Research Article, Issue 3
Analytical Methods in Environmental Chemistry Journal
Journal home page: www.amecj.com/ir
AMECJ
------------------------
Negar Motakef-Kazemia,*
a,* Department of Medical Nanotechnology, Faculty of Advanced Sciences and Technology, Tehran Medical Sciences, Islamic Azad University,
Tehran, Iran.
[8], photonic [9], ion exchange [10], molecular array
[11], biomedicine [12], sensing [13], drug delivery
[14], luminescent [13, 15], magnetic [16], and
semiconductors [17]. Several methods have been
proposed to remove hazardous materials from water
such as electrochemical [18], chemical coagulation
[19], reverse osmosis membrane [20], and adsorbent
[21-23]. The absorbent materials have been studied
for different species such as nitrobenzene [24-26],
phenol [27], p-xylene hydrocarbon [28], dye [29-
32], heavy metal [33-34], humic acid [35], and
nitrate [36-37] from the waste water. Mercury is a
chemical element and heavy metal with very toxic
effect. This non-essential metal can be distributed
A novel sorbent based on metal–organic framework for mercury
separation from human serum samples by ultrasound assisted- ionic
liquid-solid phase microextraction
1. Introduction
Today, metal-organic frameworks have received
considerable attention as porous coordination
polymers (PCPs) and porous hybrid organic–
inorganic materials because of their unique
properties [1-2]. MOFs can be synthesized via self-
assembly of metal ions (or metal clusters) as metal
centers, and bridging ligands as linkers [3-4]. In
recent years, MOFs wildly have been studied for
their potential applications in many areas such as
gas storage [5], separation [6], catalysis [7], optics
* Corresponding author: Negar Motakef-Kazemi
Email: motakef@iaups.ac.ir
https://doi.org/10.24200/amecj.v2.i03.68
A R T I C L E I N F O:
Received 14 Jul 2019
Revised form 19 Aug 2019
Accepted 30 Aug 2019
Available online 30 Sep 2019
Keywords:
Metal–organic framework;
Ultrasound assisted -micro-solid phase
extraction;
Mercury;
Serum samples;
Cold vapor atomic absorption
spectrometry
A B S T R A C T
In this research, the metal–organic framework (MOF) as a
solid phase was used for separation mercury [Hg (II)] inhuman
serum sample by ultrasound assisted- Ionic Liquid-solid phase
microextraction procedure (USA- IL-μ-SPE). Mercury extracted
from serum sample by [Zn2(BDC)2(DABCO)]n as MOF at pH=8.
Hydrophobic ionic liquid ([BMIM] [PF6]) was used as solvent
trap for Hg-MOF-NC from the sample solution. The phase of Hg-
MOF-NC was back extracted by 0.5 mL of HNO3 (0.2 mol L-1)
and finally mercury concentration determined with cold vapor-
atomic absorption spectrometry (CV-AAS) after dilution with 0.5
mL of DW. Under the optimal conditions, the linear range, limit
of detection and preconcentration factor were obtained 0.02–
5.5 µg L−1, 6.5 ng L−1 and 9.8 for serum samples, respectively
(%RSD<5%). The validation of methodology was confirmed by
standard reference materials (SRM).
MOF for mercury separation in serum Negar Motakef-Kazemi
Analytical Methods in Environmental Chemistry Journal Vol 2 (2019) 67-78
68 Analytical Methods in Environmental Chemistry Journal; Vol. 3 (2019)
in the environment, natural products, and human
body [38-39]. The exposure to high mercury can
be resulted to the changes in the central nervous
system, irritability, fatigue, behavioral changes,
tremors, headaches, hearing and cognitive loss,
dysarthria, incoordination, and hallucinations
[40]. Mercury compounds can be harmed the liver
and kidneys, resulting some disorder in enzyme
activity, illness, and death [41-42]. Recently, the
applications of mercury adsorbents are expanded
due to increased level and toxic effect [43-44].
In present study, Zn2(BDC)2(DABCO) MOF was
synthesized by solvothermal method for mercury
absorption from serum and standard solution
1-octyl-3-methylimidazolium hexafluorophosphate
([OMIM][PF6]) as a hydrophobic ionic liquid was
used for separating of Hg-MOFfrom liquid phase.
The proposed method was validated by spike of
real samples and CRM (NIST).
