A comprehensive experimental and theoretical study on BN nanosheets for the adsorption of pharmaceutical drugs

Article abstract of DOI:10.1039/c9nj06029d

BN nanomaterials have revolutionized the scientific world with their outstanding physiochemical properties leading to far-fetched applicability in the field of adsorption. In this context, the present investigation dealt with the synthesis and characterization of BN nanosheets and their applicability for the adsorption of pharmaceutical drugs. BN nanosheets have exhibited excellent adsorption for levofloxacin, tetracycline, and curcumin. To get further insights into the feasibility of the adsorption of drugs over BN nanosheets and to scrutinize the interactions between the two, computations were performed within DFT formalism. The theoretical investigations unveiled the presence of hydrogen bonding and negative adsorption energies liable for favorable adsorption. The synthesized BN nanosheets had good biocompatibility and were proven to be proficient adsorbents for the sustainability of the environment.

Full text of DOI:10.1039/c9nj06029d

View Article Online
View Journal
NJC
New Journal of Chemistry
Accepted Manuscript
A journal for new directions in chemistry
This article can be cited before page numbers have been issued, to do this please use: A. Goyal, D.
Aggarwal, S. Kapoor, N. Goel, S. Singhal and J. Shukla, New J. Chem., 2020, DOI: 10.1039/C9NJ06029D.
Volume 42
Number
March 2018
Pages 3963-4776
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
6
21
NJC
New Journal of Chemistry
rsc.li/njc
A journal for new directions in chemistry
Accepted Manuscripts are published online shortly after acceptance,
before technical editing, formatting and proof reading. Using this free
service, authors can make their results available to the community, in
citable form, before we publish the edited article. We will replace this
Accepted Manuscript with the edited and formatted Advance Article as
soon as it is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
Please note that technical editing may introduce minor changes to the
text and/or graphics, which may alter content. The journal’s standard
Terms & Conditions and the Ethical guidelines still apply. In no event
shall the Royal Society of Chemistry be held responsible for any errors
or omissions in this Accepted Manuscript or any consequences arising
from the use of any information it contains.
ISSN 1144-2546
PAPER
Chechia Hu, Tzu-Jen Lin et al.
Yellowish and blue luminescent graphene oxide quantum dots
prepared via a microwave-assisted hydrothermal route using
H2O2 and KMnO4 as oxidizing agents
rsc.li/njc

Page 1 of 40
New Journal of Chemistry
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
A comprehensive experimental and theoretical study on BN nanosheets for the adsorption
of pharmaceutical drugs
a
b
b
b
b
Ankita Goyal , Diksha Aggarwal , Surbhi Kapoor , Neetu Goel , Sonal Singhal* and Jaya
Shukla*a
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
aDepartment of Nuclear Medicine, PGIMER, Chandigarh-160012, India
bDepartment of Chemistry, Panjab University, Chandigarh-160014, India
Corresponding Authors:
Dr. Jaya Shukla
Dr. Sonal Singhal
Professor
Additional Professor
Department of Nuclear Medicine and PET
Department of Chemistry
Post Graduate Institute of Medical Education Panjab Univeristy, Chandigarh 160014
and Research
INDIA
Chandigarh 160012
INDIA
sonal1174@gmail.com
shuklajaya@gmail.com
1

New Journal of Chemistry
Page 2 of 40
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
Abstract
BN nanomaterials have revolutionized the scientific world with their outstanding
physiochemical properties leading to far-fetched applicability in the field of adsorption. In this
context, present investigation deals with the synthesis and characterization of BN nanosheets and
applicability for the adsorption of pharmaceutical drugs. BN nanosheets exhibited excellent
adsorption for Levofloxacin, Tetracycline and Curcumin. To get further insights into the feasibility
of adsorption of drugs over BN nanosheets and to scrutinize the interactions between the two,
computations have been performed within DFT formalism. The theoretical investigations unveiled
the presence of hydrogen bonding and negative adsorption energies liable for favorable adsorption.
The synthesized BN nanosheets being biocompatible proved to be proficient adsorbents for the
sustainability of environment.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Keywords
Boron nitride, Pharmaceutical drugs, Adsorption Isotherms, Adsorption Kinetics, DFT
computations
1
.
Introduction
Boron nitride (BN) nanomaterials being one of the most promising and popular inorganic
nanomaterials are now-a-days furiously reigning the scientific world of applications. This
mounting enthusiasm towards the BN nanomaterials is attributed to the chemical structure and
1
properties exhibited by BN at nano level. BN nanomaterials offer excellent physical and chemical
properties which make them suitable for a wide variety of applications. The properties include
high thermal conductivity, low density, high surface area, presence of structural defects, wide band
gap, high pore volume, low thermal expansion, resistance to oxidation, good thermal shock
resistance, high electrical resistance, low dielectric constant and loss tangent, microwave
transparency, non-toxicity, bio-compatibility, chemical inertness and non-wetting by most molten
2
metals. These unique attributes have dragged the use of BN nanomaterials in a plethora of
applications such as surface investigation, composite ceramics, high temperature cooling
components, in transistors, protective shielding, high temperature lubricants, cosmetics, gas
adsorption, insulation, as catalyst for high temperature treatment, as adsorbents for the removal of
2

Page 3 of 40
New Journal of Chemistry
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
heavy metal ions, dyes, drugs and other organic pollutants and as drug carriers for in-situ drug
delivery.3–7
Out of all these areas of interest, the need of adsorbents which are stable, recoverable,
reusable, non-toxic, facile to handle; irrespective of the field- whether it is adsorptive removal of
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
8
,9
pollutants or drug delivery, is budding. In this regard, the employment of BN nanomaterials with
morphological variations as adsorbents has been the hot area of research lately.10 Both
experimental and theoretical studies have been available in literature wherein adsorption
characteristics of BN nanomaterials have been explored with a view of remediation of
environmental pollution as well as with the perspective of drug delivery. The features that render
BN nanomaterials as potential candidates for adsorption of drugs include high adsorption capacity,
high surface area, presence of structural defects, chemical and thermal stability, high chemical
inertness and easy cycling ability.11-14 Different research cohorts have been actively engaged in the
production of modified BN nanostructures for the adsorptive removal of different kinds of
recalcitrant pollutants.15–19 Oh et al. explored the insights into the adsorption of Cu(II) and Ni(II)
on h-BN synthesized at different temperatures-750, 900 and 1050ꢀ°C. The sample prepared at
750ꢀ°C exhibited the best performance. The adsorbents possessed micro-particle morphology with
15
2
−1
BET specific surface area between 12–18 m g . The surface oxygen functional
groups (particularly B-O) were found to play an important role in facilitating
the electrostatic attraction and complexation of Cu(II) and Ni(II) during adsorption process. Liu et
1
6
al. explored few-layered BN nanosheets synthesized at lower temperature for the adsorption of
2
+
2+
Pb . The process of removal of Pb ions was fitted in the pseudo-second order model and
Langmuir model, which indicated that it was an endothermic and spontaneous reaction. The
-1
equilibrium absorption capacity could get to 845 mg g at 25 ºC within 15 min with favourable
reusability. Hexagonal boron nitride (BN) bundles formed by the assembly of plenty of BN fibers
with high adsorption capacity and outstanding recyclability were explored for the adsorption of
17
18
sulfadiazine, oxytetracycline and erythromycin antibiotics. Singla et al. explored the antibiotic
adsorption on the surface of two different morphologies of BN. Two commonly used
fluoroquinolones i.e. ofloxacin (OFL) and moxifloxacin (MOXI) were chosen and the adsorption
process followed pseudo-second-order kinetic model with good adsorption capacities. Shayan and
Nowroozi19
performed
a
theoretical
investigation
on
the
armchair
boron
nitride nanotubes (BNNTs) interacting with the 5-fluorouracil (5-FU) (an anticancer drug) using
3

