Proceedings of CUChE Alumni Symposium 2022
On “Circular Economy on Sustainable Basis: The Role of Chemical Engineers”
CUChEAA ISBN: 978-81-954649-1-3
December 2022 P a g e | 41 Volume 2, Issue 1
Photocatalytic Decomposition of Ciprofloxacin Drug: Proposed Degradation Mechanism
and Antimicrobial Study
Ardhendu Sekhar Giri
*
*
Department of Chemical Engineering
Indian Institute of Science Education and Research Bhopal
Bhopal, PIN: 462066, India
*Corresponding author
Email: agiri@iiserb.ac.in
Tel: +91-755-267-2637, Fax: +91-755-267-2332
Abstract
Ciprofloxacin (CIP), fluoroquinolones class metabolite, are detected in aquatic environment due to lack of supervision and
an improper removal of CIP. It can act as bidentate chelating ligand and take part in chelation reaction forming iron-CIP
coordination complexes that are degraded in the photo-Fenton process (PFP). This study discovers the performance of PFP
in terms of decomposition of CIP to develop the mechanistic paths of drug cleavage under UV-
irradiation
and the stability
of iron-CIP chelate complexes (FeCIPCOM)
. In PFP, the optimal dose of Fe
2+
and H
2
O
2
were found to
be 1.25 and 10 mM
with pH of 3.5. PFP showed the maximum CIP elimination and mineralization efficiency
of
89.3
and 65.6 %, respectively.
An
eleven number of intermediate products including iron-CIP complexes (FeCIPCOM) were identified using mass
spectra in PFP. The proposed mechanistic pathways of CIP degradation were supported by the mass spectra and the
decomposition routes of FeCIPCOM chelate in PFP was also elucidated here. In PFP, HO
.
radical acts as common
oxidants and attacks in the piperazine ring of the CIP molecule, and the cleavage of FeCIPCOM is evident in PFP. About
61.3% of death of E. coli bacteria was found after 45 min treatment of PFP in comparison to the control media.
Keywords: Metabolites; Antibiotic decomposition; Photo-Fenton; Chelate complex; Antimicrobial activity
1. Introduction
Pharmaceutically active compounds (PhACs) are
generally designed to produce a biological activity on
humans and animals. Manufacturing processes of PhACs
lead to release of toxic organic compounds and their
metabolites into the environment. The side effects of
pharmaceuticals on human and animal health are usually
investigated through the safety and toxicology studies
(Li et al., 2020). PhACs can create a biological activity
well below the concentrations usually used in the safety
tests. Many PhACs and their metabolites are nowadays
are detected not only in wastewater but also in drinking
water (Espindola et al., 2021). They are common in
liquid and solid wastes around manufacturing and mass
administration facilities such as health centres (Ternes et
al., 1998). Ciprofloxacin (CIP) is an antibiotic drug
belongs to fluoroquinolone classes effective against both
gram-positive and gram-negative bacteria. It imparts the
action through the inhibition of microorganism protein
synthesis. Liu (2014) reported that about 18.7 million
defined daily doses (DDD) of CIP is globally given in
the year of 2010. It corresponds to an increase of 6.2%
compared to 2009 reflecting a total consumption of 9.5
tons. CIP scums as contaminants are generally
discharged from hospital effluents, surface water and
sewage treatment plant (Giri et al., 2014a; Li et al.,
2011). CIP molecules are strongly adsorbed on sewage
sludge with as high as 6.3 mg/kgof dry matter (Golet et
al., 2002).
CIP molecule acts as a chelating ligand and forms
charge transfer (LMCT) complex with metal (Lai et al.,
1995). CIP molecule has both carbonyl (=CO) and
hydroxyl (-OH) groups that could form coordination
complexes with many 3d-transition metals like Fe
2+
,
Fe
3+
, Co
2+
, Ni
2+
, etc. (Mase et al., 2013). It has been
observed that 4-quinolones acting as chelating agent
forms complex both with alkaline earth and transition
metal ions (Turel et al., 2002). CIP drug can coordinate
with Fe
3+
ion which is promoted by LMCT through the
Proceedings of CUChE Alumni Symposium 2022
On “Circular Economy on Sustainable Basis: The Role of Chemical Engineers”
CUChEAA ISBN: 987-81-954649-1-3
December 2022 P a g e | 42 Volume 2, Issue 1
redox reaction in an aqueous solution (Luis et al., 2009).
