Low temperature catalytic oxidation of volatile organic compounds (vocs) over catalysts of Cuo - Co3O4 on supports

MINISTRY OF EDUCTION AND TRAINING 
HA NOI UNIVERSITY OF SCIENCE AND TECHNOLOGY 
Ngo Quoc Khanh 
LOW TEMPERATURE CATALYTIC OXIDATION OF 
VOLATILE ORGANIC COMPOUNDS (VOCs) OVER 
CATALYSTS OF CuO-Co3O4 ON SUPPORTS 
DOCTORAL DISSERTATION OF 
ENVIRONMENAL ENGINEERING 
Ha Noi – 2021 
MINISTRY OF EDUCTION AND TRAINING 
HA NOI UNIVERSITY OF SCIENCE AND TECHNOLOGY 
Ngo Quoc Khanh 
LOW TEMPERATURE CATALYTIC OXIDATION OF 
VOLATILE ORGANIC COMPOUNDS (VOCs) OVER 
CATALYSTS OF CuO-Co3O4 ON SUPPORTS 
Major: Environmental Engineering 
Code: 9520320 
DOCTORAL DISSERTATION OF 
ENVIRONMENAL ENGINEERING 
SUPERVIORS: 
1. Assoc. Prof. Dr. Vu Đuc Thao 
2. Prof. Dr. Le Minh Thang 
Ha Noi - 2021
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ACKNOWLEDGEMENT 
First of all, I would like to thank Prof. Nguyen Huu Phu, who raises my 
interest in catalysis. Secondly, I would like to thank Associate Prof. Dr. Vu Duc 
Thao and Prof. Dr. Le Minh Thang, who are my supervisors, because of their 
guidance, encouragement, and kindly help in the scientific works. 
Also, I would like to thank my colleagues at Vietnam National Institute of 
Occupational Safety and Health (VNNIOSH), lectures in School of Environmental 
Science and Technology (INEST) and School of Chemical Engineering (SCE), and 
all members in Laboratory of the Petrochemical Refining and Catalytic Materials 
(LPRCM), and Laboratory of Environmentally Friendly Material and Technologies, 
that I believe my work cannot be completed without their generous assistance. 
Moreover, I would like to thank Dr. Sebastian Wohlrab and all staff in 
LIKAT for their friendly attitude and support, when I conducted the short-course 
research in University of Rostock - Germany. 
Finally, I would like to give special thanks to my parents, my wife, and my 
beloved daughters because of their faced difficulties, supports, encourage as well as 
love. 
The financial supports of the Rohan Program – DAAD & BMZ, German, 
and the Project no 216/02/TLD (VNNIOSH) are acknowledged in this thesis. 
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COMMITMENT 
The study has been conducted at the School of Environmental Science and 
Technology (INEST), School of Chemical Engineering (SCE), Hanoi University of 
Science and Technology (HUST), Leibniz-Institute for Catalysis (LIKAT), 
University of Rostock (Germany) and Vietnam National Institute of Occupational 
Safety and Health (VNNIOSH). The work has been completed under the 
supervision of Associate Prof. Dr. Vu Duc Thao and Prof. Dr. Le Minh Thang. 
I assure that this is my research. All the data and results in the thesis are 
entirely true, were agreed to use in this paper by the co-author. This research has not 
been published by other authors than me. 
