TITLE:
Methylene Blue Dye Adsorption onto Polyoxometalate Ionic Liquid Supported on Bentonite: Kinetic, Equilibrium and Thermodynamic Studies
AUTHORS:
Norah Alsubaie, Rawan Alshamrani, Doaa Domyati, Nadiyah Alahmadi, Fatma Bannani
KEYWORDS:
Adsorption, Bentonite, Polyoxometalates, Ionic Liquid, Wastewater Treatment
JOURNAL NAME:
Open Journal of Physical Chemistry,
Vol.11 No.2,
May
26,
2021
ABSTRACT: The potential of polyoxometalate ionic liquid POM-IL supported on low-cost
and available eco-friendly Saudi raw bentonite in the adsorption of MB cationic
dye was investigated. For this purpose, TOAx[α-XW11O39]@Bentonite (X = Si, P; TOA =
TetraOctylAmmonium), namely SWB and PWB were prepared and characterized by IR,
XRD, XRF,
SEM, TEM and BET. Batch adsorption experiments showed that SWB and PWB have
higher adsorption capacity than the raw bentonite with an enhancement of about
37% for SWB. The adsorption capacities of both SWB and PWB improved with
increasing contact time and temperature and decreased with higher salt
concentration in solution. The pH is shown to have insignificant effect on the
adsorption of MB onto SWB and PWB. This result is quite meaningful in the adsorption process application
since it makes pH complicated adjustment of the discharged contaminated water
before treatment unnecessary. The Kinetic study expressed that the pseudo-second-order
model described the adsorption process better than the pseudo first order. The
experimental isotherm data were found to fit the Langmuir model compared to the
Freundlich model with a maximum adsorption capacity 277.78 mg/g and 113.6 for
PWB and SWB respectively. The thermodynamic parameters illustrated that the
adsorption process was favorable, spontaneous and endothermic.