Optimization of operating conditions for the catalytic alcoholysis of waste PET for the synthesis of BHET by sunflower seed husk matrix materials

Abstract

A sunflower seed shell matrix catalyst (SMS-750) was prepared from sunflower seed shell waste by pretreatment and pyrolytic carbonization. A series of characterization analyses showed that the prepared catalyst was rich in Ca, Mg, K, and other mineral elements and mainly existed in the form of metal oxides. SMS-750 was used to catalyze the glycolysis of waste PET, and the main factors affecting the BHET yield were screened out by a one-way experimental design, and then the BHET yield was used as the response value, and the response surface method was used to design and analyze the effects of the respective variables and their interactions on the degradation of PET according to the principle of Box–Behnken central combinatorial design. The optimum reaction conditions were optimized using the predicted quadratic regression model with a reaction temperature of 185 °C, a reaction time of 4.9 h, a catalyst dosage of 0.89%, and an ethylene glycol dosage of 14.6 ml, and the BHET yield of 79.57% was obtained under these conditions. The degradation of waste PET by SMS-750 prepared in this paper provides a useful reference for the resourceful use of waste and sustainable development.