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Appendix A. Supplementary data for
Radical chemistry of diethyl phthalate oxidation via UV/peroxymonosulfate
process: Roles of primary and secondary radicals
Yu Lei a,b, Jun Luc, Mengyu Zhu a,b,d, Jingjing Xie a,d, Shuchuan Peng a,b,d, Chengzhu Zhu a,b,d,*
a School of Resource and Environmental Engineering, Hefei University of Technology, Hefei 230009, P.R.
China
bInstitute of Atmospheric Environment & Pollution Control, Hefei University of Technology, Hefei 230009,
P.R. China
cCenter of Analysis & Measurement, Hefei University of Technology, Hefei 230009, P.R. China
d Key Laboratory of Nanominerals and Pollution Control of Anhui Higher Education Institutes, Hefei
University of Technology, Hefei 230009, P.R. China
*Corresponding author. Tel: +86 551 62903990, fax: +86 551 62901649
E-mail address: [email protected]
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Lists of captions:
Text S1. Chemicals and materials S4
Text S2. Estimation of the steady-state concentration of reactive species S5
Text S3. The examination of O2•- and kinetic measurements between DEP and O2
•- S8
Text S4. The photolysis rate (r) of PMS under 254 nm UV irradiation S9
Text S5. GC-MS analysis S10
Text S6. Determination of the rate constants S11
Text S7. Calculations of the quenching ratios by using TBA as a specific quencher S15
Text S8. Determination of the reaction rate constant of DEP with 1O2 S16
Table S1. Principal reactions in the Kintecus® model S19
Table S2. Structures of products detected in the presence of chloride (CI mode) S20
Figure S1. The pH variations during all degradation experiment. S21
Figure S2. (a) Typical growth kinetics of DMP-OH adducts at 320 nm with different
concentrations of DMP. (b)-(d) Plot of the first-order formation rate constants of
DMP/DEP/DBP-OH adducts vs. DMP/DEP/DBP concentrations. S22
Figure S3. (a) Typical decay kinetics of SO4•- at 450 nm with different concentrations of
DMP. (b)-(d) Plot of the first-order decay rates of SO4•- vs. DMP/DEP/DBP concentrations.
S23
Figure S4. (a) Typical decay kinetics of Cl2•- at 340 nm with different concentrations of DMP.
(b)-(d) Plot of the first-order decay rates of Cl2•- vs. DMP/DEP/DBP concentrations. S24
Figure S5. (a) Typical formation kinetics of SCN2•- at 480 nm with different concentrations of
DMP in competition kinetics method. (b) Competition kinetics plot for the reaction of Cl • with
DMP/DEP/DBP. S25
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Figure S6. Data fitting of DEP degradation in UV/PMS process (a) effect of pH (b) effect of
chloride (c) effect of bicarbonate and (d) effect of NOM S26
Figure S7. UV-Vis absorption spectra of NBT, NBT/PMS and NBT/UV/PMS S27
Figure S8. Typical chromatogram of steady-state transformation products of DEP degradation
via UV/PMS process at pH 7 S28
Figure S9. Mass spectra of identified products by electron ionization (EI) S29
Figure S10. Determination of rate constant of DEP with O2•- S30
Figure S11. AOX concentration of DEP degradation during the UV/PMS process contained
different concentrations of chloride. S31
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Text S1. Chemicals and materials
Dimethyl phthalate (DMP, 99.5%), diethyl phthalate (DEP, 99%), di-butyl phthalate (DBP,
99%), nitrobenzene (NB, 99%), para-chlorobenzoic acid (pCBA, 99%), potassium
thiocyanate (KSCN, 99.99%) and hydrogen peroxide (H2O2, GR, 30% wt. in H2O) were
purchased from Aladdin Industrial Corporation (Shanghai, China). Furfuryl alcohol (FFA,
98%) and nitro blue tetrazolium (NBT2+) was obtained from Sigma-Aldrich Chemical Co.,
Ltd. Peroxymonosulfate (PMS, KHSO5·0.5KHSO4·0.5K2SO4, 99%) and persulfate (PS,
K2S2O8, 99.5%) were purchased from J&K chemical company (Shanghai, China).
Chloracetone (98%) was obtained from Adamas Reagent, Ltd. HPLC grade acetonitrile,
ethanol and tert-butanol (TBA) was obtained from Fisher Scientific. Analytically pure NaCO3,
NaOH, H2SO4, NaCl and NaHCO3 were purchased from Sinopharm Chemical Reagent, Ltd
(Shanghai, China). High-purity N2 (≥99.999%) was obtained from Nanjing special gas Co.
Ltd. Suwannee River Fulvic Acid (SRFA, lot no. 2S101F) purchased from the International
Humic Substances Society was employed as the model NOM. All solutions were prepared
with ultrapure water (18.2 MΩ cm).