When exposed to UV light, such LMCT complexes
frequently become less stable than their parent
molecules. (Giri et al., 2014b). Fe
3+
forms octahedral 1:3
coordinations with the drug ligands in complexes with
different quinolone drugs like CIP and norfloxacin
(Bandoli et al., 2009). In the presence of solar/UV
radiation, tris(ciprooxacino) iron(III) and [Fe(CIP)
3
]
molecules could decompose in various stages (Mjos et
al., 2017). Additionally, the complexation of CIP with
Fe
3+
would result in a greater antibacterial potency as
compared to the quinolone moiety (Kartick et al 2017).
Hence, the decomposition of CIP present in water
occurred due to quicker and reversible redox conversion
of Fe(II) to Fe(III)
and this change plays an significant
role especially in the Fenton like photocatalytic process
(Buchanan et al., 2005). Photo-Fenton process (PFP) in
the presence of UV light (180-290 nm) shows a rapid
oxidation as a consequence of the higher quantum yields
compared to the convention Fenton process (Diagne et
al., 2009). Thus, in this process, the classical Fenton’s
reaction (Eq. 1) takes place; however, the generation of
·
OH could be increased by application of UV irradiation
and using as catalyst soluble Fe
3+
salt at pH around 3.0
(Tang and Wang et al., 2020). At this pH, the
predominant species of Fe
3+
is Fe(OH)
2+
(Eq. (2)) which
strongly absorbs UV light and generates
·
OH radicals
according to Eq. (3), and Fe
2+
ion which can react with
H
2
O
2
following Eq. (1) to form
·
OH. An excess amount
of ·OH accelerates strongly the oxidation rate of organic
pollutants present in the solution (Diagne et al. 2009;
Casado et al., 2021).
Therefore, the efficiency of photo-Fenton process (PFP)
on CIP removal to distinguish the proposed formation
mechanism of Iron (III)-CIP complexes and its degraded
products under UV-light is the main objective of this
work. Apart from this, novelty based on what is the
effect of UV-light on the degradation of such complexes
was reflected in this study. The toxicity reduction of CIP
in PFP was studied to explore the influence of both
solution and surface phase reactions for CIP
decomposition.
2. Material and Methods
2.1. Materials
Ciprofloxacin (purity >98%) was purchased from Sigma
Aldrich Chemical Ltd. (USA). Triethylamine (98% v/v
purity), acetonitrile (97% v/v purity), ferrous ammonium
sulfate [Fe(NH
4
)
2
(SO
4
)]. 6H
2
O, 98% w/w purity),
K
2
Cr
2
O
7
(>98% w/w purity), Ag
2
SO
4
(> 98% w/w
purity), H
2
SO
4
(98% v/v purity), titanium dioxide (TiO
2
)
(98 %, w/w purity, crystallinity: rutile phase with surface
area of 393 m
2
/g), H
2
O
2
(50% v/v purity), NaOH (97%
v/v purity), and K
2
HPO
4
(97-99% w/w) were obtained
from Merck Specialties Pvt. Ltd. (India). Mili-Q water
(model: Elix-3, USA) was used to prepare both reagents
and drug solutions.
Figure 1: Chemical structure of Ciprofloxacin drug
2.2. Analytical Techniques
2.2.1. High performance liquid chromatography
(HPLC)
CIP concentration was determined by HPLC equipped
with a C
18
column (150 mm length, ∅ 3.5 mm) with a
UV-visible detector (model: 26462, Shimadzu, Japan). A
mixture of water, acetonitrile (CH
3
CN) and
triethylamine (Et
3
N) (80:20:10 v/v/v) were used as the
mobile phase at a flow rate of 1.0 mL/min. The cellulose
acetate filter paper (0.45 µm) was used to eliminate the
suspended particle, if any. About 20 μL sample was used
to inject for the determination of drug concentration with
a wavelength of 278 nm.
2.2.2. Liquid chromatography/ Mass spectroscopy
(LC/MS)
LC/MS was used to determine both mass numbers of
CIP and its intermediate products based on mass to
charge (m/z) ratio (Waters Q-Tof Premier, USA). A
YMC Hydrosphere C
18
(150 mm × 4.6 mm) reverse
phase column and a YMC Hydrosphere 10 mm4 mm
guard column was used for the chromatographic
separation. As the mobile phase, 2 mL/min of a
combination of water and acetonitrile (80:20 v/v) with
0.1 percent (v/v) HCOOH acid was utilized. Using an
auto injector, a dose of 10 µL sample was injected into
the column along with the calibration solution (model:
AS3000, Thermo Finnigan, USA). The source
temperature is about 200°C was kept using a cone
voltage of 25 V.