New Journal of Chemistry
Page 4 of 40
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
B3LYP/6-31G (d,p) level of theory. The encapsulation and adsorption of 5-FU molecule on the
studied BNNTs surface was found to be a favorable process, with a few exceptions. BNNTs were
established to be considered as a drug delivery vehicle for the transportation of 5-FU as anticancer
drug within the biological systems.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Having a view at the above literature, BN nanostructures with different morphologies are
extensively being explored for the adsorption of different pollutants as well as drugs. Keeping this
in mind, in the present investigation two different types of BN nanosheets- with pores and without
pores have been synthesized and explored as adsorbents for two antibiotics belonging to two
different classes i.e. Levofloxacin (an anti-bacterial drug belonging to fluoroquinolone family) and
Tetracycline (an anti-microbial drug). Additionally, the adsorption of curcumin (Having high
therapeutic value against side-effects of chemotherapy) with a view to explore BN for drug
delivery application has also been explored. To obtain the best conditions for adsorption, different
reaction parameters such as pH, drug loading and adsorbent loading have also been varied. Also,
the adsorption kinetics and adsorption isotherms have been explored to acquire the best fit for the
obtained data. To get further understanding of the feasibility of adsorption of drugs over BN
nanosheets and to examine the interactions between the two, DFT computations have additionally
been performed.
2.
Experimental
2
.1. Materials and reagents
Boric Acid (H BO , 99.5%), Melamine pure (C H N 99%) and Urea (CH N O) were
3
3
3
6
6,
4
2
purchased from Sigma-Aldrich. Levofloxacin (C H FN O , >98%) and Tetracycline
1
8
20
3
4
Hydrochloride (C H ClN O , >98%) were obtained from Tokyo Chemical Industry (TCI)
2
2
25
2
8
Limited. All chemicals were of analytical grade and used without further purification.
2
.2. Fabrication of BN nanosheets
Both the boron nitride nanosheet were prepared using solid state thermal annealing
technique with different choice of precursors and different temperature program as discussed
below:
2.2.1. Synthesis of BN nanosheets
4

Page 5 of 40
New Journal of Chemistry
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
In the synthesis of Boron Nitride nanosheets, boric acid and urea were used as the raw
materials. A mixture of boric acid and urea was prepared (i.e. in a molar ratio of 1:12) by adding
40 mL of deionized water to the mixture. The mixture was heated at about 65 C with continuous
stirring until it got homogenized and completely dissolved in water. Further, it was heated in an
oven at 60C for 13 h. After the completion of this time, the transparent solution was taken out of
the oven and stirred with a glass rod and in few minutes the transparent liquid turned into a white
precipitates mass. The dried white compound was further loaded in alumina boats and treated in
muffle furnace under continuous flow of nitrogen at 900C for 5 h. The furnace was allowed to
cool and the obtained cooled product was collected, washed with 2M HCl so to remove the
impurities, and then dried at about 85 C for 12 h to obtain BN nanosheets.
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
2.2.2. Synthesis of porous BN nanosheets
Porous BN nanosheets were prepared using a two-step solid state thermal annealing
technique. The first step employed boric acid and melamine as starting materials to obtain the
precursor. Typically, boric acid and melamine (2:1 molar ratio) were dissolved in 200 mL of
distilled water. The mixture was heated at 85C for 12 h under continuous stirring and was then
allowed to cool down at room temperature. The cooling process turned it in to white flocculated
mass. The flocculated mass was filtered and dried at 90 C for 12 h to obtain a white powder of
melamine diborate. In the second step, the white powder was loaded in alumina boats and then
treated, first at 300 C for 1hr and then at 1100 C for 2 h under continuous flow of N . The furnace
2
was allowed to cool down to room temperature and then the product was collected from the
alumina boats followed by washing with 2M HCl to remove the impurities. The pure product was
finally dried at about 85 C for 12 h to obtain porous BN nanosheets.
Also, the formation of pores during the synthesis of porous BN nanosheets could be
accounted to the use of melamine as N-containing precursor (source of nitrogen). The thermal
decomposition of melamine led to the release of various gases that could result in the formation of
2
0
porous structure. But in the synthesis of BN nanosheets, urea was used as N-containing precursor
and it is well evident from the previous literature report that the porosity of BN nanosheets
remained limited in case of employment of urea as precursor.21
2.3. Procedure for adsorption and release of drugs
5

New Journal of Chemistry
Page 6 of 40
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
In order to examine the adsorption ability of the synthesized BN nanomaterials, adsorption
studies were carried out for the adsorption of antibiotic drugs (Levofloxacin and Tetracycline) and
Curcumin. The aqueous stock solution was prepared with 50 mg/L concentration. For the
adsorption experiments, 100 mL of antibiotic solution with known concentration was taken in 250
mL beaker to which desired amount of adsorbent was added. The adsorption reaction started at
once with the addition of adsorbent into the drug solution which was continuously stirred using
magnetic bar on magnetic stirrer. Subsequent sample aliquots were taken after fixed time intervals
and adsorbent was removed using centrifugation. UV-visible spectroscopy was then employed for
obtaining the corresponding concentration of the drug solution. The effect of different reaction
variables such as pH, drug concentration, adsorbent dosage and time of contact has also been
evaluated.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
The procedure for the release of drugs involves the dispersion of 10 mg of BN-drug
complex in 10 mL PBS buffer solution at different pH values (2, 6 and7.4). At different time
intervals, 3 mL aliquots of PBS solution were collected and centrifuged to obtain clear supernatant
solution. The concentrations of the released drug were analyzed using UV-visible spectral
measurement. Further, 3 mL of fresh PBS buffer was added back to retain the initial volume of the
solution.22
2
.4.
Physical Measurements
The knowledge of different kinds of bonds present and their vibrational modes was acquired
using iS50-FTIR (Fourier transform infra-red spectroscopy (FT-IT)) (Model no. AUP1200343)
-1
-1
-1
instrument with the resolution of 1 cm and scan range of 4000 cm to 400 cm . The details of
the structural aspects, knowledge of type of crystal lattice, corresponding lattice planes and space-
group was attained using powder X-ray diffraction (XRD) technique. Panalytical's X'Pert Pro
diffractometer equipped with vertical theta-theta goniometer and x'Celerator solid-state detector,
was employed for recording the XRD pattern of the powdered sample. Shape, size, morphology
and elemental composition of the synthesized BN nanostructures were examined using Field
emission scanning electron microscopy (FESEM) employing Hitachi (SU-8010) operated at 15
kV. EDS and elemental mapping were also done using the attached accessory with FESEM
instrument. High resolution transmission electron microscopy (HR-TEM- FEI Tecnai (G2 F20)
operating at 200 keV) further confirmed the shape and size and provided information about the
6

