1. D. Nkazi, K. Owusu-Ansah and S.E. Iyuke Investigating the effect of a zeolite and calcium carbonate catalyst support on the production of carbon nanotubes

2. Carbon Nano-materials (CHMT - Wits University/ South Africa) Cancer treatment  PSI + CNTs  Solubilizing agent, FA and Drug Membrane Filtration  Polymeric membrane + fCNTs Membrane used in PEAM fuel cell  Polymeric membrane + CNBs 2

3. CNTs Gases (CO, CO 2,C 2 H 2, CH 4 …) & Liquids (Ethanol, benzene,…) Ferrocene: Carbon source & Catalyst Coal: Pyrolysis Char (Carbon solid) Liquid products Gaseous products Such as C 2 H 2 at Very H. Temp 3

4.  Low and non-volatile price (compare to Oil) and wide geographically distributed in South Africa;  Purity and production yield depend on the region (origin of coal) and carbon content;  Key technologies to clean coal utilization (Energy saving and environmental protection);  Low temperature: more CH 4 and High temperature: more acetylene C 2 H 2 4

5. 5 Apparatus for CNTs production from Coal

6. 6  Low Temperature (From 400 0 C): CO and CH 4 were produced as CNTs sources in the above furnace Increasing Temp. from 400 to 900 decrease CH 4 from 32.41 to 0.89 %  High enough temperature: Formation of acetylene (Appropriate lab. condition: Plasma pyrolysis) Coal C2H2C2H2 H 2, Ar

7. Fe(NO 3 ) 3.9H 2 O 3.62 g Co(NO 3 ) 2.6H 2 O 2.46 g H 2 O distilled 30 ml (stirring) Supports (Zeolite or CaCO 3 ) Droppewise Dried and calcination (400 0 C) Fe-Co on support 7 Set up for Wet impregnation method

8. 8 XRD spectrum Fe-Co on zeolite Fe-Co on CaCO 3 (Equipment: Bruker D2 Phaser XRD)

9. 9 SEM images for Zeolite and Fe-Co catalyst on zeolite Cubic crystalline structures Few defect on the structure after WIM SEM images For CaCO 3 and Fe-Co catalyst on CaCO 3 Rhombic crystalline structures Few defect on the structure after WIM

10. 10 EDS Zeolite and Fe-Co on zeolite EDS CaCO 3 and Fe-Co on CaCO 3 Fe and Co imbedded into Micro-pores of supports

11. 11 CVD set up for CNT synthesis Acid treatment of synthesized CNTs

12. 12 TEM images For CNTs grown from zeolite supported Fe-Co catalyst CNTs with smaller diameter After fctnalization, diameters were reduced TEM images For fCNTs grown from zeolite supported Fe-Co catalyst TEM images For CNTs grown from CaCO 3 supported Fe-Co catalyst TEM images For fCNTs grown from CaCO 3 supported Fe-Co catalyst CNTs with larger diameter After fctnalization, diameters were reduced

13. 13 Diameter distribution as grown CNTs for both supports (Using image processing software)  CNT-zeolite and fCNT-zeolite: 10 nm to 40 nm  CNT-CaCO 3 and fCNT-CaCO 3 : 20 nm to 80 nm  Difference in pore sizes of CaCO 3 and zeolite

14. 14 Raman spectra for CNTs and fCNTs G band confirm graphene structure I D/G show the amount of structural defect in CNTs increase in I D/G from CNTs to fCNTs : graphene increase in disorder after fctnalization CNTs: C=C at 1600 cm -1 and carboxylic gp at 1030 cm -1 FTIR spectra for CNTs and fCNTs

15. 15 TGA profile for CNTs and fCNTs CNTs-CaCO 3 and fCNTs-CaCO 3 : Lost of 90% and 97% of weight after decomposition CNTs-zeolite and fCNTs-zeolite: Lost of 40% and 63% of weight after decomposition > CNTs grown on CaCO 3 supported catalyst are more pure than from zeolite. DTG profile for CNTs and fCNTs CNTs-CaCO 3 and fCNTs-CaCO 3 : 2 decomposition peaks – existence of larger range of outer diameters which double peaks CNTs-zeolite and fCNTs-zeolite: > For both, Increase in peak size after acid treatment confirms the presence of fctional gp in CNT wall

16. 16  CNT grown from a zeolite supported catalyst produce tubes with smaller diameter from 10nm to 40nm while that grown from CaCO 3 yield larger diameter tubes, from 20nm to 80nm.  CNTs grown from the CaCO 3 catalyst support produce almost twice as much as from the zeolite due to the larger pore sizes and surfaces are of the CaCO 3 supported catalyst.  Concentrated HNO 3 can be used to purify and functionalize CNTs. This acid removes both CaCO 3 supports and any remaining metals from the CNT-cs without affecting their wall structures. The acid failed to remove about 37% of SiO 2 from the CNT-zs.  Concentrated HF however e!ectively removes the SiO 2 and yields very pristine CNTs with no residual materials without destroying the nanotubes.

17. 17 CHIETA Chemical Industries Education and Training Authority, South Africa