超顺磁微纳米MFH功能材料对铅污染土壤的修复研究

Remediation of Lead-contaminated Soil by Superparamagnetic Micro-nano MFH Functional Materials

为有效、快速、廉价地修复废水和土壤铅污染,研究了一种重金属铅修复去除材料(超顺磁微纳米Fe3O4@Ca10(PO4)6(OH)2功能材料,MFH)的投加量、Pb^(2+)初始浓度、吸附时间、pH、离子强度以及有机质浓度等因素对废水、污染土壤中Pb^(2+)的修复效果。结果表明,MFH对溶液中的Pb^(2+)的吸附满足准二级动力学模型,在10min左右达到吸附平衡,最大吸附量181.6 mg·g^(–1);在pH 2.00~5.00范围内Pb2+去除率随溶液pH的增加而下降;溶液中离子强度增大会抑制MFH对Pb2+的去除率,而溶液中有机质含量增加则能有效提高MFH对Pb2+的去除率。MFH对农田和工业园区铅污染土壤均有较好的去除效果,添加重金属活化剂EDTA能明显提高MFH对土壤中铅的去除效果,其中对轻度铅污染的农田土壤中铅总量去除量为102.74μg·g^(–1)。利用磁棒对土壤中MFH进行回收,回收率可达88%以上,再生性能恢复率89.49%,且再生后的MFH磁性能、比表面积恢复较好。

【Objective】This study aimed to effectively,rapidly,and cost-effectively purify wastewater and repair soil from lead pollution.【Method】The remediation effect of a lead-remediation material(superparamagnetic micro nano Fe3O4@Ca10(PO4)6(OH)2 functional material,MFH)on Pb2+in wastewater and polluted soil was studied in terms of dosage,initial concentration of Pb2+,adsorption time,pH,ionic strength and organic matter concentration.【Result】The results showed that the adsorption of Pb2+in solution by MFH satisfies the pseudo-second-order kinetic model.The adsorption equilibrium was reached in about 10 min,and the maximum adsorption capacity was 181.6 mg·g^(–1);at pH 2.00–5.00.Also,the removal rate of Pb^(2+)in the pH range decreased with the increase of pH while an increase in ionic strength of the solution inhibited the removal rate of Pb2+by MFH.Nevertheless,an increase in the organic matter content in the reaction system effectively improved the removal rate of Pb2+by MFH.MFH showed a good lead-removal effect when applied to lead-contaminated soils in farmland and industrial parks.The addition of heavy metal activator EDTA can significantly improve the removal effect of MFH on lead in soil.In slightly lead-contaminated farmland soil,the total amount of lead removed was 102.74μg·g^(–1).After experimentation,the recovery rate of MFH from soil was over 88%by using a magnetic rod,while the recovery rate of MFH regeneration performance was 89.49%.Importantly,the magnetic properties and specific surface area of the regenerated MFH recovered well,suggesting that MFH had a good recovery and regeneration ability.【Conclusion】Therefore,MFH is a good material for the decontamination of lead-contaminated wastewater and soils and its usage is promising given that it can easily be recovered with its basic properties intact.