2.2.3. pH and Total organic carbon (TOC)
measurement
An accuracy of a pH meter (model: pH/ion 510) of
Eutech Instruments (Malaysia) was measured by the
solution pH. The non-dispersive infrared method was
used in TOC analyzer (model: 1030C Aurora TOC
analyzer, O.I. Analytical, USA) to quantify the
concentration of total organic carbon.
2.3. Experimental
Photocatalytic experiment was performed in a batch
reactor with continuous stirring at 300 rpm containing
300 mL CIP solution kept in a 500 mL volume of
Proceedings of CUChE Alumni Symposium 2022
On “Circular Economy on Sustainable Basis: The Role of Chemical Engineers”
CUChEAA ISBN: 987-81-954649-1-3
December 2022 P a g e | 43 Volume 2, Issue 1
cylindrical borosilicate reactor (∅ 105 mm) (model:
Spinot 6020 magnetic stirrer, Tarson, Kolkata, India)
with a length and diameter of the stirrer bar of 42 mm
and 0.7 mm. The entire setup for the photo-reaction was
kept in a black box with water circulating jacket which is
used to reduce an excess heat within the system. The UV
light (362 nm and 12 W/m
2
, Hong Kong Jie Meng
International Lighting Ltd. Company, China) was
exposed on the top of the solution at 10 cm apart by
placing centrally. A circulating cooling arrangement was
established to maintain the solution temperature between
20 and 25°C. The initial CIP concentration of 50 mg/L
(0.15mM) was selected based on our previous study
(Giri et al., 2014a). The identification of FeCIPCOM
with its higher concentration is easier as CIP presents in
water at higher concentration. Likewise, the overall drug
concentration in terms of both discreet molecule and
complex form with metals, which is very high in aquatic
environment (Giri et al., 2014a). A fixed amount of Fe
2+
catalyst in terms of [Fe(NH
4
)
2
(SO
4
)
2
.6H
2
O] salt with the
concentration of 1.25 mM was added with continuous
stirring for 20 min for making a homogeneous solution
with water. The solution pH was maintained by using
0.05N H
2
SO
4
that was added after the addition of Fe
2+
in
drug solution. This reproving experiment was conducted
just to minimize Fe
2+
-oxidation.
A fixed amount of H
2
O
2
(10 mM) was then added to the
acidified CIP solution containing Fe
2+
catalyst.
In PFP,
the optimal dose of Fe
2+
and H
2
O
2
were found to
be 1.25
and 10 mM with pH of 3.5 for removal of CIP drug. The
process parameters like pH, Fe
2+
, H
2
O
2
and CIP doses of
PFP were optimized for CIP degradation based on our
previous study (Giri et al., 2014).
The solutions were taken out at different time intervals
during the reaction and,0.1 N NaOH added immediately
to stop the reaction by raising the sample pH at around
12.8 (Giri et al., 2014). The centrifugation was then used
at 1800 rpm for 30 min to separate the sludge formed
during PFP. The clear supernatant was then utilized to
analyze both CIP concentration and TOC. As the change
of CIP concentration was not detected significantly
under pH tuning, both –NH
2
and –COOH groups are
attained an equilibrium during CIP decomposition.
About 5.1% adsorption of CIP molecule was found on
the surface of iron sludge, Fe(OH)
3
yielded during PFP.
2.4. Antimicrobial Activity Test
An antimicrobial activity experiment was performed
using E. coli bacteria that was cultured in Luria-Bertani
(LB) media (Liang et al., 2013). A calibration curve in
the control LB media was used to determine the number
of colonies forming units per mL (CFU.mL
-1
) versus
absorbance was established as detailed in our earlier
work (Giri et al., 2015). The clear supernatant obtained
after 45 min of treatment process was used to calculate
antimicrobial activity. A small volume of CIP solution
(1 mL) was added in 9 mL LB media and incubated for
24 h at 25°C with mild stirring at 150 rpm in dark
(Levard et al., 2013). Both before and after the treatment
the antimicrobial activity was evaluated by counting the
number of CFU.mL
-1
between in presence and in
absence of drug solution.