Ngo Quoc Khanh 
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TABLE OF CONTENTS 
ACKNOWLEDGEMENT ........................................................................................... i 
COMMITMENT ......................................................................................................... ii 
TABLE OF CONTENTS .......................................................................................... iii 
LIST OF TABLES ..................................................................................................... vi 
LIST OF FIGURES ................................................................................................. viii 
LIST OF ACRONYM AND ABBREVIATIONS ..................................................... xi 
INTRODUCTION ....................................................................................................... 1 
CHAPTER 1. LITERATURE REVIEW .................................................................... 5 
1.1. Overview of volatile organic compounds ........................................................ 5 
1.2. Overview of VOCs treatment technologies...................................................... 7 
1.2.1. Oxidation method ...................................................................................... 9 
1.2.2. Biological method .................................................................................... 11 
1.2.3. Absorption method .................................................................................. 14 
1.2.4. Adsorption method .................................................................................. 14 
1.2.5. Condensation method .............................................................................. 15 
1.3. Catalytic oxidation of VOCs .......................................................................... 16 
1.3.1. Mechanisms and kinetics of catalytic oxidation of VOCs ...................... 16 
1.3.2. Catalysts for oxidation of VOCs.............................................................. 17 
1.3.2.1. Noble-metal based catalysts .............................................................. 17 
1.3.2.2. Non-noble metal oxides .................................................................... 22 
1.3.2.3. Non-noble mix metal oxides ............................................................. 26 
1.3.3. Catalytic supports and preparation methods for VOCs oxidation ........... 29 
1.4. The summary of literature review .................................................................. 30 
CHAPTER 2. EXPERIMENT .................................................................................. 32 
2.1. Catalyst preparation ........................................................................................ 32 
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2.1.1. Wet impregnation method ....................................................................... 32 
2.1.2. Solid-solid blending method .................................................................... 34 
2.2. Catalyst characterization ................................................................................ 36 
2.2.1. Thermal analysis ...................................................................................... 36 
2.2.2. Physical adsorption .................................................................................. 37 
2.2.3. X-ray diffraction ...................................................................................... 38 
2.2.4. Scanning electron microscopy ................................................................. 39 
2.2.5. Chemical and temperature programmed desorption ................................ 40 
2.3. Adsorption and catalytic activity measurement .......................................... 43 
2.3.1. Adsorption and nitrogen desorption measurement .............................. 43 