2. Experimental
2.1. Reagents and Materials
All reagents with high purity and analytical grade
were purchased from Merck (Darmstadt, Germany),
unless otherwise stated. Materials including zinc
acetate ehydrate (Zn(Oac)2.2H2O), 1,4 benzenedi-
carboxylic acid (BDC), 1,4-diazabicyclo [2.2.2]
octane (DABCO), dimethylformamide (DMF)
were used for synthesis of Zn2(BDC)2(DABCO)
MOF. All aqueous solutions were prepared in ul-
-1) from
Milli-Q plus water purification system (Millipore,
Bedford, MA, USA). An Hg (II) standard stock so-
lution (1000 mg L-1 in 1% nitric acid, 250 mL) was
purchased from Fluka, Buchs, Switzerland. The
experimental and working standard solutions were
prepared daily by diluting the stock solutions with
deionized water. The solutions were freshly pre-
pared and stored just in a fridge (4 °C) to prevent
decomposition. A 0.6% (w/v) sodium borohydride
reagent solution was prepared daily by dissolving
an appropriate amount of NaBH4 in 0.5% (w/v)
sodium hydroxide and used as a reducing agent.
1-butyl-3-methylimidazolium hexafluorophosphate
[HMIM][PF6] was obtained from Sigma–Aldrich
(M) Sdn. Bhd., Malaysia. The pH adjustments of
samples were made using nitric acid (0.1 mol L-1)
for pH 1-2, and appropriate buffer solutions in-
cluding sodium acetate (CH3COONa/CH3COOH,
1-2 mol L-1) for pH 3.75-5.75, sodium phosphate
(Na2HPO4/NaH2PO4, 0.2 mol L-1) for pH of 5.8-8.0,
and ammonium chloride (NH3/NH4Cl, 0.2 mol L-1)
for pH 8-10. All the laboratory glassware and plas-
tics were cleaned by soaking in nitric acid (10%,
v/v) for at least 24 h and then rinsed with deionized
water before use. Due to hazardous effects of Hg
solutions, gloves, safety mask, and laboratory hood
should be used when mercury standard solutions
are prepared.
2.2. Characterization
The MOF was characterized by Fourier transform
infrared spectroscopy (FTIR), powder X-ray
diffraction (XRD), and scanning electron
microscope (SEM). FTIR spectra were recorded
on a Shimadzuir 460 spectrometer in a KBr matrix
in the range of 400–4000 cm. Powder X-ray
diffraction pattern was performed for evaluation
of crystalline structure of bismuth oxide NP using
a Philips Company X’pert diffractometer utilizing
Cu-Ka radiation (ASENWARE, AW-XBN300,
China). Scanning electron microscope was
investigated the morphology and MOF (KYKY,
EM3200, China). Determination of mercury was
performed with an atomic absorption spectrometer
(GBC 932– HG3000-AUS, Australia) equipped
with a flow injection cold vapor module (FI-CV-
AAS), deuterium-lamp background corrector, Hg
hollow-cathode lamp, and a circulating reaction
loop. The working conditions of FI-CV-AAS were
given in Table 1. The pH values of the solutions were
measured by a digital pH meter (Metrohm, model
744, Herisau, Switzerland). A Hettich centrifuge
(model EBA 20, Germany) and an ultrasonic bath
with heating system (Tecno-GAZ SPA, Italy) were
used throughout this study.
2.3. Synthesis of MOF
The Zn2(BDC)2(DABCO) MOF was prepared via
69
MOF for mercury separation in serum Negar Motakef-Kazemi
the self-assembly of primary building blocks. In
a typical reaction, Zn (OAc)2.2H2O (0.132 g, 2
mmol), BDC (0.1 g, 2 mmol), and DABCO (0.035
g, 1 mmol) were added to 25 ml DMF [3]. The
reactants were sealed under reflux and stirred at 90
°C for 3 h. Then, the reaction mixture was cooled to
room temperature, and filtered. The white crystals
were washed with DMF to remove any metal and
ligand remained, and dried in a vacuum. DMF
was removed from white crystals with a vacuum
furnace at 150 °C for 5 h.
