MIAMI UNIVERSITY The Graduate School Certificate for Approving the Dissertation We hereby approve the Dissertation of Aleksey N. Pisarenko Candidate for the Degree: Doctor of Philosophy _____________________________________ Director Dr. Gilbert E. Pacey _____________________________________ Director (Committee Chairperson) Dr. Gilbert Gordon _____________________________________ Reader Dr. Richard T. Taylor _____________________________________ Reader Dr. Michael W. Crowder _____________________________________ Graduate School Representative Dr. Luis A. Actis Abstract ANALYTICAL MEASUREMENTS AND PREDICTIONS OF PERCHLORATE ION CONCENTRATION IN SODIUM HYPOCHLORITE SOLUTIONS AND DRINKING WATER: KINETICS OF PERCHLORATE ION FORMATION AND EFFECTS OF ASSOCIATED CONTAMINANTS by Aleksey N. Pisarenko The dissertation consists of six chapters that summarize the investigation of factors impacting perchlorate ion formation in sodium hypochlorite solutions and the development of a predictive model for perchlorate ion formation. There are also two appendices detailing the synthesis and applications of nanomaterials for designing sensors. Chapter 1 gives a brief history of perchlorate ion as an emerging contaminant. A background on the occurrence, toxicology, and regulatory actions is provided. Chapter 2 focuses on the analytical methods that were developed and validated for analysis of perchlorate, bromate, chlorate, hypochlorite, and chlorite ions in various hypochlorite ion solutions. Comparison of a LC-MS/MS method and an iodometric titration method is provided. The chapter also details sample preparation methods, such as the use of malonic acid to stop formation of perchlorate ion. Chapter 3 details the experimental matrix to identify factors that impact perchlorate ion formation. Effects of different contaminants were investigated at elevated temperatures. Chapter 4 provides a detailed investigation of the effects of concentration of hypochlorite and chlorate ions, ionic strength, and temperature. The order of the perchlorate ion formation with respect to hypochlorite and chlorate ions was determined. A thorough investigation of the various effects led to derivation of a simple expression that relates the effects of ionic strength and temperature on the second-order rate constant. Chapter 5 focuses on validation and application of the developed predictive expression on various hypochlorite ion solutions. Bleach 2001 Predictive Model was used to predict the decomposition of hypochlorite ion, and the output was used together with the predictive expression developed in this work to predict formation of perchlorate ion in hypochlorite ion solutions. Potential formation of perchlorate ion in stored hypochlorite ion solutions is discussed, and recommendations to minimize formation of perchlorate ion are provided. Chapter 6 summarizes the findings of this Dissertation and provides conclusions in the context of perchlorate ion contamination of drinking water when hypochlorite ion is used as a disinfectant. ANALYTICAL MEASUREMENTS AND PREDICTIONS OF PERCHLORATE ION CONCENTRATION IN SODIUM HYPOCHLORITE SOLUTIONS AND DRINKING WATER: KINETICS OF PERCHLORATE ION FORMATION AND EFFECTS OF ASSOCIATED CONTAMINANTS A DISSERTATION Submitted to the Faculty of Miami University in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Chemistry and Biochemistry by Aleksey N. Pisarenko Miami University Oxford, Ohio 2009 Dissertation Directors: Dr. Gilbert E. Pacey and Dr. Gilbert Gordon © Aleksey N. Pisarenko 2009 Table of Contents List of Tables vii List of Figures x Dedication xviii Acknowledgements xix 1. Introduction 1 1.1 Perchlorate Ion: Introduction 1 1.2 Perchlorate Ion: Toxicity and Regulation 3 1.3 Hypochlorite Ion Solutions as Potential Source of Perchlorate Ion 4 1.4 Research Objectives 5 2. Analysis and Sample Preparation of Hypochlorite Ion Solutions: Analytical Methods Summary 7 2.1 Introduction to the Analysis of Sodium Hypochlorite Solutions 7 2+ 2+ 3+ 2+ 2+ 2.1.2 Transition metal ions: Co , Cu , Fe , Mn , and Ni 9 2.1.3 Specific Conductance, Ionic Strength, and pH Measurements 10 2.2 Results and discussion 10 2.2.1 The LC-MS/MS Analysis of Perchlorate, Bromate, and Chlorate Ions 10 2.2.2 Validation of LC-MS/MS Method for the Analysis of Hypochlorite Solutions 12 2.2.3 Iodometric Titrations: Analysis of Chlorite, Chlorate, and Hypochlorite Ions 18 2.2.3.1 Adam-Gordon Method 19 2.2.4 Method Selection for the Measurement of Chlorate Ion 21 2.2.5 Selection of Quenching Agent 24 2.2.5.1 Safety, Ease of Handling, Transport, and Stability 26 2.2.5.2 Ability to Quench Hypochlorite Ion Reproducibly 28 2.2.5.3 Impact on the Analysis of Bromate, Chlorate, and iii Perchlorate Ion 29 2.2.5.3 Quenching Agent Selection Summary 32 2.3 Conclusions 34 3. Experimental Design: Identifying Factors Impacting the Perchlorate Ion Formation in Hypochlorite Ion Solutions 36 3.1 Experimental Matrix and Chemicals 38 3.2 Effect of Hypochlorite Ion Concentration 39 3.3 Effect of Chlorate Ion Concentration 41 3.4 Effect of