Substance On Biochar Surface Impacts Microorgnism Activities

Biochar, which is a novel environmental functional material, posseses adeveloped pore structure and an enormous specific surface area. It has the capability ofadsorbing heavy metals and organic pollutants as well as being carrier for microorgnism.In this paper, the availability of surface substance of biochar as microbial carbon sourcethrough denitrification experiments; the influnce of surface substance of biochar formicrobial activity and population structure composition was investigated; whetherbiochar can alleviate toxic effects for microorgnism in the presence of heavy metals.Those conclusion are gained:①Some surface substance of biochar can be used as microbial carbon source, theavailability of biochar as microbial carbon source is limiting factor. With the increase ofpyrolysis temperature of biochar, the availability of surface substance of biochar willhave been downward trend; The unit weight of biochar pyrolysised at300temperaturedegraded by microorgnism through33d is1.76mg·g-1; when the particle size of thebiochar pyrolysised at700temperature are0.18mm-0.83mm, the particle size of biocharis not the main factors for biochar degraded by microorgnism.②When biochar was degraded by microorgnism, the internal residual organicingredients of biochar pyrolysised, such as cellulose, have not been used; and they arelocated in the surface of biochar，so that the degree of carbonization and aromaticity ofbiochar degraded by microorgnism decrease slightly.③When the microorgnism adsorb on the surface of biochar, surface toxicchemical substance of biochar, such as phenol andnaphthalene, has inhibitory effect onthe microbial activity, the main reason is surface chemical properties of biochar. Withthe increase of pyrolysis temperature of biochar, the surface toxic substances of biocharis associated with the preparation technology of biochar；generally with increase ofpyrolysis temperature of biochar, the surface toxic substances of biochar will decreaseaccordingly.④When biochar was added to the activated sludge process, it will make themicrobial population structure change, but looked from the overall trend, the influnce ofbiochar for microbial population structure is weak.⑤When heavy metal Pb2+and Cd2+is presence, biochar can not alleviate the toxiceffect for microorgnism in environment that have biochar and microorgnism.