Electronic Supplementary Material (ESI) for Environmental Science: Water Research & Technology. This journal is © The Royal Society of Chemistry 2020 1 SUPPORTING INFORMATION 2 3 UV/Chlorine vs. UV/H2O2 for water reuse at Orange County Water 4 District, CA: A pilot study 5 Minhwan Kwon†,‡, Alan Royce†, Ying Gong†, Kenneth P. Ishida§, Mihaela I. Stefan*,† 6 7 † Trojan Technologies, 3020 Gore Road, London, ON, N5V 4T7, Canada 8 ‡Department of Chemical and Biochemical Engineering, University of Western Ontario, London, 9 ON, N6A 5B9, Canada 10 §Research and Development Department, Orange County Water District, 18700 Ward Street, 11 Fountain Valley, CA 92708, USA 12 * Corresponding author (Email: [email protected]; Phone: +1-519-457-3400) 13 14 Table S1. Selected elementary reactions considered in the kinetic model No. Reaction Rate constant = 371 M−1 cm−1 1 1 NH Cl + hν → NH • + Cl• 2 2 = 0.294 2 = 126 M−1 cm−1 1 2 NHCl + hν → NHCl• + Cl• 2 = 0.82 1 = 58 M−1 cm−1 2 3 HOCl + hν → •OH + Cl• = 0.55 3 = 19.6 M−1 cm−1 4 4 H O + hν → 2•OH 2 2 = 0.5 4 5.2 × 108 M−1 s−1 5 6.1 × 108 M−1 s−1 6 8 −1 −1 2 5 •OH +NH2Cl → NHCl• + H2O 8.64 × 10 M s 1.02 × 109 M−1 s−1 7 2.8 × 109 M−1 s−1 8 2.57 × 108 M−1 s−1 6 6 •OH +NHCl → NCl • + H O 2 2 2 6.21 × 108 M−1 s−1 9 8 −1 −1 6 7 •OH +NCl3 → NCl2• + HOCl 1.67 × 10 M s 8.5 × 104 M−1 s−1 10 1.4 × 108 M−1 s−1 11 8 •OH + HOCl → ClO• + H O 2 5.0 × 108 M−1 s−1 7 2.0 × 109 M−1 s−1 12 1.8 × 109 M−1 s−1 7 9 •OH + OCl− → ClO• + OH− 8.8 × 109 M−1 s−1 13 5.3 × 109 M−1 s−1 14 10 •OH + NO − → OH− + NO • 2 2 1.0 × 1010 M−1 s−1 15 7 −1 −1 15 11 •OH + H2O2 → HO2• + H2O 2.7 × 10 M s 12 •OH + Cl− → ClOH•− 4.3 × 109 M−1 s−1 16 13 •OH + ONOO− → ONOO• + OH− 4.8 × 109 M−1 s−1 17 − − 6 −1 −1 15 14 •OH + HCO3 → CO3• + H2O 8.5 × 10 M s 2− − − 8 −1 −1 15 15 •OH + CO3 → CO3• + OH 3.9 × 10 M s 1.0 × 109 M−1 s−1 7 16 Cl• + NH Cl → NHCl• + HCl 2 2.4 × 107 M−1 s−1 18 17 Cl• + HOCl → ClO• + H+ + Cl− 3.0 × 109 M−1 s−1 19 18 Cl• + OCl− → ClO• + Cl− 8.2 × 109 M−1 s−1 19 6.5 × 109 M−1 s−1 19 7.8 × 109 M−1 s−1 20 19 Cl• + Cl− → Cl •− 2 8.0 × 109 M−1 s−1 21 8.5 × 109 M−1 s−1 22 − − 9 −1 −1 23 20 Cl• + NO2 → Cl + NO2• 5.0 × 10 M s + − 9 −1 −1 24 21 Cl• + H2O2 → H + Cl + HO2• 1.0 × 10 M s 2.0 × 109 M−1 s−1 20 22 Cl• + OH− → ClOH•− 1.8 × 1010 M−1 s−1 19 7.2 × 104 s−1 16 1.6 × 105 s−1 19,25 23 Cl• + H O → ClOH•− + H+ 2 1.8 × 105 s−1 20 2.5 × 105 s−1 23,26 2.2 × 108 M−1 s−1 27 24 Cl• + HCO − → CO •− + H+ + Cl− 3 3 2.4 × 109 M−1 s−1 23 2− − − 8 −1 −1 