机械化学法修复柴油污染土壤的效率、产物及影响

针对常规污染土壤修复处理方法存在有毒降解产物、容易产生二次污染等问题,本研究采用行星球磨仪研究了机械化学法(MC)对柴油污染土壤的修复效能,利用GC/MS对柴油烃组分的降解产物进行分析,并采用SEM、XRD、BET、FTIR和TGA等方法对不同处理条件下的土壤样品进行表征.结果表明,MC处理在0.5～4.0 h内对土壤...

Remediation of diesel-contaminated soil by mechanochemical treatment: Efficiency,products and impacts

Aiming at the problems including toxic degradation products and secondary pollution in conventional treatment methods,the planetary ball mill was used to study the remediation efficiency of diesel-contaminated soil by mechanochemical method (MC). The degradation products of diesel were analyzed by GC/MS. The SEM,XRD,BET,FTIR and TGA were used to characterize soil samples under different treatment conditions. The results showed that the removal rate of total petroleum hydrocarbon (TPH) in the soil can reach more than 95% within 0.5~4.0 h by MC treatment. With the increase of initial TPH concentration and ball-to-soil ratio,the TPH removal rate increases. The degradation difficulty order of diesel components by MC treatment is as follows:alkane < olefin < cycloalkane < aromatic compounds. After 4 hours of ball milling,no toxic and harmful residual product was detected. After ball milling,the soil particle size became smaller,the surface became rougher,and the silica tetrahedron in the clay mineral was exposed on the soil surface. The crystallinity of the mineral structure gradually decreased,and the crystal structure gradually ruptured or deformed,which can form an electron-rich region on the soil surface or promote higher activity of the soil. It may be the main mechanism of total petroleum hydrocarbons degradation by MC treatment. Secondly,the main functional groups of soil organic matter are destroyed,the nano-scale pore capacity became shrink,which may reduce the adsorption capacity of soil components,increase the availability of diesel in soil,and thus also contributes to the desorption and degradation of diesel. As the milling time increased,the soil organic carbon (SOC) content increased first and then decreased,but both were higher than that before treatment. MC treatment can quickly and completely degrade diesel in the soil,and increase the soil organic carbon content,so it has good application potential for remediation of soil contaminated by petroleum hydrocarbon.