大豆脲酶对Zn^(2+)污染土的修复试验研究

Remediation Tests of Zn^(2+) Contaminated Soil by Soybean Urease

为了研究植物脲酶诱导碳酸钙沉淀技术(EICP)对Zn^(2+)污染土的处理效果,从大豆中提取了丰富的脲酶,在底物诱导下实现对重金属污染土中Zn^(2+)的矿化处理。通过Tessier五步连续提取法对修复前、后污染土中不同形态Zn^(2+)进行提取检测,并对不同修复次数的土体进行无侧限抗压强度试验。结果表明:所提取的大豆脲酶能有效催化尿素水解生成碳酸根离子,使其在底物诱导下生成碳酸盐沉淀并矿化Zn^(2+);EICP技术能有效降低污染砂土中Zn^(2+)的含量,使其以碳酸盐的形式固定封存;随着修复次数的增加,砂土的无侧限抗压强度从碎散状0 MPa增加至0.44 MPa。EICP技术为重金属Zn^(2+)污染土修复提供了新的选择。

In order to study the treatment effect of Enzyme Induced Calcium Carbonate Precipitation(EICP) on Zn^(2+)contaminated soil, abundant urease was extracted from soybean, mineralization of heavy metal Zn^(2+)with substrate induction was implemented. The different forms of Zn^(2+)in contaminated sand before and after remediation were extracted and detected by Tessier’s five-step continuous extraction method, and the mechanical properties of different remediation times were compared through unconfined compressive strength tests. Results showed that the extracted urease had a good activity and it could effectively catalyzed the hydrolysis of urea to form carbonate ions, which could form carbonate precipitation and mineralize Zn^(2+)in the induction of substrate. EICP technology could effectively reduce the content of Zn^(2+)in contaminated sand, and fix it in the form of carbonate, moreover, the unconfined compression strength of the repaired sand increased from 0 to 0.44 MPa after repaired 3 times. EICP technology provided a new choice for the remediation of heavy metal Zn^(2+)contaminated soil.