Transport Of Surfactant Dispersed Engineering Nano Particles In Porous Media

Engineering Nanoscal Particles (ENPs) are used in many fields. Such as chemistry,medical biotechnology, composite materials, information technology, catalyst, etc.. Theymay be reaeased into the environment in the processs of producing, transport, or utilization,water and soil environment is the ultimate sinks of ENPs in environment. ENPs are difficultto be degredated, and are deterious to human cells and microbes in some conditions. ENPscan be spreaded through the atmosphere, and will enter into soil and water environment,and bring harm to the entironment eventually.The knowledge of its dispersion and transportbehavior in water and natural porous media is a key component of its environmental riskassessment.In this research, dodecylbenzenesulfonic acid, sodium salt (SDBS), were used todisperse ENPs in water. Five ENPs, i.e., nano zero valent iron (nanoFe), nano silver(nanoAg), Nano-titanium dioxide (nanoTiO2), Nano-ferric oxide (nanoFe2O3) andnano-zinc oxide (nanoZnO) were selected. We contrast the stability of the five kinds ENPssuspensions in de-ionized water and under different inoic conditions. The engineeringnanoparticle with the best stability, nanoZnO was selected for further transport study.NanoZnO suspension was also transport to two kinds of porous media, i.e., pure quartzsand and natural sand. The transport ability and mechanism under different conditions wereanalysed, such as different flow, Different ionic strength, Porous media of different particlesize, etc. And a series of important conclusions were drawn according to these analyses:1.Five types of ENPs have different suspending ability in pure water and in thesolutions of surfactant.In pure water, the dispersing ability of five ENPs are in the order: nanoFe<nanoFe2O3<nanoTiO2<nanoAg <nanoZnO; In SDBS solution, their dispersing abilities are: nanoFe<nanoAg <nanoTiO2<nanoFe2O3<nanoZnO.2.Seepage velocity variable lower would to hindered nanoZnO migration in the soilenvironment some extent.3.The particle sizes of soil or aquifer can affect the migration ability of nanoZnO.4.The presence of Ca2+can compress the migration ability of nanoZnO drastically.5.Some mineral in natural sand can affect the migration of nanoZnO, and so the migrationof nanoZnO in natural sand is smaller than in the quartz sand which have the same particle size obviously.6.In the presence of1M Ca2+, SDBS facilitated nanoZnO suspensions can transport44.5m in coarse quartz sand, but this distance will be decreased by changing into fine quartzsand.The migration of nanoZnO in natural sand is smaller than in the quartz sand which hasthe same particle size with natural sand.