Page 7 of 40
New Journal of Chemistry
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
crystallinity and different lattice planes. X-ray photoelectron microscopy (XPS) analysis was
carried out using ESCA+, (omicron nanotechnology, Oxford Instrument Germany) equipped with
monochromator Aluminum Source (Al kα radiation hʋ =1486.7eV) operated at 15 kV and 20 mA.
For the absorbance measurements, JASCO V-750 spectrophotometer was employed. For the
estimation of surface area, BET method was employed and calculation was done using Belsorp
max. To acquire the charge present on the surface of BN, Zeta potential instrument was employed.
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
2
.5. Computational Methodology
DFT calculations were employed for the validation of feasibility of adsorption and better
understanding of principle interactions between drugs and BN nanosheet. The geometrical
optimization of drugs and BN nanosheet was carried out by hybrid generalized gradient
approximation i.e. Becke, 3-parameter, Lee–Yang–Parr (B3LYP)23,24 in conjunction with 6-31G
25
basis set as implemented in Gaussian 09 simulation package. The vibrational frequency analysis
was also performed for the confirmation of the optimized geometries as minima (no imaginary
frequency). The adsorption energy (E ) of drug adsorbed over BN nanosheet was calculated as:
ads
퐸푎푑푠 = 퐸푎푑푠표푟푏푎푡푒 + 푎푑푠표푟푏푒푛푡 ― (퐸푎푑푠표푟푏푎푡푒 + 퐸푎푑푠표푟푏푒푛푡
)
(1)
where, Eadsorbate+adsorbent, Eadsorbate and Eadsorbent represents the total energy of drug adsorbed over BN
nanosheets, energy of drug and energy of BN nanosheet, respectively. The exothermic nature of
the adsorption is governed by negative adsorption energy (E < 0).
ads
3.
Results and discussion
3
.1. Structural and Morphological Characterization
For the confirmation of successful formation of the BN nanostructures, FT-IR spectra were
recorded. In the FT-IR spectra (Fig. 1.) for porous BN and BN nanosheets, two characteristic peaks
-1
corresponding to BN bonding were observed. Strong asymmetric band appeared at 1365 cm and
-1
2
7
68 cm corresponding to in-plane B-N transverse optical mode of sp -bonded h-BN and B-N-B
out of plane bending vibrations, respectively, were observed. An additional broad band in the range
-1
of 3400-3200 cm was also observed owing to the –OH groups present in the adsorbed H O
2
molecules.26
The structural characteristics of adsorbents were observed using powder XRD analysis.
The XRD patterns (Fig. 2.) for porous BN and BN nanosheets matched well with standard
7

New Journal of Chemistry
Page 8 of 40
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
27
patterns corresponding to pure h-BN with P63/mmc space group (JCPDS no. 34-0421). Peaks
corresponding to six major planes i.e. (0 0 2), (1 0 0), (1 0 1), (0 0 4), (1 1 0) and (1 1 2) were
observed at 2θ positions of 27.16°, 41.59°, 43.87°, 55.16°, 75.93° and 82.17° respectively. It was
observed that the intensity of peaks corresponding to BN nanosheet was lower in comparison with
porous BN. The lower intensity of peaks of BN nanosheet could be ascribed to the BN disorder or
defect density.28,29 Also, the difference in intensity of peaks of BN nanosheet and porous BN could
also be attributed to the variance in the temperature range employed in the synthesis procedure. It
is known from the previous literature reports that increase in temperature results in the increase in
peak intensity.30,31 The processing temperature used in the preparation of BN nanosheet was quite
lower in comparison with that used in the synthesis of porous BN that could account for the lower
intensity of peaks corresponding to BN nanosheet. The values of lattice parameters “a” and “c”
were calculated using Le-Bail refinement method and crystallite size was appraised from the line
broadening of the most intense peak observed at 2θ position of 27.16° for (0 0 2) plane and are
given in Table. 1.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
FE-SEM studies revealed the morphological characteristics of the BN nanostructures. Low
resolution FE-SEM images (Fig. 3 (a) and (d)) for both BN nanostructures confirmed the formation
of sheet like structures. Further magnification revealed that in one case (for the case of porous)
there are pores present on the surface while for other pores were not there as confirmed from Fig.
3
(b) and (e), respectively. The samples were further observed at higher resolution (Fig. 3 (c) and
(f)) and were found to be made up of very minute quasi-spherical particles with size in the range
of 10-15 nm.
HR-TEM data obtained for Porous BN and BN nanosheets have been given in Fig. 4 and
Fig. 5, respectively. Fig. 4 (a) and (b) depict the low resolution TEM images showcasing the minute
quasi-spherical particles gathered together forming the porous structure. Fig. 4 (c) and (d) are the
high resolution TEM images showing the interplanar distance corresponding to different lattice
planes present in the structure. The interplanar spacing (0.33 nm) corresponding to most intense
peak (0 0 2) as observed in XRD has been marked. Fig. 5 (a) and (b) display the presence of tightly
packed spherical particles forming sheet like structure. Fig. 5 (c) shows the interplanar spacing
corresponding to the most intense peak as observed in XRD. Fig. 4 (e) and Fig. 5 (d) are the SAED
patterns which display concentric electron diffraction rings obtained corresponding to electron
8

