Kinetics and Pathways of Bezafibrate Degradation in the UV/Chlorinedisinfection Process

Supporting information for

Kinetics and pathways of Bezafibrate degradation in the UV/chlorinedisinfection process

Xue-Ting Shi, Yong-Ze Liu, Yu-Qing Tang, Li Feng, Li-Qiu Zhang

Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, PR China

Corresponding author. Address: Beijing Forestry University, No. 35 Tsinghua East Road, Beijing 100083, PR China.

Tel: +86 010 62336528; Fax: +86 010 62336900.

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This document consists of 15 pages including 2 tables,1 testand5 figures

Table S1. Principal reactions in UV/Chlorine system.

No / Reactions / Rate constants and pKa / Reference
1 / HOCl/OCl- + hv → HO• + Cl• / rHO•=I0ФHOClfHOCl(1-e-A)
rO•-= I0ФOCl-fOCl-(1-e-A)
rCl•=I0{ФHOClfHOCl(1-e-A)+ ФOCl-fOCl-(1-e-A)};
A=2.303b(εHOCl[HOCl]+εOCl[OCl-]+Σεsi[Si]；
fHOCl=2.303bεHOCl[HOCl]/A;
fOCl-=2.303bεOCl-[OCl-]/A;
ФHOCl=1.45±0.1, ФOCl-=0.7±0.1;
εHOCl=59±0.1 M-1 cm-1, εOCl-=66±0.1 M-1 cm-1
I0=1.291×10-7EinsteinL-1 s-1 / (Crittenden et al. 1999; Guan et al. 2011)
2 / H+ + ClO- → HOCl / k2=5.0×1010 M-1s-1 / (Fang et al. 2014)
3 / HOCl → H+ + ClO- / k3=1.6×103 s-1 / (Fang et al. 2014)
4 / HOCl ↔ H+ + OCl- / pKa=7.5 / (Fang et al. 2014)
5 / Cl• + Cl- ↔ Cl2•- / k5+=6.5×109 M-1 s-1; k5-=1.1×105 s-1 / (Jayson et al. 1973)
6 / Cl•+ Cl•→ Cl2 / k6=1.2 × 1010 M-1s-1 / (Kadam and Chuan 2016)
7 / Cl• + H2O ↔ ClOH•- + H+ / k7+=2.5×105 s-1; k7-=2.1×1010 M-1 s-1 / (Kläning and Wolff 2010)
8 / Cl• + OH- ↔ ClOH•- / k8+=1.8×1010 M-1 s-1;k8-=23 s-1 / (Kläning and Wolff 2010)
9 / Cl• + HOCl → H+ + Cl- + ClO• / k9 =3.0×109 M-1 s-1 / (Fang et al. 2014)
10 / Cl• + OCl- → Cl- + ClO• / k10=8.2×109 M-1 s-1 / (Tao et al. 2008)
11 / HO• + Cl- ↔ ClOH•- / k11+=4.3×109 M-1 s-1; k11-=6.1×109 s-1 / (Tao et al. 2008)
12 / HO•+ OH- → O•- + H2O / k12=1.3 ×1010 M-1s-1 / (Fang et al. 2014)
13 / HO• + HClO → H2O + ClO• / k13=8.46×104M-1 s-1 / (Sharpless and Linden 2003)
14 / HO• + ClO- → OH- + ClO• / k14=8.8×109 M-1 s-1 / (Sharpless and Linden 2003)
15 / HO• + HO• = H2O2 / k15=5.5×109 M-1 s-1 / (Connick 2002)
16 / HO• + H2O2 = HO2• + H2O / k16=2.7×107 M-1 s-1 / (Buxton 1988)
17 / O•- + H2O → HO•+ OH- / k17=1.8 ×106 M-1s-1 / (Buxton 1988)
18 / ClOH•- + Cl- ↔ Cl2•- + OH- / k18+=1.0×105 M-1 s-1; k18-=4.5×107 M-1 s-1 / (Buxton 1988)
19 / ClOH•- → HO•+ Cl- / k19=6.1 ×109 s-1 / (Buxton 1988)
20 / ClOH•- → OH-+ Cl• / k20=23 s-1 / (Sharpless and Linden 2003)
21 / ClOH•- + H+ → Cl•+ H2O / k21=2.1 ×1010 M-1s-1 / (Sharpless and Linden 2003)
22 / ClOH•- + Cl- → Cl2- + OH- / k22=1.0 ×105 M-1s-1 / (Sharpless and Linden 2003)
23 / Cl2•- + Cl2•- → Cl2 + 2Cl- / k23=2.1×109 M-1 s-1 / (Kadam and Chuan 2016)
24 / Cl2•- + OH• → HOCl + Cl- / k24=1.0×109 M-1 s-1 / (Buxton 1988)
25 / Cl2•- + OH- → ClOH•- + Cl- / k25=4.5 ×107 M-1s-1 / (Tao et al. 2008)
26 / Cl2•- + HO2• → O2 + 2Cl-+ H+ / k26=4.5×109 M-1 s-1 / (Kadam and Chuan 2016)
27 / ClO• + ClO• + H2O → ClO2- + ClO- + 2H+ / k27=2.5×109 M-1 s-1 / (Kadam and Chuan 2016)
28 / ClO2- + OH• → ClO2• + OH- / k28=4.2×109 M-1 s-1 / (Kadam and Chuan 2016)
29 / ClO2• + OH• → ClO3- + H+ / k29=4.0×109 M-1 s-1 / (Kadam and Chuan 2016)
Reactions with BZF
30 / HO• + BZT→ products / k30=8.0×109 M-1 s-1 / (Buxton 1988)
31 / Cl• +BZF → products / k31=5.0×108 M-1 s-1 / Estimated
32 / Cl2•- +BZF → products / k32=5.0×108 M-1 s-1 / Estimated
33 / ClO•+BZF→products / k33=5.0×108 M-1 s-1 / Estimated
other reactions
34 / Cl2 + H2O↔HOCl + H++ Cl- / k34=5.1 ×10-4 / (Fang et al. 2014)
35 / 2HOCl ↔ Cl2O + H2O / k35=8.7 ×10-3 / (Fang et al. 2014)
HCO3-
36 / HO•+ HCO3-→H2O+CO3•- / k36=8.5×106 M-1 s-1 / (Buxton 1988)
37 / Cl•+HCO3-→H++Cl-+ CO3•- / k37=2.2×108 M-1 s-1 / (Buxton 1988)
38 / Cl2•-+HCO3-→H++2Cl-+ CO3•- / k38=8.0×107 M-1 s-1 / (Buxton 1988)
39 / ClO•+CO32-→ClO-+ CO3•- / k39=600 M-1 s-1 / (Buxton 1988)
Cl-
40 / HO•+Cl-↔ClOH•- / K40+=4.3×109 M-1 s-1; k40-=6.1×109 M-1s-1 / (Kong et al. 2016)
41 / ClOH•-+ H+↔ Cl•+ H2O / k41+=2.1×1010 M-1 s-1; k41-=2.5×105 M-1s-1 / (Kong et al. 2016)
42 / Cl- +Cl•↔ Cl2•- / k42+=6.5×109 M-1 s-1; k42-=1.1×105 M-1s-1 / (Kong et al. 2016)
NB and t-BuOH
43 / HO•+NB→products / k43=3.9×109 M-1 s-1 / (Buxton 1988)
44 / HO•+t-BuOH→products / k44=6.0×108 M-1 s-1 / (Sharpless and Linden 2003)