Text S2 Estimation of the steady-state concentration of reactive species
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•OH. Nitrobenzene (NB) was employed as the probe compound for determining the
steady state concentration of •OH ([•OH]SS). NB can selectively react with •OH (kNB-•OH = 3.9 ×
109 M-1 s-1) and resists SO4•- and CO3
•- (kNB-SO4•- = 8.4 × 105 M-1 s-1, kNB-CO3•- < 1 × 103 M-1 s-1)
[1, 2]. However, no kinetic data for reactions of NB with reactive chlorine species (RCS) was
available, so [•OH]SS was modeled by Kintecus® in the presence of chloride. NB (1.0 μM) was
added to solutions and exposed to UV/PMS system. The concentrations of NB were
determined at specified time intervals. [HO•]SS was then calculated based on Eq. S1 and Eq.
S2:
- ln( [ NB ] t[ NB ]0 )= kNB-∙OH [∙OH ]SS t (S1)
k’NB = kNB-•OH[•OH]SS (S2)
Where [NB] is the concentration of NB, kNB-•OH is the second-order rate constant between •OH
and NB of 3.9 × 109 M-1s-1. k’NB represents the observed first-order decay rate of NB
degradation in the UV/PMS process. NB was quantified using a HPLC system (Thermo
U3000) with a PDA detector at a wavelength of 265 nm.
SO4•-. There is no probe available that is specific to SO4
•-, a compound exhibits high
reactivity toward SO4•- must be in concert with high reactivity toward •OH. Para-
chlorobenzoic acid (pCBA) was used to detect both •OH and SO4•- radicals (kpCBA-•OH = 5.0 ×
109 M-1 s-1; kpCBA-SO4•- = 3.6 × 108 M-1 s-1) but resists CO3•-. Similarly, [SO4
•-]SS was modeled by
Kintecus® in the presence of chloride since the reactivity of pCBA toward RCS was unknown.
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pCBA (1.0 μM) was added to solutions and exposed to UV/PMS system. [SO4•-]SS was
calculated from Eq. S3 and Eq. S4.
- ln( [ p CBA ]t[ p CBA ]0 )=( kp CBA-∙OH [∙OH ]SS + kp CBA-SO4∙- [ SO4 •- ]SS) t (S3)
k’pCBA = kpCBA-SO4•-[SO4•-]SS + kpCBA-•OH[•OH]SS (S4)
Where [pCBA] is the concentration of pCBA, kpCBA-SO4•- and kpCBA-•OH are the second-order
rate constant for reactions of pCBA with SO4•- (kpCBA-SO4•- = 3.6 × 108 M-1 s-1) and •OH (kpCBA-
•OH = 5.0 × 109 M-1 s-1), respectively [3]. k’pCBA represent the observed first-order decay rate of
pCBA degradation in the UV/PMS process. pCBA was quantified using a HPLC system
(Thermo U3000) with a PDA detector at a wavelength of 280 nm.
1O2. The selective probe compound furfuryl alcohol (FFA, 0.1 mM) was used to measure
the steady-state concentration of singlet oxygen (1O2). 100 mM ethanol was used to scavenge
both •OH and SO4•- but have no effects to 1O2. FFA is photo-resistant under 254 nm UV
irradiation. The steady-state concentration of 1O2 ([1O2]SS) is given by following equation:
k’FFA = kFFA-1O2 [1O2]SS (S5)
Where kFFA-1O2 is 1.2×108 M-1 s-1 [4]. FFA was quantified using a HPLC system (Thermo
U3000) with a PDA detector at a wavelength of 214 nm.
Cl•, Cl2•-, CO3
•- and other potential reactive species. The steady-state concentrations of
these reactive species were modeled by commercial software, Kintecus® V6.7. Three input
spreadsheet files, a reaction spreadsheet, a species description spreadsheet and a parameter
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description spreadsheet were involved. The model contained 107 reactions with their rate
constants during the UV/PMS process, which obtained from literature when available or
assumed based on similar reactions (Table S1). The Kintecus® software has been applied to
estimate the steady-state concentrations of inorganic radicals in wastewater effluents and
achieve satisfied results [3, 5]. Compared to the previous model, reactions of target compound
(DEP) were involved, since the kinetic data of DEP with various radicals were determined in
this study.
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Text S3 The examination of O2•- and kinetic measurements between DEP and O2
•-
Nitro blue tetrazolium (NBT2+) is a widely used reagent to detect superoxide radicals
(O2•-). NBT2+ could be reduced by O2
•- (k=5.88×104 M-1 s-1) to monoformazan (MF+, maximum
absorption at 530 nm) and may be further reduced into diformazan (DF, maximum absorption
at 560 nm) [6, 7]. 0.01 mM NBT was used to detect O2•- and the UV-Vis spectra were
examined. As shown in Fig. S6, EtOH was used to quench photo-generated •OH and SO4•- but
has no effect on O2•-. No absorption at either 530 nm or 560 nm was observed in both PMS
process and UV/PMS process, indicating negligible formation of O2•- in this system. A similar
result was also found in Fe(III)-Doped g-C3N4/PMS process [6].
