Abstract
M.Tech. (Chemical Engineering)
The production of nanofillers from plastic wastes plays a significant role as an alternative to plastic waste management. Plastic waste is reported to be a threat to the ecosystem, hence the urgency to reduce it. Nanofillers were developed by catalytic chemical vapor decomposition (CVD) technique, using plastic waste high-density polyethylene (HDPE) and polypropylene (PP) as a carbon source in the presence of Fe-Mn/Al2O3 catalyst. Fe-Mn/Al2O3 catalyst was prepared by sol-gel method and characterized by XRD, SEM-EDS and TEM. A single-stage catalytic process was used to allow a considerable yield at a low cost. A mixture of Ar/H2 gas was used as a reducing agent and N2 to activate pyrolysis gases and to also supply inert conditions. The Fe-Mn/Al2O3 catalyst was reduced at a temperature of 700℃ and the plastic wastes were introduced at the same temperature to decompose at the surface of the catalyst to form nanofillers. Different types of characterization techniques were utilized to study the properties of the synthesized nanofillers. The TEM images showed bundles of MWCNTs with lattice fringes and diameters that range between 9.5 to 19.42 nm. After purification, the diameters of MWCNTs were enhanced and ranges between 19 and 30 nm. SEM images showed the uniformity of the catalyst and its amorphous morphology. It also revealed the porosity of the inner surface of the catalyst and the composition of the catalyst with manganese and iron dominating. Spiral tubes with rectangular shape were observed for HDPE while PP had intertwined strings and some shreds for the hybrid sample. The XRD results showed crystalline structure through sharp peaks and confirmed the formation of CNTs by detecting the (002) peak. After purification, it showed purity by the disappearing of the (002) peak. Raman spectrum showed average purity of the material as the intensive ratio was 0.85 with the 1% error to that of commercial CNTs. Thermal stability was studied using TGA-DSC and it showed that the MWCNTs produced from plastic wastes were resistant to heat but not as much as the commercial CNTs. Based on the analysis of the current study, it was concluded that plastic wastes (bags and yoghurt, margarine and ice cream containers) can be used as the carbon source to develop nanofillers, to be precise MWCNTs synthesized from HDPE exhibited closer thermal stability as with the commercial CNTs. Therefore, this work could be a profitable and beneficial method for recycling plastic waste.