2.3.2. Catalytic activity measurement for complete oxidation of toluene ..... 45 
2.3.3. Catalytic activity measurement for complete oxidation of methane ... 50 
CHAPTER 3. RESULTS AND DISCUSSIONS ...................................................... 52 
3.1. Characterizations of supports and catalysts.................................................... 52 
3.1.1. Thermal analysis ...................................................................................... 52 
3.1.2. Physisorption ........................................................................................... 53 
3.1.3. X-ray diffraction (XRD) .......................................................................... 59 
3.1.4. Scanning electron microscopy ................................................................. 66 
3.1.5. Chemisorption .......................................................................................... 69 
3.1.5.1. CO pulse ............................................................................................ 69 
3.1.5.2. Oxygen temperature programed desorption (O2-TPD) ..................... 71 
3.2. Total oxidation ability of the catalysts for methane ....................................... 73 
3.3. Toluene treatment ........................................................................................... 82 
3.3.1. Toluene adsorption on catalysts/ sorbents ............................................... 82 
3.3.1.1. Toluene adsorption over Cu-Co/Activated carbon ........................... 82 
3.3.1.2. Toluene adsorption over Cu-Co/Silica gel ........................................ 83 
3.3.1.3. Toluene adsorption over Cu-Co/MCM-41 ........................................ 84 
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3.3.2. Oxidation over catalysts in desorption process ....................................... 87 
3.3.2.1. Toluene oxidation over Cu-Co/Activated carbon in desorption 
process ............................................................................................................ 87 
3.3.2.2. Toluene oxidation over Cu-Co/ /Silica gel in desorption process .... 91 
3.3.2.3. Toluene oxidation over Cu-Co/MCM-41 in desorption process ...... 93 
3.3.3. Toluene treatment by complete oxidation over catalysts ........................ 97 
3.3.3.1. Complete oxidation of toluene on Cu-Co/Silica gel ......................... 97 
3.3.3.2. Directed oxidation of toluene on Cu-Co/MCM-41 ........................... 98 
3.3.3.3. Directed oxidation of toluene on Cu-Co oxides ............................. 100 
CONCLUSIONS ..................................................................................................... 104 
RECOMMENDATIONS ........................................................................................ 105 
LIST OF PUBLICATIONS .................................................................................... 106 
REFERENCES ........................................................................................................ 107 
APPENDIX ............................................................................................................. 116 
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LIST OF TABLES 
Table 1.1. Definition of volatile organic compounds (VOCs) .................................... 5 
Table 1.2. The temperature required for complete oxidation of VOCs .................... 10 
Table 1.3. The required temperature for catalytic oxidation of VOCs ..................... 11 
Table 1.4. Performance evaluation of bioreactors for VOCs and odor control ........ 13 
Table 1.5. The absorption solutions can absorb the organic solvent vapor .............. 14 
Table 1.6. The noble metal catalysts for VOCs oxidation ........................................ 19 
Table 1.7. The non-noble metal oxide catalysts overview ........................................ 24 
Table 1.8. The mixed non-noble metal oxide catalysts overview ............................ 27 