3. Results and Discussion
3.1. CIP Removal and Mineralization
The dynamics of CIP removal in terms of decreasing in
both CIP concentration and total organic carbon (TOC)
at the optimum condition are shown in Fig. 1. The
process parameters like pH, Fe
2+
, H
2
O
2
and CIP doses of
PFP were optimized for CIP degradation based on our
previous study (Giri et al., 2014). A maximum CIP
removal of 89.3% was achieved at pH 3.5 (Fig.1). The
removal efficiency of the drug was found to be lowered
(pH < 3) due to the formation of H
3
O
+
ion in the
solution. The removal efficiency released to 87.1% at pH
3.5 owing to proton reduction and Fe(OH)
3
formation
(Eq. A.1) with increasing further pH to 9.0. The
corresponding mineralization of CIP was found to be
65.6% at 45 min in PFP. Initially, PFP significantly
shows the faster mineralization due to easy conversion
of –COOH group into CO
2
from the quinolone moiety.
After that the opening and mineralization of piperazine
ring in second stage shows the slower rate for the CIP
removal (Giri et al., 2014a). The intermediate products
originated upon drug decomposition showed higher
mineralization efficiency due to the formation of lower
molecular weight products like oxalic (HCOOH) and
acetic acids (CH
3
COOH) that are converted from the
daughter products with higher molecular weight
(Lionidas et al., 2007). Kavitha et al. (2004) suggested
that photocatalytic reaction showed the first stage of
oxidation of CIP forming aliphatic acids that are
generally removed very fast. A significant difference of
CIP and TOC removals of 23.7% was noted in PFP. UV-
light didn’t alone show any substantial effect on CIP
removal but it plays an important major role on CIP
mineralization from Iron-chelate complex in PFP (Eq.
A.2). It has been observed that 31% and 6.2% CIP
removals were found in presence of H
2
O
2
and UV alone,
respectively. Hence, only H
2
O
2
shows more removal
efficiency compare to UV-light because of the
production of HO
.
radicals under H
2
O
2
cleavage under
normal light.
Fe
3+
has a greater chance to bind with three CIP
molecules that acts as chelating agents due to having its
six-coordination number and acting as a negative
bidentate ligand (Giri et al., 2014a). UV-light more
sensitive towards FeCIPCOM formed by iron-chelation
becomes active because of the presence of extended
conjugation between C=O group and N-atom.
Knight et al. (1975) suggested that H
2
O
2
breaks Fe
3+
-
humate complexes easily in presence of UV-light
irradiation. Humic acids originated from Fe(III)
complexes are also photo-degraded in presence of UV-
light (Trovo et al., 2009). Metal-chelate coordination
compounds were degraded in PFP forming free different
organic acids (Klameth et al., 2013).
Proceedings of CUChE Alumni Symposium 2022
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CUChEAA ISBN: 987-81-954649-1-3
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Figure 2: CIP removal and mineralization with reaction
time in PFP. Reaction condition: [CIP]
0
= 0.15 mM, pH
= 3.5, Fe
2+
= 1.25 mM, H
2
O
2
= 10 mM, reaction time =
45 min, UV lamp = 12 W/m
2
and temperature = 25°C.
3.2. Proposed mechanistic pathways for CIP
degradation
Total eleven number of intermediate products were
formed in PFP under CIP molecule degradation
identified in the MS spectra (Figs. 3 and 4). The
proposed mechanistic pathways of CIP could involve (i)
oxidation in presence of UV-light, (ii) Fe(II)-CIP chelate
formation, (iii) defluorination and, (iv) cleavage of
piperazine ring. The acid-base characteristic of CIP
molecule due to the presence of –COOH and –NH
2
groups is influenced by the solvent (Zang et al., 2005).
The pK
a
values of 6.8 and 8.9 of CIP are showing for the
ionization of the corresponding O-H and N-H bonds
(Zhang et al., 2015). N
1
is expected to be less reactive
than the N
4
centre due to its weak basicity (Klavarioti et
al., 2009). So, N
4
in piperazine ring acts as the specific
site of the CIP (Fig. 1) for the HO
•
attack (Zang et al.,
2005). The aromatic ring containing two strong electron-
withdrawing functional groups, i.e., -F and -COOH in
CIP molecule suffers a steric effect which is originated
by the interaction between them that leads to prompt the
elimination of CO
2
.
