Adsorption of selected pharmaceuticals on LDPE, PA, and PET microplastics

Abstract

Unappropriated disposing of unused drugs leads to an increase in their concentration in the environment. Furthermore, wastewater treatment plants are not sufficient to prevent the transport of drugs. Microplastics (MPs), which are also recognized as important pollutants, can be divided into primary and secondary. The primary MPs are produced for commercial purposes, while the secondary MPs are formed by the decomposition of plastic residues. The hydrophobic nature and large specific surface area of MPs facilitate pollutants binding. Animals misunderstand MPs for food and consume it, which could have harmful health impacts because both MPs and adsorbed pollutants are ingested. In this paper, the adsorption of the selected drugs - azithromycin, carbamazepine, sulfamethoxazole, and diclofenac on low-density polyethylene (LDPE), polyamide (PA), and poly(ethylene terephthalate) (PET) microplastics are presented. The experiment showed that drugs bind best to PA and that azithromycin has the highest binding affinity.

Neadekvatno odlaganje neiskorišćenih lekova dovodi do povećanja njihove koncentracije u životnoj sredini. Pored toga, postrojenja za prečišćavanje otpadnih voda nisu dovoljna barijera za sprečavanje transporta lekova. Mikroplastika (MP), koja je takođe detektovana kao bitan polutant, može se podeliti na primarnu i sekundarnu. Primarna se proizvodi za komercijalne svrhe, a sekundarna nastaje razgradnjom plastičnih ostataka. Hidrofobna priroda i velika specifična površina MP olakšava adsorpciju polutanata na ove materijale. Životinje mešaju MP sa hranom i unose je u svoj organizam, što može imati negativni uticaj na njihovo zdravlje, jer se tako unose i MP i adsorbovani polutanti. U ovom radu je prikazana adsorpcija odabranih lekova - azitromicina, karbamazepina, sulfametoksazola i diklofenaka na sledećim vrstama mikroplastike - polietilenu niske gustine (LDPE), poliamidu (PA) i poli(etilen tereftalatu) (PET). Eksperiment je pokazao da se lekovi najbolje vezuju za PA, kao i da azitromicin ima najveći afinitet vezivanja.