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Sorption of sulfamethazine onto different types of microplastics: A combined experimental and molecular dynamics simulation study

Marine Pollution Bulletin 2019 251 citations ? Citation count from OpenAlex, updated daily. May differ slightly from the publisher's own count.
Xuan Guo, Yong Liu, Jianlong Wang

Summary

The sorption of sulfamethazine (a veterinary antibiotic) onto different microplastic polymer types was studied through laboratory experiments and molecular dynamics simulations, revealing that sorption kinetics and binding strength varied by polymer type and antibiotic concentration. The findings help predict how microplastics in agricultural waterways contaminated with livestock antibiotics could transport these drugs in the environment.

Microplastics are becoming a global concern due to their potential to accumulate pollutants in aquatic environments. In this paper, sulfamethazine (SMT) sorption onto six types of microplastics, including polyamide (PA), polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC) was investigated by experimental and molecular dynamics simulation methods. The experimental results indicated that SMX sorption reached equilibrium within 16 h. The kinetics of SMT sorption by PA, PVC, PE, and PP could be fitted by pseudo first-order model, while SMT sorption by PA and PET could be described by pseudo second-order model. The partition coefficient K values were 38.7, 23.5, 21.0, 22.6, 18.6 and 15.1 L·kg for PA, PE, PS, PET, PVC and PP, respectively. SMT sorption onto microplastics decreased when pH and salinity increased. The molecular dynamics simulation results indicated that the main mechanisms involved in sorption are electrostatic and Van der Waals interaction.

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