However, due to presence of highly electron-
withdrawing substituent -F atom the fluoroquinolone
ring shows less reactive in nature (Klavarioti et al.,
2009). The separate degradation pathways for
fluoroquinolone occurred due to loss of -COOH moiety
and –F atom (Zang et al., 2005). The proposed
mechanistic pathways for CIP molecule oxidation are
demonstrated in Figs. 5 and 6 in PFP. The triplet state is
shown upon UV light absorption in fluoroquinolone
compounds, influencing the hydroxylation reaction due
to its strong electrophilic character (Agarwal et al.,
2007). The symbol ‘P’ indicates the intermediate
originated under CIP decomposition in PFP. The peaks
were obtained in the mass spectra based on their mass to
charge (m/z) ratio (Figs. 3 and 4). In addition to
protonated CIP molecule with m/z of 332.2, P
1
(305.0),
P
2
(242.3), P
3
(186.09), P
4
(159.3), P
5
(217.09), P
6
(344.1), P
7
(302.1), P
8
(256.3), P
9
(259.06), P
10
(386.09)
and P
11
(261.07) were found with the retention time of
5.24 and 5.66 min, respectively in PFP (Figs.3 and 4).
The fragment 7-[2-amino-ethyl) amino]-6-
fluoroquinoline (P
1
) with m/z of 305.1 was formed (Fig.
5) with the loss of the piperazine ring in an acidic
condition. Other daughter products with m/z of 242.09
(P
2
), 186.13 (P
3
), 159.3 (P
4
) originated from F
1
molecule
and were originated through the proposed mechanistic
route of piperazine ring cleavage. The daughter product,
P
2
with m/z of 242.09 is formed through decarboxylation
(-CO
2
) followed by hydroxylation (-OH) and partial
piperazine ring breaking in this photocatalytic process
(Fig.5).
P
3
and P
4
were originated from P
1
intermediate through
decarboxylation followed by defluorination (-F),
respectively. An intermediate of m/z of 287.10 showed
the formation of P
4
molecule, was obtained from
piperazine ring grieved an angle stress due to the
presence of F atom. Giri et al. (2014) reported that P
1
compound represents a fragment of CIP formed by the
loss of piperazine moiety rather than decarboxylation. P
5
(m/z 217.0) fragment along with others like P
6
(m/z
344.1), P
7
(m/z 302.1), and P
9
(m/z 259.03) were
originated by breaking of N-C bond of cyclic amine ring
followed by protonation (H
+
) and partial cleavage of
piperazine ring of CIP molecule. Subsequently, the
elimination of ethylene glycol indicating a substantial
reduction of organic carbon in PFP during the formation
of P
7
from P
6
. These three fragments (P
6
, P
7
and P
9
) were
formed directly due to cleavage of piperazine ring of
CIP molecule. P
6
molecule was formed under complete
oxidation of piperazine ring followed by hydroxylation,
P
7
was formed in PFP (Fig. 5). P
8
and P
9
were both
yielded from F
7
molecule by piperazine ring
degradation. After breaking of piperazine ring in P
7
followed by hydroxylation
,
P
8
was originated with the
evaluation of ethylene diamine as byproduct.
Decarboxylation of P
6
molecule shown in Fig.5 formed
P
10
(m/z 283.1) and P
11
(m/z 201.12). P
11
molecule
originated with a secondary amine (2
0
), is a reduced
product of P
1
compound. As both phenol and pyrazolone
ring are activated by a lone pair of electrons from
piperazine sub-fragment, decarboxylation would not
occur that leads to the reduction of mineralization
efficiency.
The degradation of FeCIPCOM in PFP showed the
formation of P
11
molecule (Fig. 5) under UV-light
irradiation. P
10
is a chelating compound with molar mass
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of 386.09 originated from the chelation reaction between
CIP molecule as chelating agent Fe
3+
ions. Ethylene
diamine (NH
2
CH
2
CH
2
NH
2
) as a neutral bidentate ligand
coordinated with Fe
3+
ion to form complex (Agarwal et
al., 2007). CIP acts as a bidentate negative ligand and
could form a chelate complex at 1:3 (metal to ligand)
ratio Fe
3+
(Finar et al., 2001 and Sykes et al., 2005).
Therefore, an octahedral chelate complex could easily be
formed in acidic medium in presence of such ligand
molecules. Hydrolysis of CIP molecule showed the
formation of P
11
fragment originated by partial
degradation of piperazine ring.
Figure 3: MS-spectrum of intermediate products at 10
min in PFP with retention time of 5.24 min. Intensity of
UV-light = 9 W, [CIP]
0
= 0.15 mM, Fe
2+
= 1.25 mM,
H
2
O
2
= 10 mM, pH = 3.5, and temperature = 25°C.