The reaction rate constant between O2•- and DEP was determined by using a
chemiluminescent method using a flow injection analysis (FIA) system (Waterville
Analytical, USA) [8]. The decay behaviors of O2•− in solutions was described as following:
−d ¿¿ (S6)
Where, kd was the second-order uncatalyzed dismutation rate constant of O2•− (3.4 × 105
M-1 s-1), and reactions with DEP was described by the pseudo-first order rate kpseudo. The
analytical solution to Eq. S6 was given as following equation.
¿ (S7)
Fig.S9a shows that the decay rates of O2•- (0.0032−0.019 s-1) increased with the increase
of DEP concentrations ([DEP]) at pH of 7.0. By plotting [DEP] versus the pseudo-first order
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decay rates of O2•−, the second-order rate constant of O2
•− with DEP was derived to be (30±1)
M-1 s-1 (Fig. S9b).
Text S4 The photolysis rate (r) of PMS under 254 nm UV irradiation
The photolysis rate (r) of PMS with a 254 nm UV lamp was calculated as Eq. S8-S11:
r = Φ × I0 × fPMS × fsolution (S8)
f PMS=εHSO5
- [ HSO5- ] + εSO5
2- [SO52- ]
∑ ε ic i
(S9)
f solution= 1-10-( α+∑ε i ci ) l (S10)
HSO5- + OH- → SO5
2- + H2O pKa = 9.4 (S11)
Where Φ is the quantum yield of PMS of 0.52 [9], I0 is the surface irradiance (4.7 × 10-7
Einstein L-1 s-1), fPMS is the fraction of incident light absorbed by PMS and fsolution is the fraction
absorbed by the total solution. α is the molar absorption coefficient of the solution in the
absence of added compounds at 254 nm. εHSO5- and [HSO5-] are the molar extinction
coefficient and the concentration of HSO5- (εHSO5- = 14 M-1 cm-1), εSO52- and [SO5
2-] are the
molar extinction coefficient and the concentration of SO52- (εSO52- = 149.5 M-1 cm-1). εi and ci
are the molar extinction coefficient and the concentration of all solution constituents, and l is
the effective light path of the reactor (4 cm) [10, 11].
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Text S5 GC-MS analysis
Pre-treatment of samples. In order to identify the steady-state transformation products
of DEP during UV/PMS process, 500 mL of air-saturated solutions containing 0.4 mM DEP
and 10 mM PMS were prepared. Solutions at pH 5, 7 and 9, in the presence of 100 mM
chloride (pH 7), 20 mg/L NOM (pH 7) and 20 mM bicarbonate (pH 7) were irradiated
separately by a 6 W 254 nm UV lamp. 100 mL of irradiated samples were extracted by 100
mL CH2Cl2, the extraction procedure was repeated three times to ensure the full transfer of
organic phase, and then using a rotary evaporator to concentrate it to 1 mL.
Methods for samples containing chloride. The samples were analyzed by an Agilent
7890A-5975C GC-MS equipped with a WAX column (30 m × 0.25 mm × 0.25 μm). The
carrier gas was methane with a flow rate of 1.0 mL min-1. The injector temperature was 230
ºC, the oven temperature was programmed from 60 ºC (2 min) to 230 ºC with a speed of 10 ºC
min-1 followed by a 2 min hold at 230 ºC. The MS was operated in the chemical ionization
(CI) mode with (negative ion mode) and a source temperature of 230 °C.
Methods for other samples. The samples were analyzed by an Agilent 7890A-5975C
GC-MS equipped with a HP-5MS capillary column (60 m × 0.25 mm × 0.25 μm). The carrier
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gas was helium with a flow rate of 1.5 mL min-1. The injector temperature was 280 ºC, the
oven temperature was programmed from 40 ºC (2 min) to 300 ºC with a speed of 15 ºC min -1
followed by a 10 min hold at 300 ºC. The MS was operated in the electron ionization (EI)
mode with an ionization voltage of 70 eV and a source temperature of 220 °C.
Text S6. Determination of the rate constants
The second-order rate constants for reactions of three PAEs, DMP, DBP and DBP with
•OH, SO4•-, Cl2
•-, Cl• and CO3•- were determined by using 266 nm laser flash photolysis. In
order to minimize the potential effects of generated intermediates from substrate photolysis,
the emission of the laser was filtered with an aqueous solution highly concentrated in target
compounds [12]. We examined the spectra of aqueous solutions of target compounds after
filtration and no significant signal was observed.
