During the COVID-19 pandemic, the extensive use of face masks and protective personal equipment (PPE) kits has led to increasing degree of microplastic pollution (MP) because they are typically discarded into the seas, rivers, streets, and other parts of the environment. Currently, microplastic (MP) pollution has a negative impact on the environment because of high-level fragmentation. Typically, MP pollution can be detected by various techniques, such as microscopic analysis, density separation, and Fourier transform infrared spectrometry. However, there are limited studies on disposable face masks and PPE kits. A wide range of marine species ingest MPs in the form of fibers and fragments, which directly affect the environment and human health; thus, more research and development are needed on the effect of MP pollution on human health. This article provides a perspective on the origin and distribution of MP pollution in waterbodies (e.g., rivers, ponds, lakes, and seas) and wastewater treatment plants, and reviews the possible remediation of MP pollution related to the excessive disposal of face masks and PPE kits to aquatic environments.
We
describe the preparation of block polymer beads by aqueous suspension
polymerization to create poly(caprolactone) (PCL)-block-poly(styrene-co-divinylbenzene) beads that can
be selectively etched under basic conditions to yield mesoporous polymer
microspheres with uniform pore size. Polyvinylalcohol was used to
stabilize the suspension polymerization in which styrene and divinylbenzene
monomers were polymerized from a PCL macrochain transfer agent (macroCTA).
The resulting polymerization-induced microphase separation process
led to a nanostructured bicontinuous morphology. The particle size
and pore size were independently tunable: the particle size was controlled
by the stir rate of the suspension polymerizationyielding
average diameters ranging from 60 to 300 μmwhile the
pore size was determined by the molar mass of the PCL block, with
the mode pore diameters being 6 nm and 11 nm after etching beads made
using 13 and 45 kg/mol PCL blocks, respectively. Based on nitrogen
sorption measurements, the surface areas of the beads were ∼300
m2/g when using a PCL macroCTA of 13 kg/mol. The beads
were homogenous throughout on the micron length scale as determined
by confocal Raman microscopy and lacked an impermeable skin layer
as confirmed by scanning electron microscopy. Furthermore, the scalability
of suspension polymerization allows for the simple synthesis of large
quantities of thermoset microspheres with uniform pore size. We also
demonstrate the ability to incorporate functional pore walls into
the beads using multiblock precursor polymers. These functionalized
mesoporous polymer beads show high affinity for ionic dyes in aqueous
solutions (as a proof of principle) and remove dye from the solution
at rates exceeding those of commercial ion-exchange resins. The developed
procedure could be used to generate other functional surface chemistries
with important applications in heterogeneous catalysis, chromatography,
and water remediation.
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