27 25 Cl• + CO3 → CO3• + Cl 5.0 × 10 M s − + − 6 −1 −1 18 26 Cl2• + NH2Cl → NHCl• + H + 2Cl 6.5 × 10 M s ≤ 100 s−1 20 27 Cl •− + H O → Cl− + ClOH•− + H+ 2 2 ≤ 1300 s−1 26 5.7 × 104 s−1 20 − − 4 −1 28 28 Cl2• → Cl• + Cl 6.0 × 10 s 1.1 × 105 s−1 16 − − 9 −1 −1 29 29 Cl2• + Cl• → Cl2 + Cl 2.1 × 10 M s 9.0 × 108 M−1 s−1 28 30 Cl •− + Cl •− → 2Cl− + Cl 2 2 2 3.5 × 109 M−1 s−1 20 − − 5 −1 −1 30 31 CO3• + H2O2 →HO2• + HCO3 4.3 × 10 M s 32 ClOH•− → Cl− + •OH 6.0 × 109 s−1 20 33 ClOH•− → Cl• + OH− 23 s−1 16 − − − − 4 −1 −1 31 34 ClOH• + Cl → OH + Cl2• 1.0 × 10 M s 2.1 × 1010 M−1 s−1 16 2.4 × 1010 M−1 s−1 20 35 ClOH•− + H+ → Cl• + H O 2 2.6 × 1010 M−1 s−1 25 5.0 × 1010 M−1 s−1 23 2.5 × 109 M−1 s−1 19 36 ClO• + ClO• → Cl O 2 2 7.5 × 109 M−1 s−1 32 6.3 × 109 M−1s−1 32 37 •OH + ClO − → ClO • + OH− 2 2 7.0 × 109 M−1s−1 33 − + 9 −1 −1 19 38 •OH + ClO2• → ClO3 + H 4.0 × 10 M s 1.0 × 109 M−1s−1 34 39 •Cl + ClO • → Cl O 2 2 2 4.0 × 109 M−1s−1 7 − − 9 −1 −1 34 40 Cl2• + ClO2• → Cl2O2 + Cl 1.0 × 10 M s 9 −1 −1 35 41 ClO• + ClO2• → Cl2O3 1.4 × 10 M s − − − 9 −1 −1 11 42 Cl2• + ClO2 → ClO2• + 2Cl 1.3 × 10 M s − − 8 −1 −1 36 43 ClO• + ClO2 → OCl + ClO2• 9.4 × 10 M s − − − 9 −2 −1 37 44 Cl2O2 + ClO2 + Cl → 2ClO2• + 2Cl 8.4 × 10 M s 1.2 × 104 M−1 s−1 38 45 Cl O + ClO − + H O → ClO − + 2HOCl 2 2 2 2 3 5.3 × 105 M−1 s−1 37 − + 6 −2 −1 39 46 ClO2 + HOCl + H → Cl2O2 + H2O 1.12 × 10 M s − − − − + −2 −1 38 47 ClO2 + HOCl + Cl → ClO3 + 2Cl + H 180 M s 5 −1 32 48 Cl2O2 → 2ClO• k45/(1.3×10 )/1.93 /0.034 s 1.0 × 107 M−1 s−1 40 1.2 × 108 M−1 s−1 41 8 −1 −1 42 49 NH2• + O2 → NH2O2• 3.0 × 10 M s 1.1 × 109 M−1 s−1 43 1.2 × 109 M−1 s−1 44 8 −1 9 50 NH2O2• → NO• + H2O 1.0 × 10 s 8 −1 9 51 NH2O2• → transient species →N2O 5.98 × 10 s 50−3000 M−1 s−1 45 52 NO• + O → ONOO• 2 1 × 106 M−1 s−1 46 5.8 × 105 M−1 s−1 46 53 ONOO• + NO• → 2NO • 2 1.0 × 109 M−1 s−1 45 6500 s−1 45 54 ONOO• → NO• + O 2 2.0 × 105 s−1 46 1.0 × 1010 M−1 s−1 47 55 NO• + •OH → HNO 2 2.0 × 1010 M−1 s−1 48 9 −1 −1 49 56 NO• + NO2• → N2O3 1.1 × 10 M s 8 −1 −1 50 57 NO2• + NO2• → N2O4 4.5 × 10 M s 2.2 × 104 s−1 51 4 −1 49 58 N2O3 → NO• + NO2• 8.0 × 10 s 4.3 × 106 s−1 52 530 s−1 49 − + −1 53 59 N2O3 + H2O → 2NO2 +2H 1600 s 2000 s−1 51 −1 50 60 N2O4 → 2NO2• 6900 s 300 s−1 51 61 N O + H O → NO − + NO − + 2H+ 2 4 2 2 3 1000 s−1 50 6 −1 −1 54 62 2HNO → [HONNOH] → N2O + H2O 8.0 × 10 M s 3.8 × 102 M−1 s−1 55 3 −1 −1 56 63 HNO + O2 → ONOOH 3.0 × 10 M s 1.8 × 104 M−1 s−1 57 7.6 × 106 M−2 s−1 58 64 H+ + NH Cl + NO − → NH + NO Cl 2 2 3 2 1.2 × 107 M−2 s−1 59 − − −1 −1 60 65 NO2Cl + NO2 → N2O4 + Cl 8000 M s − − + −1 60 66 NO2Cl + H2O → NO3 + Cl + 2H 4.8 s 0.232 s−1 61 67 ONOOH → NO • + •OH 2 0.35 s−1 62 0.568 s−1 61 − + −1 62 68 ONOOH → NO3 + H 0.90 s 1.15 s−1 63 − − −1 64 69 ONOO → O2• + NO• 0.02 s − − −6 −1 62 70 ONOO → NO3 8.0 × 10 s − − 7 −1 −1 65 71 O2• + HO2• → HO2 + O2 9.7 × 10 M s −1 −1 15 72 HO2• + H2O2 → •OH + H2O + O2 3.0 M s − − −1 −1 15 73 O2• + H2O2 → •OH + OH + O2 0.13 M s 6 −1 −1 66 74 HOCl + NH3 → NH2Cl + H2O 4.2 × 10 M s −1 −1 66 75 HOCl + NH2Cl → NHCl2 + H2O 280 M s − − 9 −2 −1 67 76 HOCl + NHCl2 + OH → NCl3 + OH + H2O 3.3 × 10 M s − − 5 −2 −1 67 77 HOCl + NHCl2 + OCl → NCl3 + OH + HOCl 1.0 × 10 M s −5 −1 66 78 NH2Cl + H2O → HOCl +NH3 2.1 × 10 s −7 −1 68 79 NHCl2 + H2O → HOCl + NH2Cl 6.5 × 10 s −5 −1 68 80 NCl3 + H2O → HOCl + NHCl2 3.2 × 10 s + + −2 −1 69 81 NH2Cl + NH2Cl + H → NHCl2 + NH4 6944 M s + − −2 −1 69 82 NH2Cl + NH2Cl + H2CO3 → NHCl2 + NH4 + HCO3 11 M s − − −2 −1 69 83 NH2Cl + NH2Cl + HCO3 → NHCl2 + NH3 + HCO3 0.22 M s + −1 −1 70 84 NH2Cl + NHCl2 → N2 + 3H + 3Cl (assumed products) 0.015 M s + + 4 −2 −1 67 85 NHCl2 + NH3 + H → NH2Cl + NH2Cl + H 6.0 × 10 M s − −1 −1 71 86 NHCl2 + OH → I + products 110 M s 4 −1 −1 72 87 I + NHCl2 → HOCl + products 2.8 × 10 M s 3 −1 −1 72 88 I + NH2Cl → products 8.3 × 10 M s − 9 −2 −1 70 89 NH2Cl + NCl3 + OH → HOCl + products 1.4 × 10 M s − 10 −2 −1 70 90 NHCl2 + NCl3 + OH → 2HOCl + products 5.6 × 10 M s −1 −1 73 91 H2O2 + NH2Cl → products 0.0276 M s (24.6 °C) 7.4 × 103 M−1 s−1 74 92 HOCl + NO − → NO Cl + OH− 2 2 4.4 × 104 M−1 s−1 58 − + 4 −1 −1 13 93 H2O2 + HOCl → Cl + H2O + O2 + H 1.1 × 10 M s − − 5 −1 −1 13 94 H2O2 + OCl → Cl + H2O + O2 1.7 × 10 M s 2.8 × 109 M−1 s−1 15 95 •OH + 1,4−dioxane → 3.1 × 109 M−1 s−1 75 4.4 × 106 M−1 s−1 76 96 Cl• + 1,4−dioxane → 2.8−3.4 × 109 M−1 s−1 77 − 6 −1 −1 76 97 Cl2• + 1,4−dioxane → 3.3 × 10 M s HOCl ↔ OCl− pKa=7.5 78 98 OCl− + H+ → HOCl 5.0 × 1010 M−1 s−1 HOCl → OCl− + H+ 1.58 × 103 s−1 − 2− 79 H2CO3 ↔ HCO3 ↔ CO3 pKa1=6.3 & pKa2=10.3 − + 10 −1 −1 HCO3 + H → H2CO3 1.0 × 10 M s 99 + − 3 −1 H2CO3 → H + HCO3 5.0 × 10 s 2− + − 10 −1 −1 CO3 + H → HCO3 5.0 × 10 M s − 2− + −1 HCO3 → CO3 + H 2.5 s − 65 HO2• ↔ O2• pKa= 4.8 − + 10 −1 −1 100 O2• + H → HO2• 5.0 × 10 M s − + 5 −1 HO2• → O2• + H 7.9 × 10 s ONOOH ↔ ONOO− pKa= 6.6 62 101 ONOO− + H+ → ONOOH 5.0 × 1010 M−1 s−1 ONOOH → ONOO− + H+ 1.26 × 104 s−1 = 1650 M−1 cm−1 80 102 NDMA+ hν → = 0.28 80 15 16 17 Section S1.