Arsenate removal from aqueous solution by montmorillonite and organo-montmorillonite magnetic materials

BARRAQUÉ F,; MONTES M L; FERNÁNDEZ, MARIELA A.; CANDAL, ROBERTO; MARÍA ROSA SANCHEZ TORRES; MARCO BROWN JOSE LUIS

ENVIRONMENTAL RESEARCH

ACADEMIC PRESS INC ELSEVIER SCIENCE

Lugar: Amsterdam; Año: 2021

0013-9351

Magnetic-clay (MtMag) and magnetic-organoclay (O100MtMag) nanocomposites were synthesized, characterized and evaluated for arsenic adsorption. Batch arsenic adsorption experiments were performed varying pHconditions and initial As(V) concentration, while successive adsorption cycles were made in order to evaluate thematerials reuse. The highest As(V) removal efficiency (9 ± 1 mg g− 1 and 7.8 ± 0.8 mg g− 1 for MtMag andO100MtMag, respectively) was found at pH 4.0, decreasing at neutral and alkaline conditions. From As(V)adsorption isotherm, two adsorption processes or two different surface sites were distinguished. Nanocompositesresulted composed by montmorillonite or organo-montmorillonite and magnetite as the principal iron oxide,with saturation magnetization of 8.5 ± 0.5 Am2 Kg− 1 (MtMag) and 20.3 ± 0.5 Am2 Kg− 1 (O100MtMag). Thus,both materials could be separated and recovered from aqueous solutions using external magnetic fields. Bothmaterials allowed achieving arsenic concentrations lower than the World Health Organization (WHO) recommended concentration limit after two consecutive adsorption cycles (2.25 and 4.5 μg L− 1 for MtMag andO100MtMag, respectively).