学改性,制备出改性丝瓜络阴离子交换纤维(LS-AEF),重点探讨了LS-AEF的形态特征并对其形态特征进行了表征分析,还考察了碱预处理对产品吸附水体中的NO-3的影响。研究结果表明,(1)LS-AEF引入带正电的胺基基团,可以提高对NO-3的吸附性能;(2)乙二胺剂量对产品吸附性能影响比较大,最佳剂量为9 mL,吸附率达到75%;(3)碱性预处理能够显著提高产品的吸附性能,碱处理前后的产品吸附率分别为76%和85%;(4)吸附过程符合伪二级动力学方程。     

生物质废弃物快速热解制取富氢气体的实验研究

采用管式炉对红松锯屑快速热解制取富氢气体进行了实验研究,分析了反应器温度、物料粒径和催化剂对热解产物组成的影响.结果表明高温能加快生物质快速热解进程,减少炭和焦油生成量,利于富氢气体的生成,800℃时气态产物比例可达56.9 wt.%,气态产物中H2体积分数由4.3%(500℃下)上升至17.2%,H2 CO体积分数达68.3%.小粒径能增大热解气态产物的比例,但对气态产物组成的影响很小,这可能与红松锯屑本身质地疏松有关.以与生物质直接混合方式添加的煅烧白云石能使热解产物中H2含量增加,但造成产气过程变缓,炭生成量增多,富氢气体总产量未能得到提高.