Page 9 of 40
New Journal of Chemistry
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
density present in different planes, marked in the images. EDS patterns (Fig. 4 (f) and 5 (e)) show
the presence of B, C, N, O and Cu. C and Cu have been observed owing to the use of C coated Cu
grid for the measurement.
The purity of the synthesized BN nanostructures was further supported by XPS
spectroscopy. The XPS spectra for both the BN nanostructures have been shown in Fig. 6 and Fig.
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
7
. The peaks corresponding to B1s, C1s, N1s and O1s were observed to be there. C and O emerged
3
2
in the spectrum owing to the XPS measurement. The observed binding energies for B and N were
33
in close agreement corresponding to hexagonal BN reported in literature. The B/N ratio from the
XPS survey for porous BN and BN nanosheet were observed to be 1.03 and 1.05, respectively.
3.2.
Surface Area and Surface Charge studies
The Brunauer-Emmett-Teller (BET) N adsorption/desorption measurements were
2
performed to determine the surface area. The N adsorption/desorption isotherms for porous BN
2
and BN nanosheets matched with type IV and type I adsorption isotherms, respectively (Fig. 8 (a)
and (b)). These adsorption isotherms depict monolayer adsorption for BN nanosheet and
monolayer adsorption at low pressure and multilayer adsorption at high pressure for porous BN
nanosheet. Type IV BET isotherm is observed for porous BN which suggests the predominance of
mesoporous structure. The presence of mesopores could lead to a greater enhancement in the
adsorption capacity. Also, the persistence of the capillary condensation effect in case of Type IV
isotherm also plays its role that could lead to an addition better adsorption. 34-35
36
The BET adsorption relation is given by equation (2). ‘P’ and ‘P ’ are the equilibrium
0
and saturation pressure, ‘Q’ is the quantity of the gas adsorbed on the adsorbate, ‘Q ’ is the
m
monolayer adsorbed gas quantity and ‘C’ is the BET constant.
1
퐶 ― 1 푃
1
= 푄푚퐶 ( )
+
(2)
푃
0
푃0
푄푚퐶
푄[
(
) ― 1
푃
]
According to equation (2) graphs were plotted between 1/[Q{(P /P)-1}] vs. P/P named as BET
0
0
adsorption isotherm (Fig. 8(c) and (d)). From the plot the values of slope (A) and intercept (I) were
deduced and the values of ‘Q ’ and ‘C’ were calculated according to the equations (3) and (4).
m
9

New Journal of Chemistry
Page 10 of 40
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
1
푄 =
(3)
(4)
푚
퐴 + 퐼
퐴
퐶 = 1 + 퐼
Further, the values of Total surface area (Stotal) and Specific surface area (SBET) were calculated
according to the equations (5) and (6).
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
푄푚푁푠
푆푡표푡푎푙
=
(5)
(6)
푉
푆푡표푡푎푙
푆퐵퐸푇
=
푀
2
Where, ‘N’ is Avogadro’s number, ‘s’ (0.1620 nm ) is molecular cross-sectional area, ‘V’ is the
molar volume of the adsorbate gas and ‘M’ is the mass of the adsorbent sample. The value of Qm,
C, M, Stotal and SBET for both the samples have been included in Table. 2.
The surface charge is very crucial parameter that could facilitate the knowledge of the type
of adsorbate to be absorbed. To gain this idea, Zeta potential analysis was performed for both the
BN nanomaterials. For the surface charge measurement, the medium used was water at neutral pH.
A constant voltage (3.4 V) was applied between the electrodes placed in the dispersion medium
and conductivities of both the BN nanomaterials were measured depicting the zeta potential values
to be -25.5 mV and -22.8 mV for porous BN and BN nanosheets respectively. The negative values
of the zeta potential demonstrate the presence of negative charge on their surface.
The characterization results revealed that both the BN nanostructures were obtained in pure
form with well-defined structural characteristics, high surface area and possess negative charge on
their surface. Further, the adsorption characteristics were explored for both the BN nanostructures.
3
.3.
Adsorption Studies
For the evaluation of the adsorption characteristics of the synthesized BN nanostructures,
adsorption of Levofloxacin and Tetracycline as model compounds was carried out. The time
dependent progress of the adsorption reaction was evaluated using UV-visible spectroscopy.
Levofloxacin which is an antibiotic belonging to fluoroquinolone family exhibits absorption
maxima at ~293 nm in the UV-visible range and Tetracycline which is an antibiotic used to fight
against bacterial infections exhibits absorption maxima at ~381 nm. The absorption maxima were
10

Page 11 of 40
New Journal of Chemistry
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
found to decrease with the passage of time for both the drugs with both the BN nanostructures
under chosen experimental conditions, indicating their potential towards adsorptive removal. Also,
to evaluate the effect of different pH conditions, initial drug concentration and adsorbent dosage,
a series of adsorption experiments were performed. The initial pH has been varied from 2 to 10
with fixed adsorbent dosage (1 g/L) and drug loading of 10 mg/L for Levofloxacin and 50 mg/L
for Tetracycline. It can be inferred that maximum adsorption could be obtained at pH=4 with an
adsorption % of 96.4% for porous BN and 94.1% for BN nanosheets for Levofloxacin, while, for
Tetracycline it was maximum at pH-6 with 84.2% for porous BN and 82.7% for BN nanosheets.
Also, the drug dosage has been varied for both the BN nanostructures and it was found that drug
dosage of 10 mg/L for Levofloxacin and 50 mg/L for Tetracycline exhibited the best results. The
adsorbent dosage of 1g/L was found to be optimum for both the drugs and for both the BN
nanostructures. The obtained results have been given in Fig. S1 and S2 and Fig. S3 respectively
(supporting information). After obtaining the optimum conditions adsorption kinetics and
adsorption isotherms were explored.
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
The kinetic study of adsorption plays a very important aspect of adsorption process as it
gives an idea of adsorbate uptake rate, adsorption efficiency and feasibility. For detailed analysis
for the adsorption data several kinetic models have been used in the literature.37
Here, in this work two kinetic models have been evaluated i.e. pseudo-first-order and
pseudo-second-order. Pseudo first order kinetics equation is:
k1
log
(
qe ― qt
)
= logq ― 2.303t
(7)
e
-1
where q and q are the adsorption capacities (mg g ) at equilibrium and at time t, respectively,
e
t
-1
while k is the pseudo-first-order rate constant (min ). The slope and intercept of linear plot of log
1
(
q - q ) vs. t (Fig. S4) were used to evaluate the values of k and q respectively.
e
t
1
e
The pseudo-second-order model depicts the variation of adsorption rate with adsorption capacities
and is formulated as:
t
1
t
=
+
(8)
k2qe2
qt
qe
-1
-1
where k is the pseudo-second-order rate constant (g mg min ). The values of q and k can be
2
e
2
obtained from the linear plot of t/q vs. t via deducing the slope and intercept respectively (Fig.
t
11