•OH. Desired concentrations of PAEs were added into a solution of 100 mM H2O2, which
was serve as a •OH precursor.
H2O2 + hv → 2 •OH (S12)
The absorption band with a peak around 320 nm was observed, which was attributed to
•OH-adducts, generated from •OH addition to the aromatic ring [13]. The second-order rate
constants were determined by monitoring the build-up traces of •OH-adducts at 320 nm (Fig.
S1a). From the liner relationship between the first-order build-up rate constant against PAEs
concentrations, the second-order rate constants of •OH reacting with DMP, DEP and DBP
were determined as (3.7 ± 0.1) × 109, (4.2 ± 0.2) × 109 and (4.4 ± 0.2) × 109 M-1 s-1,
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respectively (Fig. S1). These were consistent with the rate constants of •OH reactions with
four phthalates of (3.4~4.7) × 109 M-1 s-1 obtained by using competition kinetics [14].
SO4•-. SO4
•- was generate upon photolysis of 100 mM K2S2O8.
S2O82- + hv → 2 SO4
•- (S13)
SO4•- + H2O → •OH + HSO4
- (S14)
30 mM TBA was added to scavenge •OH (k = 6 × 108 M-1 s-1) while have almost no effect
on SO4•- (k = 4 × 105 M-1 s-1) [1]. The second-order rate constants for the reactions of PAEs
with SO4•- were determined by monitoring the decay traces of SO4
•- at 450 nm [15]. The first-
order decay rate constants of SO4•- increased with the concentrations of PAEs (Fig. S2a). From
the linear relationship, the second-order rate constants of SO4•- reacting with DMP, DEP and
DBP were determined as (4.9 ± 0.2) × 108, (5.6 ± 0.3) × 108 and (5.5 ± 0.2) × 108 M-1 s-1,
respectively (Fig. S2).
Cl2•-. The generation of Cl2
•- was achieved by addition of 100 mM NaCl to 100 mM
K2S2O8 solution. This high chloride concentration gave effectively quantitative conversion of
the initially Cl• to Cl2•- which exhibited strong absorbance at 340 nm (ε340 nm = 8800 M-1 cm-1)
[16].
SO4•- + Cl- → Cl• + SO4
2- k = 3.1 × 108 M-1 s-1 (S15)
Cl• + Cl- ↔ Cl2•- K = 1.4 × 105 M-1 (S16)
The decay rate constants of Cl2•- at 340 nm increased linearly with increasing of PAEs
concentrations (Fig. S3a). From the linear relationship, the second-order rate constants for
reactions of DMP, DEP and DBP with Cl2•- were determined as (1.4 ± 0.3) × 107, (1.1 ± 0.2) ×
107 and (1.1 ± 0.2) × 107 M-1 s-1, respectively (Fig. S3).
Cl•. Cl• was generated by the photolysis of chloroacetone [17]. Reaction rate constants of
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Cl• were determined by using a SCN- competition kinetics method [18].
Cl• + DEP → intermediates kS17 (S17)
Cl• + SCN- (+SCN-) → Cl- + (SCN)2•- kS18 = 5.3 × 109 M-1s-1 (S18)
Cl• + CH3COCH2Cl → products kS19 = 1.1 × 107 M-1s-1 (S19)
Cl• + H2O → products kS20[H2O] = 1.6 × 105 s-1 (S20)
The competition can be analyzed to give as:
A0
A=
kS17[DEP]kS18[SCN - ]+ kS19 [CH3COCH 2Cl]+ kS20[H2O ]
+1 (S 21 )
A0 is the transient absorbance of (SCN)2•- at 480 nm in absence of DEP, the transient
absorbance of (SCN)2•- (A) will be reduced with DEP addition. Given the parameters that
[SCN-] and [CH3COCH2Cl] are 1 mM and 10 mM, kS18, kS19 and kS20[H2O] are 5.3 × 109 M-1s-1,
1.1 × 107 M-1s-1 and 2.5 × 105 s-1 [17]. The item kS19[CH3COCH2Cl]+kS20[H2O] (3.6 × 105 s-1) is
far less than kS18[SCN-] (5.3 × 106 s-1). So the competition can be simplified to the following
one.
A0
A=
kS17[DEP]kS18[SCN- ]
+1 (S22)
A plot of A0/A against the ratio [PAEs]/[SCN-] yields a straight line of slope k9/k10. From
the established rate constant of Cl• reacting with SCN- (k=5.3×109 M-1s-1 [17]), the rate
constants of Cl• reacting with DMP, DEP and DBP were determined as (1.80 ± 0.20) × 1010,
(1.97 ± 0.13) × 1010 and (1.99 ± 0.22) × 1010 M-1s-1 (Fig. S4).
SCN- competition kinetics have been used in determination of rate constants of HO• with
many complicated compounds (e.g. microsystin-LR) in pulse radiolysis experiments and
achieved satisfied results [18]. To minimize the potential effects of secondary reactions (e.g.