2.4. General procedure of mercury adsorption
polytetrafluoroethylene (PTFE) centrifuge tube
was used for this study. First, 10 mL of serum
sample or standard aqueous solution containing
Hg (II) with concentration in the range of 0.1-
5.5 L was adjusted to optimum pH of 8 with
sodium phosphate buffer solution (Na2HPO4/
NaH2PO4, 0.2 mol L-1) and transferred into the
10 mL PTFE centrifuge tube. Then 50 mg of
[OMIM][PF6] dispersed in 100 µL acetone was
mixed with 20 mg Zn2(BDC)2(DABCO) as MOF
sorbent and rapidly injected by a syringe into the
serum/ standard solution. The resulting mixture
was shaken in ultrasonic bath for 5 min at 25 ºC.
Hg (II) was extracted and separation by MOF. The
[Zn2(BDC)2(DABCO)]n-Hg was trapped with
IL and centrifuged at 4000×g for 3 min. The Hg-
MOF /IL was settled down in bottom of the conical
centrifuge tube and the aqueous phase was removed
with a transfer pipette. Finally, mercury species
retained on the sorbent were eluted by adding 0.5
mL of 0.3 molar HNO3 and vigorously shaking the
tube for 1 min. The eluent phase was separated by
centrifuging of the remaining mixture and Hg (II)
ions were analyzed by CV-AAS after dilution with
deionized water up to 1 ml. Figure 1 was shown
general procedure of mercury adsorption.
3. Results and Discussion
3.1. Fourier transforms infrared spectroscopy for
MOF
The FTIR spectra of MOF were recorded in the
range of 400–4000 cm-1 with KBr pellets by
fourier transforms infrared spectroscopy (Fig. 2).
The C–H aromatic band is shown at 3424 cm-1. The
aliphatic C–H asymmetric stretching is assigned at
2960 cm-1. The peak at 2357 cm-1 is related to CO2
which exist in environment. The C=O stretching
and carboxylic group are assigned at 1587 cm-1 and
1387 cm-1 respectively. FTIR spectra corresponded
to the reported results [1].
3.2. X-ray diffraction of MOF
The XRD measurement was used to determine the
° to °
(Fig. 3). The position and diffraction properties of
the peaks are similar to the pattern of previously
reported result [1].
3.3. Scanning electron microscopy for MOF
The size and morphology structures of samples
Table 1. The FI-CV-AAS conditions for determination of mercury in standard samples.
Features Value
Linear range, L-1 0.2-55
Wavelength, nm 253.7
Lamp current, mA 3.0
Slit, nm 0.5
Mode Peak area
HCl carrier solution 37%, mol L-1 3.0
NaBH4 reducing agent, % (m/v) 0.6 (in 0.5% w/v NaOH)
Argon flow rate, mL min-1 10.0
Sample flow rate, mL min-1 3.0
Reagent flow rate, mL min-1 5.0
70 Analytical Methods in Environmental Chemistry Journal; Vol. 3 (2019)
Fig. 3. XRD pattern of Zn2(bdc)2(dabco) MOF
Fig. 2. FTIR spectra of Zn2(bdc)2(dabco) MOF
Fig. 1.
71
MOF for mercury separation in serum Negar Motakef-Kazemi
were studied using SEM that shown rod-shaped
with an average diameter of 70 nm, and the length
of 350 nm (Fig. 4).
3.4. Adsorption mechanism
The compounds of MOF [Zn2(bdc)2(dabco)]n
such as, bdc (COO-) and dabco( N:) was used for
chemical extraction of mercury from serum and
standard solution samples at optimized pH. These
ligands as a suitable material can be extracted
the mercury ions in human biological sample at
pH=8. The MOF are coordinating with the cations
of Hg via nitrogen and carbocyclic bond which
was deprotonated at basic pH. The mechanism of
chemical and physical adsorption carried out by
MOF at pH 7.5-8.5 for mercury in serum samples.
The results showed us the recovery of physical
adsorption in low pH without nitrogen covalence
increased more than 95% by chemical bonding
(Fig. 5)
3.5. The optimization
The optimization was investigated for the
ultrasound-assisted ionic liquid-micro solid phase
extraction conditions. The USA- IL-SPE procedure
provides novel and interesting approach using the
MOF sorbent for extraction of mercury from water
and serum samples. In order to obtain optimum
speciation conditions and quantitative recoveries of
inorganic and organic mercury species with good
sensitivity and precision, the presented USA- IL-
SPE method was optimized for various analytical
parameters. Moreover, in order to optimization of
effecting parameters, standard solutions containing
different concentrations of Hg (II) in the range of
0.1–5.5 µg L-1 were examined.
