Multivalent cobalt nanoparticles supported on silica for efficient and sustainable methanolysis of commercial polyethylene terephthalate waste bottles†

Abstract

Plastic waste management is a huge challenge in today's world wherein polyethylene terephthalate (PET) is one of the major contributors. Chemical upcycling of plastic waste into valuable chemicals is one of the most effective methods for plastic waste management. In this work, multivalent cobalt nanoparticles supported on silica were used as a heterogeneous catalyst for the methanolysis of PET under mild reaction conditions, wherein PET was converted into dimethyl terephthalate (DMT) as the major product in the presence of methanol. In this PET methanolysis process, the effects of various reaction parameters, such as reaction time, temperature, cobalt loading on silica and catalyst amount on the conversion of PET and the yield of DMT were investigated. The developed catalyst results in significantly high DMT yield and PET conversion under mild reaction conditions. To investigate the heterogeneous nature of the developed catalyst, recyclability studies were performed which show excellent reusability with good conversion and product yield. Thus, multivalent cobalt nanoparticles supported on silica have the advantage of good conversion efficiency, high product yield, nontoxicity, excellent recyclability, and ease of separation for the methanolysis of PET. This work is anticipated to open new avenues in the field of plastic upcycling.