Comparison studies: The aging character of mask melt blown layers, polypropylene, and polyethylene terephthalate and their adsorption behavior for tetracycline hydrochloride

Abstract

Melt-blown layer as a crucial component in medical surgical masks could release microplastics (MPs) into the environment after discarding. This study investigated the aging characteristics of the mask melt-blown layer, polypropylene (PP) and polyethene terephthalate (PET) MPs, as well as compared the adsorption capacity of tetracycline hydrochloride (TCH) on the virgin and aged MPs to gain adsorption mechanism. The carbonyl index (CI) index and two-dimensional correlation spectroscopy (2D-COS) analysis showed that the melt blown layer had the lower degree of aging than PP. Compared with the virgin PP and PET, the main reason for the lowest adsorption capacity of TCH on the virgin melt blown layer was that its unique dense microchannel structure led to the strongest hydrophobicity. The virgin PP and PET which had different chemical structures exhibited similar adsorption capacity of TCH. The adsorption of TCH on the MPs was physisorption, which was both controlled by diffusion, partitioning interaction and pore filling. The increase in the adsorption capacity of TCH on the aging MPs was attributed to the increase of hydrophilicity, pore size and specific surface area. In addition, the influence of environmental factors on the adsorption of TCH were discussed. Allover, this research provided comprehensive insights into the enrichment behavior associated with mask melt-blown materials in aquatic environments, and offered valuable data to support the investigation of the desorption behavior between MPs and antibiotics on organisms.