Fig. 4. SEM of Zn2(bdc)2(dabco) MOF
Fig. 5. The mechanism of mercury absorption by MOF
72 Analytical Methods in Environmental Chemistry Journal; Vol. 3 (2019)
3.5.1. Back extraction of mercury from MOF
The recovery percentage was investigated for
mercury absorption by MOF in presence of different
acids such as HNO3, HCl, H2SO4, and CH3COOH
(Fig. 6), and selected 0.3 molar HNO3 as optimum.
3.5.2. The pH effect of MOF
The pH of the sample is an important role to high
recovery and extraction of Hg in human serum
matrixes. The effect of serum pH on the extraction
of Hg(II) based on MOF has studied from pH of 2
to 11, containing 0.1-5.5 µg L-1 of standard Hg(II)
Figure 7, the
extraction of Hg ions in serum and standard solution
samples were increased between pH from 7.5 to 8.5.
The recovery of mercury extraction were achieved
more than 95% in pH=8 and decreased at pH more
than 8.5 and less than 7.5. Consequently, the pH of
8 was used in further study for Hg extraction from
serum and standard solution samples. In addition,
the extra extraction of mercury was achieved by
increasing MOF mass but, some of essential metals
(Cu, Zn, Ca, Mn, Mg,) may be removed from
Fig. 6. Recovery percentage in presence of different acids
Fig.7. The effect of pH on mercury extraction by MOF
73
MOF for mercury separation in serum Negar Motakef-Kazemi
human body and caused different acute disease. In
proposed conditions, the recovery of Hg extraction
was obtained 25% and 97.6% by IL and MOF/IL,
respectively at pH=8. The mechanism of mercury
extraction of MOF/IL was mainly obtained by
the electrostatic attractions of deprotonated
nitrogen and carbocyclic groups (N, COO) with
the positively charged mercury ions at pH=8. At
acidic pH, the surface of MOF, especially charge
of groups have positive (+) and similar to Hg2+, so,
the recovery of extraction mercury was decreased.
However, in optimized pH, the MOF sorbent had
negative charge and electrostatic attraction caused
to extract mercury. At high pH more than 8.5, the
recovery efficiencies were decreased due to the
formation of hydroxyl complexes of mercury [Hg
(OH)2]. Therefore, Ph=8 selected as optimized pH
3.5.3. Effect of MOF Mass
The mass of MOF was evaluated as effective
parameter for mercury absorption among 1-40
mg. Based on mass results, the optimal value
was mass 20 mg for mercury absorption by the
MOF. For optimization of proposed method, the
amounts of [Zn2(bdc)2(dabco)]n in the range of 1
to 40 mg were studied for mercury extraction in
serum and standard samples. The results showed
us, less than 18 mg of MOF caused to decrease
the extraction efficiency of mercury. So, 20 mg of
[Zn2(bdc)2(dabco)]n
procedure (Fig. 8).
3.5.4. Effect of volume of serum
The optimized sample volume on the recovery of
were examined from 1 mL to 25 mL of standard
and serum samples. The volume of serum was
investigated as effective parameter for mercury
absorption. Based on the results, the optimal value
was obtained less than 18 ml for water sample by
the MOF. By results, the quantitative recovery was
achieved (< 95%) for 15 mL and 12 mL of standard
solution and serum, respectively with concentration
of 0.1 – 5.5 µg L of mercury (CV-AAS). The
recovery was decreased more than 12 mL and 15
mL for volume of serum and standard samples by
proposed method. So, 10 mL of volume sample was
Fig. 9).
Fig. 8. The effect of MOF mass on mercury extraction
74 Analytical Methods in Environmental Chemistry Journal; Vol. 3 (2019)
3.5.5. Effect of ILs for mercury extraction
The IL was investigated as effective parameter for
mercury absorption between 5-100 mg, and the
optimized result was selected 50 mg. A hydrophobic
ionic liquids such as; [MMIM] [PF6], [HMIM]
[PF6] and [OMIM][PF6] as a green solvent was
used to separate MOF from the serum and standard
solution (Fig. 10). The different amount of IL (5-
100 mg) for separation of [Zn2(bdc)2(dabco)]n from
serum phase were used and examined. The results
showed us, the good recovery was achieved with 65
mg of [HMIM][PF6] and 45 mg of [OMIM][PF6].
