Effect Of Graphene Oxide On The Co-migration Of As(?)and Iron In Porous Media

As one of the three new technology science fields of this century,nanoscience has received widespread attention now.Graphene oxide(GO)as a representative of artificial nanoparticles has been widely used in various fields in recent years.However,the widespread use of GO makes it easy to enter the water environment from every process of GO production.Studies have shown that GO has the high adsorption efficiency of other pollutants.Therefore it may affect the migration and transformation of other pollutants and cause unexpected environmental risks.Arsenic(As)and iron(Fe)are common co-existing pollutants in groundwater.Arsenic has different valence states in water,and trivalent arsenic(As(?))is the most toxic.As(?)can cause many serious damage to human health.Therefore,it is necessary to study the co-migration behavior of GO,As(?)and Fe in groundwater.In this study,natural quartz sand was used as the porous medium.The sand column experiment and model fitting were used to study the GO migration behavior in porous media.The co-migration behavior of graphene oxide with arsenic and iron was also discussed,and the migration mechanism of them was explained.By testing the effluent quality of sand column with different height,the migration rates of As(?),Fe and GO in porous media under different conditions were obtained.By analysing SEM images of the filter material,the morphological changes of As and Fe was informed,and the changes of GO surface functional groups was illustrated.The influence mechanism of these changes on the migration of pollutants in quartz sand column was also inferred.The main research results are as follows:(1)The cotransport of GO,As(?)and Fe(?)in porous media showed that Fe(?)could enhance interception of GO,As(?)and Fe(?)significantly in different level.The recovery rate of GO in the porous media contaminated with As(?)and Fe(?)is significantly lower than that in the clean porous media.(2)Under the GO,As(?)and Fe(?)combined pollution condition,GO did not significantly affect the fluidity of As(?)and Fe(?)in the porous media,while Fe(?)decreased the mobility of GO slightly.When GO,As(?),Fe(?),and Mn oxide composite pollution migrate together in porous media,GO promotes the migration of As(?),Fe,and Mn.Conversely,Fe and Mn significantly delayed the migration of GO and As(?).(3)By comparing the penetration curves under different Fe morphologies,the size of floc formation and the zeta potential of the solution.It was proved that the process of Fe(?)oxidation to produce new ecological Fe(?)and floc formation delayed the migration of Fe,Mn,As(?)and GO in the quartz sand column.(4)Through the analysis of the side sampling results of the quartz sand column under different conditions,it was found that under the conditions of GO&As(?)&Fe(?),GO&As(?)&Fe(?)&Mn oxide,GO penetration of the quartz sand column was delayed.The retention of As,Fe and Mn by quartz sand column mainly occurred in the upper layer(10 cm)sand column.