Table 2.1. Properties of chemicals using to prepare catalysts .................................. 32 
Table 2.2. List of catalysts prepared by wet impregnation method .......................... 34 
Table 2.3. List of catalysts prepared by solid-solid bleeding method ...................... 36 
Table 2.4. Technique of thermal analysis ................................................................. 37 
Table 2.5. Operating factors of GC ........................................................................... 44 
Table 3.1. The Surface characteristics of AC, silica gel and MCM-41 .................... 56 
Table 3.2. The surface characteristics of catalysts on AC and silica gel .................. 56 
Table 3.3. The surface characteristics of catalysts on MCM-41 ............................... 57 
Table 3.4. Crystalline size and phase of Cu-Co/Silica gel ........................................ 60 
Table 3.5. Crystalline sizes and phases of 10% Cu-Co on MCM-41 ....................... 62 
Table 3.6. Crystalline sizes and phases of 20% Cu-Co on MCM-41 ....................... 64 
Table 3.7. Crystalline sizes of Cu-Co oxides ............................................................ 65 
Table 3.8. Crystalline sizes of catalysts without supports ........................................ 66 
Table 3.9. Metal dispersion of catalysts .................................................................... 71 
Table 3.10. O2 - TPD profile of catalysts .................................................................. 73 
Table 3.11. CH4-TPD quantities of Cu-Co/MCM-41 .............................................. 75 
Table 3.12. Adsorption amount of toluene on Cu-Co/Activated carbon .................. 83 
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Table 3.13. Adsorption amount of toluene on Cu-Co/Silica gel ............................... 84 
Table 3.14 Adsorption amount of toluene on Cu-Co/MCM-41 ............................... 86 
Table 3.15. Generated toluene by thermal desorption .............................................. 90 
Table 3.16. Evaluation of total toluene oxidation over the catalysts on AC ............ 90 
Table 3.17. Toluene adsorption capacity of catalysts on Silica gel base .................. 93 
Table 3.18. Evaluation of total toluene oxidation over the catalysts on silica gel .... 93 
Table 3.19. Evaluation of total toluene oxidation over catalysts on MCM-41 ......... 95 
Table 3.20. Comparison with other studies ............................................................. 103 
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LIST OF FIGURES 
Figure 1.1. Photochemical smog formation. ............................................................... 7 
Figure 1.2. VOCs emission control technologies. ...................................................... 8 
Figure 1.3. Catalytic oxidation technology for treatment of VOCs. ......................... 10 
Figure 1.4. The relationship between temperature and vapor pressure of the most 
common VOCs. ......................................................................................................... 15 
Figure 1.5. The mechanisms of VOCs oxidation over catalysts. .............................. 16 
Figure 2.1. Procedure of wet impregnation method.................................................. 33 
Figure 2.2. Procedure of solid-solid blending method. ............................................. 35 
Figure 2.6. Bragg ‘s diffraction. ................................................................................ 38 
Figure 2.7. Schematic diagram of the core components of an SEM microscope. .... 39 
Figure 2.8. Experimental for temperature programmed reduction, oxidation and 
desorption. ................................................................................................................. 41 
Figure 2.9. Adsorption and desorption experiment systems. .................................... 43 
