微生物/生物炭系统修复重金属污染土壤实验研究

An Experimental Research on the Remediation of Heavy Metal Polluted Soil by Microbial-biochar System

以稻草和高粱秆为原材料,400℃条件下热解,制备并筛选出对重金属吸附固定效果最佳的生物炭,构建微生物/生物炭盆栽实验系统(枯草芽孢杆菌+生物炭,灵芝真菌+生物炭,枯草芽孢杆菌+灵芝真菌+生物炭),培养56 d,考察该系统对重金属污染土壤中重金属总量、重金属形态,以及土壤的基本理化性质、呼吸强度、酶活性等的影响.结果表明:1)稻草生物炭对重金属具有更好的吸附固定作用; 2)土壤p H值和土壤有机质含量显著下降,脲酶活性和土壤有机质含量呈正相关,土壤p H值与磷酸酶活性呈负相关; 3)微生物/生物炭能抑制土壤样品中重金属Cr、Ni、Zn和Cu的生物有效性,可用作土壤重金属污染修复的固定药剂,且加入枯草芽孢杆菌对重金属Cr、Ni、Cu固化效果最佳,加入灵芝真菌对重金属Cu固化效果最佳,加入枯草芽孢杆菌和灵芝真菌混合菌对重金属Zn固化效果最佳; 4)修复后的土壤,其重金属浸出毒性均远小于毒性鉴别标准.

Taking straw and sorghum stalks as raw materials,we use pyrolysis at 400°C to prepare and select the biochars with the best adsorption and fixation effect on heavy metals.Then we establish a microorganism-biochar pot experimental system(bacillus subtilis+biochar,ganoderma lucidum fungus+biochar,bacillus subtilis+Ganoderma lucidum fungus+biochar)and culture for 56 days,and investigate the effects of this system on the total amount and the morphology of heavy metals in the polluted soil samples,and the basic physical and chemical properties,the respiratory intensity as well as the enzyme activity of the soil.The results show that:1)The straw biochar has better adsorption and fixation effects on heavy metals;2)The soil pH and the soil organic matter content decrease significantly,and the urease activity and the soil organic matter content are positively correlated while the soil pH and the phosphatase activity are negatively correlated.3)The addition of microbial-biochar can inhibit the bioavailability of heavy metals,chromium,nickel,zinc and copper in the soil samples and it can be used as a fixed agent for heavy metal polluted soil restoration.And the addition of bacillus subtilis has the best effect on the solidification of Cr,Ni and Cu,ganoderma lucidum fungus on Cu,and both bacillus subtilis and ganoderma lucidum fungus on Zn;4)After remediation,the leaching toxicity of heavy metals of the soil is far below the toxicity identification standard.