Recovery and Recycling of Terephthalic acid from PET hydrolyzing

摘要

The work developed a new process in recovering the high pure TPA from PET hydrolyzing in order to recycle it. Purifying the mother liquid has been researched. The results has shown that the characters of recovered TPA was improved firstly by the method of coagulation-sedimentation when the pH of wastewater is 7-8 under the existence of 300-400mg/l Al_2(SO_4)_ 3·18H_2O, and then much more by the method of carbon absorption when the amount of activated carbon is 1.5g/l in 20 min incubation. The purity of it based on carboxyl content was found to be 99.3%. This TPA when esterified and polycondensed with EG gave a pure white polymer that showed an intrinsic viscosity, [η]=0.56dl/g.