Extraction of plastic nanoparticles using surface engineered kapok tubes from water

The nano- and microplastic particles from plastic wastes are emerging pollutants that cause significant harm to living organisms and the environment. Little is known on the removal of these emerging pollutants from water. The adsorbents reported to date have been designed to remove dissolved pollutants from water, such as dyes and heavy metals. Here, kapok tubes (KT) were modified and used for the removal of polymer nanoparticles from water. In order to enhance the interaction between the adsorbent surface and plastic particles in water, polyethyleneimine (PEI) was grafted onto the surface of the KT (PEI@KT). A series of techniques such as optical microscopy, FT-IR spectroscopy, scanning electron microscopy (SEM), elemental analysis, and thermal analysis were used to characterize KT and PEI@KT adsorbents. The adsorption of nanoparticles on the surface of the tubes was monitored using UV-Vis spectroscopy and electron microscopy. The modified fibers showed high removal rates (> 96 %) for negatively charged nanoparticles of polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), and polystyrene (PS) within 90 min. Additionally, the factors affecting the adsorption of nanoparticles, isotherm, and kinetic models were explored to investigate the adsorption mechanism of polymer nanoparticles (PNPs) on the PEI@KT surface. The collected adsorption data fit well with the Langmuir isotherm and pseudosecond-order kinetic models. The adsorption capacities of PEI@KT for the three types of polymer nanoparticles were high (> 240 mg/g). As a proof of concept, PEI@KT was used to remove plastic microparticles from a diluted solution of a commercial body scrub gel with excellent adsorption and removal efficiencies. Overall, the environmentally friendly PEI@KT adsorbent showed high adsorption efficiencies toward removing plastic particles from water.

Automated summary

The study focuses on the removal of nano- and microplastic particles from water using modified kapok tubes (KT). Polyethyleneimine (PEI) was grafted onto the surface of KT to enhance the interaction with plastic particles. The modified fiber showed high removal rates (> 96%) for various types of polymer nanoparticles within 90 minutes.