Study On Influence Factors Of Transport Of Magnetite Nanoparticles In Saturated Porous Media

With the rapid development of the national economy,the problem of groundwater soil pollution is becoming more and more serious.Nanomaterial have been widely used in the repair and removal of groundwater and soil pollutants because they can be transported in porous media.This study focuses on the migration of nanomaterials in groundwater.According to the soil column experiments,the effects of types of porous media,diesel pollution in environmental media,and surfactants existence of groundwater environment on magnetite nanoparticles transport have been studied.The study results can provide the basic data for in-situ repair technology.The main contents include:1.A co-precipitation method was used to synthesize a magnetite nanoparticles,which was characterized by transmission electron microscopy and XRD.The results showed that the magnetite nanoparticles are well dispersed spheroid standard ferric tetroxide particles.The particle size is less than 30 nm.2.Adopt synthetic nano-Fe₃O₄ferric oxide to inject quartz sand column and soil column to conduct penetration experiment respectively.The mobility of nano-Fe₃O₄in quartz sand column is significantly higher than that in soil column.The outflow rate in quartz sand column?78%?is significantly higher than that in soil column?32.2%?.The maximum migration distances of nano-Fe₃O₄in quartz sand and soil are 1864.72cm and 137.41cm,respectively,which also shows that the migration ability of nano-Fe₃O₄in quartz sand is significantly stronger than that in soil.3.Nano-Fe₃O₄was used to conduct the penetration experiment in the untreated porous media column and diesel-treated porous media column.The results shown that the mobility of nano-Fe₃O₄in the untreated porous media column is higher than that of the diesel-treated porous media column,and the outflow rate of nano-Fe₃O₄in the untreated porous media column is higher than that of the diesel-treated porous media column.The maximum migration distances of nano-Fe₃O₄in untreated quartz sand,diesel-treated quartz sand,untreated soil,and diesel-treated soil are 1864.72cm,843.89cm,137.41cm and84.60cm,which also shows that the migration ability of nano-Fe₃O₄in untreated porous media is higher than that of the porous media polluted by diesel.4.Nano-Fe₃O₄synthesized in the presence of different types of surfactants was injected into the quartz sand column and the soil column to study the influence of migration respectively.The results shown that the migration ability of nano-Fe₃O₄in the presence of SDS is better than the other two types of surfactants,and the retention is lower.Compared with the other two types of surfactants,the migration of nano-Fe₃O₄in the presence of CTAB has the lowest speed and the highest retention.Therefore,the effects of three types of surfactants on the mobility of nano-Fe₃O₄in the soil column are respectively anionic surfactant>nonionic surfactant>cationic surfactant.Simultaneous L_maxis largest in the presence of SDS and smallest in the presence of CTAB for the same porous media.