磺化石墨烯对土壤中镉的异位淋脱修复效果

土壤异位淋洗技术具有修复速度快、效果好、适用范围广等优势,在欧美等国家已形成较为完善的法律体系与方法体系。本研究针对Cd污染土壤,以磺化石墨烯(SGO)作为一种淋洗剂,探讨磺化石墨烯在不同淋脱条件下对Cd污染土壤的异位修复效果。结果表明:磺化石墨烯对土壤中Cd的最优淋脱参数为洗脱浓度为4 000 mg/L,液土比为10︰1,连续淋洗4次,其土壤中Cd的去除率可达50%。同时还发现磺化石墨烯对不同类型土壤中Cd的洗脱效率存在明显差异,即与土壤黏粒含量、铁铝及其游离态含量、Cd有效态含量等因素有关。与常见洗脱剂(如Fe Cl3、CaCl_2)相比,在相同条件下磺化石墨烯洗脱1次后,土壤中Cd的去除率达24.7%,明显高于Fe Cl3(17.9%)(P0.05)和CaCl_2(9.1%)(P0.01)。可见,磺化石墨烯对Cd污染土壤具有更好的洗脱修复效果。

Ex-situ Washing Remediation on Soil Cadmium by Sulfonated Grapheme

Graphene and its modified functional graphene are research hotspot of carbon nano materials, and the sulfonated graphene has received great attention, especially in environmental protection area. Using sulfonated graphene as the eluent, the different eluting parameters were evaluated for the ectopic leaching remediation effect of Cd contaminated soil. It was found that the optimum eluent parameters were respectively 4000 mg/L of eluent concentration, 10:1 of liquid-soil ratio, four times for continuous washing, the removal rate of Cd could reach up to 50%. With the elution of different contaminated soils, it was showed that the removal rate of Cd was related to the proportion of soil clay, Fe or Al and the content of their free state, the availability of Cd,etc. With 24.7% of Cd removal rate for washing once, sulfonated graphene was better than those of current common eluents (FeCl₃ and CaCl₂) in the same conditions. Therefore, sulfonated graphene played a certain role on the washing remediation of Cd contaminated soil.