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Cl• consumption of transient products), all our kinetic experiments were run at very low
conversion (<5%) of target compound.
CO3•-. CO3
•- was produced by photolysis a mixed solution of 100 mM H2O2 and 100 mM
Na2CO3. CO3•- was generated from the reaction of •OH with CO3
2-.
•OH + CO32- → CO3
•- + OH- (S23)
CO3•- exhibits an absorption peak at 600 nm with an extinction coefficient of 1900 M-1
cm-1 [2]. We attempted to measure the second-order rate constants through monitoring the
decay traces of CO3•- at 600 nm. Unfortunately, no change of traces at 600 nm was found,
indicated their reactivity toward CO3•- was negligible. And hence, an upper limit of k < 1.0 ×
106 M-1 s-1 was given for the rate constants of CO3•- reacting with these three PAEs.
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Text S7. Calculations of the quenching ratios by using TBA as a specific quencher
The main consumption of •OH and SO4•- reactions are shown as following [19]:
•OH + DEP → products kS24 = 4.2 × 109 M-1s-1 (S24)
•OH + TBA → products kS25 = 6.0 × 108 M-1s-1 (S25)
•OH + HSO5- → products kS26 = 1.7 × 107 M-1s-1 (S26)
SO4•- + DEP → products kS27 = 5.6 × 108 M-1s-1 (S27)
SO4•- + TBA → products kS28 = 4.0 × 105 M-1s-1 (S28)
SO4•- + HSO5
- → products kS29 = 1.0 × 106 M-1s-1 (S29)
The quenching ratios by TBA can be expressed as:
quenching ratio (•OH )= kS25[TBA]kS24 [ DEP ] +kS25 [TBA]+ kS26 [ HSO 5 - ]
(S30 )
quenching ratio (SO4 •- )= kS 28 [TBA]kS 27 [ DEP ] +kS2 8[TBA]+ kS 2 9 [HSO5 - ]
(S31 )
We need to guarantee that the quenching ratio of •OH is small and the quenching ratio of SO4•-
is large at the same time. [DEP] is 0.4 mM in the steady-state irradiation experiments. 30 mM
TBA can quench 91.1 % •OH but only quench 4.8 % SO4•-. More TBA could enhance the
quenching ratio of •OH but SO4•- would also be inhibited strongly. So 30 mM is a suitable
concentration of TBA.
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Text. S8 Determination of the reaction rate constant of DEP with 1O2
To determine the rate constants of 1O2 with DEP, Rose Bengal (RB, 0.05 mM) was used
as the photosensitizer for yielding 1O2, and 0.1 mM FFA was added for competition kinetics in
the solar simulator. During the sunlight exposure, the loss of DEP was monitored along with
the loss of FFA [4].
DEP + 1O2 → products k32 (S32)
FFA + 1O2 → products k33=1.8×108 M-1s-1 (S33)
The rate constant of DEP reacting with 1O2 by calculated by following equation:
k32
k33=
ln ([DEP]/ [DEP]0)ln ([FFA]/[FFA]0 )
(S34 )
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Table S1. Principal reactions in the Kintecus® model
NO.
Reactions Rate constants (M-1s-1) Reference
Photolysis of PMS1 HSO5
-/SO52- + hv → HO• + SO4
•- eq. S5-S8 This study
Non-halide reactions2 H+ + HO2
- → H2O2 5.0 × 1010 M-1 s-1 [20]
3 H2O2 → H+ + HO2- 1.3 × 10-1 s-1 [20]
4 H+ + OH- → H2O 1.0 × 1011 M-1 s-1 [20]
5 H2O → H+ + OH- 1.0 × 10-3 s-1 [20]
6 H+ + O2•- → HO2
