Arsenic adsorption on iron modified montmorillonite: kinetic, equilibrium and surface complexes

ANALÍA IRIEL; JOSE LUIS MARCO BROWN; MAJA DILJKAM; M. ALCIRA TRINELLI; MARIA DOS SANTOS AFONSO; ALICIA FERNÁNDEZ CIRELLI

ENVIRONMENTAL ENGINEERING SCIENCE

MARY ANN LIEBERT INC

Lugar: New York; Año: 2019

1092-8758

Arsenic is an element widely distributed constituting an important issue to public health due to the implications of its consumption mainly dissolved in drinking water. Actually, the situation is worst in rural and periurban areas where no treatment is applied for decontamination. Intercalated clays are interesting materials to be used as adsorbents, due to the abundance and low cost of clay mineral (raw material), as well as to the fact of being tuneable in terms of their properties. The iron incorporation into the clay material improved their properties regarding its adsorption capacity in two forms: first, the iron chemical nature enhances the affinity by the As(V) dissolved, and second, the major surface area also contributes with the adsorption process. In this study, the applicability of this material for As(V) removal from groundwater was evaluated from kinetic and equilibrium perspectives. Iron modified clay materials have showed an excellent performance for As(V) removal even at neutral and basic pH values and high conductivity conditions. Both, Langmuir and Freundlich models fitted suitably to the experimental data where the maxima adsorption capacity was 6.3 g Kg-1. Kinetic studies indicated that about 99% of As(V) was removed into the first 30 min of time from starting concentration of 3 mg L-1 following a pseudo-second order kinetic. Moreover, As(V) adsorption was higher with the increasing of ionic strength of the solution and the formation of inner sphere complex of As(V) at the surface was stated by zeta-potential measurements.