Optimizing the Synthesis of Terbium(III) Molybdate
Nanoplates Through an Orthogonal Array Design
Seied Mahdi Pourmortazavi ,
a
Mehdi Rahimi-Nasrabadi,
b,c
Mustafa Aghazadeh,
d
Meisam Sadeghpour Karimi,
e
Mohmmad Reza Ganjali,
e,f
and Parviz Norouzi
e,f
a
Faculty of Material and Manufacturing Technologies, Malek Ashtar University of Technology, Tehran, Iran; pourmortazavi@yahoo.
com (for correspondence)
b
Chemical Injuries Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences,
Tehran, Iran
c
Faculty of Pharmacy, Baqiyatallah University of Medical Sciences, Tehran, Iran; rahiminasrabadi@gmail.com (for correspondence)
d
Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran
e
Center of Excellence in Electrochemistry, University of Tehran, Tehran, Iran
f
Biosensor Research Centre, Endocrinology & Metabolism Molecular and Cellular Research Institute, Tehran University of Medical
Sciences, Tehran, Iran
Published online 00 Month 2018 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ep.13091
The study focuses on the application of orthogonal array
design for optimizing of the experimental parameters influenc-
ing the synthesis of terbium(III) molybdate nano-plates
through the direct precipitation method (DPM). The method
conditions, included the concentrations of the cation and
anion solutions (C
x
and C
y
), flow rate of adding the cation
solution to that of the anion (F
x
), and reactor temperature
(T
z
), were optimized in terms of the thickness of the produced
nanoplates. Performing the analysis of variance (ANOVA) on
the results revealed that the synthesis procedure can be opti-
mized through using proper concentrations of the solutions
(0.005 and 0.01 mol/L one-to-one for Tb(III) and MoO
2 -
4
) as
well as the reactor temperature (0
C). The morphology and
purity of the optimal product were also evaluated through
X-ray diffraction (XRD), scanning electron microscopy (SEM),
transmission electron microscopy (TEM), and fourier trans-
form infrared spectroscopy (FT-IR) spectroscopy. The results
displayed that the thickness of the deposited terbium(III)
molybdate nano-plates is about 26 nm. The optimal product
was also tested and found to be an efficient catalyst in the UV-
induced degradation of methyl orange (MO) by degrading
about 97% MO after 80 min. © 2018 American Institute of Chemi-
cal Engineers Environ Prog, 2018
Highlights
• Terbium(III) molybdate nanoplates were fabricated via
chemical precipitation route.
• Nanomaterial was synthesized without any surfactant, tem-
plate, or catalyst.
• Synthesis process was optimized by Taguchi design to pre-
pare nanoplates.
• Product nanoplate were characterized by TEM, XRD, FT-IR,
and DRS.
• Nanoplates were examined as photocatalyst to degrade
organic pollution in water.
Keywords: terbium, molybdate, nanoplates, photocatalyst,
statistical optimization
INTRODUCTION
In the modern world, management and removal of the envi-
ronmental contaminations are an important challenge. Up to
date, diverse techniques have been explored and proposed for
the effective decontamination and removal of the organic pollut-
ants from wastewater. These methods including adsorption,
photocatalytic degradation, chemical oxidation/reduction, and
electrochemical oxidation as an advanced oxidation technology
(AOT) have been used in many fields of the environmental
chemical engineering [1,2]. Photocatalysis is an interesting area
of study due to its potentials for degrading different pollutants
using light energy. The efficiency of a photocatalyst depends
very much on its chemistry, morphology, and surface proper-
ties, and this has been the grounds for a great deal of research
in the area of photocatalysts for use in fuel cells [3–5], as well
as, those used for addressing environmental issues [6–9] such as
degrading organic pollutant, reducing heavy metal cations and
removing arsenic, and/or Cr(VI). Photocatalysts can decompose
different organic compounds like dyes or phenol producing
CO
2
and H
2
O under UV light irradiation [9–11].
Molybdate salts of rare-earth elements have been used in
phosphors, optical fibers, scintillators, laser hosts, and so forth.
More specifically rare earth trimolybdates constitute an impor-
tant class of compounds, which crystallize in different forms,
that is, C2/c (α form), P421m (β form), Pba2(β form), and
Pnca (γ form) as the monoclinic, tetragonal, orthorhombic, and
cubic structures [12–14], while the (α) form is being thermody-
namically stable for the rare-earth salts of cations from Pr to
the Ho. Upon cooling, the melt is converted to the metastable
(β) form. Salts of cations in the range of Er to Lu crystallize to
the very stable γ form [15–17]. © 2018 American Institute of Chemical Engineers
Environmental Progress & Sustainable Energy DOI 10.1002/ep 1