• 5.0 × 1010 M-1 s-1 [20]
7 HO2• → H+ + O2
•- 7.0 × 105 s-1 [20]
8 H+ + SO52- → HSO5
- 5.0 × 1010 M-1 s-1 [21]
9 HSO5- →H+ + SO5
2- 19.9 s-1 [21]
10 H+ + HCO3- → H2CO3 5.0 × 1010 M-1 s-1 [21]
11 H2CO3 → H+ + HCO3- 2.5 × 104 s-1 [21]
12 H+ + CO32- → HCO3
- 5.0 × 1010 M-1 s-1 [21]
13 HCO3- → H+ + CO3
2- 2.5 s-1 [21]
HOX• reactions
14 HO• + HO• → H2O2 5.5 × 109 M-1 s-1 [20]
15 HO• + H2O2 → HO2• + H2O 2.7 × 107 M-1 s-1 [20]
16 HO• + HO2- → HO2
• + OH- 7.5 × 109 M-1 s-1 [20]
17 HO• + HO2• → O2 + H2O 7.1 × 109 M-1 s-1 [5]
18 HO• + O2•- → O2 + OH- 1.0 × 1010 M-1 s-1 [20]
19 HO2• + HO2
• → H2O2 + O2 8.3 × 109 M-1 s-1 [20]
20 HO2• + O2
•- → HO2- + O2 9.7 × 107 M-1 s-1 [20]
21 HO2• + H2O2 → O2 + HO• +H2O 3.0 M-1 s-1 [5]
22 O2•- + H2O2 → O2 + HO• + OH- 1.3 × 10-1 M-1 s-1 [5]
23 O•- + H2O → HO• + OH- 1.8 × 106 M-1 s-1 [5]
24 HO• + HSO5- → H2O + SO5
•- 1.7 × 107 M-1 s-1 [22]
25 HO• + SO52- → SO5
•- + OH- 2.1 × 109 M-1 s-1 [22]
26 HO• + CO32- → CO3
•- + OH- 3.9 × 108 M-1 s-1 [20]
27 HO• + HCO3- → CO3
•- + H2O 8.5 × 106 M-1 s-1 [5]
17
338
339
340
341
342
343
3334
28 HO• + H2CO3 → CO3•- + H2O + H+ 1.0 × 106 M-1 s-1 [20]
29 H2O2 + CO3•- → HCO3
- + HO2• 4.3 × 105 M-1 s-1 [20]
30 HO2- + CO3
•- → HCO3- + O2 3.0 × 107 M-1 s-1 [20]
31 HO• + CO3•- → product 3.0 × 109 M-1 s-1 [20]
32 O2•- + CO3
•- → CO32- + O2 6.0 × 108 M-1 s-1 [5]
33 CO3•- + CO3
•- → product 3.0 × 107 M-1 s-1 [20]
SOX•- reactions
34 SO4•- + OH- → SO4
2- + H2O 7.0 × 107 M-1 s-1 [21]
35 SO4•- + H2O → HSO4
- + HO• 660 s-1 [21]
36 SO4•- + HO• → HSO5
- 1.0 × 1010 M-1 s-1 [21]
37 SO4•- + HSO5
- → HSO4- + SO5
•- 1.0 × 106 M-1 s-1 [22]
38 SO4•- + SO5
2- → SO42- + SO5
•- 1.0 × 108 M-1 s-1 [22]
39 SO5•- + SO5
•- → SO4•- + SO4
•- + O2 2.1 × 108 M-1 s-1 [21]
40 SO5•- + SO5
•- → S2O82- + O2 2.2 × 108 M-1 s-1 [21]
41 SO4•- + S2O8
2 → SO42- + S2O8
•- 6.5 × 105 M-1 s-1 [21]
42 S2O82- + CO3
•- → CO32- + S2O8
•- 3.0 × 107 M-1 s-1 [21]
43 SO4•- + HCO3
- → CO3•- + HSO4
- 2.8 × 106 M-1 s-1 [21]
44 SO4•- + CO3
2- → CO3•- + SO4
2- 6.1 × 106 M-1 s-1 [21]
Chloride reactions45 H+ + Cl- → HCl 5.0 × 1010 M-1 s-1 [20]
46 HCl → H+ + Cl- 8.6 × 1016 s-1 [20]
47 HO• + Cl- → ClOH•- 4.3 × 109 M-1 s-1 [20]
48 ClOH•- → HO• + Cl- 6.1 × 109 s-1 [20]
49 ClOH•- + H+ → Cl• + H2O 2.1 × 1010 M-1 s-1 [20]
50 ClOH•- + Cl- → Cl2•- + OH- 1.0 × 105 M-1 s-1 [20]
51 Cl• + H2O → ClOH•- + H+ 3.0 × 103 M-1 s-1 [5]
52 Cl• + OH- → ClOH•- 1.8 × 1010 M-1 s-1 [20]
53 Cl• + H2O2 → HO2• + Cl- + H+ 2.0 × 109 M-1 s-1 [20]
54 Cl• + Cl- → Cl2•- 6.0 × 109 M-1 s-1 [20]
55 Cl• + Cl• → Cl2 8.8 × 107 M-1 s-1 [20]
56 Cl• + HOCl → ClO• + H+ + Cl- 3.0 × 109 M-1 s-1 [5]
57 Cl• + OCl- → ClO• + Cl- 8.3 × 109 M-1 s-1 [5]
58 Cl2•- → Cl• + Cl- 6.0 × 104 s-1 [20]
59 Cl2 + OH- → HOCl + Cl- 1.0 × 109 M-1 s-1 [5]
60 Cl2•- + Cl2
•- → Cl2 + 2Cl- 8.3 × 108 M-1 s-1 [20]
61 Cl2•- + Cl• → Cl2 + Cl- 2.1 × 109 M-1 s-1 [20]
62 Cl2•- + H2O2 → HO2
• + 2Cl- + H+ 1.4 × 105 M-1 s-1 [20]
63 Cl2•- + HO2
• → O2 + 2Cl- + H+ 3.0 × 109 M-1 s-1 [20]
64 Cl2•- + O2
•- → O2 + 2Cl- 1.0 × 109 M-1 s-1 [20]