New Journal of Chemistry
Page 12 of 40
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
S5). The data obtained from the kinetic plots is tabulated in Table. 3. By comparing the correlation
2
coefficient (R ) values, pseudo-second-order kinetic model exhibited good agreement between the
experimental and calculated values and correctly described the adsorption kinetics via having
2
higher R values as compared to first order kinetic model.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
The study of adsorption isotherms is very helpful to understand the feasibility of an
3
8
adsorbate-adsorbent system. In this work, Langmuir and Freundlich adsorption isotherm models
were used for the interpretation of the experimental data. In order to determine the adsorption
isotherm, adsorbent dosage of 1g/L was used under the optimized experimental conditions with
varying drug dosage. The linear representation of the Langmuir isotherm model can be expressed
as follow:39,40
Ce
qe
1
Ce
+ qmax
=
(9)
qmaxKL
where qmax and K are Langmuir constants related to maximum adsorption capacity of
L
adsorbents (mg/g) and Langmuir adsorption constant (L/mg), also known as effective dissociation
constant, respectively, while C and q represent the drug concentration (mg/L) and adsorption
e
e
capacity (mg/g) at equilibrium, respectively. From the linear plot between (C /q ) against C (Fig.
e
e
e
S6), values of the Langmuir constants i.e. qmax and K were determined from the slope and intercept
L
and listed in Table. 4. The essential characteristic of the Langmuir isotherm is the dimensionless
4
1
constant called equilibrium parameter (R ) and it can be expressed as follows:
L
1
RL = 1
(10)
+ KLCo
where C is the initial drug concentration in (mg/L). Depending upon the value R adsorption is
o
L,
considered to be unfavorable (R > 1), linear (R = 1), favorable (0 < R < 1), or irreversible (R
L
L
L
L
=
0). It was found that value of R for both the drugs is between 0 and 1, depicting favorable
L
adsorption.
The mathematical representation of the Freundlich isotherm model is as follows:
푙표푔퐶푒
푙표푔푞 = 푙표푔퐾 +
(11)
푒
퐹
푛
12

Page 13 of 40
New Journal of Chemistry
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
1/n
where K ((mg/g) (L/mg) ) and n are Freundlich constant representing the adsorption capacity
F
of the adsorbent and the energy of adsorption effectiveness, respectively. The values of K and n
F
are calculated from the intercept and the slope of the plot of log q vs. log C (Fig. S7) are tabulated
e
e
2
in Table. 4. The R values from two kinds of adsorption isotherms are summarized in Table. 4 and
it indicates that the experimental adsorption equilibrium data of the system data fit the Langmuir
isotherm better as it had significantly higher correlation coefficient in comparison to Freundlich
isotherm. Therefore, it is imputed from the results that the adsorption of drugs takes place in a
monolayer manner over the surface of both BN nanostructures. Further, the maximum adsorption
capacities attained for Levofloxacin and Tetracycline as calculated from Langmuir plots were
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
-1
-1
17.6056 mg g and 129.8700 mg g , respectively, employing 1g/L porous BN; and 20.0803 mg
-1
g and 86.206, respectively, employing 1g/L BN nanosheet.
The adsorption studies revealed that for both the BN nanostructures and for both the drugs
the adsorption R values lies between 0 and 1, suggesting favorable adsorption. For both the BN
L
nanostructures, the best results for Levofloxacin were observed at pH-4 followed by pH-6.
Levofloxacin exist in cationic form below pH-5 and at pH-6 it exist in zwitter-ionic form. As the
surface of BN nanostructures possess negative charge maximum adsorption could be expected at
+
pH-2, but at pH-2, H present in the reaction mixture start competing with drug molecules thus,
lowering the adsorption of drug.42
For Tetracycline, best results for both the BN nanostructures were observed at pH-6
followed by pH-4. At pH-6, Tetracycline exist in zwitter-ionic form, at pH less than 4, it exist in
cationic form. The best results at pH-6 could be related to the dominant π-π interaction
mechanism.43
Having a view on the adsorption results obtained for the adsorption of both the drugs on
the surface of both the BN nanosheets, it was inferred that better results were obtained for porous
BN nanosheets. So it was further decided to explore porous BN nanosheets for the adsorption of
curcumin on its surface. Curcumin has been chosen based upon its therapeutic action against the
side-effects of chemotherapy. It is safe to intake curcumin with a dosage of 8 g/day for patients
undergoing chemotherapy. But curcumin when undertaken directly it decomposes or degrades
before its therapeutic action owing to its sensitivity towards elevated temperature, basic pH and
exposure to light and insolubility in aqueous medium.44,45 So an attempt has been made to stabilize
13

New Journal of Chemistry
Page 14 of 40
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
it via its adsorption over some solid surface to increase its bio-availability. Prior to adsorption
studies, different reaction parameters (pH, adsorbent dosage, drug concentration) were optimized
to explore the best conditions for adsorption. Three acidic pH were tested i.e. 1, 3 and 5. Alkaline
pH values were not explored owing to the instability of curcumin in alkaline medium. Adsorbent
dosage has been varied from 50 mg to 125 mg and drug concentration has been varied from 5 mg/L
to 50 mg/L. The variation of pH, adsorbent dosage and drug concentration for the adsorption of
curcumin over the surface of porous BN nanosheet has been shown in Fig. S8. It was observed
that percent adsorption was found to be maximum at pH-5. The percent adsorption was found to
increase with increase in adsorbent dosage and it decreased with increase in drug dosage. This
could be related to the fact that with increase in adsorbent dosage number of available adsorption
sites got increased and with increase in drug dosage number of molecules to be adsorbed on the
same number of sites got increased thus, decreasing the adsorption. Further, adsorption kinetic and
adsorption isotherms for the adsorption of curcumin over the surface of porous BN nanosheets
were explored as per the prior discussed equations-equation (1-5). For the understanding of
adsorption kinetics and adsorption isotherms, pseudo-first-order and pseudo-second-order kinetic
models and Langmuir and Freundlich adsorption isotherms were explored (Fig. S9 and Fig. S10).
The adsorption was found to follow pseudo-second order kinetics and fitted well with Langmuir
adsorption isotherm.46,47 The corresponding values of rate constants and correlation co-efficients
and adsorption parameters have been given in Table. 4. The maximum adsorption capacity attained
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
-1
for Curcumin as calculated from Langmuir plot was 32.3620 mg g employing 1g/L porous BN.
3
.4.
Release studies
To examine in vitro drug release, porous BN-Levofloxacin complex was dispersed in PBS
buffer at different pH (2, 6 and 7.4) for 48 h. The above pH values were selected in accordance
with the pH of stomach (1.5-3.5) and normal tissue and blood (7.4).46 Further, UV-visible
spectrophotometric measurements of Levofloxacin concentrations were performed and the release
kinetics is represented in Fig. 9. It was clearly visualized that the release of Levofloxacin from
porous BN-Levofloxacin complex was pH-responsive. At pH 2, around 19% Levofloxacin was
released within 48 h. On the other hand, at pH values of 6 and 7.4, around 35% and 62% of loaded
Levofloxacin were released in 48 h, respectively. Thus, the release rate was found to increase with
increase in the pH value. The enhanced Levofloxacin release from porous BN-Levofloxacin
14

