The Effect of Natural Clays Catalysts on Thermal Degradation of a Plastic Waste Mixture

Abstract

Abstract. The thermal and catalytic degradation of a plastic wastes mixtures using two types of natural clays catalysts has been carried out in order to obtaining liquid oils with potential use in the chemical industry. Thus, the polymer waste mixture (PWM) of polystyrene (PS), poly(ethylene terephthalate) (PET) and poly(vinyl chloride) (PVC) were thermally degraded at 420 °C in absence and presence of studied catalysts in mass ratio 1:10, catalyst/PWM. The catalysts were characterized by N 2 adsorption-desorption isotherms (BET), Scanning Electron Microscopy (SEM) and Fourier-transform infrared spectrometry (FTIR) for determined the structural and textural properties. The degradation of plastic wastes produces gases, liquids and solid residue products. The effect of the catalyst types on the yields and distribution of end-products obtained by thermal and catalytic degradation of mixed plastic waste has been studied. The yields of liquid oils fractions were calculated between 54.98 wt.% and 62.18 wt.%. The liquids and solid products were analyzed by different analytical techniques: gas chromatography mass spectrometry (GC-MS), ultraviolet visible spectroscopy (UV-Vis) and/or FTIR, in order to establish the chemical compositions. The GC-MS results showed that the liquid products contain in principal monoaromatic compounds like styrene, toluene, ethylbenzene or α-methylstyrene. The FTIR and UV-Vis spectra of products indicated the specific vibration bands or transitions between electronic energy levels of the functional groups of the constituent compounds.

Thermocatalytic Conversion of Plastics into Liquid Fuels over Clays

“…For example, Filip et al investigated the thermal degradation processes at 420 °C of a plastic waste mixture (PS + PET + PVC) in the absence and presence of two types of natural Romanian clay catalysts [ 65 ]. The GC-MS results showed that the liquid fractions contained mainly monoaromatic compounds.…”