Preparation Characterization And Applation On PET Degradation Of Magnetic Solid Base Catalysts

Polyethylene terephthalate (commonly abbreviated PET) is an important raw material of textile with huge amount of consumption and waste. PET can be depolymerized to yield the constituent monomers, namely, bis(2-hydroxyethyl) terephthalate (BHET). It can improve recovery ratio of the BHET through development of a suitable catalyst to fully convert the polyester. In this paper, the magnetic solid base catalysts were prepared and applied to the PET catalytic degradation system, which can be recycled and re-use easily.The magnetic solid base catalysts were prepared by loading alkaline earth metal MgO, CaO, or transition metal NiO on the surface of Fe3O4magnetic carrier. It was studied the influence of synthesis such as the molar ratio of magnetic matrix and the active ingredient, ignition temperature, burning time. The catalysts were used in the catalytic degradation of waste PET and polyester-cotton blended fabric containing PET, to recover and purify the degradation products.The magnetic catalysts Fe3O4/MgO had good results with the highest recovery rate of74.74%of BHET. This catalyst was applied to depolymerized polyester for separation the PET/cotton at the reaction temperature of180℃in lh, with the BHET recovery of70%and the cotton unchanged. It was shown that the catalysts can be applied to separate the polyester-cotton fabric materials.The magnetic solid the alkali catalysts of Fe3O4/CaO had relatively poor catalytic effect, and the yield of BHET was fluctuations with the highest recovery rate of70%. The catalysts of Fe3O4/NiO were quite better, with the BHET recovery rate more than80%, which significantly higher than that of MgO and CaO. TG and XRD results showed that the Fe3O4were wrapped by NiO. It was not easy to oxidation by oxygen in the air.The catalysts were magnetism and easily reused by applying a magnetic field. With the increasing recycling of the catalysts, the catalytically active components were lost, to make BHET recovery ratio in a downward trend.The degradation products of PET were Characterized and confirmed as BHET through the melting point analysis, DSC, IR, MS,1H-NMR and TG etc.