Page 15 of 40
New Journal of Chemistry
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
complex at 7.4 could be attributed to the change in electrostatic interactions between porous BN
nanosheet and Levofloxacin.48,49,50
3
.5.
Theoretical studies
To investigate the interactions between drugs and BN nanosheet and to determine the
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
adsorption energies, calculations were performed using DFT framework. Prior to the adsorption
studies, the geometries of antibiotic drugs (Levofloxacin and Tetracycline) and Curcumin were
optimized and are represented in Fig. S11. Also, the optimized geometry of finite sized BN
nanosheet consisting of 36 boron atoms and 36 nitrogen atoms in hexagonal manner was modeled
as representative of both porous BN and BN nanosheets where open ends were saturated with
hydrogen atoms (Fig. S12). Further, the adsorption of above drugs on BN nanosheet was
investigated separately and the most stable configurations are shown in Fig. 10. It is well evident
that when the sum of van der Waals radii of constituent atoms is greater than bond length, it
signifies the presence of hydrogen bonding. In the present case, hydrogen bond was formed
between hydrogen atom present in drugs and nitrogen of BN nanosheet. The sum of van der Waals
radii of hydrogen (0.12 Å) and nitrogen (0.155 Å) i.e. 0.275 Å was found to be greater than bond
lengths i.e. 2.61 Å (levofloxacin), 2.16 Å (tetracycline) and 2.32 Å (curcumin). This convection
revealed the presence of hydrogen bonding between drugs and BN nanosheet. Also, the oxygen
present in the drug molecules was at a close proximity with boron of BN nanosheet signifying the
interactions between the atoms due to their partial opposite charges. The distances between oxygen
and boron atoms were observed to be 2.96 Å, 2.89 Å and 2.95 Å for levofloxacin, tetracycline and
curcumin, respectively. In the case of adsorption of curcumin over BN nanosheet, stacking
interactions between the rings were also observed. The adsorption energies of drugs adsorbed on
BN nanosheet as calculated by equation (1) were observed to be -0.76 eV (Levofloxacin), -0.79
eV (Tetracycline) and -0.60 eV (Curcumin). The negative adsorption energies unveiled the
exergonic nature and thermodynamic favorability of adsorption process. The order of adsorption
energies of drugs on BN nanosheet was found to be Tetracycline > Levofloxacin > Curcumin.
Molecular electrostatic potential (MEP) surfaces were also generated for the better understanding
of adsorption of drugs over BN nanosheet (Fig. 11). The merging of charge clouds of drugs and
BN nanosheet was clearly visualized depicting the affinity of BN nanosheet towards drug
molecules. Also, the interactions between hydrogen of drug and nitrogen of BN nanosheet; and
electronegative oxygen or fluorine of drug and electropositive boron were observed by analyzing
15

New Journal of Chemistry
Page 16 of 40
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
the overlapping areas. Thus, MEP surfaces also accounted for the interactions between drugs and
BN nanosheet for the favorable adsorption.
Both the experimental results and theoretical calculations validated both the BN nanosheets
as high potential candidates for the rapid and effective adsorption of pharmaceutical drugs with a
view to fight against the pollution menace and infections via drug delivery.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
3
.6. Recyclability
In order to establish the reusability and stability of BN nanostructures, recyclability
experiments were performed for the adsorptive removal of Levofloxacin under the optimized
experimental conditions using porous BN as adsorbent. After the complete adsorption,
Levofloxacin adsorbed BN was separated from the reaction mixture using centrifugation and the
obtained pellet was dried in an oven at 80 °C for 10 hr. To remove the adsorbed drug, the BN
nanostructures were annealed at 500 °C for 1 hr. The obtained BN nanostructures were then
repeatedly used for the proceeding experiments. The recyclability was established up to 3 cycles
without any significant loss in the adsorption capability, while, for the fourth cycle a slight
decrease in adsorption capacity was there. The recyclability results have been shown in Fig. 12.
Further, characterization of recovered adsorbents (porous BN and BN nanosheet) was
done and the results were compared with the adsorbents before drug adsorption. The structure of
the recovered adsorbents was examined using XRD (Fig. 13(a)) and FT-IR analysis (Fig. 13(b)).
The XRD patterns and FT-IR spectra demonstrated that the structure of the adsorbents remained
unchanged after recycling when compared with the adsorbents before drug adsorption indicating
high stability of the adsorbents. Also, the morphology of the recovered porous BN and BN
nanosheet was scrutinized by FE-SEM analysis that revealed no change in the surface morphology
of the recovered adsorbents (Fig. 14). Thus, the post reaction analysis established that the
synthesized adsorbents displayed excellent stability during adsorption processes.
Conclusions
Porous BN and BN nanosheets were successfully explored as high performance adsorbents
for pharmaceutical drugs. The adsorption of drugs was fitted well in the pseudo-second-order
kinetic model and Langmuir model. The porous BN nanosheets were observed to be superior
adsorbents in comparison with BN nanosheets and displayed adsorption capacities of 17.61 mg
16

Page 17 of 40
New Journal of Chemistry
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
-1
-1
-1
g , 129.87 mg g and 32.36 mg g for Levofloxacin, Tetracycline and Curcumin, respectively.
DFT computations further demonstrated the presence of interactions between adsorbed drugs and
BN nanosheet accountable for favorable adsorption. Also, the negative adsorption energies
unveiled the exothermic and thermodynamically favorable nature of adsorption. Thus, the present
study offers insightful prospective for the employment of BN nanosheets as potential candidates
for the environmental sustainability as well as for drug delivery.
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Conflicts of interest
There are no conflicts of interest.
Acknowledgement
The authors are highly thankful to Post graduate Institute of Medical Education and Research,
Chandigarh (Endst No.71/2-Edu-16/161-62) and SERB-NPDF (PDF/2017/000423) for the
required financial support.
References
1
.
S. Yu, X. Wang, H. Pang, R. Zhang, W. Song, D. Fu, T. Hayat and X. Wang, Chem. Eng. J.,
018, 333, 343–360.
2
2. X.F. Jiang, Q. Weng, X.B. Wang, X. Li, J. Zhang, D. Golberg and Y. Bando, J. Mater. Sci.
Technol., 2015, 31, 589–598.
3
4
. Y. He, D. Li, W. Gao, H. Yin, F. Chen and Y. Sun, Nanoscale, 2019, 11, 21909–21916.
. C.C. Cheng, A.A. Muhabie, S.Y. Huang, C.Y. Wu, B.T. Gebeyehu, A.W. Lee, J.Y. Lai and
D.J. Lee, Nanoscale, 2019, 11, 10393–10401.
5
6
.
W.D. Oh, M.G.H. Lee, W.C. Udayanga, A. Veksha, Y. Bao, A. Giannis, J.W. Lim and G.
Lisak, J. Environ. Chem. Eng., 2019, 7, 102872.
.
X. Mao, S. Zhou, C. Yan, Z. Zhu and A. Du, Phys. Chem. Chem. Phys., 2019, 21, 1110–1116.
7. M.B. Jakubinek, B. Ashrafi, Y. Martinez-Rubi, J. Guan, M. Rahmat, K.S. Kim, S. Dénommée,
C.T. Kingston and B. Simard, Boron Nitride Nanotube Composites and Applications, William
Andrew Publishing, Nanotube Superfiber Materials, 2019.
8. R.S. Bangari and N. Sinha, J. Mol. Liq., 2019, 293, 111376.
9
.
E. Duverger, S. Balme, M. Bechelany, P. Miele and F. Picaud, Appl. Surf. Sci., 2019, 475,
66–675.
6
17

