铁基改性生物炭对Sb污染土壤稳定化修复效果的研究

Study on Stabilized Remediation of Sb-contaminated Soil by Fe-modified Biochar

以某冶炼生产废弃场地土壤为对象,研究了不同稳定剂对Sb污染土壤的稳定化修复效果。试验结果表明:三种稳定剂对土壤Sb的稳定化效果依次为铁基改性生物炭>三氯化铁>未改性生物炭。当使用三氯化铁作为稳定剂时,将显著降低土壤的pH值,造成土壤酸化。最佳的稳定剂添加量为3%,养护时间在3~5d左右可实现土壤Sb的稳定化平衡。基于Tessier连续提取法分析了不同稳定剂施加后土壤中Sb的形态和比例,当施加三氯化铁和铁基改性生物炭后,原土中的可交换态(EX)Sb的占比显著降低,与施加三氯化铁相比,施加铁基改性生物炭后土壤Sb的可交换态(EX)仍进一步降低20%左右,表明铁基改性生物炭充分发挥了生物炭和铁基稳定剂各自的优点,不仅表现出最好的土壤Sb稳定效果,而且对土壤pH的影响也最小,具有良好的潜在应用前景。

Taking the soil of an abandoned antimony smelting site as the object, the effect of different stabilizers on immobilization and remediation of Sb contaminated soil were investigated.The experimental results show that the stabilization performance of the three stabilizers on Sb was Fe-based modified biochar >FeCl_(3)> pristine biochar.The soil pH wassignificantly decreased while FeCl_(3) was used as a stabilizer, which may lead to soil acidification.The optimum dosage of stabilizer was 3%,and immobilization equilibrium can be achieved when curing time is about 3~5 days.The fraction of Sb in the soil after the application of different stabilizers was analyzed using Tessier continuous extraction method.The proportion of exchangeable Sb(EX) in the soil decreased significantly, after the application of Fe-based modified biochar.Compared with the Iron Trichloride, The proportion of exchangeable Sb(EX) in soil was further reduced by about 20%.Taking the advantages of Fe-based stabilizers and biochar, Fe-based modified biochar shows the best Sb stabilization performance and thus exhibits promising application prospects.