Figure 2.10. The toluene adsorption – desorption oxidation experiment systems. .. 46 
Figure 2.11. The complete oxidation of toluene experiment systems. ..................... 49 
Figure 2.12. Total methane oxidation experiment systems. ..................................... 51 
Figure 3.1. Thermal analysis in static air of catalyst on AC. .................................... 52 
Figure 3.2. Isotherm linear plot of AC, silica gel and MCM-41 .............................. 55 
Figure 3.3. Pore distribution of AC, silica gel a ...  M. Valkaj, “A 
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APPENDIX 
Appendix 1: Adsorption-desorption of toluene 
Appendix 1.1: Adsorption-desorption of toluene on Cu-Co/Activated carbon 
Time 
(min) 
WI-AC180 WI-AC7Cu3Co WI-AC5Cu5Co WI-AC3Cu7Co 
Ad 
(ppm) 
De 
(ppm) 
Ad 
(ppm) 
De 
(ppm) 
Ad 
(ppm) 
De 
(ppm) 
Ad 
(ppm) 
De (ppm) 
0 0 0 0 0 0 0 0 0 
1 0 2336 0 1417 0 1760 0 1680 
15 0 2063 0 1186 0 1428 0 1431 
30 0 1695 0 1295 0 1248 0 1053 
45 0 1411 0 870 0 944 0 574 
60 0 973 0 575 0 645 0 494 
75 0 550 0 501 0 482 0 313 
90 0 237 0 378 0 428 0 232 
105 0 185 0 326 0 377 0 157 
120 0 119 0 253 0 168 0 87 
135 0 107 0 197 0 111 0 0 
150 0 69 0 135 0 0 0 
165 0 0 0 73 0 0 
180 0 0 0 57 0 0 
195 0 0 0 0 0 0 
210 0 0 0 0 0 
225 0 0 0 0 
240 0 0 180 0 
255 0 69 432 0 
270 0 308 454 0 
285 0 407 454 0 
300 0 550 514 373 
315 0 821 876 454 
330 0 940 1075 552 
345 69 997 1075 876 
360 181 997 1075 985 
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375 829 997 1075 985 
390 776 997 1075 985 
405 1012 997 1075 985 
420 1012 997 1075 985 
435 1012 997 1075 985 
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Appendix 1.2: Adsorption-desorption of toluene on Cu-Co/Silica gel 
Time 
(min) 
SS-S5Cu5Co 
SS-S20Co 
Ad (ppm) De (ppm) Ad (ppm) De (ppm) 
0 0 0 0 0 
1 0 12704 0 3538 
12.75 7053 539 10408 499 
25.5 8649 120 11389 75 
38.25 9315 0 11389 0 
51 10375 0 
63.75 10572 
76.5 10738 
89.25 10889 
102 10889 
119 | P a g e 
Appendix 1.3: Adsorption-desorption of toluene on Cu-Co/MCM-41 prepared by solid-solid blending method 
Time 
(min) 
SS-M7Cu3Co SS-M5Cu5Co SS-M3Cu7Co SS-M10Co SS-M10Cu SS-M20Co 
Ad 
(ppm) 
De 
(ppm) 
Ad 
(ppm) 
De 
(ppm) 
Ad 
(ppm) 
De 
(ppm) 
Ad 
(ppm) 
De 
(ppm) 
Ad 
(ppm) 
De 
(ppm) 
Ad 
(ppm) 
De 
(ppm) 
0 0 0 0 0 0 0 0 0 0 0 0 0 
1 0 15968 0 12639 4739 10388 0 11522 247 9610 0 11281 
12.75 0 15330 0 12314 0 5122 0 12288 0 8510 2081 9298 
25.5 0 15513 339 9664 0 2526 35 12125 0 5726 4456 6523 
38.25 0 11645 466 6561 1489 1674 56 10543 61 3217 7189 4166 
51 0 8749 1036 4159 4801 945 971 9268 2357 1848 7746 2870 
63.75 129 6142 1778 3191 6284 471 2575 7475 4446 1660 9587 2239 
76.5 0 4845 3192 2448 7267 273 4827 5970 6399 0 10717 1595 
89.25 2067 3853 5808 1893 7943 16 6740 5115 6835 0 11690 1231 
102 5033 2968 7354 1551 8291 0 8182 4184 6579 0 11804 851 
114.75 7771 2140 8270 1287 9019 0 9656 3482 8111 0 12356 762 
127.5 10241 1819 8648 0 8965 0 10591 2592 8141 0 12356 0 
140.25 12210 1438 9344 9688 0 11552 0 8576 0 
153 13601 1209 9522 10192 0 12377 0 8547 0 
165.75 14333 0 10264 10262 0 13492 0 8662 0 
178.5 17187 0 11420 10549 0 11178 0 9075 0 
191.25 16954 0 11791 10714 0 10931 0 9266 0 
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204 0 12001 10816 9370 
216.75 12001 9983 
229.5 
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Appendix 1.4: Adsorption-desorption of toluene on Cu-Co/MCM-41 prepared by 
wet impregnation method 
Time 
(min) 
WI-M5Cu5Co WI-M20Co MCM-41 
Ad (ppm) De (ppm) Ad (ppm) De (ppm) Ad (ppm) De (ppm) 
0 0 0 0 0 0 0 
1 0 5706 620 3689 0 20009 
12.75 0 6903 3387 7783 0 16013 
25.5 458 5773 8224 1479 9903 4476 
38.25 1504 3985 11910 497 13453 1788 
51 4893 2946 12909 0 15273 863 
63.75 6120 2865 13528 16091 482 
76.5 7173 2245 14098 17893 0 
89.25 7444 1936 14098 18702 
102 8025 1566 19185 
114.75 8729 1327 19977 
127.5 8830 994 20747 
