污泥基生物炭对砷污染土壤的稳定修复

Stable Remediation of Arsenic-contaminated Soil by Sludge-based Biochar

以普通污泥基生物炭和铁改性污泥基生物炭为钝化剂,以油菜上海青(Brassica chinensis,珍品66)为植物标志物,采用盆栽试验研究不同砷污染浓度(20、40、60和100 mg·kg^(-1))条件下两种生物炭对砷污染土壤的稳定修复效果。结果表明:施加生物炭后,土壤中硫、磷、铁和铝含量均明显增加,铁改性污泥基生物炭处理组铝含量较普通污泥基生物炭处理组平均低4.64 mg·g^(-1)。生物炭的添加使土壤中有效态砷含量减少16.9%~33.6%,而固定态砷比例增加8.3%~31.0%。与施加普通污泥基生物炭处理组相比,施加铁改性污泥基生物炭处理组残渣态砷比例增加3.9~11.4个百分点。不同生物炭的施加均可使上海青中砷含量明显降低,砷富集系数约为0.1,但两种生物炭之间没有显著差异。

Sewage sludge-based-biochar and bioleaching sewage sludge-based-biochar were used as restorative to remediate arsenic polluted soil.Brassica chinensis was planted in pot to explore the influence of biochar on soil and plants absorbing arsenic.Arsenic content in pots were 20,40,60,and 100 mg·kg^(-1).The results show that:After adding biochar,the soil pH was decreased,and the content of sulfur,phosphorus,iron,and aluminum were greatly increased.However,the aluminum content of bioleaching sludge-biochar is 4.64 mg·g^(-1) lower than that of sludge-biochar.The effective arsenic content in the soil was reduced by 16.9%-33.6%;while the fixed arsenic content was increased by 8.3%-31.0%.Compared with sludge-biochar adding pots,the bioleaching sludge-biochar adding pots had a higher residual arsenic percentage in 3.9-11.4 percentage point.The application of biochars can significantly reduce the arsenic content in Brassica chinensis,and the arsenic enrichment coefficient is about 0.1,but there is no significant difference between the two biochars treatments.