UNIVERSITY OF CALIFORNIA Los Angeles Competitive Adsorption of Cyclotrimethylenetrinitramine (RDX) and Cyclotetramethy lenetetrani trarnine (HMX) A thesis submitted in partial satisfaction of the requirements for the degree Master of Science in Civil Engineering by Carmen Kar Men Lee 1996 L The thesis of Carmen Kar Men Lee is approved. Menachem Elimelech ~Thomas C. Harmon .. Michael K. Stenstrom, Committee Chair University of California, Los Angeles 1996 11 L TABLE OF CONTENTS TABLE OF CONTENTS............................................................................................ iii LIST OF FIGURES.................................................................................................... vii LIST OF TABLES ....................................................................................................... x ABSTRACT ................................................................................................................ xi 1. IN"TRODUCTION ........ ........ ................................ ........ ........ ........................ ...... ..... 1 2. LITERATURE REVIEW........................................................................................ 5 2.1 Properties and Toxicity of RDX. ........................... ,. ............. ........ ........ ...... 5 2.2 Properties and Toxicity of HMX.. ........... ..... ..... ... ................ ................... ... 7 2.3 Principal Treatment Technologies for RDX and HMX....... ... ... .......... ... ... 10 2.3.1 Alkaline Hydrolysis. .......... ......... ....... ..... ... ........ ..... ... ..... ........ ... 10 2.3.2 Ultraviolet RadiationlPhotolysis ............................................... 10 2.3.3 Polymer Adsorption ................................................................... 11 2.3.4 Biological Treatment.. ................................................................ 12 2.3.5 Activated Carbon Adsorption .................................................... 14 2.4 Adsorption Isotherm Models .................................................................... 14 2.4.1 Monocomponent Isotherm Models ............................................ 15 2.4.1.1 Langmuir Monocomponent Isotherm......................... 15 2.4.1.2 Brunauer, Emmett, Teller (BET) Isotherm................. 17 2.4.1.3 Freundlich Monocomponent Isotherm....................... 17 2.4.2 Multicomponent Isotherm Models............................... .............. 19 111 L 2.4.2.1 Langmuir Multicomponent Isotherm...... .............. ...... 19 2.4.2.2 Langmuir Extension- First Approximation ModeL .... 20 2.4.2.3 Langmuir Partially Competitive Multicomponent Isotherm..................................................................... 21 2.4.2.4 Freundlich Multicomponent Isotherm.... ........ ............ 22 2.4.2.5 Empirical Bisolute Extension of the Freundlich Isotherm..................................................................... 24 2.4.2.6 Crittenden et al.'s lAS-Freundlich Isotherm............... 24 2.4.2.7 Fritz & Schlunder's lAS-Freundlich ModeL ............. 26 2.4.2.8 Simplified Ideal Adsorbed Solution (SIAS) Isotherm..................................................................... 27 2.4.2.9 Improved Simplified Ideal Adsorbed Solution (ISlAS) Isotherm................................................. .................... 28 2.4.2.10 Ideal Adsorbed Solution (lAS) ModeL................... 30 2.4.2.11 Polanyi Adsorption Potential Theory.. ...... ........ ....... 32 2.5 Previous Work on Activated Carbon Adsorption of RDX and HMX..... 40 3. EXPERIMENTAL METHODS ............................................................................. 57 3.1 Analytical Techniques .............................................................................. 57 3.1.1 High Performance Liquid Chromatography (HPLC)................ 57 3.1.2 Solid Phase Extraction (SPE)................................................... 58 iv 3.1.2.1 Previous Work on SPE and Other Extraction Methods .................................................................... 59 3.1.2.2 SPE Method Development.. ...................................... 61 3.1.2.3 The SPE Method ....................................................... 63 3.2 Experimental Design and Methods ......................................................... 66 3.2.1 Isotherm Experimental Design ................................................. 66 3.2.1.1 Program's Results & Usage ....................................... 66 3.2.1.2 Experimental Conditions ........................................... 71 3.2.1.3 Isotherm Experiments: Materials & Method.. ........... 71 3.2.2 Solubility Tests: Materials & Methods............ ............. ............ 72 3.3 Error Analysis .......................................................................................... 