140.25 8980 0 
153 9016 
165.75 9097 
178.5 9097 
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Appendix 2: Oxidation in desorption process 
Appendix 2.1. Oxidation in desorption process over Cu-Co/Activated carbon 
Time 
(min) 
WI-AC7Cu3Co WI-AC5Cu5Co WI-AC3Cu7Co 
Toluene 
(ppm) 
COx 
(ppm) 
Toluene 
(ppm) 
COx 
(ppm) 
Toluene 
(ppm) 
COx 
(ppm) 
0 0 0 0 0 0 0 
1 1067 4368 693 5761 1371 5395 
15 739 1939 627 3681 1114 4289 
30 465 2128 418 2528 928 3035 
45 378 1505 185 1320 748 1320 
60 185 450 83 820 574 1292 
75 123 0 0 0 551 380 
90 88 0 0 0 304 0 
105 0 0 0 0 97 0 
120 0 0 0 0 0 0 
123 | P a g e 
Appendix 2.2. Oxidation in desorption process over Cu-Co/MCM-41 
Time 
(min) 
SS-M7Cu3Co SS-M5Cu5Co SS-M3Cu7Co SS-M10Co SS-M10Cu WI-M5Cu5Co WI-M20Co 
Toluene 
(ppm) 
COx 
(ppm) 
Toluene 
(ppm) 
COx 
(ppm) 
Toluene 
(ppm) 
COx 
(ppm) 
Toluene 
(ppm) 
COx 
(ppm) 
Toluene 
(ppm) 
COx 
(ppm) 
Toluene 
(ppm) 
COx 
(ppm) 
Toluene 
(ppm) 
COx 
(ppm) 
0 10773.05 0 8476 0 14568.79 0 12062.92 0 8451.669 0 10875 0 13247 0 
12.75 7173.878 0 7511 0 7026.384 0 7638.593 0 6826.916 0 5578 0 1544 0 
25.5 4368.943 0 4587 0 3815.359 0 4259.829 0 3527.449 0 3291 0 2 0 
38.25 2501.978 0 2849 0 1354.354 0 2230.476 0 1968.266 0 1789 0 0 0 
51 1593.242 0 1935 0 619.5319 0 1324.665 0 1534.247 0 1049 0 0 0 
63.75 1136.649 0 2043 0 379.6313 0 583.0763 0 1078.386 0 662 0 
76.5 7.959375 0 1078 0 0 0 6.8175 0 540.4388 0 485 0 
89.25 0 0 835 0 0 0 0 0 0 0 247 0 
102 0 0 644 0 0 0 0 0 0 0 234 0 
114.75 594 0 0 0 0 178 0 
127.5 0 0 137 0 
124 | P a g e 
Appendix 2.3. Oxidation in desorption process over Cu-Co/Silica gel 
Time 
(min) 
SS-S5Cu5Co SS-S20Co 
Toluene 
(ppm) 
COx 
(ppm) 
Toluene 
(ppm) 
COx 
(ppm) 
0 12143 0 2901 0 
1 125 0 180 0 
12.75 13 0 0 0 
25.5 0 0 0 0 
38.25 0 0 0 0 
51 0 0 o 0 
125 | P a g e 
Appendix 3: Directed oxidation over Cu-Co/MCM-41 and Cu-Co/Silica gel 
Samples 
Toluene conversion at temperature (%) 
150oC 180oC 200oC 250oC 300oC 350oC 400oC 450oC 500oC 
SS-M7Cu3Co 99.9 65.9 55.9 54.1 54.4 62.5 100 100 100 
SS-M5Cu 5Co 96.2 80.3 97 76.7 28.4 43.6 73.3 100 100 
SS-M3Cu7Co 98.2 66.7 58.9 57.2 59.1 69.8 100 100 100 
SS-M10Co 100 79.6 59.5 61.3 57.1 62.5 100 100 100 
SS-M10Cu 100 63.7 52.1 50 61.1 69.1 99.9 100 100 
SS-M20Co 58.7 100 68.2 73.1 81.2 77.2 98.8 100 100 
WI-M5Cu 5Co 100 100 86.8 56.2 23.5 70.9 73.6 96.8 100 
WI-M20Co 99 95.9 96.4 19 55 63.5 100 100 100 
SS-100Co 100 79.1 66.9 66.1 67.3 100 100 100 100 
SS-100Cu 59.6 50.1 42.6 38.9 38.4 67.3 100 100 100 
SS-5Cu5Co 73.5 63.9 51.9 53.2 52.8 100 100 100 100 
SS-S5Cu 5Co - - - 55.3 59.6 68.3 70.1 71.2 100 
SS-S20Co - - - 49.1 49.5 81.5 100 100 100 
126 | P a g e 
Samples 
CO2 yield at temperature (%) 
150oC 180oC 200oC 250oC 300oC 350oC 400oC 450oC 500oC 
SS-M7Cu3Co 0 0 0 0 1.1 10.2 100 93.5 90.7 
SS-M5Cu 5Co 0 0 0 0 0 4 23.6 100 100 
SS-M3Cu7Co 0 0 0 0 2.2 24.8 80.6 75.1 74.1 
SS-M10Co 0 0 0 0 1.9 14.8 96.1 80 89.2 
SS-M10Cu 0 0 0 0 2.5 19.6 91.1 80.2 65.4 
SS-M20Co 0 0 0 15.6 53.3 50.2 100 100 100 
WI-M5Cu5Co 0 0 0 0 0 2 10.4 100 100 
WI-M20Co 0 0 0 6 13.8 41 100 100 100 
SS-100Co 0 0 0 1.7 2.3 75.2 78.2 78.6 79.7 
SS-100Cu 0 0 0 0 2.9 76.6 100 100 100 
SS-5Cu5Co 0 0 0 0.8 19.4 90.3 90.9 90.3 93.5 
SS-S5Cu5Co 0 0 0 0 0 0 1.8 17 64.9 
SS-S20Co 0 0 0 4.1 28.7 100 100 100 100 
127 | P a g e 
Appendix 4: Pictures of the research 
Picture 1. Toluene adsorption, desorption and oxidation experiment system 
Picture 2. Gas Chromatography with TCD detector 
128 | P a g e 
Picture 3. Temperature control and reactor 
Picture 4. Nitrogen or Oxygen Mass flow controller 
Picture 5. Toluene generator 
129 | P a g e 
Appendix 5: Pictures of some prepared catalysts 
1. Activated carbon 2. Silica gel 
3. MCM-41 4. WI-AC5Cu5Co 
5. SS-S20Co 6. WI-S20Co 
7. SS-M7Cu3Co 8. SS-M5Cu5Co 
9. SS-M3Cu7Co 10. SS-M10Co 
130 | P a g e 
11. SS-M20Cu 12. WI-M5Cu5Co 
13. WI-M3Cu7Co 14. WI-M10Co 
15. WI-10Cu 
16. SS-5Cu5Co 17. SS-100Co 
18. SS-100Cu