Supplementary data:

Enhanced degradation of ibuprofen by heterogeneous

electro-Fenton at circumneutral pH

Dun Liu, Hao Zhang, Yuquan Wei, Bo Liu, Yipeng Lin, Guanghe Li, Fang Zhang*

School of Environment and State Key Joint Laboratory of Environment Simulation

and Pollution Control, Tsinghua University, Beijing, 100084, China

Corresponding authors

Dr. Fang Zhang;

Tel.: 8610 62789655;

Fax: 8610 62785687;

E-mail: fangzhang@tsinghua.edu.cn

This supplementary material contains the following sections:

Text MS-1. UPLC-Q-TOF-MS analysis of intermediate products of IBP.

Fig. SM-1. Fig. SM-1 Schematic of (a) reactor, (b) reactor cap, and (c) photograph of reactor.

Fig. SM-2. Cell voltages at different current densities. Conditions: 250 mL initial IBP concentration = 10 mg L−1, Na2SO4 = 0.05 M, pH = 6.8, current density 1-7 mA cm−2

and O2 = 100 mL min−1.

Fig. SM-3. IBP degradation and TOC mineralization (insert figure) by heterogeneous electro-Fenton in real wastewater. Conditions: 250 mL of IBP with initial concentration of 98 μg L–1, TOC=31.4 mg L–1, Na2SO4 = 0.05 M, current density=5 mA cm–2, aeration rate of 100 mL min–1.

Fig. SM-4. The concentrations of Fe leached from Cit-Fe/ACFs after repeated experiments. Conditions: 250 mL initial IBP concentration = 10 mg L−1, Na2SO4 = 0.05 M, pH = 6.8, current density = 5 mA cm−2 and O2 = 100 mL min−1.

Fig. SM-5. SEM images of Cit-Fe/ACFs cathode been used in electro-Fenton processes.

Table SM-1. Intermediate products of IBP identified with UPLC-Q-TOF-MS during heterogeneous electro-Fenton process.

Text SM-1

The Q-TOF-MS was operated in the negative electrospray ionization mode for

intermediate identification. Before analysis, 15 mL solution sample was introduced

into an Oasis HLB cartridge (Waters, USA) at a flow rate of 3-5 mL min−1. After the

solid phase extraction, the cartridge was washed with 10 mL methanol. The extract

was then concentrated to 1.5 mL under a gentle stream of nitrogen in a water bath at

35 °C. 10 μL of concentrated extract was separated on a SB-Aq reversed-phase

column (3.5 μm, 150 mm 3 mm, Agilent). The column temperature was 30 °C. The

mobile phase consisted of 2 mM ammonium acetate in water (A) and methanol (B) at

a flow rate of 0.35 mL min−1. The gradient elution program was as follows: 0-2 min,

10% B; 2-25 min, increased linearly to 60% B; 25-30 min, maintained 60% B.

Fig. SM-1 Schematic of (a) reactor, (b) reactor cap, and (c) photograph of reactor.

Fig. SM-2. Cell voltages at different current densities. Conditions: 250 mL initial IBP concentration = 10 mg L−1, Na2SO4 = 0.05 M, pH = 6.8, current density 1-7 mA cm−2

and O2 = 100 mL min−1.

Fig. SM-3 IBP degradation and TOC mineralization (insert figure) by heterogeneous

electro-Fenton in real wastewater. Conditions: 250 mL of IBP with initial

concentration of 98 μg L–1, TOC=31.4 mg L–1, Na2SO4 = 0.05 M, current density =5

mA cm–2, aeration rate of 100 mL min–1.

Fig. SM-4. The concentrations of Fe leached from Cit-Fe/ACFs after repeated

experiments. Conditions: 250 mL initial IBP concentration = 10 mg L−1, Na2SO4 =

0.05 M, pH = 6.8, current density = 5 mA cm−2 and O2 = 100 mL min−1.

Fig. SM-5. SEM images of Cit-Fe/ACFs cathode been used in electro-Fenton processes.

Table SM-1. Intermediate products of IBP identified with UPLC-Q-TOF-MS during heterogeneous electro-Fenton process.

No. Name Formula [M] MW tR

(min)

Main fragment

mass (m/z)1 1-hydroxy-ibuprofen C13H18O3 222 10.9 221, 177, 1492 dihydroxylated ibuprofen C13H18O4 238 14.8 237, 221, 1953 4-(1-hydroxyethyl)benzaldehyde C9H10O2 150 13.9 149, 119, 1344 2-(4-methylphenyl)propanoic acid C9H8O3 164 8.2 163, 133, 1055 1-(4-isobutylphenyl)ethanol C11H13O2 178 11.7 177, 133

6 1-(4-(1-hydroxyethyl)phenyl)-2-methylpropan-1-one C12H16O2 192 2.7 191, 147, 119