Effect of Cd2+, Cr3+, Cu2+, Al3+, Co2+ ions on the chemical recycling of poly(ethylene terephthalate) in sulphuric acid

Poli(etilen-tereftalat) hidroliziran je u sumpornoj kiselini uz različite aditive (Cd2+, Cr3+, Cu2+, Al3+, Co2+) kako bi se istražio njihov utjecaj na reakcijsku konverziju. Dodavanje 5 μM pojedinačnih iona ne povećava znatno konverziju. S druge strane dodavanje 30 μM poboljšava konverziju u usporedbi s 5 μM. Čini se da su ioni Cd2+ i Al3+ najbolji aditivi, koji očito poboljšavaju reakcijsku konverziju. Povećanje koncentracije kiseline ima za posljedicu povećanje konverzije hidrolize. Dodavanje iona željeza proučavanim ionima usporava reakciju u nekim slučajevima (Cr3+, Cu2+, Co2+), stoga je konverzija bila niža nego u otopini kiseline bez iona. Uporaba binarne mješavine iona željeza s Cd2+ i Al3+ ne pokazuje znatno povećanje konverzije u usporedbi s uporabom pojedinačnih iona.Poly(ethylene terephthalate) has been hydrolyzed in sulphuric acid using various additives (Cd2+, Cr3+, Cu2+, Al3+, Co2+) in order to investigate their influence on the reaction conversion. The addition of 5 μM of the single ions does not seem to increase the conversion significantly, but the addition of 30 μM does enhance the conversion compared with 5 μM. Cd2+ and Al3+ ions seem to be the best additives which improve the reaction conversion obviously. The increase in the acid concentration leads to increase in the hydrolysis conversion. The addition of iron ions to the studied ions seems to suppress the reaction in some cases (Cr3+, Cu2+, Co2+) and the conversion was consequently lower than in the ion free acidic solution. Using binary mixture of iron ions with Cd2+ and Al3+ does not show a significant increase in the conversion compared with the use of single ions