尾矿库重金属污染土壤电动-植物模拟修复方法研究

尾矿库重金属污染土壤的修复过程复杂且缓慢。为缩短修复周期，促进土壤修复技术的智能化和精细化发展，灵活运用电动修复+植物萃取法的机理与规律，建立修复变量评价指标体系，融合随机森林分类器和GRA模拟算法，建立土壤模拟修复GRA-RF模型，并进行了模拟修复与实验修复对比。结果表明:1）修复变量中电压梯度（0.092）重要度等级值最高，其后是电流大小（0.078）、土壤湿度（0.074）、通电时间（0.069）、土壤动态pH值（0.066）、电极间距（0.063）、电极布置方式（0.06）、添加剂种类（0.057）和电极材料（0.053），其余变量等级值小于平均值。按照变量重要度次序改变修复变量大小，直到获得最优修复效果；2）8个修复样本的模拟修复效率高于实验修复效率，修复环境A1~A4的相对误差分别为2.22%、4.72%、8.75%和3.89%，B1~B4分别为9.91%、8.28%、6.74%和5.63%，环境A下Cd、Cu和Pb的修复效果优于环境B，而Zn的修复效果则相反；3）通过对比算法错误率，GRA-RF模型的修复效果优于Random-RF。该方法真实模拟了污染土壤强化修复过程，通过优化修复变量指标提高土壤修复效率，为制定和改进土壤修复方案提供了参考。

THE METHOD OF HEAVY METAL CONTAMINATED SOIL IN TAILINGS POND BASED ON PHYTO-ELECTROKINETIC OF SIMULATED REMEDIATION

The remediation process of heavy metal contaminated soil in tailings ponds is complicated and slow. To reduce the remediation cycle and accelerate the development of intelligence and refinement of soil remediation technology, the mechanism and law of the phyto-electrokinetic method were used, and the evaluation index system of soil remediation variables was established flexibly. A new GRA-RF model for soil simulated remediation was established by combining a random forest classifier and GRA simulation algorithm, and then the simulated remediation and experimental repair were compared. The results showed that:1) the highest grade value in remediation variables was the voltage gradient (0.092), followed successively by current value (0.078), soil humidity (0.074), power-on time (0.069), dynamic pH level of the soil (0.066), electrode space (0.063), electrode arrangement way (0.06), additive type (0.057), and electrode material (0.053). The weight values of the other variables were lower than the average. The size of the remediation variables would be changed following the importance order of the variables until the optimal repair effect was obtained; 2) the remediation efficiency of the simulation was higher than that of the experiment for 8 samples. The relative errors of remediation environment, for A1 to A4 were 2.22%, 4.72%, 8.75%, 3.89% and from B1 to B4 were 9.91%, 8.28%, 6.74% and 5.63% respectively. The remediation effect of Cd, Cu and Pb in environment A were better than Cd, Cu and Pb, while Zn had an opposite remediation effect; 3) by comparing the error rate of the algorithm, it was found that GRA-RF model was better than Random-RF. This method more precisely simulated the process of enhanced remediation of contaminated soil. The efficiency of soil remediation was improved by optimizing the remediation variables, it laid a foundation for making and improving soil remediation schemes.