Therefore, 50 mg of [OMIM][PF6] was selected
by proposed method. In addition, the effect of
[OMIM][PF6] for extraction of mercury in serum
matrix was investigated without [Zn2(bdc)2(dabco)]
n sorbents. The results showed us, the extraction
recoveries of Hg were obtained about 12 % by
[Zn2(bdc)2(dabco)]n which was depended to amino
acid complexation in serum.
Fig. 9. The effect of sample volume on mercury extraction
Fig. 10. The effect of different ionic liquids on mercury extraction
75
MOF for mercury separation in serum Negar Motakef-Kazemi
3.5.6. Adsorption capacity
The important factor for analyzing of mercury with
[Zn2(bdc)2(dabco)]n as MOF sorbent was adsorption
capacity factor (ACF). In batch system, the ACF of
Hg (II) was studied for 10 mL of human serum and
standard solution at pH=8. The ACF of MOF for
mercury vapor in GC closed glass was 149.56 mg
g-1. Based on characteristics of [Zn2(bdc)2(dabco)]n
the most ACF related to chemical bounding of MOF
as compared to physical adsorption by MOF. So,
[Zn2(bdc)2(dabco)]n with high ACF was considered
as excellent MOF sorbent for extraction of Hg (II)
from serum and standard solution samples.
3.6. Interference Study
real samples, the interference of some coexisting
ions encountered in serum samples on the recovery
of Hg (II) ions was investigated under the optimal
condition. This procedure was performed by adding
various amounts of the interfering ions to 10 mL
of standard sample solution containing 5.5 L-1
of Hg (II). Taking as criterion for interference
the deviation of the recovery more than ±5%, the
obtained results (Table 2) showed that most of the
probable concomitant cations and anions had no
considerable effect on the recovery efficiencies of
Hg (II) ions under the selected conditions.
3.7. Validation of results
The mercury absorption capacity was examined
among different applications of MOF as hybrid
inorganic-organic nanoporous materials by
of mercury was shown in Table 3 and based on
this result; MOF is good candidate for mercury
adsorption.
trace mercury determination in standard solution
and serum samples. The results based on average
of three determinations, for Hg (II) were achieved
in serum samples. For validation of results, real
samples in serum and standard solution was verified
by spiking of mercury standard concentration
(Tables 4). The favorate recovery showed that
the proposed method had good accuracy in serum
matrix. The recoveries of spiked samples for
serum and standard solution were obtained more
than 95%. The developed method based on MOF
/IL was satisfactory demonstrated for mercury
analysis in serum. The concentration of Hg in
petroleum (subject) and office worker (control)
50). There were no significant differences between
Table 2. The interference of some coexisting ions in serum samples on the recovery of mercury ions under the optimal
condition.
Ions Concentration ratio (Cinterferent ion/CHg
2+) Mean of Recovery (%)
Standard Serum Standard Serum
Cr3+, Co2+, Pb2+, V3+, Mn2+ 500 400 96.4 95.9
I-, Br-, F-, NO3
-, 750 620 98.6 96.2
Na+, K+, Cl-,Ca2+, Mg2+ 1400 1100 97.7 95.1
Ni2+, Ag+, Cd2+ 35 20 99.3 97.5
Zn2+, Cu2+ 120 100 97.0 96.8
Table 3.
Parameter (Intra-day) Serum sample Standard sample
PFa 9.8 10.2
LODb (n=10, ng L-1) 6.5 6.8
RSDc (n=6, %) 4.2 3.3
Linear range (𝜇g L)0.02 – 5.5 0.02 – 6.0
Correlation coefficient 0.9988 0.9992
a Preconcentration factor, b Limit of detection, c Relative standard deviation.
76 Analytical Methods in Environmental Chemistry Journal; Vol. 3 (2019)
exposed subjects and unexposed controls in terms
of age and sex. The mean concentration of mercury
in control groups was obtained under 1.0 L-1. In
addition, for validation of methodology, standard
reference material (SRM 1641e) for
inorganic mercury was analyzed by MOF/IL.
Table 5 was approved the validation of
developed USA-IL-µ-SPE method. The Ethical
Committee of Tehran Medical Sciences, Islamic
Azad University, approved the blood sampling
guidance in the human body based on the
Helsinki rules (E.C.: IR.IAU.PS.REC.1398.272).