73 4. RESULTS AND DISCUSSIONS .......................................................................... 84 4.1 RDX and HMX Adsorption... ........... ........ ............. ............. ............. ........ 84 4.2 Multicomponent Adsorption Isotherms.... ........ .................. ..................... 94 4.2.1 Langmuir Multicomponent Isotherm.............. .......................... 96 4.2.2 Langmuir Partially Competitive Isotherm ................................. 102 4.2.3 Freundlich Multicomponent Isotherm ....................................... 105 4.2.4 Simplified Ideal Adsorbed Solution (SIAS) Isotherm ............... 110 4.2.5 Improved Simplified Ideal Adsorbed Solution (ISlAS) Isotherm ....................................................................................... 113 4.3 RDX and HMX Aqueous Solubility Limits .............................................. 119 v 5. CONCLUSION ....................................................................................................... 121 APPENDIX A CALffiRATION CURVES ................................................................. 124 APPENDIX B SPE RECOVERY STUDIES ............................................................. 129 APPENDIX C PASCAL PROGRAM ......................................................................... 131 APPENDIXD COMPETITIVE ISOTHERM EXPERIMENTAL DATA ................. 142 REFERENCES ............................................................................................................. 146 vi - LIST OF FIGURES Figure 1 Structural Formula of RDX and HMX........ ........ ........ ............. ...... ............. 6 Figure 2 Solid Phase Extraction Setup ........... , ........... ........ .......... ........... ..... ... .......... 64 . Figure 3 Flowchart for the Pascal Program....... ......... ..... ........ ........ ..... ........ ........ ..... 67 Figure 4 Computer Program Prediction for RDX ............ ,. ........ ........ ..... ............. ..... 68 Figure 5 Computer Program Prediction for HMX.. ... ..... ... ........ ......... .... ..... ... ...... .... 69 Figure 6a Estimated Error for RDX Sorbed Concentration Subject to O.00025g Error in Measuring Carbon Dosages ......................................... 75 Figure 6b Estimated Error for HMX Sorbed Concentration Subject to O.00025g Error in Measuring Carbon Dosages ......................................... 75 Figure 7a Estimated Error for RDX Sorbed Concentration Subject to O.005L Error in Measuring Volume .......................................................... 76 Figure 7b Estimated Error for HMX Sorbed Concentration Subject to O.005L Error in Measuring Volume .......................................................... 77 Figure 8a Estimated Error for RDX Sorbed Concentration Subject to O.OOO339mg/L Error in Measuring Concentration .................................... 79 Figure 8b Estimated Error for HMX Sorbed Concentration Subject to O.0255mg/L Error in Measuring Concentration.. .......... ........ .................... 79 Figure 9a Estimated Error for RDX Sorbed Concentration Subject to 1% Error in Freundlich Parameter K....... ........... ..................... ........ ... ....... 81 Figure 9b Estimated Error for HMX Sorbed Concentration Subject to vii 1% Error in Freundlich Parameter K.. ....................................................... 81 Figure lOa Estimated Error for RDX Sorbed Concentration Subject to 1% Error in Freundlich Parameter n ........................ , ..... ........ ........ .......... 82 Figure lOb Estimated Error for HMX Sorbed Concentration Subject to 1% Error in Freundlich Parameter n ............. '" ............ , ........ ............. ..... 82 Figure 11 Linearized Langmuir, BET, Freundlich Isotherms for RDX ..................... 85 Figure 12 Linearized Langmuir, BET, Freundlich Isotherms for HMX. ........ ........... 86 Figure 13 Freundlich Monocomponent Isotherm for RDX and HMX. .................. ... 88 Figure 14 Freundlich Linearized Single-Solute Isotherm for Independent and Competitive RDX and HMX.. ...... ..... ........ ...... ..... ........ ... ....... ..... .... .......... 90 Figure 15 Langmuir Multicomponent Isotherm Contour for RDX...... ................ ..... 97 Figure 16 Langmuir Multicomponent Isotherm Contour for HMX.......................... 98 Figure 17 Experimental Results for RDX......... ......... .................. ........ ..... ................ 99 Figure 18 Experimental Results for HMX ................................................................ 100 Figure 19 Langmuir Partially Competitive Isotherm Contour for RDX ................... 103 Figure 20 Langmuir Partially Competitive Isotherm Contour for HMX .................. 104 Figure 21 Freundlich Linearized Bisolute