Supporting Information for: Activation of Peroxymonosulfate by Benzoquinone: A. Novel Nonradical Oxidation Process

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1 Supporting Information for: Activation of Peroxymonosulfate by Benzoquinone: A Novel Nonradical Oxidation Process Yang Zhou, Jin Jiang*,, Yuan Gao, Jun Ma*,, Su-Yan Pang, Juan Li, Xue-ing Lu, Li-Peng Yuan State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of echnology, Harbin, Heilongjiang 159, China Key Laboratory of Green Chemical Engineering and echnology of College of Heilongjiang Province, College of Chemical and Environmental Engineering, Harbin University of Science and echnology, Harbin, Heilongjiang 154, China *Corresponding Authors: Prof. Jin Jiang and Prof. Jun Ma (J.J.) Phone: ; Fax: ; jiangjinhit@126.com. (J.M.) Phone: ; Fax: ; majun@hit.edu.cn. Number of pages (including this page): 11 Number of tables: 3 Number of text: 1 Number of figures: 6 S1

2 able S1. Substructures of MP and DPA compound structure molar mass (g mol 1 ) 2,2,6,6-tetramethyl-4-pip eridinol (MP) H 3 C H 3 C OH N H CH CH 3 9,1-diphenylanthracene (DPA) able S2. Pseudo-first-order rate constants for SMX degradation derived from Figure 1 ph=7 ph=8 ph=9 ph=1 BQ(μM) k obs (min 1 ) k obs (min 1 ) k obs (min 1 ) k obs (min 1 ) 2 nd a nd nd a: nd, not determined due to the limited degradation of SMX. able S3. Second-order rate constants for reactions of selected alcohols and 1 O 2 quenchers with sulfate and hydroxyl radicals compounds reaction rate constant (M 1 s 1 ) SO 4 OH ref methanol S1, S2 ethanol S2, S3 tert-butanol (4 9.1) 1 5 ( ) 1 8 S3 NaN S2, S4 FFA not available S5 S2

3 ext S1. he rate equations derived from proposed mechanism. According to the proposed mechanism, two molecules of HSO 5 react with one molecule of BQ to form intermediate I; the conjugate base of I (i.e., intermediate II) further decomposes to a dioxirane intermediate III via intramolecular nucleophilic displacement of alkoxide oxygen at the O-O bond; intermediate III experiences nucleophilic attack by two molecules of ionized PMS ions ( SO ) to produce 1 O 2 and reform BQ (reactions 6 1 in the main text). 2 5 Because the intramolecular nucleophilic displacement reaction of intermediate II (i.e., reaction 9 in the main text) is the rate-determining step, by using the steady-state approach regarding intermediates I, II, and III the overall rate is given by d[hso 5] 1 d[so 5 ] 1 d[ O 2] r k4[ii] (S1) 2 dt 2 dt 2 dt Steady-state assumption regarding intermediates II is made to obtain d[ii] - k3[i][oh ] k-3[ii] k4[ii] (S2) dt Because k 4 k -3, it can be calculated - [II] K3[I][OH ] (S3) Steady-state assumption regarding intermediates I is made to obtain According to eq S3, k d[i] - - k2[bq][hso 5] k-2[i] k-3[ii] k3[i][oh ] (S4) dt - -3[II] k3[i][oh ], thus it can be calculated [I] K [BQ][HSO ] (S5) he total concentration of PMS ([PMS] ) is given by [PMS] [HSO ]+[SO ] (S6) hus, the decomposition rate of PMS is obtained S3

4 2 d[pms] d[hso 5] d[so 5 ] ( + ) (S7) dt dt dt According to eq S1, it can be obtained 1 2d[ O 2] d[pms] dt 4 k4[ii] (S8) dt According to eqs S3 and S5, it can be calculated Because + - [H ] 5 + d[pms] dt K2K3k4[OH ][HSO 5][BQ] (S9) [HSO ] [PMS], the decomposition rate of PMS is expressed in terms [H ] Ka of the total concentration of PMS ([PMS] ) by 2d[ O ] d[pms] [H ][OH ] dt d t [H ] Ka K2K3k4 [BQ][PMS] + (S1) [H + ][OH - ] represents the ionic product of water (i.e., K w ), then it can be obtained K 4 K K k [BQ][PMS] dt d t [H ] K 1 2d[ O 2] d[pms] w a (S11) he apparent rate constant k obs for the decomposition of PMS is expressed as kobs 4 K K k F[BQ] (S12) Kw Where F + [H ] K a, K 2 (M -1 ) and K 3 (M -1 ) are the equilibrium constants for reactions 7 and 8 in the main text, respectively; according to study of Edwards et al. S6, intramolecular nucleophilic displacement of intermediate II (reaction 9 in the main text) is a first-order reaction, and k 4 (s -1 ) is the first-order rate constant for this reaction; K 2 K 3 k 4 of the unit of M -2 s -1 represents the third-order rate constant (k DI ) for the formation of dioxirane intermediate III according to the definition of reaction order. S4