4. Conclusions
In this study, Zn2(BDC)2(DABCO) MOF was
synthesized by solvothermal method at 90 °C for
3 h via the self-assembly metal centers and linkers
using DMF solvent. Based on the results, the MOF
was propped as a good candidate for mercury
absorption. The highest mercury absorption was
observed in pH=8, mass of MOF 20 mg, volume
of serum 10 ml, volume of water 15 ml, and IL
optimized 50 mg in presence of HNO3 as optimized
acid. Also, the interference of concomitant cations
and anions had no considerable effect on the
recovery efficiencies of Hg (II) ions under the
selected conditions. Therefore, these properties
can be resulted to many advantages in the future to
absorb of hazardous materials.
5. References
[1] N. Motakef-Kazemi, S.A. Shojaosadati, A. Morsali,
Evaluation of the effect of nanoporous nanorods
Table 4.
samples ( L-1)
Sample Added FoundaRecovery (%)
Hg (II) Hg(II) Hg(II)
Serum
----- 0.48 ± 0.02 -----
0.5 0.97 ± 0.05 98
1.0 1.51 ± 0.07 103
Serum
----- 2.55 ± 0.13 -----
1.0 3.52 ± 0.12 97
2.0 4.48 ± 0.23 96.5
Water
----- 3.11± 0.14 -----
1.0 4.07 ± 0.21 96
2.0 5.14 ± 0.27 102
Water
----- 0.26 ± 0.01 -----
0.2 0.47 ± 0.02 105
0.4 0.65 ± 0.02 97.5
a Mean of three determinations±confidence interval (P= 0.95, n=5)
Table 5. Validation of developed USA- IL-µ-SPE method based on MOF with standard reference material (SRM)
Sample Certified
(µg L−1)
Added
(µg L−1)
Found a (μg L-1) Recovery (%)
Hg (II)
--- 0.952 ± 0.048 ----
SRM 1641e b1.016 ± 0.017 0.5 1.446 ± 0.087 98.8
1.0 1.921 ± 0.126 96.9
--- 0.897 ± 0.052 ----
SRM 3668c0.910 ± 0.055 0.5 1.380 ± 0.092 96.6
1.0 1.875 ± 0.103 97.8
a Mean of three determinations ± confidence interval (P = 0.95, n =5).
b NIST, SRM 1641e, total mercury in water (p=0.95).
c Mercury in Frozen Human Urine
77
MOF for mercury separation in serum Negar Motakef-Kazemi
Zn2(bdc)2(dabco) dimension on ibuprofen loading
and release, J. Iran. Chem. Soc. 13 (2016) 1205–
1212.
[2]
and evaluation of ZnO nanoparticles by thermal
decomposition of MOF-5, Heliyon 5 (2019)
e02152.
[3] N. Motakef-Kazemi, S.A. Shojaosadati, A. Morsali,
In situ synthesis of a drug-loaded MOF at room
temperature, Micropor. Mesopor. Mat. 186 (2014)
73–79.
[4] B. Miri, N. Motakef-Kazemi, S.A. Shojaosadati, A.
Morsali, Application of a nanoporous metal organic
framework based on iron carboxylate as drug
delivery system, Iran. J. Pharm. Res. 17(4) (2018)
1164-1171.
[5] S.I. Noro, S. Kitagawa, M. Kondo, K. Seki, A new
methane adsorbent, porous coordination polymer,
Angew Chem. Int. Ed. 39 (2000) 2082–2084.
[6] K.S. Min, Self‐assembly and selective guest binding
of three‐dimensional open‐frame work solids from
a macrocyclic complex as a trifunctional metal
building block, Chem. Eur. J. 7 (2001) 303–313.
[7] M. Fujita, Y.J. Kwon, S. Washizu, K. Ogura,
Preparation, clathration ability, and catalysis
of a two-dimensional square network material
composed of cadmium(II) and 4,4’-bipyridine, J.
Am. Chem. Soc. 116 (1994) 1151–1152.
[8] O.R. Evans, W. Lin, Crystal engineering of NLO
networks, Acc. Chem. Res. 35 (2002) 511–522.
[9] O.R. Evans, W. Lin, Crystal engineering of nonlinear
optical materials based on interpenetrated
diamondoid coordination networks, Chem. Mater.
13 (2001) 2705–2712.
[10] M. Oh, C.A. Mirkin, Ion exchange as a way of
controlling the chemical compositions of nano‐
polymers, Angew Chem. Int. Ed. 45 (2006) 5492–
5494.