New Journal of Chemistry
Page 18 of 40
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
1
1
1
0. W. Li, H. Yang, S. Chen, Q. Chen, L. Luo, J. Li, Y. Chen and C. Li, J. Nanomater., 2019,
https://doi.org/10.1155/2019/3572317.
1. J. Pang, Y. Chao, H. Chang, H. Li, J. Xiong, M. He, Q. Zhang, H. Li and W. Zhu, J. Colloid
Interface Sci., 2017, 508, 121-128.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
2. Q. Li, T. Yang, Q. Yang, F. Wang, K.C. Chou and X. Hou, Ceram. Int., 2016, 42, 8754-8762.
13. H. Wang, W. Wang, H. Wang, F. Zhang, Y. Li and Z. Fu, Ceram. Int.,2018, 44, 12216-12224.
1
1
1
4. Q. Song, Y. Fang, Z. Liu, L. Li, Y. Wang, J. Liang, Y. Huang, J. Lin, L. Hu, J. Zhang and C.
Tang, Chem. Eng. J., 2017, 325, 71-79.
5. W.D. Oh, M.G.H. Lee, W.C. Udayanga, A. Veksha, Y. Bao, A. Giannis, J.W. Lim and G.
Lisak, J. Environ. Chem. Eng., 2019, 7, 102872.
6. T. Liu, Y. Li, J. He, K. Zhang, Y. Hu, X. Chen, C. Wang, X. Huang, L. Kong and J. Liu, J.
Mater. Sci., 2019, 54, 5366–5380.
17. Q. Song, J. Liang, Y. Fang, C. Cao, Z. Liu, L. Li, Y. Huang, J. Lin and C. Tang, J. Hazard.
Mater., 2019, 364, 654–662.
1
1
8. P. Singla, N. Goel and S. Singhal, Ceram. Int., 2015, 41, 10565–10577.
9. K. Shayan, and A. Nowroozi, Appl. Surf. Sci., 2018, 428, 500–513.
20. S. Marchesini, C.M. McGilvery, J. Bailey and C. Petit, ACS Nano, 2017, 11, 10003–10011.
2
1. A. Nag, K. Raidongia, K.P. Hembram, R. Datta, U.V. Waghmare and C.N.R. Rao, ACS
Nano, 2010, 4, 1539–1544.
2
2. L. Xu, Y. Xue, J. Xia, X. Qu, B. Lei, T. Yang, X. Zhang, N. Li, H. Zhao, M. Wang and M.
Luo, Biomaterials, 2020, 230, 119670.
2
2
3. A. D. Becke, J. Chem. Phys., 1993, 98, 5648–5652.
4. C. Lee, W. Yang and R. G. Parr, Phys. Rev. B, 1988, 37, 785–789.
25. M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, G.
Scalmani, V. Barone, B. Mennucci, G. A. Petersson, H. Nakatsuji, M. Caricato, X. Li, H. P.
Hratchian, A. F. Izmaylov, J. Bloino, G. Zheng, J. L. Sonnenberg, M. Hada, M. Ehara, K.
Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, T.
Vreven, J. A. Montgomery, Jr., J. E. Peralta, F. Ogliaro, M. Bearpark, J. J. Heyd, E. Brothers,
K. N. Kudin, V. N. Staroverov, R. Kobayashi, J. Normand, K. Raghavachari, A. Rendell, J.
C. Burant, S. S. Iyengar, J. Tomasi, M. Cossi, N. Rega, J. M. Millam, M. Klene, J. E. Knox,
J. B. Cross, V. Bakken, C. Adamo, J. Jaramillo, R. Gomperts, R. E. Stratmann, O. Yazyev, A.
18

Page 19 of 40
New Journal of Chemistry
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
J. Austin, R. Cammi, C. Pomelli, J. W. Ochterski, R. L. Martin, K. Morokuma, V. G.
Zakrzewski, G. A. Voth, P. Salvador, J. J. Dannenberg, S. Dapprich, A. D. Daniels, Ö. Farkas,
J. B. Foresman, J. V. Ortiz, J. Cioslowski, and D. J. Fox, Gaussian, Inc., Wallingford CT,
Gaussian 09, Revision E.01, 2009.
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
2
6. L. Chen, M. Zhou, Z. Luo, M. Wakeel, A. Asiri and X. Wang, Appl. Catal., B, 2019, 241,
246–255.
2
2
7. A. Ozkan, N. Atar and M. Yola, Biosens. Bioelectron., 2019, 130, 293–298.
8. R. Que, Y. Huang, Q. Li, H. Yao, B. Geng and M. Shao, ACS Appl. Mater. Interfaces, 2014,
6
, 19752–19757.
29. Y. Lin, T.V. Williams, W. Cao, H.E. Elsayed-Ali and J.W. Connell, J. Phys. Chem. C, 2010,
14, 17434–17439.
1
3
0. D. Saha, G. Orkoulas, S. Yohannan, H.C. Ho, E. Cakmak, J. Chen and S. Ozcan, ACS Appl.
Mater. Interfaces, 2017, 9, 14506–14517.
3
1. N. Kostoglou, J. Lukovic, B. Babic, B. Matovic, D. Photiou, G. Constantinides, K.
Polychronopoulou, V. Ryzhkov, B. Grossmann, C. Mitterer and C. Rebholz, Mater. Des.,
2
016, 110, 540–548.
32. M. Du, Y. Wu and X. Hao, Cryst. Eng. Comm., 2013, 15, 1782–1786.
3
3
3
3. H. Li, S. Zhu, M. Zhang, P. Wu, J. Pang, W. Zhu, W. Jiang, H. Li, ACS Omega, 2017, 2,
385–5394.
4. M. Ghasemi, H. Javadian, N. Ghasemi, S. Agarwal and V.K. Gupta, J. Mol. Liq., 2016, 215,
61-169.
5. M. Khalfaoui, S. Knani, M.A. Hachicha and A.B. Lamine, J. Colloid Interface Sci., 2003, 263,
50-356.
36. A. Goyal, S. Bansal, P. Samuel, V. Kumar and S. Singhal, J. Mater. Chem. A, 2014, 2, 18848–
8860.
5
1
3
1
3
7. M. Jianzhe, L. Yang, A. Muhammad, W. Fengyun, C. Yuting, L. Wu, X. Mingzhu and Z. Sidi,
Int. J. Biol. Macromol., 2019, 124, 557–567.
38. X. Hu, L. Jia, J. Cheng and Z. Sun, J. Hazard. Mater., 2019, 362, 1–8.
9. W. He, X. Guo, J. Zheng, J. Xu, T. Hayat, N.S. Alharbi and M. Zhang, Inorg. Chem.,
019, 58, 7255–7266.
3
2
19