5 Residual PMS (%) Residual PMS (%) Residual PMS (%) Residual PMS (%) Figure S1 1 a 1 b BQ( ) BQ( ) 1 c 1 d BQ( ) BQ( ) Figure S1. he decomposition of PMS in SMX degradation process. (a) ph 7; (b) ph 8; (c) ph 9; (d) ph 1. Experimental conditions: [PMS] =.44 mm, [SMX] = 8 μm, [BQ] = 2 3 μm at ph 7 and 2 1 μm at ph 8 1, 2 mm borate buffer, = 25 C, and reaction time of 12 min. S5

6 Figure S2 1. a 1. b.8.8 C/C BQ free control BQ=1 BQ=8 BQ= Reaction time(min) C/C BQ free control BQ=1 M BQ=8 M BQ=2 M Reaction (min) Figure S2. Effects of BQ on the degradation of AZ (a) and BA (d) by PMS. Experimental conditions: [PMS] =.44 mm, [BQ] = 1 2 μm, [AZ] = 1 μm, [BA] = 8 μm, ph = 1 (2 mm borate buffer), and = 25 C. S6

7 Figure S C/C.4.2. FFA free control FFA=2mM FFA=4mM Reaction time (min) Figure S3. Effects of FFA on SMX degradation by PMS. Reaction conditions: [PMS] =.44 mm, [SMX] = 8 μm, [BQ] = 2 μm, [FFA] = 2 4 mm, ph = 1 (2 mm borate buffer), and =25 C. S7

8 [O 2 ] t -[O 2 ] (M -1 ) Figure S t 2 Y O2 [PMS] -[PMS] t R 2 =.99 [O ] -[O ] ph=8, BQ=1 M ph=9, BQ=5 M ph=1, BQ=3 M Fit Curve [PMS] -[PMS] t (M -1 ) Figure S4. Plot of [O 2 ] t [O 2 ] vs [PMS] [PMS] t for PMS decomposition in the presence of BQ. Experimental conditions: [PMS] =.6 mm, [BQ] = 1 μm at ph 8, 5 μm at ph 9, and 3 μm at ph 1, 2 mm borate buffer, and = 25 C. S8

9 ln(c/c ) k obs (s -1 ) Figure S a R 2 =.99 b ph=7.75 ph=8. ph=8.45 ph-8.75 ph=8.9 ph=9.25 ph=9.5 ph=9.75 ph= Fit curve. 5.x1-6 1.x x1-5 2.x1-5 Reaction time (s) F Figure S5. First order decomposition of BQ-catalyzed PMS at varying ph (a), and the linear plot of k obs vs F for BQ-catalyzed decomposition of PMS (b). Experimental conditions: [PMS] =.44 mm, [BQ] = 3 μm, 2 mm borate buffer, and = 25 C. S9

10 SMX degradation (%) Figure S6 1 8 PMS PMS+HA PMS+HA+methanol PMS PMS+HA PMS+HA+methanol Figure S6. he effects of HA on the degradation of SMX by PMS. Experimental conditions: [PMS] =.44 mm, [HA] = 1 mg C L -1, [methanol] =.22 M, ph = 8 (2 mm borate buffer), = 25 C, and reaction time of 18 min. S1

11 References: (S1) Neta, P.; Huie, R. E.; Ross, A. B., Rate constants for reactions of inorganic radicals in aqueous solution. J. Phys. Chem. Ref. Data 1988, 17 (3), (S2) Buxton, G. V.; Greenstock, C. L.; Helman, W. P.; Ross, A. B. Critical Review of rate constants for reactions of hydrated electrons, hydrogen atoms and hydroxyl radicals ( OH/ O-) in aqueous solution. J. Phys. Chem. Ref. Data 1988, 17 (2), (S3) Anipsitakis, G. P.; Dionysiou, D. D., Radical generation by the interaction of transition metals with common oxidants. Environ. Sci. echnol. 24, 38 (13), (S4) Huie, R. E.; Clifton, C. L., emperature dependence of the rate constants for reactions of the sulfate radical, SO - 4, with anions. he Journal of Physical Chemistry 199, 94 (23), (S5) Minero, C.; Mariella, G.; Maurino, V.; Vione, D.; Pelizzetti, E., Photocatalytic transformation of organic compounds in the presence of inorganic ions. 2. Competitive reactions of phenol and alcohols on a titanium dioxide fluoride system. Langmuir 2, 16 (23), (S6) Gallopo, A. R.; Edwards, J. O., Kinetics and mechanism of the oxidation of pyridine by Caro s acid catalyzed by ketones. he Journal of Organic Chemistry 1981, 46 (8), S11