[11] R. Kitaura, S. Kitagawa, Y. Kubota, T.C. Kobayashi,
K. Kindo, Y. Mita, A. Matsuo, M. Kobayashi, H.
Chang, T.C. Ozawa, M. Suzuki, M. Sakata, M.
Takata, Formation of a one-dimensional array of
oxygen in a microporous metal-organic solid, Sci.
298 (2002) 2358–2361.
[12] P. Horcajada, T. Chalati, C. Serre, B. Gillet, C. Sebrie,
T. Baati, J.F. Eubank, D. Heurtaux, P. Clayette, C.
Kreuz, J.S. Chang, Y.K. Hwang, V. Marsaud, P.N.
Bories, L. Cynober, S. Gil, G. Ferey, P. Couvreur, R.
Gref, Porous metal-organic-framework nanoscale
carriers as a potential platform for drug delivery
and imaging, Nat. Mater. 9 (2010) 172–178.
[13] B. Chen, L. Wang, F. Zapata, G. Qian, A luminescent
recognition and sensing of anions, J. Am. Chem.
Soc. 130 (2008) 6718–6719.
[14] A.J. Fletcher, K.M. Thomas, M.J. Rosseinsky,
Flexibility in metal-organic framework materials:
impact on sorption properties, J. Solid State Chem.
178 (2005) 2491–2510.
[15] M.D. Allendorf, C.A. Bauer, R.K. Bhakta, R.J.T.
Houk, Luminescent metal–organic frameworks,
Chem. Soc. Rev. 38 (2009) 1330-1352.
[16] S.M. Humphrey, T.J. Angliss, M. Aransay, D. Cave,
L.A. Gerrard, G.F. Weldon, P.T. Wood, Bimetallic
metal-organic frameworks containing the [M2,x-
pdc)2
-2](M = Cu, Pd, Pt; x = 4, 5) building block–
synthesis, structure, and magnetic properties, Z.
Anorg. Allg. Chem. 633 (2007) 2342-2353.
[17] C.G. Silva, A. Corma, H. García, Metal–organic
frameworks as semiconductors. J. Mater. Chem. 20
(2010) 3141-3156.
[18] M. Hunsom, K. Pruksathorn, S. Damronglerd, H.
Vergnes, P. Duverneuil, Electrochemical treatment
of heavy metals (Cu2+, Cr6+, Ni2+) from industrial
Res. 39 (2005) 610-616.
[19] A. El-Samrani, B. Lartiges, F. Villiéras, Chemical
metal removal and treatment optimization. Water
Res. 42 (2008) 951-960.
[20] H. Ozaki, K. Sharma, W. Saktaywin, Performance
of an ultra-low-pressure reverse osmosis membrane
(ULPROM) for separating heavy metal: effects of
interference parameters, Desalination 144 (2002)
287-294.
[21] Z. Wang, J. Xu, Y. Hu, H. Zhao, H. Zhou, Y. Liu,
Z. Lou, X. Xu, Functional nanomaterials: Study on
aqueous Hg(II) adsorption by magnetic Fe3O4@
SiO2-SH nanoparticles, J. Taiwan Inst. Chem. Eng.
60 (2016) 394-402.
[22] L. Rahmanzadeh, M. Ghorbani, M. Jahanshahi,
Effective removal of hexavalent mercury
nanoadsorbent, J. Water Environ. Nanotechnol. 1
78 Analytical Methods in Environmental Chemistry Journal; Vol. 3 (2019)
(2016) 1-8.
[23] K. Yaghmaeian, R. Khosravi Mashizi, S. Nasseri,
A.H. Mahvi, M. Alimohammadi, S. Nazmara,
Removal of inorganic mercury from aquatic
environments by multi walled carbon nanotubes, J.
Environ. Health Sci. Eng. 13 (2015) 55.
[24] Q.D. Qin, J. Ma, K. Liu, Adsorption of nitrobenzene
from aqueous solution by MCM-41, J. Colloid
Interface Sci. 315 (2007) 80–86.
[25] L. Xie, D. Liu, H. Huang, Q. Yang, C. Zhong,
using metal–organic frameworks, Chem. Eng. J.
246 (2014) 142–149.
[26] D.V. Patil, P.B. Somayajulu Rallapalli, G.P. Dangi,
R.J. R.S. Tayade, Somani, H.C. Bajaj, MIL-
nitrobenzene from aqueous solutions, Ind. Eng.