Figure 4: MS-spectrum of intermediate products at 10
min in PFP with retention time of 5.66 min. Intensity of
UV-light = 9 W, [CIP]
0
= 0.15 mM, Fe
2+
= 1.25 mM,
H
2
O
2
= 10 mM, pH = 3.5, and temperature = 25°C.
3.3. Toxicity of CIP and its decomposition
Products
The effect of the initial CIP solution treated in PFP
affected E.coli bacteria growth in contrast it to control
media is shown in Fig. 6. The exposure time and the
count of E.coli were 24h and 8.13×10
7
CFU/mL,
respectively in the control media. With 0.15 mL CIP, the
cell count was only 2.9 percent (0.21*107 CFU/mL) of
the control medium. In comparison to the control
condition, PFP showed around 61.3 percent cell death.
The increased microbial activity was generally owing to
the reduction of remaining CIP after PFP treatment and
due to the conversion of amide (-CONH
2
) to ethylene
diamine (NH
2
CH
2
CH
2
NH
2
) (Fig. 4). The conversion of -
NO
2
to -NH
2
molecules may also reduce antibacterial
action (Liang et al., 2013).
CIP molecule and the fragments formed under PFP may
have adverse effects on E.coli growth because of the
presence of quinolone moiety in it (Martinez et al., 1998;
Puma et al., 1991 and Tahir et al., 2015). Both
substitution of -F atom and hydroxylation of the -COOH
moiety (Fig. 4) in PFP might be of low antimicrobial
activity.
Figure 5: Proposed mechanistic pathways for CIP
degradation and its intermediate ions originated in PFP.
Figure 6: Degradation routes of FeCIPCOM with m/z of
386.09
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Table 1: Proposed structures and the appearance of
intermediates based on mass to charge ratio (m/z) during
CIP cleavage in PFP. The symbol ‘+’ indicates the
appearance of intermediates during photocatalytic
processes.
Daughter
ions
Mol.
Formula
m/z
Proposed cleavage
route
D
1
C
15
H
16
O
3
N
3
F
305.0
Piperazine ring
cleavage partially
D
2
C
15
H
17
O
4
N
3
242.09
Defluorination reaction
followed by
hydroxylation of D
1
D
3
C
13
H
11
O
4
N
186.13
Complete piperazine
ring cleavage of D
2
D
4
C
13
H
15
O
2
N
3
F
159.3
Decarboxylation of CIP
D
5
C
13
H
16
O
3
N
3
217.0
Defluorination
followed by
hydroxylation of D
4
D
6
C
16
H
16
ON
3
F
344.1
Dehydroxylation of D
1
D
7
C
11
H
10
ON
2
302.1
Partially piperazine
ring breaking followed
by defluorination of D
6
D
8
C
11
H
12
O
2
N
2
256.3
Hydroxylation of D
7
D
9
C
11
H
12
ON
2
259.03
Cleavage of cyclic
amine of D
7
D
10
C
11
H
10
O
2
N
2
386.09
Decomposition of
chelate complex
D
11
C
14
H
14
O
2
N
2
261.07
Piperazine ring
breaking partially
followed by
defluorination of D
1
Figure 7: Growth of E. coli in PFP after 24 h of reaction
time. Reaction condition: [CIP]
0
= 0.15 mM, pH = 3.5,
H
2
O
2
= 10 mM, Fe
2+
= 1.25 mM, temperature =25°C,
reaction time = 45 min and UV intensity = 12 W.m
-2
.
4. Conclusions
The results presented here PFP is more effective AOP
for the decomposition and also for the TOC removal
from CIP. CIP removal of 89.3 was achieved with
optimal condition swith the mineralization efficiency of
65.6% in PFP. Maximum number of intermediate
products were originated through piperazine ring
breaking and decarboxylation (-CO
2
) reaction in PFP
processes where the target site was the secondary –N
atom present in this ring. The decomposition path of
FeCIPCOM was developed by proposed mechanism
supported by the mass spectra based on mass to charge
(m/z) ratio under the supervision of UV light that led to
decarboxylation and piperazine ring cleavage in PFP.
The higher percent of removal, reduction of amide (-
CONH
2
) to ethylene diamine (NH
2
CH
2
CH
2
NH
2
) present
in CIP molecule and, substitution of F atom in PFP
decrease the inhibition of the growth of E.coli bacteria.
The cell death was found to be 61.3% after 45 min of
photoreaction with an initial CIP concentration of 0.15
mM to the control media.
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