65 Cl2•- + H2O → Cl- + HClOH 2.3 × 10 M-1 s-1 [20]
66 Cl2•- + OH- → Cl- + ClOH•- 4.5 × 107 M-1 s-1 [20]
67 HClOH → ClOH•- + H+ 1.0 × 108 s-1 [20]
68 HClOH → Cl• + H2O 1.0 × 102 s-1 [20]
69 HClOH + Cl- → Cl2•- + H2O 5.0 × 109 M-1 s-1 [20]
183536
70 Cl2 + Cl- → Cl3- 2.0 × 104 M-1 s-1 [20]
71 Cl3- → Cl2 + Cl- 1.1 × 105 s-1 [20]
72 Cl3- + HO2
• → Cl2•- + HCl + O2 1.0 × 109 M-1 s-1 [20]
73 Cl3- + O2•- → Cl2
•- + Cl- + O2 3.8 × 109 M-1 s-1 [20]
74 Cl2 + H2O → Cl- + HOCl + H+ 2.7 × 10-1 M-1 s-1 [20]
75 Cl- + HOCl + H+ → Cl2 + H2O 1.8 × 10-1 M-2 s-1 [5]
76 Cl2 + H2O2 → O2 +2HCl 1.3 × 104 M-1 s-1 [20]
77 Cl2 + O2•- → O2 + Cl2
•- 1.0 × 109 M-1 s-1 [20]
78 Cl2 + HO2• → H+ + O2 + Cl2
•- 1.0 × 109 M-1 s-1 [20]
79 HOCl + H2O2 → HCl + H2O + O2 1.1 × 104 M-1 s-1 [20]
80 OCl- + H2O2 → Cl- + H2O + O2 1.7 × 105 M-1 s-1 [20]
81 HOCl + HO• → ClO• + H2O 2.0 × 109 M-1 s-1 [20]
82 HOCl + O2•- → Cl• + OH- + O2 7.5 × 106 M-1 s-1 [20]
83 HOCl + HO2• → Cl• + H2O + O2 7.5 × 106 M-1 s-1 [20]
84 OCl- + HO• → ClO• + OH- 8.8 × 109 M-1 s-1 [20]
85 OCl- + O2•- + H2O → Cl• + 2OH- + O2 2.0 × 108 M-2 s-1 [20]
86 OCl- + CO3•- → ClO• + CO3
2- 5.7 × 105 M-1 s-1 [20]
87 Cl• + CO32- → Cl- + CO3
•- 5.0 × 108 M-1 s-1 [20]
88 Cl• + HCO3- → Cl- + CO3
•- + H+ 2.2 × 108 M-1 s-1 [20]
89 Cl2•- + CO3
2- → 2Cl- + CO3•- 1.6 × 108 M-1 s-1 [20]
90 Cl2•- + HCO3
- → 2Cl- + CO3•- + H+ 8.0 × 107 M-1 s-1 [20]
91 SO4•- + Cl- → Cl• + SO4
2- 3.0 × 108 M-1 s-1 [23]
92 Cl• + SO42- → SO4
•- + Cl- 2.5 × 108 M-1 s-1 [23]
93 Cl2•- + HSO5
- → 2Cl- + SO5•- + H+ <1.0 × 105 M-1 s-1 [23]
94 Cl2•- + SO5
2- → 2Cl- + SO5•- 1.0 × 108 M-1 s-1 [23]
95 Cl• + HSO5- → Cl- + SO5
•- + H+ 1.0 × 106 M-1 s-1Assumed (comparing with
SO4•- + HSO5
- reaction)
96 Cl•-+ SO52- → Cl- + SO5
•- 1.0 × 109 M-1 s-1Assumed (comparing with
SO4•- + SO5
2- reaction)
NOM reactions97 NOM + Cl• → X 1.3 × 104 (mg L-1)-1 s-1 [5]
98 NOM + HO• → X 2.5 × 104 (mg L-1)-1 s-1 [24]
99 NOM + SO4•- → X 5.1 × 103 (mg L-1)-1 s-1 [21]
DEP reactions100 DEP + Cl• → X 2.0 × 1010 M-1 s-1 This study
101 DEP + HO• → X 4.2 × 109 M-1 s-1 This study
102 NOM + SO4•- → X 5.6 × 108 M-1 s-1 This study
103 NOM + Cl2•- → X 1.1 × 107 M-1 s-1 This study
104 NOM + CO3•- → X <1.0 × 106 M-1 s-1 This study
Active chlorine related reactions
105 Cl- + HSO5- → SO4
2- + HOCl 2.1 × 10-3 M-1 s-1 [25]
106 Cl- + SO52- → SO4
2- + OCl- 3.8 × 10-4 M-1 s-1 [25]
107 2Cl- + HSO5- + H+ → SO4
2- + Cl2 +H2O 2.1 × 10-3 M-2 s-1 Assumed (comparing with
193738
reaction 105)
Table S2. Structures of products detected in the presence of chloride (CI mode)
TPs Retention time Measured m/z Predicted formula Proposed structure
DEP 12.47 min 222.02 C12H14O4
P257 13.79 min 257.03 C12H13O4Cl
P184 14.33 min 184.07 C9H9O2Cl
P193 15.47 min 194.08 C10H10O4
P272 18.67 min 272.06 C12H13O5Cl
20
344
345
346
347
348
349
350
351
352
353
3940
Figure S1. The pH variations during all degradation experiments (a) In the pure water (b) In
the presence of chloride (c) In the presence of bicarbonate and (d) In the presence of NOM.
