2 research outputs found
Efficient Extraction and Analysis of Nanoplastics by Ionic Liquid-Assisted Cloud-Point Extraction Coupled with Electromagnetic Heating Pyrolysis Mass Spectrometry
Nanoplastics have attracted much attention due to their
potential
hazards. However, analysis of nanoplastics remains challenging. In
this study, ionic liquid-assisted cloud-point extraction (IL-assisted
CPE) was developed to enrich nanoplastics in the aqueous environment
and further coupled with electromagnetic heating pyrolysis mass spectrometry.
The use of trace ILs improves the extraction efficiency of CPE for
nanoplastics. The effects of ILs (types, contents), nanoplastic properties
(type, size), and environmental factors (aging time, humic acid content)
were systematically investigated to evaluate the applicability. The
limits of detection of poly(methyl methacrylate) (PMMA) and polystyrene
(PS) were determined to be 1.78 and 2.67 μg/L, respectively.
Real environmental samples including lake water, rainwater, and influent
and effluent from wastewater treatment plant were analyzed with good
accuracy (79.58–116.87%) and satisfactory precision (RSD ≤
11.99%). A possible mechanism for ILs being absorbed into the ordered
surfactant micellar and generating larger micelles to synergically
enclose hydrophobic nanoplastics was proposed. This work provides
a simple and efficient approach to the extraction and analysis of
nanoplastics in aqueous environments
Magnetic Nitrogen-Doped Carbon Composites Decorated with Carbon Nanotubes for Adsorption of Malachite Green
In this work, magnetic nitrogen-doped carbon composites
decorated
with carbon nanotubes (CNT/Co@N–C) were successfully prepared
by carbonizing ZIF-67(Co) and melamine with a ZIF-67(Co)/melamine
material synthesized in situ at 525 °C under
an inert atmosphere. To improve the malachite green removal performance
of the adsorbent, calcination temperatures and mass ratios of the
ZIF-67(Co)/melamine-derived CNT/Co@N–C materials were optimized.
The malachite green removal performance was evaluated based on various
experimental parameters including adsorbent dosage, pH, contact time,
and salinity. The results showed that pH and salinity had a small
effect on the adsorption process of CNT/Co@N–C materials, thus
providing a possibility for practical application in water purification.
The adsorption of malachite green onto the CNT/Co@N–C material
was consistent with the Langmuir isothermal model and the pseudo-second-order
model, and the maximum malachite green adsorption of the material
was 3881.30 mg/g. The results also suggested that the adsorption was
a monolayer chemisorption process that occurred through electrostatic
and π–π stacking interactions. Finally, the recyclability,
magnetic properties, high adsorption performance, and high stability
of CNT/Co@N–C materials suggest that the materials are a promising
adsorbent that can be employed in the removal of malachite green.
The present work provides an idea for the synthesis of magnetic carbon
nanotubes modified with nitrogen-doped carbon materials derived from
metal–organic frameworks (MOFs)