Table S2Summary of identified intermediates determined by LC/MS-MS

Compound / Retention Time (RT, min) / Molecular Weight (MW) / Number of carbon / Structural Formula
BZF / 13.60 / 361(positive) / 19 /
C1 / 12.24 / 396(positive) / 19 /
C2 / 10.61 / 276(positive) / 19 /
C3 / 10.10 / 276(positive) / 15 /
C4 / 9.69 / 200(positive) / 9 /
C5 / 9.28 / 326(positive) / 19 /
C6 / 8.78 / 360(positive) / 19 /
C7 / 8.14 / 410(positive) / 19 /
C8 / 7.86 / 378(positive) / 19 /
C9 / 7.63 / 378(positive) / 19 /
C10 / 6.49 / 228(positive) / 10 /
C11 / 6.49 / 274(positive) / 12 /
C12 / 5.66 / 258(positive) / 12 /
C13 / 15.84 / 412(positive) / 19 /

Text S1

[HO-]= (a) [H+]= (b)

pKa=7.5=pH+lg([HClO]/[ClO-]) (c)

[HClO]+[ClO-]=[free chlorine] (d)

where [HO-], [H+], [HClO], [ClO-] and [free chlorine] are the concentrations of HO-, H+, HClO, ClO- and free chlorine. The concentration of free chlorine was detected by DPD. [HClO] and [ClO-] were calculated by solving Eqs (a)~(d). No Cl- was measured in the chlorine stock solution (detection limit = 0.005 mmol/L)(Cai et al. 2013).

Fig. S1Schematic diagram of the large-volume UV irradiator.

Fig. S2BZF degradation in UV/chlorine process. Experimental conditions: I0=1.291×10-7EinsteinL-1 s-1, [NaClO]=0.8 mM, [BZF]=10 μM, pH=7.0, at room temperature, T=20±1°C.

Fig. S3 BZF degradation in UV/H2O2 and UV/S2O82- processes. Experimental conditions: I0=1.291×10-7EinsteinL-1 s-1, [H2O2]=0.8 mM, [S2O82-]=0.8 mM, [BZF]=10 μM, pH=7.0, 10 mM phosphate buffer, T=20±1°C.

Fig.S4 Transformation pathwaysof the benzene ring in BZF by Cl•additional reaction.

Fig.S5The formation of the C6 in BZF degradation.

References

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Cai MQ, Feng L, Jiang J, Qi F, Zhang LQ (2013) Reaction kinetics and transformation of antipyrine chlorination with free chlorine Water Res 47:2830-2842

Connick RE (2002) The Interaction of Hydrogen Peroxide and Hypochlorous Acid in Acidic Solutions Containing Chloride Ion 69:1509-1514

Crittenden JC, Hu S, Hand DW, Green SA (1999) A kinetic model for H 2 O 2 /UV process in a completely mixed batch reactor Water Res 33:2315-2328

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