New Journal of Chemistry
Page 20 of 40
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
4
4
4
0. J. Zheng, M. Zhang, T. Miao, J. Yang, J. Xu, N.S. Alharbi and M. Wakeel, Mater. Chem.
Front., 2019, 3, 224–232.
1. R. Gao, Y. Hao, L. Zhang, X. Cui, D. Liu, M. Zhang, Y. Tang and Y. Zheng, Chem. Eng.
J., 2016, 284, 139–148.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
2. X. Qin, F. Liu, G. Wang, L. Weng and L. Li, Colloids Surf., B, 2014, 116, 591–596.
43. Y. Gao, Y. Li, L. Zhang, H. Huang, J. Hu, S. Shah and X. Su, J. Colloid. Interface Sci., 2012,
68, 540–546.
3
4
4. A. Duvoix, R. Blasius, S. Delhalle, M. Schnekenburger, F. Morceau, E. Henry, M. Dicato and
M. Diederich, Cancer Lett., 2005, 223, 181–190.
45. R.M. Srivastava, S. Singh, S.K. Dubey, K. Misra and A. Khar, Int. Immunopharmacol., 2011,
1, 331–341.
1
4
4
4
6. N. Wang, M. Zhang, L. Liu, J. Zheng, J. Xu, T. Hayat and N.S. Alharbi,
Nanotechnology, 2019, 30, 415602.
7. M. Zhang, T. Miao, J. Zheng, J. Xu, A.M. Asiri and H.M. Marwani, Microporous Mesoporous
Mater., 2019, 286, 207–213.
8. S. Feng, H. Zhang, C. Zhi, X.D. Gao and H. Nakanishi, Int. J. Nanomedicine., 2018, 13, 641.
49. Q. Weng, B. Wang, X. Wang, N. Hanagata, X. Li, D. Liu, X. Wang, X. Jiang, Y. Bando and
D. Golberg, ACS Nano, 2014, 8, 6123-6130.
5
0. I.Y. Zhitnyak, I.N. Bychkov, I.V. Sukhorukova, A.M. Kovalskii, K.L. Firestein, D. Golberg,
N.A. Gloushankova and D.V. Shtansky, ACS Appl. Mater. Interfaces., 2017, 9, 32498-32508.
TABLES
Table. 1. Values of lattice parameters and crystallite size for BN nanostructures.
BN nanostructures
Lattice parameters (Å)
Crystallite size (d) (nm)
20

Page 21 of 40
New Journal of Chemistry
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
a
c
Porous BN
2.5037
2.5047
6.7061
6.7203
8.81
5.55
BN nanosheet
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
21

New Journal of Chemistry
Page 22 of 40
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
Table. 2. Values of different BET surface area parameters, Total surface area and BET
surface area for BN nanostructures.
A
g/cm )
0.0199
I
Q
(cm /g)
50.0250
M
(g)
0.0792
S
S
m /g
2751.26
m
3
total
m2
BET
2
Adsorbent
C
3
3
(
(g/cm )
9*10
-5
BN nanosheet
Porous
BN nanosheet
222.11
566.06
217.90
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
0
.0226
4*10-5
44.1696
0.0765
192.39
2514.90
22

Page 23 of 40
New Journal of Chemistry
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
Table 3. Kinetic parameters for the adsorption of both the drugs over the surface of BN
nanostructures.
Pseudo-first-
order model
Pseudo-second-
order model
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Adsorbent
Drug/conc.
mg/L)
(
qe
k1
qe
-1
K (g mg
2
R2
R2
-1
min )
(min -1
(
mg/g)
)
(mg/g)
Levofloxacin/10
Tetracycline/50
Levofloxacin/10
Tetracycline/50
0.9855
12.265
1.4484
22.35
0.039
0.4957
0.6896
0.8379
0.9083
9.7465
42.74
0.2573
0.0057
0.2307
0.0019
0.9999
0.9996
0.9999
0.9993
Porous BN
0.0126
0.0587
0.0161
9.6339
44.052
BN
nanosheet
(Reaction conditions: pH-4 (Levofloxacin), pH-6 (Tetracycline); BN nanostructures: 1g/L; Drug dosage:
1
0mg/L (Levofloxacin) and 50mg/L (Tetracycline))
23

New Journal of Chemistry
Page 24 of 40
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
Table 4. Adsorption isotherm data for the adsorption of both the drugs over the surface of
BN nanostructures.
Langmuir isotherm
qmax (mg g-1)
-1
R2
Sample
Drug
K (L mg )
L
RL
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Porous BN
Levofloxacin
Tetracycline
17.6056
129.87
20.0803
2.007
0.051
1.398
0.047
0.285
0.067
0.903
0.987
0.981
BN nanosheet Levofloxacin
Tetracycline
86.206
0.097
0.171
0.985
Freundlich isotherm
-1
-1 1/n
R2
Sample
Drug
n
K ((mg g ) (Lmg ) )
F
Porous BN
Levofloxacin
Tetracycline
Levofloxacin
4.472
1.771
2.897
10.889
10.631
10.287
0.7645
0.9499
0.9398
BN nanosheet
Tetracycline
2.27
13.925
0.9208
(Reaction conditions: pH-4 (Levofloxacin), pH-6 (Tetracycline); BN nanostructures: 1g/L; Drug dosage: 5, 10,
1
5, 20, 25 mg/L (Levofloxacin) and 25, 50, 75, 100, 125 mg/L (Tetracycline).
24

Page 25 of 40
New Journal of Chemistry
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
Table 5. Kinetics and Adsorption isotherm data for the adsorption of Curcumin over the
surface of porous BN nanosheets.
Kinetics
Qe (mg/g)
R2
Rate constant
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
-
1
First-order
Second-order
22.53
24.038
0.8266
0.9996
k = 0.0149 min
1
-1
-1
k =0.00379 g mg min
2
Langmuir isotherm
KL
Freundlich isotherm
KF
qmax
mg g )
2.362
R2
0.0618 0.9942
n
R2
RL
-1
-1
-1
-1 1/n
(
3
(L mg )
0.607
((mg g ) (Lmg )
2.126
10.034
0.8247
(Reaction conditions: pH-5 Adsorbent dosage: 1g/L and Curcumin dosage: 5 mg/L, 15 mg/L, 25 mg/L, 35 mg/L
and 50 mg/L)
25

New Journal of Chemistry
Page 26 of 40
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
FIGURES
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Fig. 1. FT-IR spectra for BN nanostructures.
26

Page 27 of 40
New Journal of Chemistry
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Fig. 2. Powder XRD patterns for BN nanostructures.
27

New Journal of Chemistry
Page 28 of 40
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Fig. 3. FE-SEM images for porous BN nanosheet (a,b,c) and BN nanosheet (d,e,f).
28

Page 29 of 40
New Journal of Chemistry
View Article Online
DOI: 10.1039/C9NJ06029D
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Fig. 4. HR-TEM images for porous BN nanostructures at low resolution (a and b), at high
resolution (c and d), SAED pattern (e) and EDS pattern (f).
29