生物质炭的性质及其对土壤环境功能影响的研究进展

Progress of the research on the properties of biochars and their influence on soil environmental functions

在厌氧或者绝氧的条件下对生物质进行热解,可产生含碳丰富的固体物质,称为生物质炭。由于生物质炭在农业和环境中的巨大应用前景和对土壤碳的增汇减排作用,近期成为土壤学和环境科学的研究热点。综述了生物质炭的一些基本性质及其对土壤环境功能的影响,分析了该领域未来的发展趋势。国内外的研究表明:生物质炭含有大量植物所需的营养元素,可以促进土壤养分的循环和植物的生长;生物质炭一般呈碱性,施用生物质炭可以降低土壤的酸度和有毒元素如铝和重金属对植物的毒性;生物质炭表面含有丰富的-COOH、-COH和-OH等含氧官能团,它们产生的表面负电荷使生物质炭具有较高的阳离子交换量(CEC),施用后可以提高土壤的CEC;生物质炭对农药等有机污染物和重金属等有很强的吸附能力,可用于污染土壤的修复;生物质炭具有高度的孔隙结构,可以增加土壤的空隙度和保水能力,降低土壤容重,有利植物根系生长;生物质炭是一种含碳的聚合物,主要由单环和多环的芳香族化合物组成,这种结构特点决定了生物质炭具有较高的化学和生物学稳定性,较强的抵抗微生物分解的能力,增强了土壤的固碳作用,减少碳向大气的再释放。该文可为从事农业废弃物的资源化利用、固碳减排、污染土壤修复和土壤改良与管理等领域的科研人员提供参考。

In the partial or total absence of oxygen, thermal decomposition of plant-derived biomass can be manipulated to yield a solid carbon-rich residue generically referred to as biochar. The research on biochar has received a wide attention recently because of its potential applications in various areas including agriculture, environment protection, and carbon abatement by increasing the carbon sink in soils. This article summarizes various basic properties of biochars and their effects on soil environmental functions and discusses the future trends in this area. Biochars contain large amounts of nutrients, which can enhance nutrient cycling and plant growth. One important property of biochars is that they are commonly alkaline and thus can ameliorate soil acidity and reduce the toxicity of aluminum and heavy metals to plants. Many oxygen-containing functional groups such as -COOH, -COH, and -OH are present in biochars. These functional groups can increase the cation exchange capacity （CEC） of biachars and in turn increase the soil CEC when biochars are applied in soils. Biochars have a high adsorption capacity for organic pollutants and heavy metals and thus can be used to remediate contaminated soils. With enriched porous structures, biachars can increase the porosity and water retention capacity of soils and can thus reduce soil bulk density, which is beneficial to root growth. Biochars are carbonaceous materials that contain polycyclic aromatic hydrocarbons with an array of other functional groups. This feature is responsible for the high chemical and biological stability and strong resistance to microbiological degradation observed for biochars. It is also responsible for the en- hanced carbon sequestration capacity for soils and the reduction in the release of carbon to the atmosphere. This article should be of interest to large groups of researchers in various areas such as agricultural waste utilization, sequestration of carbon and its emission reduction, remediation of contaminated soils, and amelioration and management of soils.