21
354
355
356
357
358
359
360
361
362
363
364
365
366
4142
22
367
368
369
370
371
372
373
374
375
376
4344
Figure S2. (a) Typical growth kinetics of DMP-OH adducts at 320 nm with different
concentrations of DMP. (b)-(d) Plot of the first-order formation rate constants of
DMP/DEP/DBP-OH adducts vs. DMP/DEP/DBP concentrations.
23
377
378
379
380
381
382
383
384
385
386
387
388
389
390
4546
Figure S3. (a) Typical decay kinetics of SO4•- at 450 nm with different concentrations of
DMP. (b)-(d) Plot of the first-order decay rate constants of SO4•- vs. DMP/DEP/DBP
concentrations.
24
391
392
393
394
395
396
397
398
399
400
401
402
403
404
4748
Figure S4. (a) Typical decay kinetics of Cl2•- at 340 nm with different concentrations of DMP.
Due to the low rate constants for reactions of Cl2•- with phthalates, the gradients of kinetics
traces were not very obvious so the plot was partially enlarged (b)-(d) Plot of the first-order
decay rate constants of Cl2•- vs. DMP/DEP/DBP concentrations.
25
405
406
407
408
409
410
411
412
413
4950
Figure S5. (a) Typical formation kinetics of SCN2•- at 480 nm with different concentrations of
DMP in competition kinetics method. (b) Competition kinetics plot for the reaction of Cl • with
26
414
415
416
417
418
419
420
421
422
5152
DMP/DEP/DBP. These give the second-order reaction rate constant of Cl• with
DMP/DEP/DBP as 1.80×1010/1.97×1010/1.99×1010 M-1 s-1, respectively.
Figure S6. Data fitting of DEP degradation in UV/PMS process (a) effect of pH (b) effect of
chloride (c) effect of bicarbonate and (d) effect of NOM
27
423
424
425
426
427
428
429
430
431
432
433
434
435
436
5354
Figure S7. UV-Vis absorption spectra of NBT, NBT/PMS and NBT/UV/PMS. [NBT]=0.01
mM, [PMS]=10 mM, [EtOH]=100 mM.
28
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
5556
29
453
454
455
456
457
458
459
460
461
462
463
5758
Figure S8. Typical chromatogram of products of DEP degradation via UV/PMS process. (a)
in the pure water (EI mode) (b) In the presence of chloride (CI mode). Those unspecified
peaks in the chromatogram are mainly silica oxides from the GC system.
30
464
465
466
467
468
469
470
471
472
5960
10 20 30 40 500
10
20
30
40
0 mM 0.08 mM 0.16 mM 0.32 mM 0.64 mMO
2 c
once
ntra
tion
(nM
)
Observed time (s)
a
[Diethyl phthalate]
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.70.000
0.006
0.012
0.018
0.024
O 2
kpe
sudo
(s-1
)
[Diethyl phthalate] (mM)
b
k = (30 ± 1) M-1 s-1
Figure S9. Mass spectra of identified products by electron ionization (EI)
31
473
474
475
476
477
478
479
480
481
482
483
484
485
486
6162
Fig. S10. Determination of rate constant of DEP with O2•- by using a chemiluminescent
method. (a) Effect of DEP concentrations on the decay process of O2•- at pH 7.0. (b) The
reaction rate constant of diethyl phthalate with O2•− was derived to be (30 ± 1) M-1 s-1 based on
the slope of the linear fitting in the figure inset at pH of 7.0 (R2=0.99).
32
487
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489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
6364
Figure S11. AOX concentration of DEP degradation during the UV/PMS process containing
different concentrations of chloride. Conditions: [DEP]=0.4 mM, [PMS]=10 mM, irradiation
time=30 min.
Reference
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513
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519
6566
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