Chem. Res. 50 (2011) 10516–10524.
[27] N. T. Abdel-Ghani, G. A. El-Chaghaby, F. S. Helal,
Individual and competitive adsorption of phenol
and nickel onto multiwalled carbon nanotubes, J.
Adv. Res. 6 (2015) 405-415.
[28] Z. Zhaoa, X. Li, Z. Li, Adsorption equilibrium and
kinetics of p-xylene on chromium-based metal
organic framework MIL-101, Chem. Eng. J. 173
(2011) 150–157.
[29] A.A. Adeyemo, I.O. Adeoye, O.S. Bello, Metal
organic frameworks as adsorbents for dye
adsorption: overview, prospects and future
challenges, Toxicol. Environ. Chem. 94(10) (2012)
1846–1863.
[30] M.M. Tong, D.H. Liu, Q.Y. Yang, S. Devautour-
framework metal ions on the dye capture behavior
of MIL-100 (Fe, Cr) MOF type solids, J. Mater.
Chem. A 1 (2013) 8534–8537.
[31] M.A. Al-Ghouti, M.A.M. Khraisheh, S.J. Allen,
M.N. Ahmad, The removal of dyes from textile
wastewater: a study of the physical characteristics
and adsorption mechanisms of diatomaceous earth,
J. Environ. Manage. 69 (2003) 229–238.
[32] J. Galán, A. Rodríguez, J.M. Gómez, S.J. Allen,
G.M. Walker, Reactive dye adsorption onto a novel
mesoporous carbon, Chem. Eng. J. 219 (2013)
62–68.
[33] A. Sayari, S. Hamoudi, Y. Yang, Applications of
pore-expanded mesoporous silica: removal of
heavy metal cations and organic pollutants from
wastewater, Chem. Mater. 17 (2005) 212-216.
[34] S. Babel, T.A. Kurniawan, Low-cost adsorbents for
heavy metals uptake from contaminated water: a
review, J. Hazard. Mater. B97 (2003) 219–243.
[45] L. Rasuli, A.H. Mahvi, Removal of humic acid
from aqueous solution using MgO nanoparticles, J.
Water Chem. Tech. 38(1) (2016) 21–27.
[36] M.R. Mehmandoust, N. Motakef-Kazemi, F.
Ashouri, Nitrate adsorption from aqueous solution
by metal–organic framework MOF-5, Iran. J. Sci.
Technol. Trans. A-Science. 43(2) (2019) 443–449.
[37] A. Bhatnagara, E. Kumarb, M. Sillanpää,
Nitrate removal from water by nano-alumina:
Characterization and sorption studies, Chem. Eng.
J. 163 (2010) 317–323.
[38] J.D. Park, W. Zheng, Human exposure and health
effects of inorganic and elemental mercury, J. Prev.
Med. Public Health 45 (2012) 344–352.
[39] M.A. Bradley, B.D. Barst, N. Basu, A review of
Environ. Res. Public Health 14 (2017) 169.
[40] B.F. Azevedo, L.B. Furieri, F.M. Pecanha, G.A.
Wiggers, P.F. Vassallo, M.R. Simoes, J. Fiorim, P.R.
Batista, M. Fioresi, L. Rossoni, I. Stefanon, M.J.
Alonso, M. Salaices, D.V. Vassallo, Toxic effects of
mercury on the cardiovascular and central nervous
systems, J. Biomed. Biotechnol. 2012 (2012) 1-11.
[41] K.M. Rice, E.M. Walker Jr, M. Wu, C. Gillette,
E.R. Blough, Environmental mercury and its toxic
effects, J. Prev. Med. Public Health 47 (2014) 74–
83.
[42] S.E. Orr, C.C. Bridges, Chronic kidney disease and
exposure to nephrotoxic metals, Int. J. Mol. Sci. 18
(2017) 1039.
[43] E. Afshar, H. Mohammadi-Manesh, H. Dashti
Khavidaki, Removal of Hg (I) and Hg (II) ions
from aqueous solutions, using TiO2 nanoparticles,
Pollution. 3 (2017) 505-516.
[44] K. Suresh Kumar Reddy, B. Rubahamya, A. Al
Shoaibi, C. Srinivasakannan, Solid support ionic
liquid (SSIL) adsorbents for mercury removal from
natural gas, Int. J. Environ. Sci. Technol. 16 (2019)
1103–1110.
