Arsenic Adsorption on Iron-Modified Montmorillonite: Kinetic Equilibrium and Surface Complexes

IRIEL, ANALIA; MARCO-BROWN, JOSE L.; TRINELLI, MARÍA ALCIRA; DOS SANTOS AFONSO, MARÍA; DILJKAN, MAJA; FERNÁNDEZ CIRELLI, ALICIA

ENVIRONMENTAL ENGINEERING SCIENCE

Mary Ann Liebert, Inc.

Lugar: Amsterdam; Año: 2019

1092-8758

As(V) adsorption mechanisms on an iron-modified montmorillonite (Fe-Mt) were studied by analysis fromkinetic and equilibrium perspectives, and applicability of Fe-Mt for As(V) removal from groundwater wasevaluated. Iron-modified montmorillonite was characterized by Small Angle X-Ray Scattering (SAXS), WideAngle X-Ray Scattering (WAXS) and scanning electron microscopy technique and an excellent performancefor As(V) removal, even at neutral and basic pH values and high conductivity conditions, was determined.Moreover, As(V) adsorption was higher with the increasing of ionic strength of the solution. Both Langmuir andFreundlich models provided a suitable fit to the experimental data, and the maxima adsorption capacity was6.3 g/kg. Kinetic studies indicated that about 99% of As(V) was removed in the first 30 min of time from astarting concentration of 3 mg/L following a pseudo-second order kinetic. Formation of inner-sphere complexesof As(V) at the surface of Fe-Mt was stated by evaluation of As(V) adsorption in the presence of Cl-, NO3-, andPO43- ions and of the zeta potential versus pH curves.