Transition Metal Ions (Co2+, Cu2+, Fe3+, Mn2+, and Ni2+) 43 + + 3+ 2+ 2+ 3.5 Effect of Noble Metal Ions (Ag , Au , Ir , Pd , and Pt ) 44 3.6 Effect of Chlorite Ion Concentration 46 3.6.1 Combined Effect of Transition Metal Ions, Chlorite and Bromide Ions 50 3.7 Effect of Bromide Ion and Bromate Ion Concentration 52 3.8 Effect of Ionic Strength 54 3.9 Effect of pH 57 3.10 Conclusions 60 4. Kinetics of Perchlorate Ion Formation and Determination of the Rate Law 63 4.1 Reaction Order with Respect to Chlorate Ion: - - ln (d[ClO4 ]/dt) vs. ln [ClO3 ] 64 4.2 Reaction Order with Respect to Chlorate Ion: - - ln (d[ClO4 ]/dt) vs. ln [OCl ] 69 4.3 Multiple Reaction Pathways 75 4.3.1 Parallel Reaction Pathway 76 4.3.2 Consecutive Reaction Pathway 78 4.4 Ionic Strength Effect on the Rate of Perchlorate Ion Formation 80 4.4.1 Dependence of the Second-Order Rate Constant on the Ionic Strength 84 iv 4.4.2 Dependence of the Second-Order Rate Constant on the Temperature 88 4.4.3 Combining the Effects of the Ionic Strength and Temperature on the Second-Order Rate Constant 91 4.5 Conclusions 92 5. The Perchlorate Ion Formation Model: Validation and Applications 93 5.1 Predicted Perchlorate Ion Formation in Bulk Sodium Hypochlorite Solutions 95 5.2 Predicted Perchlorate Ion Formation in Real-World Bulk Sodium Hypochlorite Solutions 98 5.3 Using Perchlorate Ion Formation Model to Determine Implications of Bulk Sodium Hypochlorite Solutions Storage 102 5.4 Application of the Perchlorate Model to OSG Sodium Hypochlorite Solutions 107 5.5 Application of The Perchlorate Model to Calcium Hypochlorite Solutions 112 5.6 Potential Contribution of Perchlorate Ion to Drinking Water 114 from Various Hypochlorite Ion Solutions 112 5.7 Conclusions 118 6. Conclusions 119 6.1 Summary 119 6.2 Recommendation to Water Utilities 120 Appendix 1. Detection of Ozone Gas by Gold Nanoislands 122 A1.1 Introduction 122 A1.2 Experimental 123 A1.3 Results and Discussion 124 A1.4. Conclusions 131 v Appendix 2. Electrochemically Assisted Processing of Organically Modified, Perpendicularly Oriented Mesoporous Silica Films with Fluorescent Functionality 132 A2.1. Introduction 132 A2-2. Experimental Details 136 A2-3. Results and Discussion 137 A2-4. Conclusions 142 A2.5 Acknowledgements 143 References 144 vi List of Tables Table 1. ICP-MS MRLs (µg/L) in water and hypochlorite ion solutions 9 Table 2. MDL data for perchlorate, bromate, and chlorate ions (n = 8) 13 Table 3. Spike recoveries of analytes with and without filtration and at different 15 Table 4. Standardization of sulfite and thiosulfate ion solutions by - 0.109 M IO3 20 Table 5. Comparison of measurements by the LC-MS/MS and iodometric titration for bulk hypochlorite ion solutions (n = 7) 21 Table 6. Comparison of measurements by the LC-MS/MS and iodometric titration for OSG sodium hypochlorite solutions at - less than 1.0 g/L ClO3 (< 10 mM) (n ≥ 3) 22 Table 7. Effects of malonic acid (MA) on recoveries of chlorate, perchlorate, and bromate ions measured by LC-MS/MS (n = 3, replicate Samples Analyzed in triplicate; S.D. = standard deviation) 30 Table 8. Effects of malonic acid (MA) on analysis of perchlorate and bromate ions at different dilutions (n = 3; S.D. = standard deviation) 30 Table 9. Effects of quenching agent on analysis of chlorate comparison of LC-MS/MS and titration results (n = 3, replicate samples analyzed in triplicate; S.D. = standard deviation) 31 Table 10. Perchlorate ion stability in hypochlorite ion solutions quenched with malonic acid over 2-month period 31 Table 11. Bromate ion stability in hypochlorite ion solutions quenched with malonic acid over 2-month period 32 Table 12. Chlorate ion stability in hypochlorite ion solutions quenched with malonic acid over 2-month period 32 Table 13. Summary of quenching agent test results and decision-making matrix 33 Table 14. Changes in perchlorate ion concentration of samples spiked with + + 3+ 2+ 2+ Ag, Au , Ir , Pd , and Pt (Noble Me) vs. control (no spike), incubated at 50 ºC 46 Table 15. Decomposition of hypochlorite ion at 30 ºC in solutions, at various - initial concentrations of chlorate ion ([ClO3 ]0) at pH ~12.5 66 Table 16. Reaction order with respect to chlorate ion and corresponding vii correlation coefficients in solutions at constant hypochlorite ion at pH ~ 12.5 and various temperatures 69 Table 17. Decomposition of hypochlorite ion at 30 ºC in solutions at constant chlorate ion concentration at pH ~12.5 71 Table 18. Parallel reaction pathway experimental rate constants in solutions, at various hypochlorite ion and constant chlorate ion at pH ~12.5 78 Table 19. Consecutive reaction pathway experimental rate constants at various initial concentrations of hypochlorite ion and constant chlorate ion at pH ~12.5 80 Table 20. Ionic strength (μ) of hypochlorite ion solutions at various chlorate ion at 40 ºC experiments (TDS = Total Dissolved Solids) 81 Table 21. Ionic strength (μ) of hypochlorite ion solutions at various hypochlorite ion at 40 ºC experiments (TDS=Total Dissolved Solids) 81 Table 22.