Coprecipitation behaviors of fulvic acid-Fe(Ⅲ)-arsenate in groundwater system
The coprecipitation of arsenate and Fe(Ⅲ)in groundwater system can effectively reduce the re-lease of arsenic to the aquatic environment.Organic matter is easily involved in the precipitation process of Fe(Ⅲ),which affects the sequestration of arsenate.However,the C-Fe-As coupled mechanism based on co-precipitation has been poorly understood at present.In this research,we chose FA as the typical organic matter to conduct batch experiments,and explored the coprecipitation behaviors of FA-Fe(Ⅲ)-As(V)in groundwater system under different Fe(Ⅲ)concentrations and pH conditions.The mechanism of arsenate immobilization by organo-Fe hydroxides coprecipitates(OFC)in groundwater system was revealed by com-prehensively using methods of 3D-EEMs,XRD,SEM-EDS,and XPS.The results show that the higher Fe(Ⅲ)concentration in groundwater system promotes the hydrolysis coprecipitation,which is beneficial to the se-questration of arsenate and the component fractionation of FA.The macromolecular and strong aromatic components in FA preferentially bind with ferrihydrite to form OFC.As(V)is immobilized by occupying the binding sites of humus-like components with ferrihydrite in OFC.The higher pH condition in groundwater system inhibits the hydrolysis coprecipitation and promotes the dissolution of Fe(Ⅲ),which is not conducive to the se-questration of arsenate.The results are helpful to understand the geochemical cycle of arsenic and carbon in ground-water system,and provide a theoretical basis for the treatment and prevention of arsenic pollution in groundwater.
groundwater systemcoprecipitation behavior of fulvic acid-Fe(Ⅲ)-arsenatesequestration of ar-senatecomponent fractionationcoupled mechanism
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维普
